[sdiy] CA3280 instead of 3080

[harrybissell]

Hi Michael

They are "similar".   The CA3280 will allow you to run a higher Gm bias
current (greater tuning range ?).   There are linearizing diodes that (if you
use
them) will allow you to make the input attenuators smaller, and gain S/N
ratio...

...but when it clips it will be a square wave, not the softer overdrive of the
3080.
You might like it better, or worse.

You 'may' be able to get away without offset trims... I'd plan on putting them
IN and leave them out if not needed.

3280 DOES have two supply pins... you can power them separately

see Jim Patchell's site for guru advice

H^) harry

Michael Ruberto wrote:

> I have just ordered 2 samples of the CA3280 because I could not find DIP
> samples of the 3080. I have never worked with the 3280 so I'm wondering if
> I'll have to make any changes to use it in 3080 based circuits. I see from
> the datasheet the device has a lower input offset. Does that mean I can
> eliminate the offset trimmers so common in 3080 designs?
> There are also extra pins, e.g. EMITTER (pins 2,7) and ID (pins 1,8). What
> are these connections for?
>
> Also I see V+ on 11 & 14, am I right to assume each OTA can be powered
> individually? It isn't clear considering some of the example circuits employ
> both pins for power and some don't. The functional diagram is no help here
> either...
>
> I'd like to use this for a SVF which used the 3080, will it be a headache?
>
> Thanks!!
>
> M.A. Ruberto