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AMC1301: Change in gain due to on / off of VDD1

Teruhito Ishibashi
Prodigy 60 points
Part Number: AMC1301

Hi team,

I have a question about the gain of AMC1301.
I'm testing the AMC1301 and there are unclear points that are not mentioned in the datasheet.

We tested the parts individually, and measured the gain from the relationship between the input voltage and the output voltage.
When VDD1 is turned on and off, gain changes.
The voltage value of VDD1 has not changed.
The amount of change in gain is about 40-50ppm.
The gain takes two values, and it occurs randomly and discretely when VDD1 is turned on and off.
Do you have any knowledge?
How can I make gain have the same value even if vdd1 is turned on and off repeatedly?


Best regards,
Teruhito Ishibashi

 



  • +1
    TI__Guru**** 180751 points

    Hi Ishibashi-san,

    Welcome to our e2e forum!  I'm curious to know what equipment you are using that you can see a delta of 40-50ppm in the gain of the AMC1301.  Can you also let us know how many parts you tested? Was the delta you saw on a part-to-part basis or was it the mean of the sample set?  The typical gain error at room temperature is +/- 0.05%, so it sounds like the delta you have seen is well within the specification noted in the AMC1301 datasheet.

  • +1
    Prodigy 60 points

    Hello Tom

     

    Thanks for your reply mail.

    I’ll answer your question.

    I'm curious to know what equipment you are using that you can see a delta of 40-50ppm in the gain of the AMC1301. 

                  34401A / Keysight

    Can you also let us know how many parts you tested?

                  20-30 pcs

    Was the delta you saw on a part-to-part basis or was it the mean of the sample set? 

                  As far as I can tell, the phenomenon occurs in all parts.

    The typical gain error at room temperature is +/- 0.05%,

    so it sounds like the delta you have seen is well within the specification noted in the AMC1301 datasheet.

                   It is true that the range of gain error change is within +/- 0.05%,

                  but this phenomenon does not occur with IsoAMP from other manufacturers.

                  I would like to use your company's parts if possible.

                  Is the phenomenon I have confirmed a movement you know?

                  Is it within the expected range?

     

    Regards

    Teruhito Ishibashi

  • 0 in reply to Teruhito Ishibashi
    TI__Guru**** 180751 points

    Hi Ishibashi-san!

    Thanks for the added detail!  One more question for you - what was the input voltage you had applied to the AMC1301 during these tests?  There isn't anything you can do differently to avoid the small differences in gain during power up of the AMC1301, so I would recommend that you instead move to the AMC1300B, it is a newer device compared to the AMC1301, same input range, but better overall performance.  You should not see the gain differences with this device after power cycling.