I want to drive a non-inverting OPA1656 from the wiper of a volume pot -- which means a range of source resistance for the OPA1656 from 0 to <del>Rpot/2<del> Rpot/4. TI has characterized the THD vs Rs for a lot of its recent devices, but alas not the OPA1656 (at least that I could find). There isn't enough info about the topology of the input stage either that could lead one to an educated guess.
Has anyone done any testing or have any other insight about what to expect when the part is driven from something on the order of 5kΩ to 12.5kΩ?
Has anyone done any testing or have any other insight about what to expect when the part is driven from something on the order of 5kΩ to 12.5kΩ?
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Why not make it an active gain control: an inverting stage with the pot as the input and feedback resistors and the wiper feeding the inverting input?
This is a great idea if we know with confidence that the model accurately models this behavior. It's worth taking a look at the model to see if it's possibly there.
Is it not good enough for You, what was stated in the link posted by me above: not as good as the best, (OPA827, OPA1641) - - but as good or better than the difet OPA627, which had been praised for it's low common mode distortion, until those two had taken over?
I see that like an acceptable performance..
Ciao, George
I see that like an acceptable performance..
Ciao, George
I misunderstood your post! I thought you were suggesting I ask in that thread. Thank you for that. It provides very useful information!
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