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AD5791 Eval board: voltage output doesn't change

Question asked by bybly on Dec 21, 2011
Latest reply on Dec 21, 2011 by bybly

Dear Community,

 

I'm trying to evaluate AD5791 on the ADI evaluation board EVAL-AD5791SDZ.

 

I use following settings:

 

- power supply: VCC=+5V / VDD=+12V / VSS=-12V

- external reference VREF=+5V (so DAC output range is +/-10V)

- serial communication with an external SPI generator (frequency 1MHz)

- LDAC is tied low (jumper LK4 inserted)

 

 

Communication with DAC is correct because I can change Control register value (example bit DACTRI) and I see change on DAC output.

 

After board power-up, I send value 0x200012 to Control Register to disable DACTRI and OPGND. DAC output voltage is now at VREFN (-10V in my case).

 

But the problem is when I try to change the DAC value (code 0x1000FF by example), the output voltage remains still to VREFN. I have also try to use other code but the output doesn't change. Is there any other configuration that I missed?

 

Thanks for your help.

 

Benoit

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