SEM VCO buffer (was: RE: Japanese duals (was: Re: CA3046,SSM2210&2220 Replacements)))

[harry bissell]

Beware the CMOS schmitt trigger...
The threshold voltages vary widely from manufacturer to manufacturer. Also not
stable with temperature...
Standard CMOS is pretty good with respect to both trigger level and temperature.

Use Schmitt trigger when you want "some" hysteresis but don't care how much...as
long as its "some"

Double warning... Beware so called "schmitt trigger" inputs on CMOS counters...
sometimes the schmitt is in the second stage (which of course is the same as no
schmitt trigger at all) This seems to be a way for one MFG. to pirate another
without worry about mask copyrights ???  They do not work the same at all !!!

I'm trying to find a schematic for typical CMOS schmitt.

:^) Harry


Haible Juergen wrote:

>         >Another idea is to use a CMOS logic Schmitt trigger IC.  One of the
> faster
>         >logic familys.
>
> The ARP Odyssey uses a CMOS gate to detect the threshold (no schmitt
> trigger, though).
>
> How are CMOS schmitt trigger made (internally), btw ?
> I know how to configure one from two inverters and two resistors, but I
> have no idea how the genuine CMOS schmitt triggers are made.
>
> JH.