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TMS320F28388D: VREF HI + TMS320F28388D

Ralf Rink
Intellectual 420 points
Part Number: TMS320F28388D


Hello together,

i have found to values for VREF HI in document / chapter "SPRSP14 / 5.9.2.2 ADC Electrical Data and Timing":  2.5 or 3.0 V

I couldnt find any explanations to the differences / advantages / disadvantages while choosing 2.5 V or 3.0 V?

Can somebody give me further informations?

Kind regards Ralf

  • 0
    TI__Guru 60865 points

    Hi Ralf,

    2.5V and 3.0V are common options for voltage reference ICs:

    http://www.ti.com/power-management/voltage-reference/overview.html

    The ADC on the C2000 device will meet the DS specified performance with any VREFHI voltage within the operating conditions range.  However, noise in the ADC typically doesn't scale with increasing reference voltage, so nominal performance of SNR or DC codespread will be very marginally better when selecting a higher reference voltage.

    The selection of the reference voltage will probably have more to do with your signal chain.  Selecting some voltage over another may allow you to optimize the signal chain in some way

    • e.g. selecting a lower VREFHI may allow you to use 3.3V as the signal chain positive supply voltage, removing the need for a +5V supply rail
    • e.g. selecting a higher VREFHI may allow some sensor to fit in the ADC input range without scaling, saving an op-amp

  • 0 in reply to Devin Cottier
    Intellectual 420 points

    Hi Devin,

    thanks for your fast response.

    Ralf