"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
> I need to convert a _slow_ moving analog signal to "1" or "0",
> depending on whether it is above or below the digital threshold
> (CMOS).
>
> Problem: If I go directly into a gate or D-input of a flop I can get
> substantial overlap current rail-to-rail.
>
> This is a very low current application.
>
> Any suggestions?
>
> ...Jim Thompson
The knee-jerk solution is to add an off-the-shelf Schmitt trigger in front of the D input, but I would guess that you've already thought of that and have dismissed it because your dV/dt is still slow enough to result in "overlap" current in the Schmitt trigger input stage, too.
So, I would try finding an ultra-low current comparator (with ultra-low input bias current) and build your own Schmitt trigger using a multi-megohm feedback resistor. Then, that would be followed by the flop. Linear Tech would be a good starting point for the comparator.
Bob