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DAC7562: DAC 7562 Schematic Review External reference

Part Number: DAC7562
Other Parts Discussed in Thread: LP2985

Dear Team,

I am using DAC7562 with an external refrence.Below is the schematic.

May I know is this fine or not.

Do I need to take care anything particular in Hardware or Firmware when I am using external reference.

The 5V output is coming from LP2985-5.0 .The input voltage to LP2985 is 12V

Regards

Hari

  • Hi Hari,

    The internal reference is disabled by default, so you don't have to configure any settings related to the reference. 

    Be careful when loading the LP2985-5.0. Any change dropout on the output will be reflected on the DAC output because you are using this supply as the reference. 125 mV of dropout is ~102 LSBs of error in the DAC. You could consider using the internal reference of the DAC instead. 

     

    The schematic looks fine otherwise. 

    Best,

    Katlynne Jones 

  • Hi Katlyne,

    Thank you very much.

    May I know the math behind "125 mV of dropout is ~102 LSBs of error in the DAC".

    Regards

    HARI

  • Hi Hari,

    The LSB size for a 12-bit DAC using a 5-V reference is 1.22 mV. 125mV/1.22mV is 102 LSBs of error. 

    Best,

    Katlynne Jones