Decoupling for OPA627, LT115 and AD8610

[Sonusthree]

Perfect timing Rio,
This is just what I needed to read before I move my first proper DIY potototype from breadboard.

It's funny that they recommend using dual opamps to shorten the feedback loop. I might try that.

Danke Schoen,
Martin.

 

[jcx]

Hi Mads!

No, I'm not referring to OS-CON:s, although I know
they're also dry elyts. The type I've got is made
by BC components, and are sort of "drop formed",
like tantalums normally are. I'll try to attach
an image, hopefully it works...

1st page:
http://www.diyaudio.com/forums/showthread.php?postid=188715#post188715


you're getting really bad advice, the pic looks like a classic sintered Ta/MnO2 cap - the very one that is a safety hazard because it can flame out under V stress/dielectric failure

the Ta cap recommendation in most op amp data sheets is totally archaic and should be dropped, Fred's recommendation of polymer electrolyte Al electros is probably good for Ta replacement apps

but there is good info on what really happens in bypass applications and random paralleling of different caps can result in impedance peaks in the supply impedance
http://www.ultracad.com/articles/esrbcap.pdf shows the "anti-resonance" impedance peak you can get with the wrong choice of caps in parallel

http://www.pa.msu.edu/hep/d0/ftp/ru...nformation/xilinx_xapp623_decoupling_caps.pdf

also shows measured ps impedance peaking

this makes the large Al electro deliberately selected for higher esr actually a better choice sometimes

 

[crazyeight]

hi,
in case of decoupling dual mono opa627 (used with adaptator), should i use bypass on adaptator or twice on each opamp ?
regards,