offset adjusting

[Martin Czech]

Ok, not chpper, but chopper principle, you could just
specify when the thing was switching, rigth?

I have never heard of another autozero method,
I'd be interested if there is one.

NS makes an autozero IC, this can be added to any opamp,
but again, comparing the output with reference ground,
and this means switching input and output of the opamp.

m.c.

:::X-Originating-IP: [207.206.127.34]
:::From: "Hairy Harry" <paia2720 at hotmail.com>
:::To: czech at Micronas.Com, diode at hotmail.com
:::Cc: synth-diy at node12b53.a2000.nl
:::Subject: Re: offset adjusting
:::Date: Fri, 20 Oct 2000 14:53:23 GMT
:::X-OriginalArrivalTime: 20 Oct 2000 14:53:23.0422 (UTC) 
FILETIME=[7E9717E0:01C03AA5]
:::
:::Hi everybody...
:::
:::Texas Instruments has/had? some opamps that did an autocal for voltage
:::offset on power up, and there was a way you could command an autocal
:::after that. They were NOT choppers...
:::
:::If I recall, they were single supply 5V (yuck IMHO)
:::
:::Harley Davidson Engineer (true quote)
:::
:::"At Harley Davidson if we need something STRONGER, we make it BIGGER.
:::if that makes it ugly.... we chrome it!"
:::
:::H^)  harry
:::
:::
:::>From: Martin Czech <czech at Micronas.Com>
:::>Reply-To: Martin Czech <czech at Micronas.Com>
:::>To: diode at hotmail.com
:::>CC: synth-diy at node12b53.a2000.nl
:::>Subject: Re: offset adjusting
:::>Date: Fri, 20 Oct 2000 09:56:07 +0200 (MET DST)
:::>
:::>
:::>:::well folks, the free trade zone database finally identified some nice 
:::>weird
:::>:::chips for me from my weird chips box.. the LMC669 is apparently
:::>:::discontinued, but there must be something out there like it.. it's an 
:::>auto
:::>:::op amp offset calibrator.. attach to the summing node and the + in and 
:::>it
:::>:::claims to auto calibrate the offset to [typ] 5uv! independent of supply
:::>:::vtg,time,temp, and req's no user offset adj. this could be the solution 
:::>to
:::>:::many a finicky vco prob! unfortunately Ive only got 1...
:::>:::cheers,
:::>:::dan
:::>
:::>chopper? Could give some nasty frequency artefacts...
:::>
:::>m.c.
:::>
:::
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