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OPA690: Amplifier

Vishnu
Prodigy 70 points
Part Number: OPA690

Tool/software:

I am using OPA690 as summing amplifier with gain -1, will this design work?

We gave pull up resistor for disable pin so op amp can work in normal condition, is it correct?

  • 0
    TI__Genius 10560 points

    Hi,

    I have been working through the circuit and trying to think of potential concerns with the large number of inputs in the circuit. One concern is the potential for loading the amplifier as it has to in a sink/source enough current through all the branches. However, I do not think it would be a concern with this design. One thing to consider is the effect the added summing branches has on your effective bandwidth. This would effectively result in a high noise gain which would result in a lower overall bandwidth. One last consideration is the layout with this circuit. All of these branches would add capacitance to the inverting node which could result in oscillations. Having the small resistor package like you have will help but ensuring the layout is as tight as possible will be key as well as plane cutouts around the inverting pin and the area under the resistor pads directly connected to the inverting pin. The pull up resistor should not be an issue to enable this device.

    Best Regards,

    Ignacio