The SST39SF040-70-4C-NHE is a 4MB multi-purpose Flash Device with SST proprietary, high performance CMOS SuperFlash technology. The split-gate cell design and thick oxide tunnelling injector attain better reliability and manufacturability compared with alternate approaches. The SST39SF040 write (program or erase) with a 4.5 to 5.5V power supply and conforms to JEDEC standard pinouts for x8 memories. The SST39SF040 device provide a maximum Byte-Program time of 20µs. This device use toggle bit or data# polling to indicate the completion of program operation. To protect against inadvertent write, they have on-chip hardware and software data protection schemes. The SST39SF040 device is suited for applications that require convenient and economical updating of program, configuration or data memory. For all system applications, they significantly improve performance and reliability, while lowering power consumption.