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OPA202: Designing with OPA202

Vijay
Prodigy 170 points
Part Number: OPA202


Hello Team,
I am new to analog circuits
I have been reading the datasheet of the OP-AMP OPA202.

I believe every signal should have a referance.
But I don't see any reference to the input or output signals of the OPAMP.
Also, If I am supplying the opamp with a +15V and GND, the return path of the current will be through the V- pin of the OPAMP.
But what is the return path if we are providing a bipolar supply like (+/-15V) at V+ and V- pin of the opamp?

Looking for your reply.

  • +1
    TI__Genius 14135 points

    Hi Vijay,

    We have many resources for learning about op-amps; the best place to start is at TI precision labs:

    https://www.ti.com/video/series/precision-labs/ti-precision-labs-op-amps1.html

    Regarding where current will flow in a dual-supply or single-supply case, you can find the training here:

    https://www.ti.com/video/series/precision-labs/ti-precision-labs-op-amps1.html

    Generally, most of the amplifier's internal current sources are connected from the positive supply to the negative supply, so the amplifier bias current will flow from V+ to V-.  However, if there is any load connected to the amplifier, then the current may flow either from the positive or negative supply to the output, depending on if the amplifier is sourcing or sinking, respectively. 

    Regarding the reference question - A standard op-amp has no specific "gnd" reference, the system "gnd" is meaningless to an amplifier.  In order to be sure the amplifier is configured properly, the input voltages and output voltage need to be considered relative to the supply voltages.  For example, the OPA202 needs the input voltages to fall within 1.5 V above the negative supply and 1.5 V below the positive supply:

    The output voltage is similar; you can find this from the Aol specification; in order to achieve high open-loop gain (Aol) then the output voltages need to be 1.25 V above the negative supply and below the positive supply.

    Hopefully this helps clarify your questions.

    Regards,
    Mike