The DS1230W 3.3V 256k NV SRAM is a 262,144-bit, fully static, nonvolatile SRAM organized as 32,768 words by 8 bits. Each NV SRAM has a self-contained lithium energy source and control circuitry, which constantly monitors V_CC for an out-of-tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent data corruption. DIP-package DS1230W devices can be used in place of existing 32k x 8 static RAMs directly conforming to the popular bytewide 28-pin DIP standard. The DIP devices also match the pinout of 28256 EEPROMs, allowing direct substitution while enhancing performance. DS1230W devices in the PowerCap Module package are directly surface mountable and are normally paired with a DS9034PC PowerCap to form a complete Nonvolatile SRAM Module. There is no limit on the number of write cycles that can be executed and no additional support circuitry is required for microprocessor interfacing.