![]() ![]() ![]() A high level at the strobe forces the W output high, and the Y output (as applicable) low. The '150, '151A, 'LS151, and 'S151 have a strobe input which must be at a low logic level to enable these devices. The '150 selects one-of-sixteen data sources the '151A, 'LS151, and 'S151 select one-of-eight data sources. These monolithic data selectors/multiplexers contain full on-chip binary decoding to select the desired data source. Fully Compatible with Most TTL Circuits.Input-Clamping Diodes Simplify System Design.Also For Use as Boolean Function Generator.All Permit Multiplexing from N Lines to One Line.All Perform Parallel-to-Serial Conversion.Others Select One-of-Eight Data Sources.'150 Selects One-of-Sixteen Data Sources.The truth table showing all possible combinations of the inputs and outputs is shown below. ![]() When the Select pin is logic 0 the output line is connected to input A and when the select line is 1 the output pin is connected to Input B. The Enable pin of the IC is grounded and the select line pin (A’/B) is controlled using a logic state. A working gif of 74HC157 IC is shown below.Īs you can see out of the four multiplexers only the first multiplexer (1A, 1B and 1Y) is used for demonstration. If the Select Line is low (logic 0) then Input A will be reflected on the output and if the select pin is high (logic 1) then the Input B will be reflected on the output pin Y. The select line (pin 1) decides which of the two inputs should be given to the output pin. Since the multiplexer is a 2:1 Multiplexer it can take in two inputs, these two inputs are given to the pin Input A (a.k.a Input I0) and the pin Input B (a.k.a Input I1) the output of the multiplexer can be received from the output pin Y. There are four 2:1 multiplexers in this IC, for simplicity let us consider we are using only one of the available four multiplexers. The Enable pin has to be connected to the ground for normal operation of the IC, so you can either ground it permanently or connected it to a MCU/MPU to turn on or of the Multiplexers as required. The IC has an operating voltage of 2V to 6V so select the operating voltage (typically 5V is used) and then power the IC using the Vcc pin and the Ground pin. Using the 74HC157 IC is pretty straight forward. Hence if you are looking for a 2:1 Multiplexer IC with a quad package then this IC might be the right choice for you. Likewise there are 4 Multiplexers each of 2-inputs and 1-Output corresponding it, all these four Multiplexers are controlled through a single Line Select Pin (S) hence they cannot function independently. Similarly this IC has two input pins (Input I0 and Input I1) and one output pin (Output Y) which forms a 2:1 Multiplexer. A Multiplexer as we know takes in 2 or more inputs and provides one of them as the output based on the Select line status. It has four similar multiplexers inside it and hence it is called as Quad package 2-Input Multiplexer. Note: Complete Technical Details can be found in the 74HC157 datasheet given at the end of this page.ħ4HC157 is a 2-input (2:1) Multiplexer IC. Maximum Propagation Delay: 25ns Available in 16-pin PDIP, GDIP, PDSO packages.Minimum high-level Input Voltage: 3.15V Maximum low-level Input Voltage: 1.35V TTL/CMOS Input Logic compatibility.This pin powers the IC, typically +5V is used. The select pin selects one of the two input lines and gives it to output lineĪctive low pin. This is the output line pin of the Multiplexer This is the second input line of the 2:1 Multiplexer This is the first input line of the 2:1 Multiplexer ![]()
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