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TMS320F28377S: ENOB for Vref = 3.3V

Prahaladh S
Intellectual 260 points

Part Number: TMS320F28377S

Hi, 

We're planning to use TMS320F28377S MCU in our application.

We're planning to use 3.3V VREF for the ADC.

In the datasheet, we could see that for the VREF = 2.5V, ENOB is given.

We would require ENOB for 12 bit single ended ADC, for a VREF of  3.3V

Kindly guide us in this regard.


Best Regards,

Prahaladh S

  • 0
    TI__Mastermind 25283 points

    Hi Prahaladh,

    Thanks for reaching out here. The setup you described is valid with one critical requirement as described in the datasheet:

    The VREFHI pin must be kept below VDDA + 0.3 V to ensure proper functional operation. If the VREFHI pin exceeds this level, a blocking circuit may activate, and the internal value of VREFHI may float to 0 V internally, giving improper ADC conversion or DAC output.

    The voltage source for VDDA will be prone to more noise/drift/offset/transients/etc. than the voltage reference source. Regardless of the real-time operating conditions of the respective devices, the VREFHI < (VDDA + 0.3 V) must be respected.

    Unfortunately, we have only carried out our characterization and validation data for the 2.5V reference voltage.

    We expect a general degradation of ~0.2 bits to the ENOB value with a VREFHI of 3.3V and fin = 100kHz.

    Best Regards,

    Zackary Fleenor

  • 0 in reply to Fleenor
    Intellectual 260 points

    Dear Fleenor,

    Thank you for your response.

    I'll check on this aspect.

    Best Regards,

    Prahaladh S