Tech bytes for tea?

We frequently see DDR SDRAMs as a key specification of computers and digital devices. In this two-part guest commentary, Ben Miller from Keysight Technologies shares his insights into the design of DDR SDRAMs (Part 1) and how faster memory speeds shape the future (Part 2).

DDR SDRAM is a building block of many digital devices. Photo by Jeremy Bezanger on Unsplash.

Faster data processing requires faster memory.

Double data rate synchronous dynamic random-access memory (DDR SDRAM) enables the world’s computers to work with the data in memory.

Faster, not wider

Since the origins of SDRAM, engineers have faced challenges with increasing memory speeds.

Figure 1: DDR has both one-way control signals and bidirectional data buses. Click to enlarge.

DDR emerged as a faster, more efficient way to handle memory, while providing a universal standard between chip designers and device manufacturers.

As shown in Figure 1, DDR memory consists of a memory controller which transmits clock, address and control signals, and a series of DRAM chips which store the data.

In a write operation, the controller sends data and strobe signals to the DRAM; in a read operation, the DRAM sends data and strobe signals back over the same bi-directional line.

DDR SDRAM became the standard in the late 1990s and has since been improved upon many times over.

Prior to DDR, memory speeds maxed out in the range of 100 MT/s.

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