MM74C923WM

The MM74C923WM from ON Semiconductor is a CMOS key encoder IC that provides complete logic for encoding SPST switch arrays. It supports keyboard scanning via an external clock or capacitor and features on-chip pull-up devices for switches up to 50 kΩ on resistance, eliminating the need for diodes to prevent ghost switches.

This encoder includes an internal debounce circuit requiring a single external capacitor, which can be omitted if debouncing is not needed. A Data Available output signals valid keyboard entries, and a two-key roll-over feature is supported. The last key pressed is remembered by an internal register, even after release. The 3-STATE outputs are LPTTL compatible, facilitating easy expansion and bus operation.

Key specifications include a wide supply voltage range of 3V to 15V and an operating temperature range of -40°C to 85°C. The device is housed in a 20-SOIC package with surface mount mounting type. Its circuit configuration is 1 x 9:4, with one independent circuit.

This component is suitable for applications requiring efficient and reliable keyboard encoding, such as custom input devices, industrial control panels, and embedded systems where a compact and functional encoder is necessary.