74158 Technical Summary

74158 Quad 2-Line to 1-Line Data Selectors/Multiplexers Technical Summary

Overview

The 74158 is a high-speed quad 2-line to 1-line data selector/multiplexer integrated circuit. This TTL-compatible device is designed to select one of two data sources and route it to a single output line for each of its four channels. The 74158 is widely used in digital systems for data routing, signal gating, and parallel-to-serial conversion applications.

With its high-speed operation and reliable performance, the 74158 is particularly suitable for applications requiring fast data switching in computer systems, communication equipment, and digital processing units. The device features common select inputs for all four multiplexers, simplifying system design and reducing component count.

Features

High-speed operation with typical propagation delay of 15ns
Quad 2-input multiplexer with common select line
TTL-compatible inputs and outputs
Inverting outputs (complementary data available in 74157)
Wide operating voltage range: 4.75V to 5.25V
Low power consumption: typically 32mW
Fan-out of 10 TTL loads
Industrial temperature range: -40°C to +85°C
Available in multiple package options

Applications

The 74158 finds use in numerous digital system applications including:

Data routing and selection in microprocessor systems
Parallel-to-serial data conversion
Memory address multiplexing
Bus switching and gating
Digital signal processing systems
Communication equipment multiplexers
Test and measurement equipment
Data acquisition systems
Industrial control systems

Electrical Characteristics

Absolute Maximum Ratings

Supply Voltage (Vcc): 7V
Input Voltage: 5.5V
Operating Free Air Temperature Range: -40°C to +85°C
Storage Temperature Range: -65°C to +150°C

Recommended Operating Conditions

Supply Voltage (Vcc): 4.75V to 5.25V
High-Level Input Voltage: 2V min
Low-Level Input Voltage: 0.8V max
Operating Ambient Temperature: 0°C to +70°C (commercial)

DC Electrical Characteristics

High-Level Output Voltage: 2.4V min (Vcc=min, Ioh=-0.4mA)
Low-Level Output Voltage: 0.4V max (Vcc=min, Iol=8mA)
Input Clamp Voltage: -1.5V max (Vcc=min, Ii=-12mA)
High-Level Input Current: 40µA max (Vcc=max, Vi=2.4V)
Low-Level Input Current: -1.6mA max (Vcc=max, Vi=0.4V)
Supply Current (total): 16mA max (Vcc=max)

AC Electrical Characteristics

Propagation Delay Time (A or B to Y): 15ns typical, 22ns max
Propagation Delay Time (Select to Y): 18ns typical, 27ns max
Output Transition Time: 10ns typical, 15ns max
Input Capacitance: 3pF typical

Functional Description

The 74158 contains four independent 2-input multiplexers with common select (S) and enable (E) inputs. Each multiplexer has two data inputs (A and B) and one output (Y). The logic state of the select input determines which data input is routed to the output:

When S=0, the A inputs are selected
When S=1, the B inputs are selected

The enable input (E) is active LOW. When E=1 (HIGH), all outputs are forced HIGH regardless of the select and data inputs. The outputs are inverting, meaning the selected input data appears inverted at the output.