64 Mbit SPI Quad I/O FLASH in a low-voltage 8-WDFN package
The SST26WF064C-104I/MF is a 64 Mbit serial FLASH from Microchip's SST26 SQI® family, organised as 8M x 8 and accessed through an SPI Quad I/O interface running up to 104 MHz.
Clock rate and interface — what 104 MHz Quad I/O means for throughput
At 104 MHz in Quad I/O mode, the read throughput reaches roughly 52 MB/s (104 MHz × 4 bits) — enough to shadow code or boot an MCU directly from the flash without a separate RAM copy for moderate-density firmware. The 1.5 ms typical page write time sets the floor for firmware-update cycles: writing a full 64 Mbit at 256-byte pages takes about 48 seconds, plus erase overhead, so an OTA update strategy should budget for that window. The SPI interface supports standard, dual, and quad I/O commands — the quad mode requires four data lines (IO0-IO3) plus the chip select and clock, which ties up six GPIOs on the host controller.
Temperature grade and deployment context
The non-volatile FLASH technology retains data across power cycles — no battery backup needed for configuration storage or calibration constants in a field-deployed system.