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EVAL AD7841 page 4 Circuit Schematic

1. The +ve and -ve references are generated and applied to the DAC.

2. In the -ve reference part, ADR02 produces 5-V reference. Its output is connected to inverting input of op-amp (U7, OP1177)

This scheme of using an op-amp is not clear.

Can anyone elaborate on this scheme.

I presume that the purpose is to generate - 5V reference.

But the scheme is not clear.

Thanks in advance to those who can clarify this point.


  • The ADR02 normally gives a +5V output. Using it with the OP1177 as on the evaluation board generates a -5V reference voltage.

    Because the non-inverting pin of the OP1177 is at ground, the inverting pin will also be 0V. The ADR02 will generate +5V between VOUT and GND meaning that the GND pin goes to -5V giving the negative reference voltage.