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.
|Published (Last):||26 December 2016|
|PDF File Size:||5.91 Mb|
|ePub File Size:||7.98 Mb|
|Price:||Free* [*Free Regsitration Required]|
Please consider upvoting those questions you found useful like this 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.
My first question is more important Email Required, but never shown. The active-low enable inputs allow cascading of demultiplexers over many bits. If you wanted to generate a 1 of demultiplexer, you 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. All the other ouputs stay high. As for the NAND gates, there is a function being implemented in which the gates are there to realize it.
Each of the 16 outputs can be connected through a resistor and then through an LED to serve as a simple 16 LED controller.
4 Line to 16 Line Demultiplexer / Decoder
You can upvote more than one answer. The LED can be chosen at random by the status of the 4 line selector inputs. First, the inversion of the outputs simply means that the output is active low.
Will someone please explain the purpose of inverting the outputs 0 through 15 as well as the use the NAND gates here? 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. 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 adtasheet G2, are low.
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. All inputs are buffered and input clamping diodes are provided to minimize transmission-line effects and thereby simplify system design.
This allows more flexibility in the logic functions available.
74154 Datasheet PDF
So is it possible that both enables are hooked to a 2-input OR gate; this is just making use of the extra pins to make 24? When either strobe input is high, all outputs are high. These demultiplexers are ideally suited for implementing high-performance memory decoders.
Since the ouputs are active low, NAND gates do the job. The person who took time to answer the question will appreciate that. And why are there 2 of them, you ask? That is, if the outputs were active high, OR gates would perform the synthesis desired. 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.
The active-low output is just how the design for that specific decoder was carried out – there is also active-high varieties. That is, for an input ofdatasueet 0 output is selected, and it is driven low.
There are probably two enable inputs because otherwise there would be two unused pins on the 24 pin package I don’t recall seeing 22 pin DIP packages. If you want to know exactly what is going on then draw out the truth table, but it datasueet unlikely their function will make much sense to you. Understand, this is a typical example of application, not it’s sole purpose. Sign up using Email and Password.
Sign up using Facebook. 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. Sign up or log in Sign up using Google. WhatRoughBeast 49k 2 28 Post as a guest Name. Home Questions Tags Users Unanswered.
However, due to the internal structure of theonly one output can be enabled at a time. Download the datasheet below for a more comprehensive summary. This chip is often used in demultiplexing applications, such as digital clocks, LED matrices, and other graphical outputs.
I am a new user so I didn’t know I had that power.