Mark wrote...
Is a dual/quad compartor in the same DIP totally indepentant
of each other or is there some interaction between the outputs?
NSC doesn't have a spec for their quad comparator IC, but they
do for ICs designed at the same time with similar technology.
The LM392 (dual-function opamp + comparator) has a spec called
"Amplifier-to-Amplifier Coupling," (f = 1 kHz to 20 kHz), which
is −100 dB typical (input referred). And their LM324 quad opamp
data sheet spec is −120dB typ. Both specs have this same note,
"Due to proximity of external components, insure that coupling
is not originating via stray capacitance between these external
parts. This typically can be detected as this type of capacitance
increases at higher frequencies."
Assuming a 12V output swing, a -100dB spec would imply a 120uV
input feedthrough effect. In addition to external-component
stray capacitance, one should watch out for power-supply-rail
feedthrough. The LM324 opamps have a 100dB typical power-supply
rejection ration spec. The opamp's input circuit is similar to
the LM339 comparator and we can expect it has a similar weakness.
So care should be taken that current switched by the comparator's
output doesn't cause too much pin 12 supply-rail noise.
Thanks,
- Win
whill_at_picovolt-dot-com