by Anton Shilov
12/17/2013 | 11:37 PM
While the LPDDR4 standard remains on-track to be finalized in 2014, its adoption by mainstream devices will unlikely be too fast, given the traditionally high initial price and limited production. However, premium devices will likely jump on the LPDDR4 bandwagon relatively rapidly thanks to its high performance, which is up to two times higher compared to LPDDR3, amid 50% lower power consumption.
At present JEDEC is discussing LPDDR4 standard that includes 3200Mb/s data rate (3.2GHz effective clock-speed), 350mVpp max signaling with configurable termination using low-voltage swing terminated logic as well as 1.1V voltage. In addition, data bus inversion has been added to improve signal integrity. Perhaps, one of the main changes of LPDDR4 over previous-generation standards is that LPDDR4 memory die will architecturally be two-channel x16 DRAM.
"The challenge is how to achieve that energy reduction at 3200Mb/s, and the sub-committee had to look at architectural, signaling and voltage changes. […] The objective is to improve timing closure, as well as reducing internal DRAM die power,” said Hung Vuong, chairman of JEDEC's JC-42.6 subcommittee for low power memories, in a conversation with EETimes-India.
Recently JEDEC updated its LPDDR3 standard to support 2133Mb/s data rate. At present DRAM manufacturers are looking forward to extend LPDDR4 data rate to 4266Mb/s.
"Our goal was to double the bandwidth performance, but also we took a much harder look at the power usage. […] Once [desired] performance level is reached, then doing so at the best power point is the top priority " said Dan Skinner, director of architecture development at Micron Technology and a JC-42.6 Subcommittee member.
LPDDR memory is used mainly for smartphones, media tablets and various other portable devices. In fact, even the latest Apple MacBook Air also uses LPDDR3 memory to boost battery life. Since modern smartphones and slates are hungry for memory bandwidth (due to increasing performance of graphics processing units inside mobile gadgets), new LPDDR memory types with higher frequencies are likely be welcome by the market, especially by its premium part. Still, it will take several years for mainstream devices to fully adopt LPDDR4; for example, even today, about two years after finalization of LPDDR3, the majority of mobile devices use LPDDR2.