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ADS1216: PWDN(bar) go as high as AVDD or is it limited to DVDD

Mark Philip Felipe
Genius 9705 points
Part Number: ADS1216

Hi Team,

If my AVDD is 5V and my DVDD is 3.3V, can PWDN(bar) go as high as AVDD or is it limited to DVDD?

I understand you would be needing assistance if can PWDN(bar) go as high as AVDD or is it limited to DVDD?

If all of the following pins can float or if they need to be terminated to GND or high (also I did not find this in the datasheet). D0-D7, IDAC1, IDAC2, DRDY (bar), DSYNC (bar, POL, Xin, RDA, VrefOut, and BUFEN My assumption is that these can float but I wanted to check before I commit the design.

Thank you.

-Mark

  • 0
    TI__Guru** 113765 points

    Hi Mark,

    The circled pins are all digital and CMOS digital input pins should never float as large current draw from the supply could take place at the transition between logic high and logic low (where the input floats).  Digital output pins can be left unconnected.

    Pins that should not float include:

    • BUFEN
    • RESET
    • PDWN
    • POL
    • DSYNC
    • CS
    • DIN
    • SCLK
    • and DO-D7 if used as inputs.  See page 18 and section DIGITAL I/O INTERFACE

    Digital input pins must follow the DVDD supply voltage.  If AVDD is 5V and DVDD is 3.3V connecting PDWN to AVDD would be a violation and can damage the device.  See the ABSOLUTE MAXIMUM RATINGS on page 2 for Digital Input Voltage to GND in the table.

    Best regards,

    Bob B