4Kbit serial EEPROM for calibration and configuration storage
The Microchip 93C66B-I/P is a 4Kbit serial EEPROM organized as 256 x 16 bits, communicating over a Microwire bus at up to 2 MHz.
Industrial temperature range and 5V-only operation
The 4.5V minimum supply means it cannot run from a 3.3V rail without a level translator — if your BOM is mixed-voltage, budget a 5V supply or a separate regulator for the EEPROM bus. The Microwire interface uses chip select (CS), serial clock (SK), and data in/out (DI/DO) lines; the 2 MHz clock rate gives about 250 kbytes/s read throughput, adequate for storing calibration tables, serial numbers, or boot configuration words.