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ADA4807-2 Voltage follower configuration problem

Other Parts Discussed in Thread: TPS60400

Hi there,


I have a circuit with a two channel DAC going to a ADA4807-2 opamp to be able to output the DAC voltage level with a higher current capability. After the opamp there's a couple of relays going to a BNC connector. The problem is, there's always a difference between the voltage input and the voltage output of the opamp, sometimes even going to 20 or 30mV. I'm trying to have a DC precision voltage source and it's being ruined by the opamp. Not only that, but the whole system is very susceptible if any hands are around the PCB or the cables.


What am I doing wrong?

To generate the negative voltage rail I'm using a voltage inverter (TPS60400) and it's not very stable, the voltage levels keep on changing. I took it out of the circuit and grounded the -Vs but that only made the circuit perform worse at low voltage levels (0.1V, 0.2V and so on until 0.7V).


I'm attaching the schematic for the analog part of the circuit.

Thanks for reading!circuit_voltage_generator.pdf