2Kbit serial EEPROM with Microwire — calibration and parameter storage
The ROHM BR93G56F-3BGTE2 is a 2Kbit serial EEPROM organized as 128 x 16 bits, accessed through a Microwire (3-wire) interface at up to 3 MHz. It stores configuration parameters, calibration constants, or small lookup tables in a non-volatile memory that retains data without power. The wide supply range from 1.7V to 5.5V lets it operate on a 1.8V, 3.3V, or 5V rail without a separate level translator, simplifying the power architecture on mixed-voltage boards. Write endurance and data retention are typical for a serial EEPROM — the 5ms write cycle time per word or page means the host must wait for the write-complete polling or a timed delay before the next access.
3 MHz Microwire — bus timing and throughput
The 3 MHz clock rate on the Microwire bus gives a raw bit time of 333 ns. For a 16-bit read or write command plus data, the total transfer takes roughly 5–6 µs before the 5ms write cycle begins. That write cycle is the throughput bottleneck — the interface speed matters more for read-back or status polling than for bulk writes. At 3 MHz the bus timing is compatible with most SPI-capable microcontrollers running at 8 MHz or higher, though the Microwire protocol (start bit, opcode, address, data) differs slightly from standard SPI. Check the host's SPI peripheral for Microwire mode support or bit-bang the sequence on GPIOs.
The 1.7V minimum supply ensures operation during battery discharge or brownout conditions in portable equipment. The 5.5V maximum allows direct connection to legacy 5V logic without a regulator on the memory rail.
ROHM lists the BR93G56F-3BGTE2 as Active (current production). The part is ROHS3 compliant.