Using 4700 series logic ICs

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Using 4700 series logic ICs

Post by cyprian21 » Mon Apr 27, 2020 12:56 am


I'm trying to use some 4700 series logic with one of the 3.3v only
inputs on the Kflop. I'm looking for ICs in DIP packages in particular.

Looking at Digikey, there are 74HC, 74HCP, 74AC, 74ACT and 74AHC
families that are still available in DIP. I don't really know which
ones would work, let alone which ones are a good choice. I'm looking
for something that's common and has compatible outputs with the Kflops
3.3V only pins.

What are the VImput_high (min) and Vimput_low (max) values for the Kflop?

Thank you,

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Re: Using 4700 series logic ICs

Post by TomKerekes » Mon Apr 27, 2020 2:15 am

Hi Cyprian,

Vih min = 2.0V
Vil max = 0.8V

74AC powered with 3.3V will work on the pins without 150ohm termination.

We use 74LVC541 powered with 3.3V to drive the KFLOP inputs with 150ohm termination. The 74LVC541 guarantees at least 2.2V @ -24ma with supply voltage of 3.0V.


Tom Kerekes
Dynomotion, Inc.

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