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How to implement flexible gain settings using the ADA4960-1

The ADA4960 datasheet mentions:

"The buffered inputs of the ADA4960-1 isolate the gain-setting

resistor (RG) from the signal inputs, maintaining a constant 10 kΩ

input resistance, easing matching and input drive requirements."

Does this affect the behaviour of the feedback resistor? Can I use several gain resistors switched by a coax relay?

What is the best way to implement 2 or 3different gain settings?

  • Hi, Bernhard.

    ADA4960-1 has dedicated pins for the gain setting which makes it easier to configure the desired gain from a range of 0dB to 18dB by using a single resistor. This feature eliminates the use of two resistors, as Rg and Rf, to configure the gain which is mostly done in conventional op amps. You may refer to page 15 of the datasheet for more details about this.

    Yes, you can use a relay to set the gain but there are disadvantages like "OFF"-state leakage currents that flow through the switching device, high "ON"-state voltage drop and high power dissipation that you have to consider in using it. As alternative to this, you may use ADI's multiplexers for a more controlled signal path and are in smaller package. You may look at this link and also you may refer to this tutorial for multiplexers.

    Hope this helps. Let me know if you have other concerns.



  • Hi, Bernhard.

    Good day! Have you already solved your problem? Let me know of your progress on this.



  • Hi, Anna,

    Yes,  thank you very much for your help. I will set up my design using a set of relay switched gain resistors.

    Best regards