INA2137 LF noise on output

Peter Hanes

Other Parts Discussed in Thread: INA2137

Hi, I'm using the INA2137 on an analogue audio A-D board. The device seems to be picking up / generating LF noise on the output at around 10Hz. Schematic attached, any advice on this appreciated.

Thanks,

Pete

over 11 years ago

0 John Caldwell over 11 years ago

TI__Genius 12325 points

Hi Peter,

Do you have an oscilloscope screenshot of this noise? Also, where is this 10Hz noise being measured from, is it directly at the output of the INA2137 (it looks like there are two monitor outputs at these points) or after the op amps?

0 Peter Hanes over 11 years ago in reply to John Caldwell

Prodigy 25 points

Hi John,

Thanks for looking at this. Unfortunately i'm not able to see any LF noise on an oscilloscope. The op-amp filter circuit feeds into an A-D (CS5368) and using an FPGA to convert to AES. I'm using a PC based AES FFT audio analyzer.

With INA2137 output caps removed (C201 and C200, INA2137 out of circuit) I'm not seeing any LF noise.

The circuit also seems to be microphonic if you tap anywhere on the PCB.

Please see attached FFT plots. Is it possible to contact you outside the forum so i can send over the complete schematics etc?

Thanks,

Peter

6177.LF Noise plots.pdf

0 John Caldwell over 11 years ago in reply to Peter Hanes

TI__Genius 12325 points

Peter,

I've sent you a friend request on here, once you accept I can message my email address to you and we can communicate that way.

0 John Caldwell over 11 years ago in reply to John Caldwell

TI__Genius 12325 points

You should have a message with my email. You can send documents to that address.

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INA2137 LF noise on output