SST25PF040C 4Mbit 2.3-3.6V SPI Serial Flash Microchip Technology SST25PF040C 4Mbit 2.3-3.6V SPI Serial Flash features a four-wire, SPI-compatible interface. This allows a low pin-count package with less board space to lower system costs. The SST25PF040C devices are enhanced with an extended operating voltage of 2.3V to 3.6V. These devices are manufactured with proprietary, high-performance CMOS SuperFlash technology. The split-gate cell design and thick-oxide tunneling injector attain better reliability and manufacturability than alternate approaches.