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Frequently Asked Questions

Products(7)
DRAM(10)
DDR4 SDRAM(12)
What newer power saving features does DDR4 provide compared to DDR3?

DDR4 added several new power saving features over DDR3, including:

1. Lower power pseudo-open drain drivers for the DQ pins

2. Optional ODT Input Buffer Disable Mode For Power-Down feature

3. Optional Maximum Power Saving Mode feature

4. Optional Command Address Latency (CAL)

What new features does DDR4 have that DDR3 did not have?

DDR4 has more than 20 new features compared to DDR3, focused on power saving, performance, manufacturability and reliability. These features, coupled with DDR4’s 1.2v core, can provide power savings of 25% compared to standard DDR3. DDR4’s architecture and added performance features offer a substantial performance boost in bandwidth and command scheduling, which can be realized for 100% or better effective bandwidth increase. Premium DDR4 offers over 170% faster max data rates than top-tier DDR3, with speeds as high as 3200MT/s.

Can DDR4 operate at slower DDR3 speeds?

DDR4 is backward compatible as far back as DDR3-1333. For systems that do not need speed increases above DDR3-1333 and DDR3-1600, DDR4 can support these slower bandwidth requirements with substantially lower power requirements.

Where are DDR4 devices manufactured?

DDR4 is produced in Micron fabs around the world, including Virginia, Japan, and Taiwan.

Are there any features on DDR3 that have been eliminated by DDR4?

Not really; however, DDR4 does not require an external VREFDQ, but it does provide an internally generated VREFDQ that requires calibration by the DRAM controller.

Does DDR4 use the same signaling protocol as DDR3?

Not exactly.  DDR4 still uses VTT mid-point termination on the data bus for good signal quality, however it uses pseudo open-drain drivers for less switching current compared to full push-pull drivers.

Does DDR4 use the same power sources as DDR3?

No, DDR3 requires VDD and VDDQ equal to 1.5V, VREFCA equal to 0.5 x VDD, and VREFDQ equal to 0.5 x VDDQ, while DDR4 requires VDD and VDDQ equal to 1.2V, VREFCA equal to 0.5 x VDD, and VPP equal to 2.5V.

What is DDR4’s VPP supply, and why does DDR4 have it?

The VPP supply replaces the internal word-line charge pumps that were present in earlier versions of DDR SDRAM including DDR3. Providing this voltage externally allows DDR4 to operate at a lower voltage level in a more cost-effective manner rather than providing the internal charge pumps.

Are DDR3 and DDR4 pin-to-pin compatible to each other?

No, the DDR4 ballout is different from the DDR3 ballout. However, DDR4 uses the same package sizes and ball pitch as DDR3.

DDR4 doubled the data rate of DDR3—did the prefetch also double from 8n to 16n?

No, DDR4 kept the 8n-bit prefetch used by DDR3; thus, BL8 is still supported.

Did DDR4 finally add boundary-scan or JTAG support?

DDR4 now has a Connectivity test mode to simplify testing with a boundary scan enabled controller. Designed to work with a boundary scan device, CT mode is supported in all Micron ×4, ×8, and ×16 devices (Though JEDEC requires only for x16). CT model allows a boundary scan device to load and read a pattern from a DDR4 in CT mode. DDR4 does not directly support IEEE 1149.1.

Does DDR4 support DLL Disable Mode or DLL-off Mode for slower clock rates?

Yes, DDR4 supports DLL-off Mode similar to DLL Disable Mode in DDR3, up to 125 MHz

DDR3 SDRAM(15)
Are the DDR3 voltages backward compatible?

Yes, all of our 1.35V parts are backward compatible with 1.5V.

Can I run Micron’s DDR3 memory at clock speeds slower than 300 MHz?
Yes. Micron supports the optional feature to disable the DLL using the Mode Register, called DLL Disable Mode. This feature allows the DRAM to operate at frequencies slower than 125 MHz, however the timing still must satisfy the refresh interval. When operating in DLL Disable Mode, special conditions apply - refer to the device data sheets for details and restrictions.
How do I determine my CAS WRITE latency (CWL)?
In DDR3, only one CWL is valid for a given clock frequency range. - tCKavg = 2.5ns to <3.3ns, CWL = 5 - tCKavg = 1.875ns to <2.5ns, CWL = 6 - tCKavg = 1.5ns to <1.875ns, CWL = 7 - tCKavg = 1.25ns to <1.5ns, CWL = 8
What component densities are available?
Micron supports 1Gb, 2Gb, 4Gb, and 8Gb densities.
What is burst chop?
Due to use of the 8n-prefetch architecture in DDR3, a true burst length of 4 (BL4) was not possible. Burst chop mode became available in DDR3 to help mitigate this, and is also available in newer SDRAMs. Using Burst Chop in DDR3 the last 4 bits of the burst are essentially masked. Timing in Burst Chop 4 (BC4) cannot be treated like a true BL4. For READ-to-WRITE, select WRITE-to-READ, and select WRITE-to-PRECHARGE transitions, the system can achieve clock savings in the BC4 mode. While doing READ-to-READ or WRITE-to-WRITE transitions, timing must be treated like BL8; no clock savings will be realized.  DDR3 supports only either BC4 or BL8, although there is also an on-the-fly (OTF) option to switch between them via address pin A12.  Refer to the device data sheets for more details.
What is Dynamic ODT?
Dynamic ODT (Rtt_WR) enables the DRAM to change termination values during a WRITE without having to perform a MODE REGISTER SET command. When Rtt_Wr and Rtt_Nom are both enabled, the DRAM will change termination values from Rtt_Nom to Rtt_Wr at the beginning of the WRITE burst. Once the burst is complete, the termination will be changed back to the Rtt_Nom value. Rtt_Wr can be used independently of Rtt_Nom, but termination will be on WRITEs only.
What is the difference between the ZQCL and ZQCS commands?
ZQCL stands for ZQ calibration long. This command must be issued during the power-up and initialization sequence and requires 512 clocks to complete. After power-up and initialization, the command can be issued any time the DRAM is idle. These subsequent commands only require 246 clocks. This command is used when there is more impedance error correction required than a ZQCS can provide. ZQCS stands for ZQ calibration short. This command can be performed any time the DRAM is idle. One ZQCS can correct a minimum of 0.5 percent impedance error and requires 64 clocks.
What is the "MPR"?
MPR is a multi-purpose register. It is a specialized register designed to allow predefined data to be read out of the DRAM. Data is one bit wide and is output on a prime DQ. For Micron DDR3 parts, the prime DQs are DQ0 for x4/x8 and DQ0/DQ8 for x16. Two locations in the MPR are defined. One allows the readout of predefined data burst—in this case, 01010101. The other location is used to output the refresh trip points from the on-die thermal sensor.
What is the operating voltage?
DDR3 operates at Vdd = VddQ = 1.5V ±0.075V. DDR3L operates at Vdd = VddQ = 1.35V (1.283–1.45V) 
What is the output driver impedance for DDR3?
The default output driver impedance for DDR3 is 34 ohms. The impedance is based on calibration to the external 240 ohm resistor, RZQ.
What is the RESET# pin used for?
RESET# is the master reset for the DRAM. It is an active LOW, asynchronous input. When the RESET# is asserted, the DRAM outputs are disabled and ODT will turn off (High-Z). The DRAM counters, registers, and data will be unknown. A RESET must be performed as part of the power-up and initialization sequence. During this sequence, the RESET# must remain LOW for a minimum of 200µs. After power-up and initialization, RESET# may be asserted at any time. Once asserted, it must stay LOW for a minimum of 100ns and a full initialization of the part must be performed afterward.
What is "write leveling"?
For improved signaling, DDR3 modules have adopted fly-by technology for the commands, addresses, control signals, and clocks. Due to signal routing, this technology has an inherent timing skew between the clock and DQ bus at the DRAM. Write leveling is a way for the system controller to de-skew the DQ strobe (DQS) to clock relationship at the DRAM. A simple feedback feature provided by the DRAM allows the controller to detect the amount of skew and adjust accordingly.
What is "ZQ Calibration"?
The ZQ calibration command can calibrate the DRAM's output drivers (Ron) and ODT values (Rtt) over process, voltage, and temperature when a dedicated 240 ohm (±1 percent) resistor is connected from the DRAM's ZQ pin to ground. In DDR3, two different calibration commands exist: ZQ calibration long (ZQCL) and ZQ calibration short (ZQCS). ZQCL is normally used during power-up initialization and reset sequences, but may be issued at any time by the controller, depending on the system environment. ZQCS is used to perform periodic calibrations to account for small voltage and temperature variations; it requires a smaller timing window to complete.
What termination values does DDR3 offer?
DDR3 supports RTT_nom values of 120, 60, 40, 30, and 20 ohms. Dynamic ODT values (RTT_WR) are 120 and 60 ohms.
Will Micron support an extended temperature range for DDR3?
Yes. Micron DDR3 parts will support a Tcase of 0°C to 95°C.
DDR2 SDRAM(9)
Can DDR2-1066 be used with two slots?
Using DDR2-1066 with two slots is unrealistic; simulations have not shown acceptable margins.
How does on-die termination (ODT) affect power consumption?
On-die termination (ODT) power is very application-dependent. ODT is also variable, depending on the setting in the EMR of the DRAM. Use the DDR2 power calculator to determine the values.

