A 0.65-V, 500-MHz Integrated Dynamic and Static RAM for Error Tolerant Applications

The diminishing returns provided by voltage scaling have led to a recent paradigm shift toward so-called “approximate computing,” where computation accuracy is traded off for cost in error-tolerant applications. In this paper, a novel approach to achieving the power-performance-area versus data integrity tradeoff is proposed by integrating robust static memory cells and error-prone dynamic cells within a single array. In addition, the resulting integrated dynamic and static random access memory (iD-SRAM) provides the ability to trade off power consumption and accuracy on-the-fly according to the current conditions and operating mode. A 4-kB iD-SRAM array was implemented in a low-power, 65-nm CMOS technology, providing as much as an 80% power reduction and a 20% area reduction as compared with standard approaches, when applied to a video decoder at 500 MHz.