The SST39VF400A-70-4C-B3KE is a 4Mbit (512KB) Flash Memory manufactured by Microchip. It has a 70ns access time, is configured in 4 separate 1Mbit sectors, and has a 3 Volt low voltage program operation. It has a top boot block to allow software to retrieve stored parameters from the memory, a fast block erase architecture to shorten system down-time, and a JEDEC standard pinout. The device is also available in low pin count and fine pitch BGA configurations.