4-line to line Decoders/demultiplexers. Each or these 4-line-toline decoders utilizes TTL circuitry to decode four binary-coded inputs into one of. 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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Y Decodes 4 binary-coded inputs into one of 16 mutually. Post as a guest Name. There are probably two enable inputs datasheey otherwise there would be two unused pins on the 24 pin package I don’t recall seeing 22 pin DIP packages.
74154 Datasheet PDF
Rather than providing only a single enable, both pins are used. Office Distributors for availability and specifications. Download the datasheet below for a more comprehensive summary. Y Input clamping diodes simplify system design. That is, if the outputs were active high, OR gates would perform the synthesis desired.
Y Alternate Military Aerospace device is avail. As for the NAND gates, there is a function being implemented in which the gates are there to realize it. Low Level Input Current. My first question is more important 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 datasheef a very effective method of essentially multiplying you selecting lines by a 4 times.
According to the internal logic diagram on the dtasheet, 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. Email Required, but never shown.
The active-low enable inputs allow cascading of demultiplexers over many bits. That is, for an input ofthe 0 output is selected, and it is driven low. Note 2 Not more than one output should be shorted at a time.
And why are there 2 of them, you ask? The person who took time to answer datashet question will appreciate that. Y Performs the demultiplexing function by distributing data. 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 circuit.
The active-low output is just how the design for that specific decoder was carried out – there is also active-high varieties. When either strobe input is high, all outputs are high.
Datasheet(PDF) – National Semiconductor (TI)
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. Operating Free Air Temperature Range. You can upvote more dataeheet one answer. This chip is often used in demultiplexing applications, such as digital clocks, LED matrices, and other graphical outputs.
High Level Output Current. Y Typical power dissipation mW. These demultiplexers are ideally suited for implementing high-performance memory decoders. This allows more flexibility in the logic functions available. Note 3 I CC is measured with all outputs open and all inputs grounded.
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. Free Air Operating Temperature.
View PDF for Mobile. Electrical Characteristics over recommended operating free air temperature range unless otherwise noted.
National Semiconductor Electronic Components Datasheet. Each of the 16 outputs can be connected through a resistor and then through an LED to serve as a simple 16 LED controller.