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MSP432P4011IRGC: VREF+ Connection

Jason Reeder
Genius 10440 points

Have one query on MSP432P4011IRGC VREF+ connection.

When we use internal generated ADC reference (No VREF supplied externally), what is the recommended connection for Pins 45 (VREF+) & Pin 46 (VREF-)? Our schematic snippet given below is fine?

 

  • +1
    TI__Guru**** 191906 points

    Hi Jason,

    Jason Reeder said:
    we use internal generated ADC reference (No VREF supplied externally), what is the recommended connection for Pins 45 (VREF+) & Pin 46 (VREF-)?

      In the datasheet, it is stated that for unused pins with a scecondary function that is shared with general-purpose I/O follow the guidelines for the Px.0 to Px.7 pins which is to set the port function in output direction, and leave unconnected. 

  • 0 in reply to Charles Tsai
    TI__Genius 10440 points

    Charles,

    Customer came back with the below comment:

         "Thanks for the feedback. We do using pin 45 for VREF feature with internal voltage reference (VREF+, so we can’t say that pin as “unused”, see schematic in first post).

          My question is do we need to have 0.1uF decap for that pin or float the pin without any decaps?"

    Jason

  • +1 in reply to Jason Reeder
    TI__Guru**** 191906 points
    Jason Reeder said:

          My question is do we need to have 0.1uF decap for that pin or float the pin without any decaps?"

    I don't see a problem with a 0.1uF bypass cap on Vref+ although you are not really using an external reference input. 

  • 0 in reply to Charles Tsai
    TI__Genius 10440 points

    I sent your feedback and then asked to confirm that the customer plans to DNP the voltage converter and to use the internal VREF and they said;

    "Thanks for the feedback. I will leave the schematics as is then.

     That’s right. We are planning to use internal VREF and have provided external VREF option as a place holder (Do not populate)."

    Seems like they could just DNP the 0.1uF cap and follow the TRM guidance of an unconnected pin but I'll leave it alone if you think the 0.1uF cap to ground won't harm anything.

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