Hi all
I am looking for confirmation that I am reading the data sheet right for a chip
(Fairchild). The chip is a CD4081 (CMOS) and I need to pull the input down to a
"0" when the input circuitry to the gate input (AND) gets disconnected from it.
VDD is 12 volts.
Originally I had a 47K going to ground but I was getting about 2.5 volts on
that input line. I had always thought (bad assumption) that a 10-50K ohm
resistor on any CMOS input would keep that input at a zero if the line was
opened going into the gate.
I looked at the IOH and IOL data for the chip and it looks like it can handle
10-20ma of current. I tried a 1500 ohm to ground on the input to the AND gate
and it worked just fine. I don't think I am stressing the chip as that's about
8ma.
Am I reading the curves correctly?
Thanks in advance
Jay
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