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Need Help - Ultrasonic AFE

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mzdenkov:
Greetings, im working on this project which is part of masters degree.
Link here:
http://ww1.microchip.com/downloads/en/DeviceDoc/40001902A.pdf

I made everything by their schematic, ok i did use MCP6291R which is 1 OP-AMP in a chip.

My problem is that the filter is oscillating and it gives around  37khz at its output.

Here are my .sch and .brd files

Any suggestions what should i do next?

Thank You :D

EDIT:
When the filters aren't connected together there are no oscillations on both of them.

Audioguru again:
It will oscillate if you made it on a solderless breadboard with its stray capacitance between all its rows of contacts and its long wires all over the place. The breadboard and its wires will also pickup interference (compact fluorescent light bulbs operate at around 40kHz). Make it properly on a pcb with some power supply decoupling capacitors and thick ground traces.

mzdenkov:
The circuit is soldered on one sided pcb, not on solderless bredboard.. but thanks for advice

StillTrying:
I didn't notice anything obvious between the app note, schem, and PCB layout, it's hard work with the schem. being a mirror image.

I'd try a decoupling cap 0.1uF to 1uF on the Vref connected to the op amps +ve inputs.

SiliconWizard:
Yeah, I don't even know how the OP managed to get the schematic mirrored. ;D
Maybe fix that first if you want more help.

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