Hi all,
I think there is a common mistake we all used to do, whis is:
Do NOT pull down any I/P pin using a resistor, but only usu it to pull UP an I/P pin. i.e. the I/P pin is a current sourcing pin which will pass a currentthrough the pull don resistor, this will cause a voltage drop to be generated across the R & it may be (usually i think) more than the threshold value 0.8V.
When pullimg down an I/P, use another gate's O/p or a saturated transistor to ensure about 0.2V on this I/P.
Thanks...