X25401

• 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: 50mA
• 8-Lead PDIP and 8-Lead SOIC Packages
• High Reliability
   -Store Cycles: 1,000,000
   -Data Retention: 100 Years

Temperature under Bias ................... 65 to +135
Storage Temperature ....................... 65 to +150
Voltage on any Pin with
Respect to V_SS ........................................ 1V to +7V
D.C. Output Current ...........................................5mA
Lead Temperature
(Soldering, 10 seconds) ................................... 300

Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device.

This is a stress rating only and the functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

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.

The X25401 design allows data to be transferred between the two memory arrays by means of software commands or external hardware inputs. A store operation (RAM data to E2PROM) is completed in 5ms or less and a recall operation (E2PROM data to RAM) is completed in 2ms or less.

The X25401 also includes the AUTOSTORE feature, a user selectable feature that automatically performs a store operation when V_CC falls below a preset threshold.

X25401 is designed for unlimited write operations to RAM, either from the host or recalls from E2PROM and a minimum 1,000,000 store operations. Inherent data retention is specified to be greater than 100 years.