To offer some additional insight on today’s LPDDR2 announcement and trends in the mobile market, we sat down with Eric Spanneut, Micron’s director of mobile memory marketing.
Micron today announced a 2Gb monolithic LPDDR2 part, which would enable 8Gb packages for smart phones and tablet PCs. Are we really starting to see mobile applications that need this level of performance and DRAM density? How do they make use of it?
There are a lot of designs that need up to 4Gb LPDRAM this year, and we’re also seeing some designs in the tablet PC market that will need up to 8Gb, although the demand for this density is still pretty small. The fundamental drivers for higher density are multimedia applications and OS requirements. We also see a similar movement happening on the processor side with these vendors upgrading their chipsets and expressing a need for higher density LPDRAM, and NAND as well.
Why would they choose LPDDR2 over LPDDR1?
There are several reasons. First, it’s performance. LPDDR2 uses a faster interface and has better bandwidth. Second, LPDDR2 also has a better power profile with low voltage power supplies as well as enhancements to standby operations and Partial-Array Self Refresh modes, which provide further opportunities for additional power reduction. Third, LPDDR2 offers pin count reduction. Finally, the LPDDR2 standard allows for higher density components without an increase in pin-count.
Why is pin count reduction important?
On the processor side, you are pad-limited. You have the LPDRAM interface, NAND interface, USB interface, Bluetooth, etc. If the LPDRAM uses fewer pins, it lets the processor allocate these pins to other applications. Our LPDDR2 does this by multiplexing—the same pins can handle command and address.
Can you talk a little about why Micron’s LPDDR2 will be valuable to those in the ARM community? What sort of work is Micron doing with ARM?
ARM is the leader of core IP for the handset space, so naturally we work with them to do memory validation. This is an “upstream” effort where we show ARM what we’re intending to do with future memory. It’s good for ARM, because it allows them to develop their IP based on our memory recommendations and simulations. And it’s good for Micron as it provides us with some useful input on where the processor development is going and allows us to fine tune our portfolio to match that. Being validated with ARM also makes it much easier to validate our memory with the actual processors themselves. It’s not a 1:1 transfer of the work, but it does make the integration into customer products much easier.
Tablets have been getting a lot of attention lately. Would these products use LPDDR2 as well? Many netbooks use standard computing architectures—how do you see tablets shifting the mobile computing landscape?
We’re seeing that there will be entrants from two primary directions: shrunk-down Intel-based laptop platforms using mostly DDR2 or DDR3 and scaled up ARM-based handset platforms, which would mostly use LPDDR2. Choices of memories will be dictated by the price point targets, the feature requirements, and sensitivity to power consumption.
You mentioned in the LPDDR2 announcement that you were also developing versions of this technology for value-line handsets. When do you see this being adopted, and what will it mean to users?
Yes, we see LPDDR2 spreading from high-performance applications to gain share throughout the mobile space, crossing over with LPDDR1 at some time in 2012. The reason we think this will get traction is because LPDDR2 can be combined with a new generation of NOR and use a single bus. This means, again, a pin count reduction. In the low end, handset designers are really fighting for pennies of margin wherever they can. A pin count reduction allows the processor to be shrunk, which reduces the cost. These products would be offered in a LPDDR2/NOR multi-chip package, which will enable a more cost-effective system solution.