# SN54/74ALS/AS Series Synchronous Counters

## Overview
These are synchronous 4-bit decade or binary counters with internal look-ahead carry for high-speed applications. They feature synchronous operation, programmable preset, and clear functions.

## Key Features
️· Counter Types: Decade (SN54/74ALS160, SN54/74AS160, SN54/74ALS162, SN54/74AS162) or 4-bit Binary (SN54/74ALS161, SN54/74AS161, SN54/74ALS163, SN54/74AS163).
️· Synchronous Operation: All flip-flops clock simultaneously.
️· Programmable Preset: Can be preset to any value between 0-9 (decade) or 0-15 (binary).
️· Clear Function: Asynchronous clear (SN54/74ALS160, SN54/74AS160, SN54/74ALS161, SN54/74AS161) or Synchronous Clear (SN54/74ALS162, SN54/74AS162, SN54/74ALS163, SN54/74AS163).
️· Internal Look-Ahead Carry: For cascading without additional gating.
️· Temperature Ranges:
- SN54ALS/AS: -55°C to 125°C
- SN74ALS/AS: 0°C to 70°C

## Pinout (Typical - see datasheet for specific package)
️· CLK: Clock Input
️· A, B, C, D: Data Inputs
️· ENT: Enable Input
️· ENP: Enable Input
️· CLR: Clear Input
️· LOAD: Load Input
️· RCO: Ripple Carry Output
️· Q A, Q B, Q C, Q D: Outputs

## Electrical Characteristics (Typical)
️· VCC: 4.5V – 5.5V
️· Input High Voltage (VIH): 2V
️· Output High Voltage (VOH): VCC - 2V
️· Maximum Clock Frequency (fMAX): 22 - 75 MHz (depending on series and conditions)

## Switching Characteristics (Typical)
️· Propagation Delay (tPLH, tPHL): 4 - 34 ns (depending on series and conditions)

## Packages
️· Various plastic and ceramic packages (D, J, N, FK) available.

## Applications
️· High-speed counters
️· Frequency dividers
️· Binary rate multipliers
️· Timing circuits