2 Mbit FRAM with SPI — what it does on the board
The FM25V20-GTR is a 2 Mbit non-volatile FRAM organized as 256K x 8 bits, accessed over an SPI bus at up to 40 MHz. FRAM writes at bus speed with no write-cycle delay — unlike serial EEPROM or NOR flash, there is no page buffer or erase-before-write penalty. For a data logger writing 32-byte records every 100 ms, the FRAM's write endurance of 10^14 cycles means the memory outlasts the rest of the board.
Infineon lists the FM25V20-GTR as obsolete. Quantities are lot-specific and confirmed at RFQ — no stock-holding claim, sourced per order.
The footprint is standard for 150-mil SOIC — no special pad geometry needed. The SPI interface uses four signals (CS, SCK, SI, SO) plus VDD and VSS — a four-layer board is not required; two-layer breakouts work at 40 MHz with proper ground plane under the package.