In a point-to-point system, ODT would only be active on WRITE cycles, and would not consume power during idle and READ cycles. On-board termination would consume power in these instances. ODT power should be about 2–3 percent of the total DDR2 DRAM power in a typical application.
How much power does the Vref power pin draw?
The Vref pin does not draw any power, only leakage current, which is less than 5µA.
Is VREF allowed to float during self refresh mode?
No, it must be maintained at VDDQ/2.
Should DDR2 SDRAM always have ODT turned on?
It’s not recommended, as the SDRAM reads will lose voltage margin; but technically, it is allowed.
Can the DLL be disabled in DDR2? Can DDR2 be put into DLL Disable mode similar to DDR3?
Although in some cases the DRAM may work with the DLL off, this mode of operation is not documented nor supported by JEDEC. Therefore, each DRAM design may behave differently when configured to run with the DLL disabled. Micron does not support or guarantee operation with the DLL disabled. Running the DRAM with the DLL disabled may cause the device to malfunction and/or violate some DRAM output timing specifications.
What is the DDR2 RDQS pin for?
The sole purpose of RDQS is to support the use of a x8-based RDIMM in a x4-based RDIMM system. The RDQS pin enables a x8 DDR2 SDRAM to emulate two x4s.
What is the maximum clock rate for DDR2 when it’s used with a single-ended DQS?
The answer depends on the design implementation. Data setup and hold timing should be designed to have 150ps or more of margin.  There are Single-Ended DQS Slew Rate derating tables in the data sheet that must be used in evaluating the timing. It is recommended to fully analyze the timing in calculations, as well as using signal integrity simulations and hardware characterization.
Is it OK to run clock frequencies lower than indicated in the DDR2 data sheet?
For a READ operation, the DRAM edge-aligns the strobe(s) with the data. Most controllers sense the strobe to determine where the data window is positioned. This fine strobe/data alignment requires that each DRAM have an internal DLL. The DLL is tuned to operate for a finite frequency range, which is identified in each DRAM data sheet. Running the DRAM outside these specified limits may cause the DLL to become unpredictable. The DRAM is tested to operate within the data sheet limits. Micron does not suggest or guarantee DRAM operation outside these predefined limits.
SDRAM(3)
Can CKE be tied HIGH throughout SDRAM operation (initialization and normal operation)?
JEDEC does not specify the exact state of CKE during initialization; it is supplier specific. Micron strongly recommends CKE be kept at an LVTTL logic LOW before applying a stable CLK signal. During normal operation, CKE can be tied HIGH. The initial LOW state of CKE prevents parts from receiving an illegal LMR command, which could put the part into an unknown or unexpected state.
Can the SDRAM clock frequency be changed?
Micron SDR SDRAM data sheets require that the clock frequency be constant during access or precharge states. However, because there is no DLL in SDRAM, it may be possible to shift the clock frequency dynamically, though this is not recommended by Micron. If a design requires shifting frequency, lowering SDRAM frequency may be OK, even if you are not doing an LMR and CAS latency change. In case of increasing frequency, ensure tCK and CAS latency specifications are met. In either case, all other data sheet timing specifications must always be adhered to.
Is there a minimum clock frequency for SDR SDRAM?

Because SDR SDRAM does not have a DLL, there is no minimum clock frequency.  However, if the device is clocked at lower frequencies, it is still important to maintain a reasonably fast slew rate on the clock edges to avoid risk of setup and/or hold-time violations. Also, for operating frequencies of 45 MHz, tCKS = 3.0ns. For more information, see LVTTL Derating for SDRAM Slew Rate Violations (TN-48-09).

DDR SDRAM(10)
Can a -6 or -6T speed grade DDR part be substituted with a faster -5B speed grade part without encountering problems due to the 2.6V operation? Can the customer run the part at slower speeds?
Yes, all speed grades are backward-compatible. So, -5B can run at -6T timing and -6T voltage levels (2.5V). At DDR400 speeds, Micron parts require (in compliance with JEDEC standard) Vdd = VddQ = 2.6V ±0.1V. At slower speed grades (DDR333 through DDR200), the Micron parts are backward compatible, only requiring Vdd = VddQ = 2.5V ±0.2V.
Do I need a separate voltage regulator to supply Vref power?
There is no requirement to use a separate regulator to supply Vref for Micron's DDR SDRAM. However, because Vref is the reference voltage for all single-ended inputs, any noise due to sharing the regulator with other I.C.s on a board or by using a voltage divider from the VDD supply, will directly impact the noise margin on those inputs. Many multi-drop systems already have a designated voltage regulator for DDR memory. Other systems that incorporate point-to-point memory typically use a simple voltage divider resistor network between VDD and VSS.  System designers should evaluate the priorities and trade-offs for each particular system and use the power supply scheme that is optimal for the system. 
How long does Micron plan to support 3.3V SDRAM?
Micron is supporting and plans to support SDR for several years. Contact your local Micron sales representative for more information.
How long does Micron plan to support DDR?
Micron is supporting and plans to support DDR for several years. Contact your local Micron sales representative for more information.
Is VREF required during self refresh? I would like to put DDR memory in self refresh mode and turn off power to the CPU (the system is battery-operated). Can I disable VREF and still have correct self refresh operation?
Yes. VREF is required during self refresh. All DDR components' on-chip address counters are still operational during self refresh mode, so VDD must be maintained within the stated data sheet limits. Again, VREF must not be disabled after the DDR memory is put into self refresh mode. Doing so could easily result in inadvertently exiting self refresh. You should understand that VREF draws almost no power; any current drawn by VREF is negligible when compared to VTT and the core VDD. DDR components typically use a differential pair common source amplifier as their SSTL_2 input receiver. Because the VREF pin is used primarily as an input to this circuit, its current draw is low. It is so low, in fact, that the device’s input leakage current (~5µA) can be considered the maximum current requirement for the VREF pin. Typical VTT power is drawn from other places on the board and depends on the other components used on the module/system in addition to DRAM devices.
On DDR, what happens when DQS write postamble (tWPST) maximum specification is exceeded? What problems could this cause?
The tWPST maximum specification is not a device limit. The device will operate with a greater value for this parameter, but system performance (bus turnaround) will degrade accordingly.
On DRAM, can a READ or WRITE command be given instead of a refresh?
If all of the different row addresses are read or written within the refresh time (tREF), a refresh need not be performed. (The different row addresses are the same number of rows as the number of REFRESH cycles. For example, in the case of 8,192/64ms, the number of rows equal 8,192.) With DRAM, selecting row addresses causes the same action as a refresh, so a REFRESH command need not be executed.
On DRAM, can unused DQ (data) pins be left floating?
Micron recommends that unused data pins be tied HIGH or LOW. Because Micron uses CMOS technology in DRAM manufacturing, letting them float could leave the pins susceptible to noise and create a random internal input level. Unused pins can be connected to VDD or ground through resistors.
What is the difference between no connect (NC), no function (NF), and do not use (DNU) pins? How should external connections to them be handled?
An NC (no connect) pin indicates a device pin to which no internal connection is present or allowed. Micron recommends that no external connection be made to this pin. However, if a connection is inadvertently made, it will not affect device operation. Sometimes NC pins could be reserved for future use. Refer to the part’s data sheet to confirm whether the pin is reserved for future use. An NF (no function) pin indicates a device pin that is electrically connected to the device but for which the signal has no function in the device operation. Micron strongly recommends that no external connection be made to this pin. A DNU (do not use) pin indicates a device pin to which there may or may not be an internal connection but to which no external connections are allowed. Micron requires that no external connection be made to this pin. Refer to the part’s data sheet for more details.
What is the maximum junction temperature at which DDR SDRAM functionality is guaranteed?
Please refer to page 3 of Micron’s technical note on thermal applications: TN-00-08. If functionality or operation is not a concern, refer to storage temperature specification limits on the part’s data sheet.
GDDR5(3)
How does Graphics DRAM differ from regular DRAM?
Graphics DRAM is a category of DDR SDRAM designed to handle very large bandwidth requirements. Unlike standard DRAM, graphics DRAM is typically soldered down on the same PCB as the SoC and always supports 32 DQs per memory component. Besides graphics cards and game consoles, graphics DRAM is being used in high-bandwidth applications like networking, automotive and high-performance computing.
What features and functions does GDDR5 have versus previous generations of Graphics DRAM?
GDDR5 provides higher densities, lower external voltage and more than twice the memory bandwidth compared to its predecessor, GDDR3. GDDR5’s 4X relationship between data rate and the CK clock is unique compared to the 2X relationship in DDR3 and GDDR3.
Is GDDR5 a direct replacement for GDDR3?
No, GDDR5 is not a direct replacement for GDDR3 due to package size differences. GDDR3 has a 136-ball BGA package while GDDR5 has a 170-ball BGA package.
GDDR5X(7)
How does Graphics DRAM differ from regular DRAM?
Graphics DRAM is a category of DDR SDRAM designed to handle very large bandwidth requirements. Unlike standard DRAM, graphics DRAM is typically soldered down on the same PCB as the SoC and always supports 32 DQs per memory component. Besides graphics cards and game consoles, graphics DRAM is being used in high-bandwidth applications like networking, automotive and high-performance computing.
What features and functions does GDDR5X have compared to previous generations of Graphics DRAM?
GDDR5X provides higher densities and lower external voltage (1.35V) compared to its predecessor, GDDR5. GDDR5X also doubles the bandwidth (10–16 Gb/s) of GDDR5 while remaining on traditional discrete package technology (FBGA).
Can GDDR5X operate in GDDR5-like mode?

Yes, GDDR5X has two operation modes:

  • QDR mode: Supports speeds of 10 Gb/s and above
  • DDR mode: Supports 0.2–6 Gb/s speeds and is compatible with GDDR5
Does GDDR5X support JTAG boundary scan?
Yes, GDDR5X has IEEE 1149.1 compliant boundary scan.
What is Micron’s competitive position with GDDR5X?
Micron is the first memory supplier in the industry supporting GDDR5X in mass production.
Is GDDR5X a JEDEC standard?
Yes, the GDDR5X SGRAM standard was first published in Dec. 2015 as JESD232. The latest JEDEC release is JESD232A.
Does GDDR5X replace GDDR5?
GDDR5X is not a direct replacement for GDDR5 due to package size differences. GDDR5 has a 170-ball, 0.8mm-pitch BGA package while GDDR5X has a 190-ball, 0.65mm-pitch package.
GDDR6(8)
How does graphics DRAM differ from regular DRAM?
Graphics DRAM is a category of DDR SDRAM designed to handle very large bandwidth requirements. Unlike standard DRAM, graphics DRAM is typically soldered down on the same PCB as the SoC and always supports 32 DQs per memory component. Besides graphics cards and game consoles, graphics DRAM is being used in high-bandwidth applications like networking, automotive and high-performance computing.
What features and functions does GDDR6 have compared to previous generations of graphics DRAM?

