When using the AD9705 with the 1.25V internal reference what should be the voltage on the FS ADJ pin?

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    •  Analog Employees 
    on Oct 19, 2018 3:48 PM in reply to ntipton

    Ahh, I see. That is what you meant by adjusting voltage across Rset. Yes, it should work.

    It looks like you are using internal reference. If you measure REFIO and FS ADJ, are they both around 1.025V? What is Vout of AD5620? It must be less than the voltage at FS ADJ, such that current flows out of FS ADJ for the DAC to work. What is Rset? Can you change Vout of AD5620 by SPI writes? (V(FS ADJ)-V(VOUT))/Rset must be within 31.25 μA and 156.25 μA .