The Microchip SST39VF400A-70-4I-B3KE is a 4 Megabit (512K x 8) CMOS Multi-Purpose Flash Memory designed to store both program code and data. It has a Uniform Sector architecture and is organized as 65,536 x 8. The part can be programmed in a single byte or word operation (8 or 16 bit) and includes features like a top or bottom bulk erase, Auto select or individual sector erase and a data polling or toggle bit to detect program or erase cycle completion. Other features include an Industry-standard intel hex file format, single 3.0V power supply, low power consumption and it is packaged in a 20-Pin SOP.