General Description
The FM25C040U is a 4K (4,096) bit serial interface CMOS EEPROM (Electrically Erasable Programmable Read-Only Memory). This device fully conforms to the SPI 4-wire protocol which uses Chip Select (/CS), Clock (SCK), Data-in (SI) and Data out (SO) pins to synchronously control data transfer between the SPI microcontroller and the EEPROM. In addition, the serial interface allows a minimal pin count, packaging designed to simplify PC board layout requirements and offers the designer a variety of low voltage and low power options.

FEATUREs
■Sequential read of entire array
■4 byte "Page write" mode to minimize total write time per byte
■/WP pin and BLOCK WRITE protection to prevent inadvert ent programming as well as programming ENABLE and DISABLE opcodes.
■/HOLD pin to suspend data transfer
■Typical 1µA standby current (ISB) for "L" devices and 0.1µA standby current for "LZ" devices.
■Endurance: Up to 1,000,000 data changes
■Data retention greater than 40 years

Functions
■SPI MODE 0 interface
■4,096 bits organized as 512 x 8
■Extended 2.7V to 5.5V operating voltage
■2.1 MHz operation @ 4.5V - 5.5V
■Self-timed programming cycle
■"Programming complete" indicated by STATUS REGISTER polling
■/WP pin and BLOCK WRITE protection