The Hitachi HM628512B is a 4-Mbit static RAM organized 512-kword x 8-bit. It realizes higher density, higher performance and low power consumption by employing 0.35 m Hi-CMOS process technology. The device, packaged in a 525-mil SOP (foot print pitch width) or 400-mil TSOP TYPE II or 600-mil plastic DIP, is available for high density mounting. The HM628512B is suitable for battery backup system.