The output observed on the pins OUT1_P/OUT1_N/OUT2_P/OUT2_N of AD9785 is always high before and after programming.

Whenever I am probing the output on L1,L2,L3,L4 connected to the pins OUT1_P,OUT1_N,OUT2_P,OUT2_N it always shows 3.3V before and after programming. I have cross checked every connection as per the reference schematic and nothing was changed significantly.

Please let me know your thoughts on what could be the issue.

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  • +1
    •  Analog Employees 
    on Mar 30, 2021 8:11 AM

    Hi psrt1995,

    I noticed you did not connect load resistors to the main DAC outputs. The output compliance voltage for the main DACs is up to 1V. So if you are operating in a full-scale output current of 31.66mA, there should be 30.1Ω load resistors connected across IOUTP and ground and IOUTN and ground.

    Regards,
    Shine

Reply
  • +1
    •  Analog Employees 
    on Mar 30, 2021 8:11 AM

    Hi psrt1995,

    I noticed you did not connect load resistors to the main DAC outputs. The output compliance voltage for the main DACs is up to 1V. So if you are operating in a full-scale output current of 31.66mA, there should be 30.1Ω load resistors connected across IOUTP and ground and IOUTN and ground.

    Regards,
    Shine

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