[sdiy] OTA performance (was SSM chip reissue)

[Neil Johnson]

Hi,

Mattias Rickardsson wrote:
> Cooper Sloan wrote:
>> Something I've been wondering about is if this principle applies for our
>> OTAs
>>
>> http://www.linear.com/solutions/5657
>>
>> I think it could only help tame one type of uncorrelated noise if the
>> principle even applies (I'm not that smart), but I dont think I've ever seen
>> it done.
>
> It works, yes. The noise sources are uncorrelated and add up less than
> the correlated signals do. I sometimes use VCAs in parallel to get a
> better SNR, but I've had some indications that it can be tricky with
> the capacitive loading on the OP-amp virtual earth, so make sure the
> construction is stable before going into mass production. Components
> are rarely even close to ideal when it comes to optimizing real-world
> scenarios. :-)

I have just that on the bench right now with a 2164.   I've measured
around 0.006% THD+N at 0dBu input and 0dB gain.  Pretty good for a
first build I think.

Neil
-- 
http://www.njohnson.co.uk