[sdiy] Discrete Op Amps

[mskala at ansuz.sooke.bc.ca]

On Mon, 10 Apr 2017, Gordonjcp wrote:
> You just need to use the TL07x family, unless you've got ridiculously
> specialised needs.  When you open up a synthesizer (a proper one, not

I think the TL07x family is itself quite specialized.  It's JFET-input,
and that has both good and bad consequences that make it appropriate for
some applications and not for others.  In particular, because it's hard to
match JFETs even on the same chip (much worse if they are discrete), the
TL074x is going to have more offset than other designs for the same price,
and wanting low offset isn't a "ridiculous" specialization.  Other things
someone might reasonably want include:

* high frequency operation/slew rate
* high voltage
* low voltage
* low offset
* ultra-low bias current (though the TL07x has this very low already)
* rail to rail output
* low distortion
* low noise
* ultra-small physical packaging

For any of these, some other IC op amp might be better.  But I'd agree
that the best solution would nearly always be some other IC op amp.  Not
trying to build one out of discrete components.

-- 
Matthew Skala
mskala at ansuz.sooke.bc.ca                 People before principles.
http://ansuz.sooke.bc.ca/