The 74HC/HCT42 are high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A.
The 74HC/HCT42 is a high-speed Si-gate CMOS device that is pin compatible with low power Schottky TTL (LSTTL). It accepts four active HIGH BCD inputs and provides 10 mutually exclusive active LOW outputs, facilitating the addressing of other MSI circuits. The logic design ensures that all outputs remain HIGH when binary codes greater than nine are applied to the inputs.
The device features mutually exclusive outputs and a 1-of-8 demultiplexing capability. The most significant input (A3) can be used as a useful inhibit function when used as a 1-of-8 decoder, or as a data input in an 8-output demultiplexer application. The document provides typical symbol parameters, ordering information, pin descriptions, function tables, and AC/DC characteristics for both HC and HCT variants.
| Logic Family | High-speed Si-gate CMOS |
|---|---|
| TTL Compatibility | Pin compatible with LSTTL |
| Inputs | Four active HIGH BCD inputs |
| Outputs | 10 mutually exclusive active LOW outputs |
All outputs remain HIGH when binary codes greater than nine are applied to the inputs.
Yes, the A3 input can be used as the data input in an 8-output demultiplexer application.