DESCRIPTION
The Xicor X25401 is a serial 256 bit NOVRAM featuring a static RAM configured 16 x 16, overlaid bit-by-bit with a nonvolatile E2PROM array. The X25401 features a Serial Peripheral Interface (SPI) and software protocol allowing operation on a simple three-wire bus. The bus signals are a clock input (SCK) plus separate data in (SI) and data out (SO) lines. Access to the device is controlled through a chip select (CS) input, allowing any number of devices to share the same bus.

FEATURES
• 1MHz Clock Rate
• AUTOSTORE™ NOVRAM
    —Automatically Performs a Store Operation Upon Loss of VCC
• Single 5 Volt Supply
• Ideal for use with Single Chip Microcomputers
    —Minimum I/O Interface
    —SPI Mode (0,0 & 1,1) Serial Port Compatible
    —Easily Interfaced to Microcontroller Ports
• Software and Hardware Control of Nonvolatile Functions
• Auto Recall on Power-Up
• TTL and CMOS Compatible
• Low Power Dissipation
    —Active Current: 10mA
    —Standby Current: 50µA
• 8-Lead PDIP and 8-Lead SOIC Packages
• High Reliability
    —Store Cycles: 1,000,000
    —Data Retention: 100 Years