[hpsdr] THD in Op Amps

[Lawrence Stoskopf]

Wrong forum perhaps, but since Steve brought this up: 

All of these Data sheets seem to indicate that the various op amps indicate 
lowest THD at some high output, perhaps 3v, and increases above and below 
that level.  Not sure I understand, (am sure that I don't), are they running 
in some non-class A mode such that the device works best with some high 
output or is there some inherent distortion that is "diluted" out by the 
stronger signal?  Several of the single ended "very low distortion" amps 
have almost no THD at the optimum level and look much worse beyond that. 

Thanks, 

N0UU 


> 1. What criteria did you use in selecting the OPA1632?  I've been reading
> the app notes that you recommended, and out of curiousity, searched the TI
> web site for full differential op amps