GDDR6 provides higher densities than previous-generation graphics memory. It doubles the bandwidth of GDDR5, extending past GDDR5X speeds. In addition, it is based on a dual-channel architecture, which enables a huge performance increase while still providing backward compatibility to GDDR5 memory access size.

Can GDDR6 operate in GDDR5-like mode?
No
Can GDDR6 operate in GDDR5X-like mode?
Yes
Does GDDR6 support JTAG boundary scan?
Yes, GDDR6 has IEEE 1149.1 compliant boundary scan
What is Micron’s competitive position with GDDR6?
Micron is leveraging its GDDR5X-based high-speed signaling know-how from more than two years of design, mass production, test and application learning in Micron GDDR6 products. This allows Micron to remain in the leading position on high-speed signaling with traditional memory components.
Is GDDR6 a JEDEC standard?
Yes, the GDDR6 SGRAM standard was first published in July 2017 as JESD250.
Does GDDR6 replace GDDR5 or GDDR5X?
GDDR6 is not a direct replacement for GDDR5 nor GDDR5X due to package size differences. GDDR5 has a 170-ball, 0.8mm-pitch BGA package, GDDR5X has a 190-ball, 0.65-mm pitch BGA package and GDDR6 has a 180-ball, 0.75mm-pitch BGA package.
RLDRAM(6)
Are CK/CK# and DK/DK# true differential inputs?
Yes, the CK/CK# and DK/DK# input buffers are true differential inputs. Both sets of clocks need to meet the specifications that are defined in the Clock Input Operating Conditions tables in the RLDRAM data sheets.
Can I connect the “Do Not Use” (DNU) pins to ground (GND)?
Yes. However, when on-die termination (ODT) is enabled, the DNU pins will be connected to VTT. Connecting the DNU pins to GND under these circumstances will cause a substantially larger load on your VTT supply.
How is RLDRAM II memory similar to SRAM?
 Simplified command set of only four commands and a Fast cycle time, as low as 7ns tRC
I’ve heard about the new multibank write feature on RLDRAM 3. What exactly is this feature?
Multibank write is a feature that allows for SRAM-like random read access time. Using this feature can reduce RLDRAM 3’s already low tRC (<10ns) by up to 75% during reads. Through the RLDRAM 3 mode register, you can choose to write to one, two, or four banks simultaneously. By storing identical data in multiple banks, the memory controller has the flexibility to determine which bank to read the data from in order to minimize tRC delay.
What new features does RLDRAM 3 add?
 Multibank write that enables SRAM-like random read capabilities. MULTIBANK REFRESH makes managing refresh overhead more flexible than ever, allowing refresh of one to four banks simultaneously. RLDRAM3 also supports a mirror function to ease layout of clamshell designs.
Will I be able to leverage any existing DRAM technology to ease the adoption of RLDRAM 3 in my system?
Yes. Even though RLDRAM 3 is a new architecture, it leverages many features from both DDR3 and RLDRAM 2 to make adoption and integration as easy as possible. The command protocol, addressing, and strobing scheme are the same as RLDRAM 2, while the I/O, AC timing, and read training register very closely resemble those found in DDR3.
LPDRAM(11)
Are Micron's LPDRAM products green/RoHS compliant?
Yes. Micron’s green engineering program is RoHS-compliant and conforms with most of the world’s emerging environmental standards, including those in Asia and Europe.
Are your LPDRAM parts JEDEC-compliant?
We design our parts to meet or exceed the JEDEC specification. As standards change, we will make the necessary changes to ensure our parts meet new specifications. Any changes made will be noted in a product change notice (PCN) and sent to our customers.
Does Micron's LPDRAM cost more than standard DRAM?
It depends. Density plays a major role in price comparisons between LPDRAM and standard SDR/DDR. Also, since LPDRAM is offered in standard configurations of x16, x32 and x64, you may be able to reduce your overall BOM cost if your application currently uses two x16 components to support a x32 bus. You could use one x32 LPDRAM instead of two x16 standard DRAM. Contact your local rep for cost information.
How does LPDDR3 differ from DDR3L-RS?

LPDDR3 is optimized for battery life and portability. DDR3L-RS is a low IDD6 version of the DDR3L die and offers a balance in price versus performance, along with improved standby power.

How does LPDDR3 differ from LPDDR2?

LPDDR3 increases performance to 1600 Mb/s (versus 1066 Mb/s for LPDDR2). Additional changes include write leveling, C/A (command/address) training, and a lower I/O capacitance limit to improve timing.

The part I was using is obsolete and the replacement is a faster speed grade. Can I run the LPDRAM parts at a lower speed?
Yes. A LPDRAM part can be run at any speed equal to or slower than its rated speed grade.
What is LPDRAM?
Optimized for products where power consumption is a concern, our low-power LPDRAM devices combine leading-edge technologies and packaging options to meet space requirements and extend battery life. LPDRAM is available with DDR/SDR interface.
What is the life expectancy of Micron's LPDRAM products?
We're excited about this fast-growing market. We plan to manufacture LPDRAM for many years to come and plan to continue to shrink our designs to achieve higher densities.
What makes Micron's LPDRAM unique?
We offer a comprehensive LPDRAM product portfolio, with a wide range of densities and package options (including JEDEC-standard VFBGA, Known Good Die, and package-on-package). With nearly a decade of LPDRAM experience, our worldwide technical support team can provide the expertise and assistance you need to get your designs to market faster.
What’s the difference between Mobile DRAM and LPDRAM?
There is no difference; Mobile DRAM and LPDRAM are the same product. We opted to add the "LP" prefix to our Mobile DRAM product line to align with the common terminology used throughout the industry and to ensure our customers know at a glance that our Mobile DRAM is a low-power memory device. In addition to the family name change, Mobile DDR SDRAM and Mobile SDR SDRAM are now called Mobile LPDDR and Mobile LPSDR, respectively. Our Web site has been wholly converted to the LPDRAM naming convention, but because we’re updating our PDFs as they come up for review you may see a few older technical documents that still use the old Mobile DRAM terminology.
How does LPDDR4 differ from LPDDR3?

LPDDR4 increases data rate to 3200Mbps ~ 4266Mbps/pin, using LVSTL(Low Voltage Swing Terminated Logic).  Die organization has changed from x32 1ch (LPDDR3) to x16/x8 2ch, and added x16/x8 1ch. There are other new features on LPDDR4 for higher speed, lower power consumption.

DRAM Modules(3)
Can Vtt and Vref be supplied by the same supply in my system design?
With proper decoupling this can be an acceptable design. However, Micron recommends ensuring all supplies are separated. Vref tends to have more noise on it because it supplies signals that are regularly switching. A robust design would typically not connect these supplies due to the possibility of introducing this noise onto the Vtt plane which should be as stable as possible. Additionally, Vref requires much less current than Vtt.
Is there a set of trace lengths and routing rules that are standard for use when designing a system that uses a specific module technology and form factor?
No. A robust memory subsystem design that includes the use of 1 or more memory modules must be simulated in order to determine the optimum trace lengths, terminations. However, our design guides such as TN-47-01 and TN-41-08 have some best practices and design examples based on some typical system assumptions. This information is not meant to be the only way your system can be designed. It is a starting point and moreover an example of the steps used to determine the best design for your system.
NVDIMM(8)
What is NVDIMM?

NVDIMM is a nonvolatile persistent memory solution that combines NAND flash, DRAM and an optional power source into a single memory subsystem. Micron’s NVDIMM is capable of delivering the performance levels of DRAM combined with the persistent reliability of NAND, ensuring data stored in-memory is protected against power loss.

How do NVDIMMs work?

NVDIMMs operate in the DRAM memory slots of servers to execute workloads at DRAM speeds. In the event of a power fail or system crash, an onboard controller safely transfers data stored in DRAM to the onboard nonvolatile memory, thereby preserving the data that would otherwise be lost. When the system stability is restored, the controller transfers the data from the NAND back to the DRAM, allowing the application to efficiently pick up where it left off.

What is persistent memory?

Persistent memory is a new addition to the memory/storage hierarchy that enables greater flexibility in data management by providing nonvolatile, low-latency memory closer to the processor. Essentially, persistent memory accelerates application performance by removing what otherwise are constricting I/O bottlenecks placed on the application by standard storage technologies. By placing nonvolatile memory on the DRAM bus, this architecture enables customers to significantly optimize data movement in order to deliver faster access to variables stored in DRAM.

With persistent memory, system architects are no longer forced to sacrifice latency and bandwidth when accessing critical data that must be preserved. Critical data can be stored close to the processor, dramatically cutting access times. Persistent memory delivers a unique balance of latency, bandwidth, capacity and cost, delivering ultra-fast DRAM-like access to critical data and enabling system designers to better manage overall costs.

What are the key use cases for NVDIMM?

Any application where performance depends on variables stored in nonvolatile media (HDD or SSD) can benefit from NVDIMMs (most applications can be accelerated). Persistent variables include metadata logs, checkpoint state, host write caches, write buffers, journals and general logs. Applications that can be accelerated by placing these variables in NVDIMM include 2-node, high-availability storage using RAID cards, SSD mapping, RAMDisk and write caching for SSDs.

What products are available today?

Micron will be offering three DDR4 NVDIMM products:

  1. 8GB DDR4 NVDIMM with legacy firmware
  2. 8GB DDR4 NVDIMM with JEDEC firmware
  3. PowerGEM® ultracapacitor for 8GB NVDIMM
What is the difference between the legacy and JEDEC firmware?

Legacy firmware refers to the firmware features and controller register locations for features determined by AgigA Tech, Inc., for initial DDR4 NVDIMM designs. JEDEC has now standardized the NVDIMM firmware features, register locations and APIs so that one vendor’s NVDIMM can be compatible with any other vendor’s NVDIMM. All new Micron NVDIMM solutions will leverage the JEDEC firmware interface.

How will NVDIMMs be enabled? What platforms support NVDIMM?

