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Plz anybody check this Schematic correct or not? Answered

it is the sch for mt8870 dtmf decoder
i wanted 16 outputs
is this sch correct
i dint place the crystal and other components

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Mayoogh

4 years ago

call you plz post a sch for mt8870 16 output circuit

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Nighter3D

4 years ago

So you want to Transform a 4-bit code into a 16 output.

But i see you want to use multiple 4-to-10 decoders to get the equivalent of a 4-to-16. Unfortunately your schematic is kinda messy but i will try to check for you with some logic math...


Ok it kinda falls apart rather quickly. If the MT8870 gives out 0101(In decimal 5) the top left gets on its inputs 1010 (in decimal 10) which would try to output to a pin that does not exist (q10).

I also see a Input B interconnected on both right side ICs...but to nothing else and same for Input C. Without a proper connection these 2 and any unconnected Input will Float causing the ICs to go a little insane and cause a lot of noise on their outputs.

So no...the schematic does not work i'm afraid.

You may want to possibly look for a larger Decoder ic. An IC i would suggest taking a look at is the 74HC4514 (or 74HCT4514). it is an 4-to-16 Active High decoder.