The document describes the features and characteristics of the CAT25010/20/40 SPI Serial CMOS EEPROM produced by Catalyst Semiconductor. The product is compatible with 10MHz SPI, operates at a voltage range of 1.8 to 5.5 volts, supports SPI modes 00 and 11, features a 16-byte page write buffer, self-timed write cycle, hardware and software protection, block write protection, low power CMOS technology, 1,000,000 program/erase cycles, 100 year data retention, and is suitable for industrial temperature range.