Other Parts Discussed in Thread: TLV9062, OPA2990
My customer is using OPA2170 in an inverting structure as below. The power supply is GND and -2.8V(not -2.5V in the picture). The circuit works, but there is 10mV pk-pk noise at output as below shows. if I designed this, I would at least add a Cpole to limit the bandwidth.
As the the design is fixed, I would like to analyze the source of the noise to reduce it. Here is the possible two,
1. The input impedance is big which covert Ibias into bigger noise;
2. Single supply reduce the CMRR.
Is there any other noise source for this output noise? Does using a 36V amp in a -2.7V low voltage make the noise bigger? Should I ask customer to change to 5V device like TLV9062?