Microchip’s 93AA66B/93C66B/93LC66B family of devices are 4 Kbit Microwire Serial EEPROMs available in a variety of package, temperature and power supply variants.

16-bit x 256 Organisation
Self-Timed Erase/Write Cycles (including Auto-Erase)
Automatic Erase All (ERAL) Before Write All (WRAL)
Power-On/Off Data Protection Circuitry
Industry Standard 3-Wire Serial I/O
Device Status Signal (Ready/Busy)
Sequential Read Function
1,000,000 Erase/Write Cycles
Data Retention >200 Years

EEPROM Serial Access - Microchip