Part Number	MM74C922 Datasheet
Manufacturer	National Semiconductor
Overview	These CMOS key encoders provide all the necessary logic to fully encode an array of SPST switches The keyboard scan can be implemented by either an external clock or external capacitor These encoders . Y Y Y Y Y Y Y Y Y 50 kX maximum switch on resistance On or off chip clock On-chip row pull-up devices 2 key roll-over Keybounce elimination with single capacitor Last key register at outputs TRI-STATE outpust LPTTL compatible Wide supply range Low power consumption 3V to 15V Connection Diagrams P.