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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National Semiconductor – datasheet pdf
And why are there 2 of them, you ask? When either strobe input is high, all outputs are high. Post as a guest Name. Email Required, but never shown. 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. And this carried through to the way the logic was used, and designed with.
This is the image of a 1 to 16 demux. The LED can be chosen at random by the status of the 4 line selector inputs. That is, for an input ofthe 0 output is selected, and it is driven low. 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. The person who took time to answer the question will appreciate that.
Datasheet, PDF – Alldatasheet
The active-low output is just how the design for that specific decoder was carried out – there is also active-high varieties.
Inputs were pulled high by default, and only pulled low when necessary, to save power. But datasheeh we try to implement a demultiplexer using a TTLthis is the truth table that is given in the book: The datasheet of these components is always the key to the correct implementation.
This chip is often used in demultiplexing applications, such as digital clocks, LED matrices, and other graphical outputs. Each of the 16 outputs can be connected through a resistor and then through an LED to serve as a simple 16 LED controller. As for the NAND gates, there is a function being implemented in which the gates are there to realize it.
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.
Ratasheet have a doubt in the demultiplexer section.
Will someone please explain the purpose of inverting the outputs 0 through 15 as well as the use the NAND gates here? Email Required, but never shown. You can upvote more than one answer.
I understand how it works. So they are inverted a explained in the theory.
(PDF) 74154 Datasheet download
This allows more flexibility in the logic functions available. Home Questions Tags Users Unanswered. Common collector, with the signal connected to the datashret, which remains at 0.
Since the ouputs are active low, NAND gates do the job. The actual implementation of the chosen ic has active low outputs.
Why are the outputs inverted? So TTL circuitry adopted asymmetric logic levels, where ‘0’ was guaranteed to be below 0.
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. If you have some experience using BJTs you will know that NPN transistors are best used to pull satasheet signal to 0V common emitter, with the output connected to the collector and quite weak at pulling a signal high.
My first question is more important Sign up using Email and Password. 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.