Many motherboards, servers and storage appliances support NVDIMMs today. Many more will come to market in 2016. Contact your supplier for more details.

Are there software requirements for NVDIMM?

NVDIMMs leverage either block mode or direct access drivers. NVDIMMs used in conjunction with a block mode driver are compatible with OS and applications with little to no necessary software modifications. Additional performance capability can be tapped by leveraging an NVDIMM with a direct mapped driver, but OS and application software will likely need some modification. Micron is currently working with major OEMs and software companies to incorporate NVDIMM hardware, driver and software support into their mainstream products.

NAND Flash(17)
eMMC(14)
What is e.MMC?

Embedded MultiMediaCard (e.MMC) is a NAND Flash-based memory solution defined by JEDEC that comes in a small BGA package. JEDEC defines both the hardware and software, enabling easy customer design-in and the ability to multisource.

What are the benefits of e.MMC?

e.MMC is a fully managed solution (all media management and ECC are handled internally), making NAND technology transitions invisible to the host and providing customers with the ability to reduce their time-to-market and to sustain products longer and more easily.

What does the term "broad market" signify?

Our embedded market e.MMC products are divided into two families: automotive and broad market. This is due to the unique requirements that are required in the automotive market; thus, there is a separate product line supported by Micron’s automotive team. Broad market covers all other market segments such as consumer, gaming, server, networking, industrial, medical, military, etc. Broad market e.MMC includes two sub-families: WT with commercial temperature grade and IT with an extended temperature range.

How can I order samples?

You can order samples through the Micron Sample Center.

Is it necessary to refer to the JEDEC specification as well as to Micron’s data sheet?

Yes, the JEDEC specification has to be read in conjunction with the data sheet. Micron e.MMC complies with the JEDEC standard; hence, Micron's data sheets provide information that is specific only to Micron’s e.MMC devices.


Are simulation models available?

Yes, IBIS models are available for WT and IT products (JEDEC 153-/169-ball and 100-ball)

What is the e.MMC offering for industrial applications?
Micron is offering an extensive number of solutions for industrial customers, such as five densities and JEDEC-standard BGA 153-/169-ball and custom 100-ball packaging. All of these products will operate in the extended temperature range of -40° to 85°C.
What are the advantages of 100-ball IT e.MMC?

Micron’s 100-ball e.MMC BGA package features a 1.0mm ball pitch for board routing simplification (saving PCB costs) and improved board-level reliability (temp cycling). This solution is particularly attractive to automotive, industrial, and networking market segments. See the following table for additional benefits.

Features of 100-ball e.MMC

Benefits

Large 1.0mm ball pitch

  • Allows for low-cost PCB trace/space designs
  • Simplifies PCB routing
  • Enables a reduction in the number of PCB layers
  • Reduces costs via a lower drill size
  • Lower DAR (drill aspect ratio) for better PCB yields
  • Allows for wider traces for better thermal dissipation

Large 0.45mm nominal ball diameter

  • Provides high PCB board-level reliability
  • Improves surface-mount yields (vs. smaller ball packages)
  • Provides better thermal dissipation

Low ball count (compared to 153-ball e.MMC JEDEC-standard)

  • Allows for easier, low-cost PCB routing
  • Reduces package and PCB costs

100-ball pattern contains 12 mechanical support balls (3 in each corner)

  • Provides excellent PCB board-level reliability
  • Allows for flexible “large package size” variations

Flexible ball-out design

  • Allows for future e.MMC feature upgrades and next-generation technology
How can I migrate from Micron e.MMC 4.4 to 4.41?

Micron has EOL’d its e.MMC 4.4 offering. Refer to your AE for support. A dedicated technical note “TN-FC-08: Migrating from Micron v. 4.4 e.MMC to 4.41 e.MMC” is available for review.

Is it possible to perform a system boot from e.MMC?

Yes, e.MMC provides two boot partitions to provide fast access to boot code for improved system boot time. Booting from boot partitions can provide access to stored data in ~50ms, whereas booting from the user area can take hundreds of milliseconds. However, in order to utilize the boot partitions, the chipset must be able to support booting from the boot partition. Check with your chipset vendor to understand if booting from the e.MMC boot partitions is supported.

Does Micron e.MMC support power-loss protection?

Yes, ESG e.MMC devices support static data protection. Devices are shipped from Micron factories as COMBO with a configuration optimized for best write performance. Customers can reconfigure the devices to protect static (previously written) data if there is power loss during a write operation.

What are the enhanced technology features mentioned in JEDEC specification, and what are the benefits?

A part or all of the MLC user space can be configured as pseudo-SLC. The partition offers better reliability, endurance, and performance compared to MLC NAND.

Can I set up partitions within e.MMC to suit different usage models?

The e.MMC specification allows customers to configure the user data area into a maximum of four separate partitions that can each be configured as MLC (default) or enhanced mode (pSLC). Enhanced mode provides better reliability in exchange for twice the space as MLC.

For more information refer to "TN-FC-40: Embedded e.MMC Configuration"

What is the required software support for e.MMC?

e.MMC drivers are generally available on the market due to the fact that it is an industry-standard product.

eUSB(7)
What is eUSB?
The embedded universal serial bus (eUSB) is a NAND flash-based memory solution that is compliant with the USB industry standards. USB is a widely adopted interface used across multiple platforms and operating systems, providing a low-cost, efficient data transfer solution for current applications and beyond.
What are the benefits of eUSB?

eUSB is a fully managed solution that utilizes NAND memory and, through an onboard controller, internally handles all media management and ECC control. The eUSB provides customers with a complete storage solution that easily integrates into their system and, in turn, fuels a reduced time to market.

Using native SLC NAND memory, combined with a rich set of management features such as global wear leveling and dynamic data refresh, eUSB offers a superior combination of performance and reliability.

How does the eUSB attach to my system board?
The eUSB device has a 10-pin (2x5) USB female connector compatible with the industry-standard 10-pin connector found on most motherboards. A mounting hole (connected directly to internal ground) is also provided on the PCB to ensure a stable connection to the system board.  Additional holes in the PC board, utilized during manufacturing for de-paneling, can also be used as additional mounting locations if required.
Can I use the eUSB as a boot device?
Yes. Micron’s eUSB can be used as the operating system boot and main storage device. However, the application’s BIOS must support the boot mode feature, which should not be a concern for most systems that were manufactured in the last five years and support USB 2.0. In either the main storage or boot mode, the eUSB should be recognized as a fixed hard drive in the system.
Does Micron offer the eUSB with a 3.3V option?
Yes. Please check the part catalog for Micron’s current eUSB offerings.
Does Micron provide a way for me to determine the useful life remaining on the device?
Our latest generation eU500, eUSB 3.1 products do provide a method to extract relevant lifetime data through the use of SMART commands. However, previous generations of eUSB products do not support a runtime method to collect lifetime data.
Is eU500 (eUSB 3.1) fully backward compatible with e230 (eUSB 2.0)?
Yes. Micron’s latest generation eU500 eUSB 3.1 products are backward compliant with the USB 2.0 protocol. The eU500 family also supports the same form factor, voltages and connector offerings as the previous generation e230. Please check the part catalog for Micron’s current eUSB offerings.
3D NAND(4)
Why is 3D NAND necessary?
Planar NAND flash memory is nearing its practical scaling limits, which poses challenges for the memory industry.  Industry innovation requires state-of-the-art NAND technology that scales with higher densities and lower cost per bit. 3D NAND allows flash storage solutions to continue aligning with Moore’s Law, bringing significant improvements in density while lowering the cost of NAND flash.
What sets apart this 3D NAND from other offerings in the industry?

The 3D NAND technology developed by Intel and Micron offers significant improvements in density and cost, and it’s the first 3D NAND to use floating gate cells.  This 3D NAND enables flash devices with three times higher capacity than other planar NAND die in production, and the first generation is architected to achieve better cost efficiencies than planar NAND. There are also various features that will improve latency, increase endurance and make system integration easier.

