This document describes the M40Z300W product from STMicroelectronics, Inc., which can be used to turn SRAM devices into non-volatile RAM (NVRAM). When the supply voltage falls below the preset threshold level, the device write protects the RAM, switches to its internal battery supply, and asserts the reset line. The document also explains the configuration of using two 128K x 8 SRAMs to form a 128K x 16 arrangement.