Small serial EEPROM for configuration and calibration storage
The STMicroelectronics M24C04-FMC6TG is a 4Kbit serial EEPROM organized as 512 x 8 bits, accessed through an I²C bus at up to 400 kHz. The wide supply range from 1.7V to 5.5V lets it operate on both 3.3V and legacy 5V buses without a level shifter.
The 5 ms write cycle time (word or page) is the period after a stop condition during which the part internally programs the EEPROM cells; the bus is busy during this window, so the host must either poll the acknowledge polling sequence or insert a 5 ms delay before the next write. At 400 kHz, a page write of up to 16 bytes takes roughly 400 µs of bus time plus the 5 ms internal write, so budget about 6 ms per page update.
Package and rework — 8-UFDFN with exposed pad
The 8-UFDFN (2 mm x 3 mm) package with exposed pad is a small, low-profile option for space-constrained boards. Rework is doable with hot air — the pad is small enough that the part lifts cleanly at 300°C with a fine nozzle, but the orientation mark (pin 1 dot) is tiny, so mark the board silkscreen clearly.
The 1.7V minimum supply ensures operation down to battery-end-of-life levels in portable gear.