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Why is the gain not equal to the value of feedback resistor when i use the Eval-ADA4350RUZ-P evaluation board?

Question asked by zaocan888 on Oct 23, 2017
Latest reply on Jan 10, 2018 by zaocan888

There is a problem when i  test the Eval-ADA4350RUZ-P evaluation board. However, i found that the gain is not equal to the feedback resistor value. Here is the process. Since i use the current resource(keithley 6221) instead of reference voltage source, I take off R1 and C1 and change the value of R2 to zero. Set the enable switch and the MODE switch both to logic 1(off position). Set the DIP switches(P0 to P2) to logic 0( on position), and also set P4 to logic 0(on position). Leave P3 to logic 1(off position). Thus, the value of feedback resistor should be 100 KΩ and also the gain should be 100K. Connect Vin-N to the current resource.  However, when i  set the value of current to 10 uA,  i found the result turned out to be 0.6V instead of the right  result.  I think the right result is 1V. I don' t know where i was wrong. I am eager to receive the letter.

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