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AD5755 unusual behavior for the 1st channel

Question asked by DIXIT on Aug 7, 2014
Latest reply on Aug 14, 2014 by msamera

Hi,

 

I am having a prototype board which has two AD5755; one configured in voltage mode and another for current output.

 

The voltage output channel, VOUT_A outputs a voltage of (-14.13V) soon after initializing the DAC for zero output. The rest three channels of the DAC shows approx. 0V and varies correctly with the change in the register values.

On a detailed analysis, we have observed a voltage of 43.6V at the VBOOST_A pin.

 

Similarly for current output DAC, the output remains to be 0mA at the IOUT_A pin irrespective of the value written to the data register. The other three channels works as specified.

 

Another observation is, while comparing the impedance of the DAC pins with that of AD5755EVM, the 23rd pin showed difference. In the EVM it showed 840K while in the non working board an open was shown.

 

Please help us in this regard to troubleshoot the cause of this behavior of the DAC

 

Thanks,

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