This document describes the features of the 74HC/HCT161 integrated circuit, including synchronous counting and loading, n-bit cascading count enable inputs, positive-edge triggered clock, asynchronous reset, etc. They are high-speed Si-gate CMOS devices that are pin compatible with low power Schottky TTL (LSTTL). They can be used for high-speed counting.
This document is a product specification datasheet for the Philips 74HC/HCT161 integrated circuit. It describes a high-speed Si-gate CMOS device that functions as a presettable synchronous 4-bit binary counter featuring an internal look-ahead carry and asynchronous reset capability.
The datasheet provides detailed technical information including features, general descriptions of operation, ordering information, pin configurations, functional diagrams, logic symbols, state diagrams, timing sequences, DC characteristics, AC characteristics, and package outlines. It specifies performance parameters such as propagation delays, clock frequencies, and setup/hold times for both HC (5V) and HCT (3.3V compatible) variants.
| Device Type | Presettable synchronous 4-bit binary counter; asynchronous reset |
|---|---|
| Technology | High-speed Si-gate CMOS |
| Logic Family Compatibility | Pin compatible with LSTTL |
A LOW level at the master reset input sets all four outputs to LOW regardless of other inputs, providing an asynchronous clear function.
The maximum clock frequency for cascaded counters is determined by a formula involving CP to TC propagation delay and CEP to CP set-up time.
The device has four flip-flop outputs labeled Q0 to Q3.