[time-nuts] Modeling vs reality question re my TIC
bruce.griffiths at xtra.co.nz
Mon Mar 10 16:53:19 EDT 2014
Metastability in the Flipflops?
Charge injection when tristating tristate buffers?
Neither of which are included in your models.
Bob Stewart wrote:
> Fellow Timenuts:
> I'm trying to square reality with the modeling that I did, and nothing makes
> sense. When I modeled the result of just my 2.4K resistor with the caps and resistor the PIC datasheet says it has in it, there's no relationship. The model says
> I'll get millivolts out. Here's how I calculate what I'm actually
> ADC VRef is 2.5V
> 10-bit ADC = 1024 positions
> Max ADC from TIC = 975
> 975/1024*2.5 = 2.38V Max TIC value
> Min ADC from TIC = 293
> 293/1024*2.5 = 0.715V Min TIC value
> A range of 0.715V-2.38V is totally outside my expectations. The only way I can get close to these values is if the internal CHOLD in the PIC is only a fraction of the 120pf they say it has - say 20pf. Any thoughts would be appreciated.
> Bob - AE6RV
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
More information about the time-nuts