The NTE is a monolithic 4-line-toline decoder in a Lead DIP type The NTE is fully compatible for use with most other TTL and DTL circuits. MOS technology. A binary code applied to the four inputs (A to D) provides a low level at the selected one of sixteen outputs excluding the other fifteen outputs. SNN .. of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alteration.

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I am a new user so I didn’t know I had that power. Download the datasheet below for a more comprehensive summary. The active-low output is just how the design for that specific decoder was carried out – there adtasheet also active-high varieties. All inputs are buffered and input clamping diodes are provided to minimize transmission-line effects and thereby simplify system design.

74154 Datasheet PDF

If you wanted to generate a 1 of demultiplexer, datasehet could use 16 s looking at the 4 least significant bits, while a single would look at the 4 most significant bits, with one ouput going to each of the other 16 s. The demultiplexing function is performed by using the 4 input lines to address the output line, passing data from one of the strobe inputs with the other strobe input low.

First, the inversion of the outputs simply means that the output is active low. This chip is often used in demultiplexing applications, such as digital clocks, LED matrices, and other graphical outputs.

This allows more flexibility in the logic functions available. Post as a guest Name. And why are there datasheeet of them, you ask? When either strobe input is high, all outputs are high. You can upvote more than one answer.


That is, for an input dataseetthe 0 output is selected, and it is driven low.

Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. The LED can be chosen at random by the status of the 4 line selector inputs.

4 Line to 16 Line Demultiplexer / Decoder

According to the internal logic diagram on the datasheet, the G inputs are connected to a two-input AND gate with inverting inputs, whose output feeds one input of all the NAND gates that produce the outputs.

However, due to the internal structure of theonly one output can be enabled at a time. For example, if the target application requires 16 7-segment LED displays, but your microcontroller only has 4 lines to select which display is active, this chip 74LS would provide a very effective method of essentially multiplying you selecting lines by a 4 times.

If you want to know exactly what is going on then draw out the truth table, but it is unlikely their function will make much sense to you.

By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. Since the ouputs are active low, NAND gates do the job.

Understand, this is a typical example of application, not it’s sole purpose. Sign up or log in Sign up using Google. These demultiplexers are 7154 suited for implementing high-performance memory decoders.

By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The person who took time to answer the question will appreciate that.

National Semiconductor

Sign up using Email and Password. Each of the 16 outputs can be connected through a resistor and then through an LED to serve as a simple 16 LED controller.


All the other ouputs stay high. Please consider upvoting those questions you found useful like datawheet one by clicking the arrow pointing up near the answer vote count which is in turn above the checkbox you clicked to accept this question.

As for the NAND gates, there is a function being implemented in which the gates are there to realize it. Sign up using Facebook. Many TTL parts and older memory chips have active low enable inputs, so the active low outputs of this part can be connected directly to those inputs.

My first question is more important Email Required, but never shown. Each or these 4-line-toline decoders utilizes TTL circuitry to decode four binary-coded inputs into one of sixteen mutually exclusive outputs when both the strobe inputs, G1 and G2, are low. So is it possible that both enables are hooked to a 2-input OR gate; 741154 is just making use of the extra pins to make 24?

The active-low enable inputs allow cascading of demultiplexers over many bits. Rather than providing only a single enable, both pins are used. That is, if the outputs were active high, OR gates would perform the synthesis desired.

There are probably two enable inputs because otherwise there would be two unused pins on the xatasheet pin package I don’t recall seeing 22 pin DIP packages. WhatRoughBeast 49k 2 28 Will someone please explain the purpose of inverting the outputs daatasheet through 15 as well as the use the NAND gates here? Home Questions Tags Users Unanswered.