The 74×157 (ex 74LS157) is a chip that features four 2-to-1 data multiplexers. This device can be used to route one of two 4-bit data sources to a single 4-bit output bus, controlled by a common select input and featuring individual enable inputs for each multiplexer.

The 74×157 is chip with four 2-to-1 line data selectors/multiplexers. It takes two 4-bit words as inputs and lets you choose which you want to send to the output using select lines.

74LS157 Features & Specifications

• Technology Family: LS

• Rating: Catalog

• Supply voltage: 5.25V

• Channels: 4

• Bits: 4

• Configuration: 2:1

• IOL (Max): 8mA

• IOH (Max): -0.4mA

• Frequency at nominal voltage: 35 MHz

• Typical propagation delay: 21nS

• Low power consumption: 32mW

• ESD protection

• Operating temperature: 0ºC to 70ºC

• ESD CDM (kV): 0.75

• ESD HBM (kV): 2

• Balanced propagation delays

• Designed specifically for high speed

• Product type: Standard

Here’s how it works:

• A 4-bit word is selected from one of two sources (A or B) ans routed to the 4 Y outputs.

• Use the input (A/B) to decide which input is connected to the output.

• There’s also an enable input called Strobe (G). When it’s active, the selected input is sent to the output; when it’s not, the output stays in a disabled state.

Multiplexers like the 74×157 are handy for directing data from multiple sources to a single destination, especially useful in digital circuits where you need to manage data from various paths.

How To Use This Chip

The 74HC157 comes in a 16-pin package, and you need to connect it to power before you can use it. Most 7400 ICs support a VCC voltage of 5V. One difference between the HC and LS version of the chip is that the 74HC157 supports 2V to 6V, while the 74LS157 only supports 5V.

74HC chips can normally supply a maximum of 4 mA from an output pin. If you’re using the 74LS version, the maximum current you can pull out of one output pin is 0.8 mA when the pin is high (sourcing) or 16 mA when the pin is low (sinking).