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Original question:

PGA900: gate driver

PGA900: the AVDD and DVDD outputting of PGA900 near to the GND

jinyan ma
Prodigy 150 points
Part Number: PGA900

Hi :

 I have some problem with PGA900, the outputting of the AVDD and DVDD of some PGA900 is a voltage near ground ,I want to know what can cause this. the below is the  schematic .

thanks and best regards

Kim

  • 0
    TI__Mastermind 31655 points

    Hi Kim,

    What voltage are you supplying to VDD, and what is the total current draw of the PGA900? If you remove R3 and R4 do you see a difference in the AVDD and DVDD voltages? Also, what is the total impedance of the bridge sensor that is connected to VBRGP?

    Regards,

    Scott

  • 0 in reply to Scott Cummins
    Prodigy 150 points

    HI Scott:

    thanks for your reply.

    the VDD range is 5 to 30V,the normal voltage is 24V.

    I removed the R3 and R4,there is no change in the AVDD and DVDD voltage.And the total input impedance to the VBRGP is 5.27MΩ。

    Best regards

    Kim

  • 0 in reply to jinyan ma
    TI__Mastermind 24288 points

    Kim,

    Scott is on travel, so I will help while he is out.  When you mention "some PGA900 is a voltage near ground ", are you saying that you have built multiple modules and some of these modules behave correctly and others will output a bad voltage near ground?  Or, are you talking about an initial prototype and it always outputs a voltage near ground.  My interpretation is that you have multiple units and some output a value of AVDD and AVSS that is near GND.  If some devices operate correctly, than I believe it is likely that the bad units have soldering issues.

    Art