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ADuCM360 internal reference


I got a couple of questions about ADuCM360:

  • How can I get voltage from internal reference off chip?
    • Can I use Int_Ref pin for it? From functional block diagram I can see, that Int_Ref pin is buffered internal reference output, but datasheet sais only to connect 0.47uF bypass cap to it.
    • If I use DAC in NPN-driver mode AIN8 connected to internal reference and can be used as ref output pin. In that case what is possible output current of AIN8?
  • Is there any information about on-chip high frequency oscillator PSRR?
  • You can't draw any current out of the Int_Ref pin.

    It's only brought out on a pin so that the internal reference can be decoupled.

    If you need to use it outside the chip you need to buffer it first.

    In NPN mode the same reference is connected back internally to the chip into the DAC buffer so very little current is drawn out of the reference.

    We have specs for the PSRR for the ADC and the reference which would be the most sensitive to power supply noise.

    What are you worried about when it comes to the oscillator?