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AD5755-1 Output Stage Power Supplies

Question asked by teap on Apr 27, 2016
Latest reply on Apr 29, 2016 by teap

Hello,

I'm a bit confused regarding the AD5755-1 DA converter output stage power supplies.

 

The data sheet indicates that the VBOOST power supply is not only used for the current mode output stage, but also for the voltage mode output stage.

"Within a channel, the VOUT_x and IOUT_x stages share a common VBOOST_x supply so that the outputs of the IOUT_x and VOUT_x stages can be tied together."

 

Could anybody please explain for voltage output mode? Does this mean that the final output stage buffer is supplied by VBOOST only? How does the voltage mode output stage generate negative voltages (in bipolar output mode) with VBOOST being +15V (only)?

 

(1) In current output mode, the output load current has an impact on the VBOOST/AVCC power supply current, but not really on the AVDD/AVSS power supply, right?

 

(2) In voltage output mode, any output load current has an impact on the AVDD/AVSS power supply current, but not really on the VBOOST, AVCC power supply, right?

 

(3) What is the VBOOST function in voltage output mode?

 

Thank you!

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