Micron’s 3D is a “smarter” NAND technology. What do you mean?
We have integrated various features to deliver improved performance and new functionality, including new programming algorithms and power management modes that help make system integration easier. See FortisFlash to learn more about these features.
What are the details of your cell and process technology for 3D NAND?
The new 3D NAND technology uses floating gate cells and stacks flash cells vertically in 32 layers to achieve 256Gb multilevel cell (MLC) and 384Gb triple-level cell (TLC) die that fit within a standard package.
Do you support small block devices?
Currently, Micron only offers large block devices. For more information, please refer to Technical Note, TN-29-07: Small Block vs. Large Block NAND Devices.
How do I achieve greater PROGRAM/READ throughput for the NAND device?
To get the maximum PROGRAM/READ throughput for Micron NAND Flash devices, use the PROGRAM and READ CACHE operations. See the NAND device data sheet and our NAND Technical Notes Page for details on how to use these commands.
How is High-Speed NAND different from traditional NAND?
High-Speed NAND can read data at speeds up to 200 megabytes per second (MB/s) and can write data at speeds up to 100 MB/s. These speeds are achieved by leveraging the new ONFI 2.0 interface specification and a four-plane architecture with higher clock speeds. In comparison, conventional SLC NAND is limited to 40 MB/s for reading data and less than 20 MB/s for writing data. To maximize the performance benefits of High-Speed NAND, users must use the new ONFI 2.0 synchronous interface standard.
How is Nvb specified?
Nvb is specified as the minimum number of valid blocks at the end of the P/E cycle spec.
How much ECC do I need to support your devices?
We define our ECC requirement per 512-byte section. MLC NAND devices have a higher ECC requirement than SLC NAND due to the increased number of bits per cell. ECC requirements differ for designs, so consult the device data sheet for the amount of ECC needed.
I am seeing a lot of READ DISTURB errors. Can you tell me if there is a problem with your part?
READ disturb occurs when the same data is read repeatedly. By its nature, NAND technology has a very low occurrence of read-disturb errors. But, to mitigate any errors received due to read disturb, we recommend that users refresh the data to reduce the amount of times the same data is read.
I am using the correct amount of error correction code (ECC) for the NAND device, but I’m still seeing bit/byte errors in data I read back from the NAND device.
Make sure that you are issuing a READ STATUS command to the NAND device after any type of PROGRAM or ERASE operation. Checking status after a PROGRAM or ERASE operation will report whether the PROGRAM or ERASE operation was successful. If the READ STATUS command reports a failure with a PROGRAM operation, that data should be programmed somewhere else and the block being programmed should be retired. If the READ STATUS command reports a failure with an ERASE operation, that block should also be retired.
I’ve heard that NAND has too many errors to boot from. Is this true?
With ECC, NAND can achieve bit error rates (BER) that are comparable with NOR, which is commonly used as a booting device. Applications that use NAND typically copy the booting code to DRAM and execute from DRAM. For more information, read Tech Note 29-16, which is geared to a specific processor, but the concepts can be applied generally. TN-29-19 is a very useful technical note on the general concepts of NAND.
Should I be marking blocks bad due to READ errors?
Yes.
When I issue a Read ID command (90h) to a two-die NAND device, I get a device ID back that states it is a one-die NAND device.
In a two-die NAND device, where a single die is on each CE#, the device ID that is returned is per CE# for one die. For example, an 8Gb two-die NAND device with two CE# pins would return a 4Gb device ID on each CE#. See the Read ID section of the NAND device data sheet for more details.
Where can I find additional technical information about Micron NAND devices that is not covered in the device data sheets?
Additional Micron NAND Flash technical information—including details on performance enhancing commands—can be found on the Technical Notes page for NAND.
Where can I find simulation models for NAND Flash devices?
Micron posts Verilog, HSPICE, and IBIS models for NAND devices. To find the right model for your needs, see the appropriate NAND part catalog and select your device to view the available models.
Why am I getting a bit/byte error reading back the information I programmed into the NAND device?
Check that you are using the appropriate amount of error correction code (ECC) for the NAND device. The ECC threshold can be found in the "Error Management" section of the NAND device data sheet. Also ensure that none of the bad blocks marked by the NAND manufacturer (Micron) are used. See the "Error Management" section of the NAND device data sheet for more details on how to search for manufacturer-marked bad blocks.
Why doesn't the NAND Flash device respond correctly to commands issued to it?
Be sure you are issuing a reset command (FFh) to the NAND device after powering on the device. A reset command (FFh) must be issued to each valid chip enable (CE#) of the NAND device before any commands are allowed to be issued to that CE#.
Hybrid Memory Cube(1)
Short-Reach HMC(8)
What problem does HMC solve?

Over time, memory bandwidth became a severe bottleneck to optimal system performance. Conventional memory technologies were struggling to keep pace with the increasing performance demands of the latest microprocessor and application-specific integrated circuit (ASIC) roadmaps. Microprocessor and ASIC enablers are doubling cores and threads per core to greatly increase performance and workload capabilities. They are doing this by distributing work sets into smaller blocks among an increasing number of work elements (cores). Multiple compute elements per processor require an increasing amount of memory accesses per element. The term “memory wall” has been used to describe this dilemma. With bandwidth performance levels that break through the memory wall, HMC enables greater performance for next-generation computing and high-speed networking systems.

What are the measurable benefits of HMC?
  • Increased Bandwidth − A single HMC unit can provide up to 160GB/s bandwidth
  • Reduced Latency – With vastly more responders built into HMC, we expect lower queue delays and higher bank availability, which will provide a substantial system latency reduction—a key advantage in networking system design.
  • Power Efficiency − HMC’s revolutionary architecture enables greater power efficiency and energy savings, utilizing up to 70% less energy per bit than DDR3-1333 DRAM technologies.
  • Smaller Physical Footprint − HMC’s stacked architecture uses nearly 90% less physical space than today’s RDIMMs.
  • Pliable to Multiple Platforms − Logic layer flexibility enables HMC to be tailored to multiple platforms and applications.
  • Ultra Reliability HMC delivers greater resilience and field reparability with a new paradigm of system-level, advanced reliability, availability, and serviceability (RAS) features that include embedded error-checking and correction capabilities.
  • Abstracted Memory − Designers can leverage HMC’s revolutionary features and performance without having to interface with complex memory parameters. HMC manages error correction, resiliency, refresh, and other parameters exacerbated by memory process variation.
What does the implementation of HMC look like?

HMC is tightly coupled with CPUs, GPUs, and ASICS in direct point-to-point configurations where HMC performance is essential to system performance. The result is low pin counts with easy board routing in straightforward designs. In systems that require higher density, HMC supports chaining and half-width link configurations to keep the host pin counts down and the designs simple.

What industries/segments do you anticipate will be affected the most?

Any applications where high performance and energy efficiency are critical will be dramatically affected by this technology. For example, the challenge for network systems to maintain line speed performance provides an excellent opportunity for HMC. System developers recognize that a memory bottleneck exists for system development beyond 100Gb and are actively looking for high-performance memory applications for data packet processing and data packet buffering or storage.

The high-performance computing segment is also hitting the memory wall. While processor roadmaps attempt to keep pace through core and thread doubling, core and thread count has not been matched with adequate memory performance. The second major challenge for high-performance computing is energy consumption. Higher-performance processing and exponential bit growth requirements are pushing data centers beyond practical limits for managing power and total cost of ownership. A more energy-efficient solution is desperately needed.
What is the HMCC and what are its goals?

The Hybrid Memory Cube Consortium (HMCC) is a working group made up of industry leaders who build, design in, or enable HMC technology. The goal of the HMCC is to define industry-adoptable HMC interfaces and to facilitate the integration of HMC into a wide variety of applications that enable developers, manufacturers, and enablers to leverage this revolutionary technology.

What does the HMCC specification cover?

The specification includes two PHY definitions and a common protocol. The short-reach (SR) PHY is designed for applications needing channel lengths up to 8 inches, and the ultra short-reach (USR) PHY is intended for applications requiring very short and power-efficient channels with lengths from 1 to 2 inches.

Where can the HMCC specification be accessed?

The HMCC specification is publically available on hybridmemorycube.org.

What Micron parts are available?

Our 2GB HMC device composed of a stack of four 4Gb DRAM die is available. HMC is designed using the HMCC’s short-reach (SR) PHY definition and is available in a 31mm x 31mm package offering four links with full 160 GB/s bandwidth.

Multichip Packages(8)
Do you have any reliability data on the PoP?
Yes. We do have reliability data on the PoP. Contact Micron for more information.
For a PoP/MCP, does the qualification testing at the factory differ from testing on the discrete components?
No. the PoP/MCP parts undergo the same qualification testing as the discrete components.
How do I know the Micron part number for the part on the Beagle Board?
The Beagle Board uses our NAND + Mobile LPDDR PoP combination parts, and the densities vary depending on which version of the Beagle Board you have. Type the second 5-digit alphanumeric code on the physical part into our FBGA Decoder, which will provide you with the corresponding Micron part number.
I’ve heard that opting for a PoP/MCP solution is more expensive than using discretes, so why should I use it?
From a system-solution perspective, because the PoP mates directly onto the processor, it eliminates the need to have traces routed on the PCB. This saves costs for the customer, as well as provides better signal integrity.
Our contract manufacturer has little experience with PoP. Why should we try something new?
The market is driving the requirement for the smaller PoP form factor, and several contract manufacturers have already enabled this technology. PoP can help save in routing costs and improve signal integrity. Given those cost and performance advantages, Micron recommends that you work very closely with your CM to ensure a good transition to this technology. Micron worked closely with Texas Instruments (TI) on the technical notes PCB Design Guidelines Part I and PCB Assembly Guidelines Part II. These can also help provide guidelines to help you work with your CM for the best success on your conversion to PoP.
We designed in discrete parts, but now we are using PoP parts. They appear to be limited in what speeds we can achieve. What is the problem?
When moving from testing with discrete parts to PoP, care should be taken that no stubs are left from the design containing the discrete components. If needed, a 0 Ohm resistor could isolate the memory from the traces used for the discrete part.
What are your PoP/MCP offerings for x8 NAND and/or x16 Mobile LPDDR?
Our standard offerings are x16 NAND and x32 Mobile LPDDR. We also have x8 NAND and x16 Mobile LPDDR. For the most current information, contact your local Micron support.
What is an MCP? What is a PoP? What is the difference between the two devices?

MCP is multichip package that contains multiple die and can be used by any controller. PoP is a form of an MCP made specifically to stack on top of a processor that has pads on the top side that mate to the ballout of the PoP. Because the PoP package stacks right on top of the processor, it eliminates the need to have traces routed on the PCB and provides better signal integrity. A variety of PoP packages are designed for various processors. PoP and MCP devices give designers the ability to take advantage of z space and to provide the flexibility to offer different logic in one package (for example, NAND + Mobile LPDDR or e.MMC™ + NAND + Mobile LPDDR). We have a wide selection of offerings to meet our customer’s needs.

Solid State Storage(1)
Client SSD(1)
Can I buy a Micron SSD for personal use?

We sell SSDs (and memory) direct to the consumer through our Crucial brand. Crucial SSDs offer the same great quality, reliability, and performance of Micron SSDs, but are packaged for consumer sales. You can buy one today at crucial.com/ssd.

