74154 DATASHEET PDF
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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That is, if the outputs were active high, OR gates would perform the synthesis desired. When either strobe input is high, all outputs are high. The LED can be chosen at random by the status of the 4 line selector inputs.
4 Line to 16 Line Demultiplexer / Decoder
I am a new user so I didn’t know I had that power. Understand, this is a typical example of application, not it’s sole purpose. 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.
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. 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.
And why are there 2 of them, you ask? However, due to the internal structure of theonly one output can be enabled at a time. For example, if the target application requires datahseet 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.
Datasheet(PDF) – National Semiconductor (TI)
The active-low output is just how the design for that specific decoder was carried out – there is also active-high daasheet. Sign up or log in Sign up using Google.
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. Sign up using Dataasheet and Password.
74154 Datasheet PDF
First, the inversion of the outputs simply means that the output is active low. This allows more flexibility in the logic functions available. That is, for an input ofthe 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. Each ratasheet the 16 outputs can be connected through a resistor and then through an LED to serve as a simple 16 LED controller.
My first question is more important Datasheft the datasheet below for a more comprehensive summary.
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.
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? Since the ouputs are active low, NAND gates do the job. Post as a guest Name. The active-low enable inputs allow cascading of demultiplexers over many bits. Rather than providing only a single enable, both pins are used.
These demultiplexers are ideally suited for implementing high-performance memory decoders. This chip dayasheet often used in demultiplexing applications, such as digital clocks, LED matrices, and other graphical outputs.