[sdiy] CA3080 switch driving voltage

[harrybissell]

Hmmm... My NJM13700s did not do at all well once I let them zener...
the bleedthrough was awful (I was using them in a gated app btw).  Reducing
the input voltage helped a lot.  The National parts worked OK (i assume I did
not reach their breakdown voltage)

The CA3094 iirc... specifies that the input voltage range can be exceeded
without
damage if the current is limited. I could not find that note on ANY other OTA.

Probably best not to exceed the input range.  That said they make very nice,
fast
comparators.

H^) harry

Grant Richter wrote:

> > 60mV - much lower than I expected.
> > Doesn't this mean that there is a temperature drift from the diff pair
> > still working in the "almost linear" area?
> > But anyway - if saturation must be avoided, then this is the way to go.
> > Probably compensating for the tempco somewhere else. (I remember
> > there was another EN article with diodes setting the thresholds of
> > the schmitt trigger - maybe this was exactly for that reason.)
>
> Are you referring to this? From an RCA ap-note. Response is only 45 ns, with
> 1 ma. See:
>
> http://www.musicsynthesizer.com/DIY/Grant/OTA.html
>
> >
> > Thanks for pointing this out. All my previous triangle cores show
> > the effect you describe in EN#112. Not tracking ore than 3 octaves
> > accurately, and HFT trimmers won't help. This time I'll try the 60mV.
>
> I'm using just a 100K in series with the NJM13700 input. It will zener at
> around 7 volts. Works OK for an LFO, I'll have to see how it tracks as a
> VCO.