Advanced Computing Solutions(4)
General(2)
Is Pico Computing now part of Micron?
In 2015 Micron Technology acquired Pico Computing, an industry leader in FPGA solutions. Now known as Micron Advanced Computing Solutions (ACS), our modular, highly scalable FPGA-based HPC and embedded systems comprise the industry’s leading technology for high-performance computing.
Does Micron favor Xilinx® or Altera® (Intel®) FPGAs?
Micron does not favor one or the other. Our ACS modules are designed around the latest-generation FPGA components from either Xilinx or Intel, depending on design goals and specific customer requirements.
Getting Started(3)
How do I get started with your system?
All of our ACS hardware comes with an installer file. Simply print out the Getting Started file and follow the directions. The C++ API source files that are included contain a PicoDrv, which represents an FPGA.
How do I interface with a host processor?
You interface like you would in any other system that utilizes PCIe® add-in cards.
How do I use more than one module?
Our PicoFramework provides access to all basic FPGA functionality regardless of the number of modules. The software API includes a source file called PicoDrv, which creates a PicoDrv object for each FPGA module in a system, making FPGA module communication simple.
Programming FPGAs(3)
How do I upload my bitfile to an FPGA in your system?
Our PicoFramework provides access to all of the basic FPGA functionality in your system. When you build a configuration file for an FPGA, the PicoFramework software will be the top level, and your module will be instantiated inside the framework. You create a PicoDrv object for each FPGA in the system.
What is the loading mechanism for backplane-mounted modules?
Programming an ACS module is accomplished via the PCIe® bus. Our EX-700 and EX-750 backplanes include a Spartan-6 FPGA that is used to load the ACS FPGA modules utilizing API calls. We also support and provide examples of DMA transfers through PCIe.
If I have a size-constrained application, do I need to use a backplane?
Our EX-700 and EX-750 backplanes are not technically required when using Micron’s ACS FPGA modules. Our modules can run in stand-alone with the bitfile programmed into the configuration flash, which then loads the FPGA.
Design Flows(6)
Do I need to migrate my entire application to a Micron ACS FPGA module to realize the performance advantage?
No. Simply move your application’s “hot spot” to the FPGA module and then execute a function call from the main application that remains on the traditional CPU-based system.
How do I recompile my legacy serial code to run on Micron’s ACS products?
Existing code written for serial processors should not be recompiled to run on highly parallel FPGA architectures because the many parallel benefits of the FPGA will not be realized. In fact, FPGAs are clocked much slower than CPUs (a significant power consumption benefit), so serial code would run even slower. Existing code should be analyzed to discern where the parallel nature of FPGAs offers the largest benefits, and only that part of the code should be rewritten to take advantage of the parallel nature of FPGAs. This way, the biggest benefit can be realized with the smallest effort.
Which tools do I need to use to utilize Micron’s ACS FPGA modules?
The PicoFramework doesn’t constrain your selection of FPGA design tools. Use whichever tools you are currently using for your FPGA development and whichever tools you are most comfortable with.
Does Micron ACS support OpenCL?
Yes. Both Intel’s OpenCL™ and Xilinx’s SDAccel can be used with PicoFramework. Use whichever tools you are currently using for your FPGA development and whichever tools you are most comfortable with.
Do I need to start from scratch?
No. To start your own project, simply find the sample that best matches your communication model and ACS module/board, and copy it to your work directory. The copy function will provide all source files for the PicoFramework; you will just need to add your own code.
What simulators does Micron’s ACS support?
We currently support both the Xilinx® ISim and the Altera® ModelSim (Mentor’s simulator) simulators.
Solutions(1)
Bare Die(3)
Does Micron offer product in whole wafer form and singulated die?

Nearly all Micron memory die shipments are now sold as whole wafers, not singulated die (check with your local sales contact for availability). Wafer maps are provided in each wafer shipment. For more information on wafer mapping, see TN-00-21. (For information regarding Aptina image sensor die orders, see aptina.com)

How does Micron ship bare die product?

Micron die are provided as whole wafers and are shipped in horizontal wafer shippers ("coin stacks") or vendor boxes. Customers must have a clean room environment to store and unpack Micron wafers. For more information, see CSN 20: Whole Wafer Packaging.

What wafer thickness options does Micron offer?
Standard "unground" wafer thickness is 750µm for 200mm wafers and 790µm for 300mm wafers. Micron offers additional wafer thickness options for 200mm wafers, depending on the product. Please see the applicable die data sheet for die thickness options beyond the standard thickness. Depending on customer demand, Micron may consider processing alternative thicknesses. Please consult your sales representative for more information.
Support(2)
Serial Presence Detect(6)
Can I verify that the hexadecimal SPD values are correct?
Converting the hexadecimal value to binary and then matching it against the associated SPD byte in the appropriate JEDEC SPD specification will provide a translation of what the byte is for and how it is set.
How are SPD values determined?
Micron utilizes a proprietary application that generates SPD values for each part number based on engineer’s input and a database of rules. The rules housed within the database are carefully written to ensure that JEDEC SPD specifications are adhered to. This process ensures compatibility and consistency.
What are the JEDEC SPD specifications?
The SPD specifications for modules are determined by JEDEC. Micron uses several SPD specifications within JEDEC Standard No. 21-C to determine and generate SPD data for SDRAM, DDR, DDR2, DDR3 and FBDIMM modules. These specifications are available (if ratified) to the public at www.jedec.org. Specifications that have not yet been completed or ratified are available to JEDEC members only.
What is the acronym SPD stand for?
Serial Presence Detect
What is the SPD data used for?
The SPD data represents different electrical and physical characteristics of the module. This data is permanently stored in an electrically erasable programmable read-only memory (EEPROM) on the module. A basic input/output system (BIOS) access SPD information through the SMBus. The system BIOS can then use this data to configure the system to optimize the memory that has been installed.
What is the SPD table for?
The SPD table shows the hexadecimal values for each byte that is held in the EEPROM on each memory module.
Sim Models(22)
Are Verilog models available for Micron modules?
Verilog models can be created for DDR, DDR2, and DDR3 modules by using a Micron-provided wrapper in conjunction with the Verilog model for the DRAM components used on the specific module you're working with. The configurable DIMM model file (ddr_dimm.v, ddr2_module.v, or ddr3_dimm.v) is included in the DRAM Verilog model .zip file download for DDR, DDR2, and DDR3 components. The readme.txt file included in the .zip provides instructions for configuring the DIMM model.
Can a parity module be used in a system that is not designed to use parity?
Micron’s modules are manufactured to be hardware-compatible with both parity and non-parity systems. Par_in (parity in) and the high order address signals have a weak (100K-ohm) pull-down resistor to stabilize the inputs from oscillating around the switch point. Err_out (parity error out) is an open drain and should be left as a true no connect unless used in a parity system. The SPD data on a parity module does reflect parity. In rare occasions, the firmware or BIOS of a non-parity system will err on the parity bit in the SPD. For this reason, the system designer should ensure that the firmware of the non-parity system expects or ignores this portion of the SPD data.
Can Micron provide models for the module connectors?
It is suggested that models for connectors be acquired from the connector manufacturers to ensure an accurate model. Micron may be able to provide a simple, uncoupled RLC connector model to be used as is or to create your own connector model. Please e-mail DRAM Support to request this model.
Can Micron provide module Gerber files to customers?
As a rule, Gerber and ODB++ files are not provided to customers, because the files contain proprietary information about our design and could be used to mass-produce our product without our consent. There is normally no reason that a customer would need Gerber files. Gerber files are provided to PCB manufacturers to mass-produce PCBs. IBIS, EBD, or board files provide enough information for customers to create models and perform signal integrity simulations.
Does Micron provide Hyperlynx models?
Micron can provide Hyperlynx models upon request for most modules. Please e-mail DRAM Support with your request and provide the complete part number of the module you are interested in. Please note, it may take up to two weeks to receive the model once your request has been acknowledged.
Does Micron provide VHDL models for modules?
Micron does not provide VHDL models for modules. We have focused our modeling resources on higher utilized modeling standards such as IBIS, Verilog, and HSPICE. However, alternatives to VHDL models are available: Denali and Synopsys both have libraries of memory components and module models available on their Web sites. These EDA packages may be an alternate way to create behavioral simulations in the absence of VHDL model. Some simulators such as ModelSim provide a dual language option (VHDL and Verilog). To simulate in this manner, a VHDL wrapper can be used around currently available Verilog models.
Does the model that I'm downloading support all the drive strengths listed in the data sheet?
To discover the model’s supported drive strengths, do the following:
- HSPICE model: Look at the .sp files for information on supported drive strengths and how to select them.
- IBIS model: Do a text search for the [Model Selector] section. This section describes the drive strengths that can be selected for a given input/output or output buffer.
How do I tell if I have the correct IBIS or HSPICE model for a given die revision indicator?
HSPICE model: Look in the readme file for die revision information.
IBIS model: Look at the top of the file for die revision information.
How does Micron validate the quality of its IBIS and HSPICE models?
To validate a model to lab measurements, Micron compares several items, such as input capacitance, power and ground clamp diode characteristics, output buffer drive strength, and output buffer slew rates. New Micron models include a quality report that compares model characteristics to lab measurements and data sheet specifications.
My simulation software does not support IBIS 4.0 and newer standards. How do I make Micron's IBIS 4.0 level model work with my IBIS 3.2-compliant simulator?
Most Micron models contain very few keywords specific to IBIS 4.0. In many cases, the model can be made IBIS 3.2-compliant with a few simple changes. First, change the [IBIS Ver] keyword to 3.2. Next, place a comment character ("|") in front of the "Vref" section under each [Model Spec] keyword. Finally, comment out each [Receiver Thresholds] section.
What advantage do dual-rank modules have over single-rank modules?

Having two ranks available to the memory controller is advantageous in terms of both performance and power. For example, while the controller is waiting for a 64-bit word to be available on one rank, the second 64-bit rank can be accessed. This interleaving increases the overall performance of the module. Power can also be reduced on a rank that is not in use, reducing the power consumption of the module.

