2.2 DDR Memory

Modern system designs are increasingly complex and often require greater memory capacity to support high-performance buffers and local data storage. While small amounts of storage can be implemented on-chip using logic resources, larger storage requirements are best addressed with external memory devices.

DDR3 is a widely adopted high-speed dynamic memory solution for storing substantial amounts of data in computing and FPGA-based systems. DDR3 operates at 1.5V, while DDR3L (a low-voltage variant) operates at 1.35V, and both require a VTT termination voltage to ensure stable data transfer. Compared to its predecessor DDR2, DDR3 offers higher bandwidth and lower power consumption. Current consumption for DDR3 can range from a few milliamps to as much as 3A, depending on operating frequency and data load. This makes DDR3 particularly suitable for applications such as video processing, artificial intelligence, and networking, where real-time data access is critical.

To ensure reliable operation with DDR3 modules, FPGA controllers must implement proper timing and memory calibration. It is important to note that each DDR memory type (see Table 2-1) has its own set of specifications and voltage requirements, and some may require multiple voltage rails. Careful consideration of these requirements is essential for successful integration and optimal system performance.