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DAC8775EVM: DAC8775EVM - Accuracy vs Load

Jose Maroto
Expert 3470 points
Part Number: DAC8775EVM

Hello team,

 

Please find customer issue below:

**************************************************************************

 

I'm testing the board and I find that the accuracy depends on the load you put on the current loop. I must be doing something wrong.

This is the configuration I am using:

 

 

Measured results:

Code 152Dà

Shortcircuit -20.000mA

160ohms -19.890mA

470 ohms -19.681mA

 

As you can see, the result is different depending on the load.  Could you please help?

**************************************************************************

Thanks and regards, Jose

  • 0
    TI__Genius 11750 points

    Howdy Jose,

    Thanks for posting to the e2e forums.  

    The DAC8775EVM connects both outputs VOUT/IOUT to the same net.  By default, the “Power-Off-Condition” of VOUT is set to 30k-to-PBKG at power-up.  This essentially connects a 30k to GND at IOUT , which will affect IOUT gain accuracy.   Therefore, you will need to instruct the customer to change the “Power-Off-Condition” field to “VOUT High-Z”.

    Please let me know if the customer has any other questions.

    Best Regards,

    Matt