What does the model revision number indicate when it changes from a 1.x level to a 2.x level?
1.x level model indicates that the model has not been correlated to any lab measurements. Typically, 1.x level models are provided for pre-silicon or pre-production devices. A 2.x level model has been correlated to lab measurements.
What is a board (.brd) file?
A board file is a complete electrical and mechanical representation of a PCB. EBD and ODB++ files are generated from board files. Board files are not to be provided to customers without an NDA since the files contain confidential and proprietary information about the module design.
What is a Gerber file?
Gerbers are files sent to PCB manufacturers to produce PCBs. Gerber is a dated term because board shops currently require ODB++ files to mass-produce PCBs. The term Gerber is used loosely. It sometimes refers to any of the files that represent the PCB’s electrical and mechanical characteristics, including EBD, ODB++, and board files. When a customer asks for Gerber files for a module, it is important to determine what specific files they really need.
What is a "rank"?
A rank typically refers to the data bus width of a system. This width is generally 64 or 72 bits. For example, if 8 components with a width of 8 bits each are mounted to a PCB, this creates a module that is 64 bits wide, enabling a 64-bit word to be read out of the module. We refer to this as a "single-rank" module. Sixteen components with a width of 8 bits each can be mounted to a PCB to form two, 64-bit-wide ranks, creating a "dual-rank" module.
What is an EBD (.ebd) file?
An EBD file is a model of a PCB used for simulations. This file describes the electrical characteristics of the pins and traces on the PCB. An EBD file used in conjunction with IBIS models of the DRAM, registers, and PLL can be used to create a model of a module.
What is an IBIS (.ibs) file?
An .ibs or IBIS file is a representation of a circuit meant to be read by a simulation application such as Cadence® Allegro® or HyperLynx®. IBIS (Input/output Buffer Information Specification) is an EIA (Electronic Industries Alliance) standard. IBIS is a text file in a specific format that represents the current versus voltage and voltage vs. time characteristics of the inputs and outputs of a circuit. IBIS models are the preferred files to provide to customers since the files do not contain any proprietary information about the internal makeup of the components. NDAs are not normally required for IBIS files.
What is the advantage of multiple banks within a component?
Memory controllers can begin an operation in one bank and perform a separate operation in a different bank while the first operation is completing. This interleaving increases the performance of the DRAM as a whole.
What is the difference between a "bank" and a "rank?"
Banks are specific to individual DRAM components and refer to sub-arrays within the DRAM component. Ranks are specific to memory modules and refer to a sub-array made of multiple DRAM components.
What makes up an IBIS model for a module?
The complete IBIS model for a module consists of several files:

1. The IBIS models of the DRAM used on that particular module
2. The IBIS models of the PLL, registers, and EEPROMs (as needed)
3. The IBIS model of the resistive parallel terminations on the PC
4. The EBD (electronic board description) file of the PCB. This file references the IBIS file of the terminations mentioned above.

Together, these files provide a complete representation of the PCB.
What trace lengths and termination values does Micron suggest I use on my memory interface?
Board designers often ask this question when they’re looking for a starting point for their CAD drawings or simulations. Because there are so many variables to consider, it is difficult to provide a "correct" answer. Clock speed, 1T or 2T timing, registered or unbuffered modules, and trace impedance are all important factors. Some controllers have on-die termination, some do not. Some controllers have two copies of the command and address bus. All of these factors can affect trace lengths and termination and can affect how acceptable signal integrity is achieved.

Micron technical notes TN-47-01, TN-47-20, and TN-46-14 can be used as a starting point, but trace length and termination must ultimately be proven by simulation and physical testing. Micron provides an online simulator for customers who do not have the expertise or resources to run simulations. The online simulator is on a secure section of Micron.com; visit the following URL to request access: www.micron.com/simulators.
Why are IBIS models for DRAM components regularly posted to micron.com but not IBIS models for modules?
We have found that it is more efficient to create module models as they are requested by our customers. If you are unable to locate the IBIS model for the module you are interested in, please e-mail your request to DRAM Support.
About Micron(4)
Elpida Acquisition(3)
General Information(5)
I currently do business with Elpida; has their employee contact information changed?

You can continue to reach your contact at the same phone number and office location. Your contact should provide you with their new Micron email address to use moving forward.

Will Elpida's company name change?

Effective Feb. 28, 2014, Elpida changed its name to Micron Memory Japan and Elpida Akita changed its name to Micron Akita, Inc.

Have Elpida sales offices or locations changed?

As we continue to integrate Elpida into Micron some of the sales office locations will change. Please contact your local sales representative for further details.

Where can I find out more information on the Micron/Elpida Transition?

Your sales representative is available to answer any questions you may have and will work closely with you to ensure that all issues are defined and resolved to the greatest degree possible. You can refer to the Micron/Elpida transition document for additional information.

I am interested in applying for a job with Micron (or the former Elpida); who do I contact?

Go to www.micron.com/jobs to apply for a job. Jobs at former Elpida sites can be found at newhire.micron.com.

For Customers(7)
I buy from both Micron and Elpida. Whom should I contact now?

Continue working with the same sales and customer service representatives as before. If changes are made to these contacts you will be notified immediately.

Where can I find Elpida product information?

Elpida product-related information has been integrated into www.micron.com. Use these helpful hints for identifying Elpida parts and navigating our expanded part catalogs:

  • All Elpida part numbers begin with the letter “E.”
  • Elpida parts appear at the beginning of the part catalog because part lists are sorted alphabetically based on the part number.
  • Part catalogs are sortable; use the filter at the top of the part catalog to narrow down part listings based on technology, density, or other features.
  • Refer to the Elpida part numbering guide for more information about deciphering Elpida part numbers.
Will there be new part numbers for the former Elpida product line?

The ordering part number will change to include the Package Media designator (Tape & Reel or Tray). A Product Change Notification was issued in December 2013. Please contact your sales representative if you have any additional questions.

Where do I get data sheets and product support information for Elpida products?

For Elpida part information, including access to Elpida-specific part catalogs and data sheets, visit micron.com/elpidaparts.

Will the marking and labeling of Elpida products change?

At this time, there are no plans to change the logo or part mark on Elpida branded products. If there are any changes, Micron will work to minimize any impact to our customers and will use appropriate channels to communicate those changes to our customers.

If I am in the process of qualifying a Micron/Elpida part, what should I do?

Continue any qualifications that are in progress, unless you hear otherwise from your account support team. If you have questions about support or what to qualify, please rely on your existing Micron or Elpida technical contacts for information.

I am currently buying Elpida products from a distributor; where do I go now for products?

Micron has made changes to the Micron Distribution network. For a complete list of authorized Micron distributors, reference the Micron Authorized Distributor list. Micron Authorized distributors will sell both Micron and Elpida products. If you have any questions or issues ordering products, please send an email to distribution@micron.com; and we will ensure that someone assists you. If over time, Micron decides to make further changes to its distribution network, we will work proactively with distribution and customers on their supply chain needs.

For Suppliers(3)
What will become of Elpida/Rexchip’s purchase orders, invoice & payment systems/processes?
  • Business systems migrate to Micron’s SAP Procurement environment.
  • The purchase order layout and numbering will change beginning in March 2014.
  • Replacement Micron purchase orders will be created for open Elpida/Rexchip purchase orders between Feb. 28, 2014 to March 7, 2014, and will reference the former Elpida/Rexchp purchase order number.
  • The bill-to address on Micron purchase orders may be different than previous Elpida/Rexchip addresses. A letter was distributed to Elpida/Rexchip suppliers the first week of February 2014 with the new legal entity and billing address.
What will become of Elpida’s agreements and contracts with its suppliers?

  • Third party agreements that are in effect for each of the Elpida legal entities will be assigned to Micron and/or ultimately terminated. Impacted suppliers will be contacted.
  • A core team of Micron and former Elpida team members are working to address these agreements. No change is anticipated however you may be contacted by Micron in the event an agreement is impacted.

I do business with both Micron and Elpida and/or Rexchip, what terms and conditions will we be using?

Micron’s terms and condition will be applicable to all purchases. Generally these are contained in a Purchase Order. For Micron Memory Japan, they are typically contained in a Master Purchase Agreement. However, if you have an existing signed agreement with Elpida, in general, the terms and conditions contained therein will continue to apply until such agreement is modified or its term ends.

Foundation(6)
Does Micron donate memory or equipment?
We do not currently have a mechanism in place to donate memory. On occasion we have semiconductor equipment available to donate to our university partners.
How do I apply for a community/K-12 grant?
Go to the "Community Grants" page to download the application and instructions.

Following the directions, submit all necessary forms and information to the Micron Foundation.

We cannot consider incomplete proposals or programs/projects that fall outside our primary funding areas.
How do I apply for a higher education grant?

Applications for Higher Education grants are by invitation only. To discuss an idea, contact Janine Rush-Byers at (208) 363-3675.

How do I qualify for a community or K-12 grant?
You must be located in a manufacturing site community: U.S. organizations must be located near Boise, ID; organizations near Micron's Manassass, VA; International organizations must be located near Singapore or Avezanno, Italy.

Please contact the Micron Foundation if you are uncertain of your eligibility.

You must show proof of your non-profit status. A completed application must be submitted. See the below section. Priority is given to those programs geared specifically at advancing science, math, and technology.
How does my university get involved?
Schools can participate in these programs at a variety of levels from individual projects to strategic partnerships with multiple levels of involvement. A school's participation is based on the level of fit and mutual interest between Micron and the interested departments at each university.

To explore potential participation for your department, contact Micron's University Relations Manager at university_relations@micron.com.
Who do I contact to discuss a grant idea?
Local Community and K-12 grants, contact Kami Faylor (208) 363-3675

Higher Education grants, contact Janine Rush-Byers (208) 363-3675
Green Engineering(10)
Are Micron’s Pb-free products RoHS-compliant? What does 5/6 RoHS mean?

Yes. Directive 2011/65/EU (replacing the Directive 2002/95/EC), Restriction of the use of certain Hazardous Substances in Electrical and Electronic Equipment (RoHS), does impact Micron's semiconductor products. The purpose of this directive is to restrict the use of certain hazardous substances in electrical and electronic equipment and protect human health and the environment. Micron’s products have always been 5/6 RoHS compliant, meaning they contain Pb solder, but otherwise comply with RoHS regulations (they meet five of six stipulations). Micron’s Pb-free products are completely RoHS compliant.

Micron's RoHS compliant module level products do contain electronic parts that may use Pb for applications exempt from Directive 2011/65/EU (see Article 4, Annex 3). Please contact your sales/marketing representative for more information.

The European Commission FAQ sheet distributed under the Directorate-General Environment may serve as a formal (but not legally binding) point of reference.

Do Micron’s Pb-free products comply with China RoHS reporting requirements? Does Micron label its products with the Environmental Protection Use Period?

Micron’s Pb-free component, die, and wafer-level products do not contain any of the six substances restricted by the China RoHS. Micron’s modules may contain Pb in both not exempted and exempted EU RoHS applications (where not reliable Pb-free alternatives are available in the market).

