OPA1612: Reducing 2.4GHz RFI

Vladimir Kvitnevskiy

Part Number: OPA1612

Tool/software:

Hey all,

I'm using the OPA1612 as an amplifier to a sensor (load cell). I picked the OPA1612 due to its great RMS noise and price.

My issue is that when there is a phone using WiFi or BLE nearby, I get spikes on the output of the op amp. I strongly suspect that the op amp is rectifying incoming RF. I could not find an RFI-hardened op-amp with the same noise performance as the OPA1612.

Are there any guidelines or recommended designs for dealing with / removing 2.4GHz RFI on this op amp? I'm new to RF, so when I tried designing a low-pass, it didn't work.

over 1 year ago

+1 Raymond Zhang1 over 1 year ago

TI__Guru* 77501 points

Hi Vladimir,

Vladimir Kvitnevskiy said:
Are there any guidelines or recommended designs for dealing with / removing 2.4GHz RFI on this op amp?

Could you show me your schematic?

It is difficult to say how the RF radiated frequency is coupled onto OPA1612. It is fairly complicate and there is not standard guidelines to cure this effect. You can use trial and error methods, but this is not very effective typically, if do you know how and where the signal is coupled onto the device or DUT.

The radiated energy can be coupled via power supply line, inputs and output or it can pick it up via PCB layout and coupled onto the OPA1612 etc.. Let me look at the schematic and see if I am able to offer some remedy for the application.

If you do not want to post the schematic in the open forum, please post "friendship" request via E2E forum, and we can communicate via private platform to address the issues.

https://www.youtube.com/watch?v=652_8MsM0pI

https://www.youtube.com/watch?v=rJK9zY0AKgo

Best,

Raymond