74C923 Datasheet PDF - Fairchild

General Description

●The MM74C922 and MM74C923 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 also have on-chip pull-up devices which permit switches with up to 50 kΩon resistance to be used.

●Features

●■50 kΩmaximum 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

●■3-STATE output LPTTL compatible

●■Wide supply range: 3V to 15V

●■Low power consumption