Micron’s products are not sold directly to consumers. The EPUP and other marking and labeling requirements apply only to the products sold directly on the consumer market. For more information contact your sales/marketing representative.

*These substances are not intentionally added by Micron during the manufacturing process but can be present in trace amounts in the raw materials used to manufacture the finished products.

 

Is Micron aware of REACh requirements?

Micron is fully aware of product requirements coming from Regulation 2006/1907/EC, Registration, Evaluation Authorization and Restriction of Chemicals. Micron constantly monitors new additions to the Candidate List and timely verifies if any Substance of Very High Concern is used in the manufacturing processes and the potential impact on the final products. Micron is committed to provide our customers with information about substances in its products as required.

For any documentation need, please contact your sales representative.

How does Micron define green products?
In addition to being RoHS compliant, Micron's Green packages do not contain substances that have been identified as harmful to the environment or known to pose serious reliability: bromine, chlorine, antimony containing substances, and inorganic red phosphorus. These substances are not intentionally added to packaging materials such as encapsulants, die attach materials, underfill epoxies, and substrates. The maximum trace amounts of these substances allowable in Micron’s green packages are listed below.

<900 ppm Chlorine
<900 ppm Bromine
<1500 ppm Chlorine & Bromine
<900 ppm Antimony
<100 ppm Red Phosphorus

Please note that while our Pb-free and green products do not contain any intentionally added Pb, our Pb-free parts are not necessarily green, since they may contain halogen or antimony compounds.

*These substances are not intentionally added by Micron during the manufacturing process but can be present in trace amounts in the raw materials used to manufacture the finished products.
Does Micron still make parts that comply with RoHS 5/6 standards?

Yes, along with our Pb-free product line, Micron also supports RoHS 5/6 products. We recognize that certain applications are exempt from the RoHS directive.

Where can I find Micron's green and RoHS products part numbers?

Micron’s full line of RoHS compliant memory products can be found in the part list tables for each product type. To perform a quick compliance check on a single part number, use the "Part Number Search" tool. For information on green products, please contact your local Micron sales representative.

How do I get Micron's RoHS certificate of compliance?

You can find a part-specific RoHS Certificate of Compliance by navigating to the part detail page or using the main products family navigation.                       

How do Micron’s green products comply with international standards?
Micron’s green engineering program is RoHS-compliant and conforms with most of the world’s emerging environmental standards, including those in Asia and Europe.
What materials does Micron use in its Pb-free semiconductors?
  • For solder balls, Micron is replacing tin-lead alloys (Sn36Pb2Ag or Sn37Pb ) with a tin (Sn), silver (Ag), and copper (Cu) alloys (e.g., SAC105, SAC305, SAC405, LF35).
  • For solder paste on modules, Micron is replacing Sn37Pb with Sn3.8Ag0.7Cu.
  • For leaded TSOP, Micron is replacing 90Sn10Pb with matte Sn plating.

These substitutions ensure Micron’s Pb-free parts are RoHS-compliant. Parts are certified for a surface mount temperature of 260°C.

When will Micron complete its transition from Pb-free to green products?
Micron can currently provide Pb-free and green product to customers who require it. The availability of these products is highly dependent on customer demand, as well as on the availability of "green" non-memory components and materials.

Please contact your local Micron sales representative for more information (look up regional sales representatives on the How To Buy page).
ISO 14001(5)
Is Micron ISO 14001 Certified?
In February of 1997, Micron Technology, Inc., was one of the first companies in the United States to attain certification under the new ISO 14001 Environmental Management Systems Standard. Micron was selected by KEMA Registered Quality, Inc., to be a pilot participant in the ANSI-RAB National Accreditation Program and is one of five U.S. pilot companies who participated in this program.
What are the Basic Elements of Certification?
Certification under ISO 14001 requires conformance with four basic elements:
  • implementation of an environmental management system
  • assurance that procedures are in place to maintain compliance with applicable regulations
  • commitment to continual improvement
  • commitment to overall prevention of pollution
What is ISO 14001?

ISO 14001 are voluntary international environmental management standards, which ensure that organizations have effective environmental systems. It is the environmental equivalent to the ISO 9000 quality standards. Various countries and companies have implemented the ISO 9000 quality standards worldwide.

Who Certified Micron?
In the ISO 14000 process, a company's environmental management systems are audited by third party registrars. Micron was audited by KEMA Registered Quality, Inc. KEMA is a worldwide full-service third party registrar accredited to ISO 9000, QS9000, and ISO 14001 by ANSI-RAB and RvA, as well as being a "Notified Body" for several areas of CE marketing, mandatory product certification of the European Union. KEMA's clients number in the thousands worldwide and include a wide variety of product and service industries. KEMA specializes in the electronics, information technology, and high technology manufacturing areas.
Why Did Micron Become Certified?
Micron has a very proactive approach to environmental compliance and protection that serves our employees, our customers, and the communities in which we operate. We are proud of both our environmental and worker safety programs. We view compliance to minimum regulations, as a baseline and work to always be better than the minimum regulations require. ISO 14001 is a good fit with our company and culture. The primary force behind the development of standards for environmental management has been the desire for environmental stewardship and accountability. ISO 14001 embodies an approach, which looks beyond regulatory compliance and challenges an organization to take stock of its environmental programs, continually improve, and commit itself to effective processes and pollution prevention. Micron already had most of the elements needed to conform to ISO 14001 in place. We saw this as an opportunity to be recognized for our commitment, level of effort, and record of accomplishments.
Other(3)
General Product(6)
Does thermal information change for IT parts?
Thermal information includes temperature limits and thermal impedance values. Temperature limits do change for IT parts (TC, TJ, and TA), but thermal impedance values (θJA, θJB, and θJC) do not because thermal impedance depends primarily on the package.
My design was based on a specification stating the JTAG was relative to VDD (1.8V), but now we’ve discovered that JTAG is actually relative to VDDQ (1.5V). It’s a fairly significant board spin to change this; what do I risk by leaving the design as-is? I assume that the specification is still for VDDQ + 0.3V = 1.8V, but with CMOS parts there’s no way I can guarantee that it won’t swing past that on transitions.
Your particular board design should not be a cause of major concern. The pins can handle the VDD voltage regardless of the VDDQ voltage.
Should the ECC memory chip share chip select and CKE signals with the other two main memory chips in our point-to-point application?
The ECC chip(s) should share the same CKE and CS# as the other devices because they are accessed as the same piece of data.
What is a "bank"?
A bank is an array of memory bits. Multiple arrays or banks are contained within a DRAM component. Depending on density, DRAM components may consist of 4 or 8 banks. For example, a bank may consist of 32 million rows, 4 bits across. This would equate to 128 megabits. Four of these banks in a single DRAM component would yield a 512Mb component.
What is the impedance tolerance of the driver in match-impedance mode relative to the expected value base on the perfect reference resistor connected to ZQ pin?
The impedance tolerance of the driver is ±15 percent.
Who do I contact if I have questions about my buymicron.com order?
If you have any questions about your order, contact buymicron.com.
Micron.com
Why Create a Profile?
A Micron profile is required for:
• Seamless, maximized access to micron.com
• Email alerts based on your product and application interests
• Access to secure product information and technical resources
• Advance notice of new features and tools on micron.com
How do I create a micron.com profile?

To register for a micron.com account, click the "Login/Sign Up" link in the header bar on any micron.com page.


1. Under the Login information, click "Sign Up Now"
2. Type your current email address in the Email Address and Confirm email fields.
3. Click Submit. The Create a new Account page displays.
4. Complete the required fields (designated with an asterisk) and click Submit. The email Verification Pending notification page displays. Instructions to verify your email address will be sent to the email address you used to create your micron.com profile.
5. From the body of your confirmation email, click the link provided. The My Micron Account Creation Complete page displays, notifying you that your micron.com registration is complete. The page will redirect you to the My Micron login page.


Note: If you have trouble, turn off any spam-blocking software and try the form again. Spam-blockers can sometimes mistakenly block the confirmation email message.

Password Tips
• Use only lowercase alphanumeric characters
• Use a minimum of six (6) characters, but no more than sixteen (16)
• Don't use special characters, such as *, &, %, ¢, >, @
• Don't use spaces, punctuation, or non-English characters

How do I find my secure site and documents?
Any documents or secure web sites that you have access to are still available on your "My Micron" site.
How do I request a secure document?
Micron offers a number of secure documents. The security status of these documents is denoted by a padlock icon. So, if you navigate to a part that has a secure document, simply click on the document link to begin the process of requesting permission to download that file. Note that if you don’t already have a Micron profile, you will be prompted to create one. From there please follow the account creation and validation steps to gain permission to the document.
ONFI(4)
Are your NAND parts ONFI-compliant?
All our 50-series NAND devices and beyond are ONFI-compliant.
How will ONFI help speed time-to-market for NAND-based products?
ONFI improves time-to-market in two principal ways: 

1. It simplifies the design of Flash controllers that support a range of components by improving uniformity in the behavior of the interface to the NAND components. 

2. It reduces the design time of Flash components in end-use applications and enables the use of a new generation of NAND components without design or firmware changes.

What is ONFI?
ONFI stands for Open NAND Flash Interface. ONFI is an industry working group that is dedicated to simplifying the integration of NAND Flash memory into consumer electronic products, computing platforms, and various other applications that require solid state mass storage. The ONFI working group defines standardized component-level interface specifications for NAND Flash. ONFI is also defining module connector and module form factor specifications (similar to DRAM DIMMs) for NAND Flash. For more information, visit www.onfi.org.
What types of products will ONFI 2.1 be seen in first?
ONFI improves the embedded integration of Flash components into a range of products, including many that use Flash today, such as mobile phones, PDAs, MP3 players, and notebooks. It’s likely, however, that the benefits of ONFI 2.1 will first be realized in PC platforms. Because of the significantly faster speeds that ONFI 2.1 delivers, SSDs and caching solutions will be able to deliver substantive benefits for PC platform workloads.