[sdiy] dragging down op-amp CV output?

Roman Sowa modular at go2.pl
Mon Jan 17 12:29:44 CET 2022

Sure it is better to keep everything that goes outside on separate 
buffer in separate chip, but you have to evaluate if your circuit is so 
well-thought in every aspect that double buffering will not become silly 
overkill. If you have spare opamp in the package, just go for it, 
there's no quesion about it. If it takes another chip to add, especially 
in limited space, I would call it unncesary waste.

As for ESD and who-knows-what type of events you mention, you have to 
deal with them separately, and not by adding more opamps. Suppression 
diode does the work here.


W dniu 2022-01-15 o 23:05, Neil Harper via Synth-diy pisze:
> On 1/15/22 3:01 AM, Roman Sowa wrote:
>> If you look under "Maximum peak output voltage swing", you'll find
>> +/-10V at 2k load, so that's +/-5V clean wave at 1k in your case.
>> There's also graph "Maximum Peak Output Voltage vs Load Resistance",
>> where you can see exactly that and more (figure 6-45 in my datasheet).
>> Even if it was 100oh, and indeed while inserting a plug you'd short it
>> to GND, and everything goes down, it happens just for a blink of an eye,
>> not a big deal IMHO. with 1k you'd have to short 2 jacks to GND at the
>> same time. I haven't seen anybody patching 2 patchcords at once. So yes,
>> that's good, you're safe with good margin.
> thanks Roman, I see  those graphs now in the TI datasheet. Very
> interesting..
> is there any merit to keeping the outside-world facing outputs on their
> own buffer in case of any other sort of user error? i'm thinking like
> static discharge or who-knows-what (connect it to another input, etc)..
> is there any failure modes that would just kill the opamp cell, or would
> it just bonk the entire chip anyways.
> i gotta be honest, i can't say I've ever killed a TL074 with manhandling
> and breadboarding, etc. SSI2164's on the other hand, i've had a few of
> those suddenly not work and the problem has always been isolated to a
> single cell.
> -- 
> /// Neil Harper
> /// Every Wave is New Until it Breaks
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