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typical voltage assignment


Guest 4electros
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Guest 4electros

Voltage between 0.8V to 2V in 5 Volt CMOS and TTL Logic, this may cause error in a digital circuit. Today's digital circuits works at 1.8 volts, so this statement may not hold true for all the logic circuits

The above statements might be easy to understand , though i didn't stand well for it ..could anyone explain it in his special way and i will be thankful!

i've attached PNG file for it!

regards!

post-0-14279142626821_thumb.png

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0.8V or less is recognized as a logic low to a TTL input. Most TTL outputs produce a low voltage of 0.4V or less to provide 0.4V of immunity to noise.
2.0V or more is recognized as a logic high to a TTL input. Most TTL outputs produce a high voltage of 2.4V or more to provide 0.4V of immunity to noise.

1.5V or less is recognized as a logic low to a Cmos input. Most Cmos outputs produce a low voltage of 0V to provide 1.5V of immunity to noise.
3.5V or more is recognized as a logic high to a Cmos input. Most Cmos outputs produce a high voltage of 5.0V to provide 1.5V of immunity to noise.

The output voltage of TTL doesn't go high enough to drive a Cmos input high.
The output current of Cmos isn't enough to drive a TTL input low.

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