[sdiy] 13700 VCA Noise Issue

[Tim Ressel]

Hi,

So I did a design with a pair of 13700 VCAs in series and I am getting a
lot of white noise on the output. With the first VCA closed and the
second wide open I get 100-200mV of noise. I made a png; where do we
share these again?

Does anyone have experience with 13700 and noise?

Here's a wonk question: if I use an opamp as a transimpedance amp (oh
Ghod I hope I'm using the right term) on the output of the 13700 to
convert current to voltage, how do I determine the amp's input current
noise contribution to the output noise? Assuming it does contribute. Or
would it be better to do a resistor to ground and have the amp be a non
inverting buffer?

Thanks!


-- 
--Tim Ressel
Circuit Abbey
timr at circuitabbey.com