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DAC8775: Configuration of buck boost converter and programming sequence of DAC8775

Naveen kumar
Prodigy 65 points
Part Number: DAC8775

We've designed DAC8775 chip based DAC board for PLC analog output application.

I've doubts about working steps of DAC8775 w.r.to Internal Buckboost converter.

Hardware design has two option as of now 

     1. DC-DC External supply to Positive (Vpos) and negative voltage (Vneg) to DAC8775.

     2. DC Supply to power up DAC8775 positive voltage (VPOS) and Internal buck boost converter to supply Negative voltage(Vneg)

In above two cases Config BB register's PNSEL bits will be 00 and 01.

In either of the case the working steps of the DAC8775 is the same or else do I need to change something in the sequence?

         Reset DAC          (Reg Id - 0x01)

         Select BB            (Reg Id - 0x06)

         Config BB            (Reg Id - 0x07)

         Select DAC          (Reg Id - 0x03)

         Config DAC         (Reg Id - 0x04)

         DAC Data write    (Reg Id - 0x05)

 

Regards,

Naveen

  • 0
    TI__Guru* 93465 points

    Naveen,


    The order of setting up the device basically follows the order shown in Figure 107 (page 45) of the datasheet. Even with the external power supplies, I would generally set up the device in the same order. Setting up BB (or setting them as disabled) and configuring the individual DACs, first by selecting it and then by configuring it. I would also point out that you would enable the internal reference (if you are using it) before the DACs are enabled.

    Did you have any specific questions about the order of setting up the device? I wasn't sure if you had seen something that was of particular concern. Note, I'm out of the office for a couple of days, so responses may take a little longer for questions here.


    Joseph Wu