JEDEC Solid State Technology Association has updated the standards for LPDDR3 And LPDDR4 mobile memory, offering enhanced performance capabilities for mobile computing devices such as smartphones, tablets, and ultra-thin notebooks.
JEDEC released the JESD209-4A, Low Power Double Data Rate 4 (LPDDR4) and JESD209-3C Low Power Double Data Rate 3 SDRAM (LPDDR3).
The latest revision adds skew definitions between dies on the channel (rank to rank parameters such as tDQS2DQ_rank2rank and tDQSCK_rank2rank). These definitions address DRAM process variation and allow the SoC to better manage DRAM timing with less complexity. JESD209-4A also adds new eMCP (embedded multi-chip packages) and provides key errata missing from the original standard.
Still widely used in array of mobile products, this latest update to LPDDR3 offers new package configurations:
- 136-ball PoP (eMMC + LPDDR3)
- 272-ball dual-Channel POP
- 221-ball single channel MCP
In addition, lower DRAM densities addressing has been added and a "refresh multiplier" parameter (tREFIM = RM x tREFI) was also introduced.