I have some noise issues on a PCB that I am having a hard time troubleshooting. Below are pictures of the schematic as well as 2 scope traces. The first trace shows the amplified signal with the noise and the second trace shows the output without any input.
The circuit is a current amplifier that utilizes 2 OPA548 amps. As shown in the schematic, I have the proper configuration for decoupling capacitors which I got from the op amp data sheet. I also grounded both the inputs each with a 10k pull-down resistor to prevent the input from floating. The rectangular symbol is a DC-DC converter that I use to power both amps with +-15V. The PCB works great except for the noise issue.
It should be pointed out that I had previously used only 1 op amp and I was not having this noise issue. It wasn't until I added a second op amp to the PCB when I started to see more noise. Even before that, I was testing this circuit on a breadboard and also was not getting noise issues.
I tried running my output signal through an appropriate low pass filter and it helped but it did not fix the issue. I then noticed that some of the noise that I am seeing on the scope is coming from the ground plane. The PCB is 2 layers with the bottom serving as a ground plane. Is ground plane noise a common issue? It makes sense that a ground plane is essentially an antenna so how do compensate for that?
Lastly, I do want to point out that I do have some traces running through my ground plane. I tried run most of the traces on the top layer but I could not avoid it. Could that also be where noise is coming from because I have some traces running through my ground plane. Any advice would be greatly appreciated. Thanks.