ADG5462F is not giving output as expected_required immediate support

Dear Analog,

We have used  ADG5462F part in our design as ADC Channel protector.  We are facing issue with its functionality as we are not getting expected output for the applied input. 

Eg: When we are giving 6V as input, we are getting some random voltages at its output.  Some channels are giving 9.9V, 11.25V . 1.2V, 0,3V for the same 6V  input.

Schematic is attached for your reference.  Could please suggest what could be the root cause for this issue. Same ADC is working for differential Channels where we have not used this protector

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Parents Reply
  • Dear David, 

    Thanks for your reply.


    We are using LFCSP package part.  It has exposed pad  connected to GND_A net  in our design which supposed to be connected to -15V as recommended in datasheet.

    Is this wrong connection causing this issue? 

    We checked resistance between GND_A and -15V,.  It is 84K ohm.

    We have measured -15V rail with respect to GND_A net.. It is -15V. No voltage drop.  

    Random voltages measured at the other end of resistors  R445, R446, R447 and R448 by applying 5V DC to input ends of the same resistors. 

    I can capture waveforms and share you for your analysis if this EP pin wrong connection is not root cause for this issue. Please confirm.

    Regards

    Nrupathunga

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