Calculating Memory System Power for DDR SDRAM

This Issue: Today’s system designer is concerned about the power used by the main memory in the system. Whether it is calculating battery life for a portable application, planning cooling for a “pizza box” desktop, or determining the power supply for a server, an accurate power budget for the memory is essential. Unfortunately, DRAM data sheets do not always make it easy to determine how much power is used by each device in a specific application. Double data rate (DDR) SDRAM allows for lower power consumption than other memory solutions. This article explains how power is used by DDR SDRAM and provides some basic tools to help calculate the system power that is consumed by the DRAM. These tools can be adapted to fit a wide range of applications and even help identify simple methods for modifying a system to use less power without significantly affecting the system’s performance. After all, a high-performance system will disappoint if it overheats or the battery life fails to meet end users’ expectations. Calculating Memory System Power for DDR SDRAM