Automotive-grade 4Kbit EEPROM for harsh environments
The ROHM BR93H66RFVM-WCTR is a 4Kbit serial EEPROM organized as 256 x 16 bits, using the Microwire interface at a 1.25 MHz clock rate. The supply voltage spans 2.7V to 5.5V, so it works on both 3.3V and 5V rails without a level translator.
Microwire interface and write timing
The Microwire interface is a three-wire serial bus (SI, SO, SK) with a chip-select line — simpler than SPI but limited to a single master. The 256 x 16 organization means each write handles 16 bits at a time; there's no byte-level granularity, so firmware needs to manage the 16-bit word alignment.
Housed in an 8-MSOP (2.80 mm width) surface-mount package, the BR93H66RFVM-WCTR fits a compact PCB footprint. The MSOP-8 body is common for serial EEPROMs.
It is ROHS3 Compliant, which keeps it usable for European and global production lines without exemption paperwork. The AEC-Q100 qualification is the main sourcing gate for automotive Tier-1 buyers: if your BOM calls for an automotive-grade serial EEPROM in this density, this part checks that box without requiring a separate PPAP document from the distributor.