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XCELLENCE IN MEMORY

DDR4 is the last of the the popular DDR line of memories that 90 percent of Xilinx customers use. Multiple contenders are vying for a chunk of that market share.

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seismic shift is shaking up the memory landscape. The cause for this shift is the fact that the line of incredibly popular DDR memories, a fundamental buffer used by 90 percent of Xilinx customers (Figure 1), will end with DDR4. This is not cause for immediate panic— DDR3 has a comfortable address on the majority of system boards and DDR4, though ramping slowly, will replace some of those sockets and serve them for years to come. Still, with the knowledge that DDR4 has no natural successor, customers are eyeing the next crop of memories and mulling over trade-offs such as bandwidth, capacity or power reductions. The likely successor is LPDDR3/4, with certain application spaces preferring serial DRAM solutions such as Hybrid Memory Cube (HMC). To get a handle on these important changes in memories, let’s look first at market trends that are affecting these devices and the limitations that are forcing the end of the DDR empire. Then let’s consider the new class of DDR alternatives, from LPDDR to serial memory, a new concept about which designers will want to stay informed. CHANGING MARKET TRENDS Usually when customers are designing for their next generation of products, they look to the next generation of the same memory to give more capacity, speed and throughput. In this regard, Figure 2 shows the current and projected DRAM market share trends. DDR3 enjoys almost 70 percent of the total DRAM market today. Its rise to dominance was assured in the steep 40 percent uptick in adoption between 2009 and 2010. DDR4 has been slower in adoption, partly because of the incursions of Mobile DRAM, also known as LPDDR. DDR4 simply doesn’t have as many sockets to claim if LPDDR is meeting the needs of the wireless market. Looking at the graph, DDR4 is indeed picking up momentum, because it does have advantages—namely, a lower supply voltage, which saves power, and higher speed. So it will eventually take over for DDR3 in almost every market, eventually driven by the PC space. Despite the fact that PCs no longer drive >70 percent of DRAM consumption, they

Third Quarter 2014

Xcell Journal

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Xcell journal issue 88  

Xcell Journal issue 88’s cover story takes a financial look at how the Zynq®-7000 All Programmable SoC is far better suited than ASICs and A...