IC question

Post by **gannon** » Mon Jun 13, 2005 4:39 pm

Just a quick question, is it bad to input voltage into the a/d lines of an IC when it's no powered on?
I have a feeling the answer is yes.
And while I'm at it, does anyone know of a good bidirectional digital switch package?

HK-47 · Post by **HK-47** » Mon Jun 13, 2005 7:11 pm

Im pretty sure thats a bad thing. I dont think ics like voltage anywhere it isnt supposed to be.

nos_slived · Post by **nos_slived** » Mon Jun 13, 2005 7:16 pm

Except CMOS ICs which take voltage or ground on unused pins. I don't know about other ICs, but if you don't tie the unused pins, static ghosts haunt the chip till it dies (because they kill it).

Post by **gannon** » Mon Jun 13, 2005 8:04 pm

looks like I'll need a cd4016 or something similar then.

Post by **Gamelver** » Mon Jun 13, 2005 8:07 pm

perhaps about 18 of them?

nos_slived · Post by **nos_slived** » Mon Jun 13, 2005 8:20 pm

I should have realized that it would be a CMOS when you said "bidirectional digital switch package". 4016s look like they would be very practical in the charging circuit that I'm designing to accompany my battery charger. It looks like those would be like an electrical SPDT, rather than a 3904 which sends excess current on the base through the output. Anyways, that will be good, and because it is I/O, tieing isn't needed.