The Cypress FM24C04B-GTR is a 4Kbit Ferroelectric RAM (FRAM) from the F-RAM series — a non-volatile memory that combines the fast write speed and low power of SRAM with the data retention of EEPROM. Organized as 512 x 8 bits and accessed through an I2C interface at up to 1 MHz, it delivers a 550 ns access time with no write-cycle delay.
5V rail and I2C bus — what the specs mean for your BOM
The 4.5V–5.5V supply range ties this part to legacy 5V domains. If your design runs on 3.3V I2C, the low-voltage sibling FM24CL04B-G (2.7V–3.6V) is the drop-in substitute — same 4Kbit density, same 8-SOIC footprint, same 1 MHz bus rate. That matters for high-frequency data logging where an EEPROM would stall for the write cycle.
The FM24C04B-GTR is supplied in an 8-pin SOIC (3.90 mm body width) on Tape & Reel — the -GTR suffix. The base part FM24C04B-G ships in Tube; same die, same electricals, just a different output medium for pick-and-place lines. Cypress lists the product status as Active and ROHS3 compliant, so no end-of-life clock is ticking. The 8-SOIC footprint is shared across the entire 4Kbit and 64Kbit F-RAM family, meaning a density upgrade to the FM24CL64B-GTR (64Kbit, I2C, same package) requires no board layout change.