Integrated Circuit. Transistor Transistor Logic (TTL). 4−Line−to−16−Line Decoder /Demultiplexer. 24−Lead DIP Type Package. Description: The NTE is a. 1) CPD is defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without load. (Refer to Test . datasheet, circuit, data sheet: NSC – 4-Line to Line for Electronic Components and Semiconductors, integrated circuits, diodes, triacs.
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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.
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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. This all has to do with the actual ic design. The person who took time to answer the question will appreciate that.
The active-low output is just how the design for that specific decoder was carried out – there is also active-high varieties. This is the catasheet of a 1 to 16 demux. 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.
WhatRoughBeast 49k 2 28 So theory will cover datasgeet the theory which explains the basic functionality of the working of a demultiplexor. Common collector, with the signal connected to the emitter, which remains at 0.
Why is the output in the truth table inverted in a ic used as a demux? The LED can be chosen at random by the status of the 4 line selector inputs. Is if hardware implementation circuit different than the one explained in theory? I have a doubt in the demultiplexer section.
All the other ouputs stay high. This allows more flexibility in the logic functions available. But when we try to implement a demultiplexer using a TTLthis is the truth table that is given in the book:. And this carried through to the way the logic was used, and designed with. The actual implementation of the chosen ic has active low outputs.
The active-low enable inputs allow cascading of demultiplexers over many bits. That is, if the outputs were active high, OR gates would perform the synthesis desired.
4 to 16 decoder logic diagram – Electrical Engineering Stack Exchange
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.
And why are there 2 of them, you ask? The datasheet of these components is always the key to the correct implementation. Sign up using Facebook.
Post as a guest Name. So is it possible that both enables are hooked to a 2-input Datashfet gate; this is just making use of the extra pins to make 24? Email Required, but never shown. Download the datasheet below for a more comprehensive summary. All inputs are buffered and input clamping diodes are provided to minimize transmission-line effects and thereby simplify system design.
However, due to the internal structure of theonly one output can be enabled at a time.