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TMS320F280049: what is the equivalent ADC input impedance?

Aki Li
Genius 9955 points

Part Number: TMS320F280049

Customer is asking for the the ADC input impedance. There is Ron defined in the ADC input model, but I wonder whether we can induce a equivalent ADC input resistor for it. Thank you.

  • 0
    TI__Guru 60865 points

    Hi Aki,

    The other aspect of the ADC not shown in the input model in the datasheet is the pin leakage current, which is also specified in the datasheet.  

    Otherwise I don't think it makes sense to view the ADC input as having an input resistance that needs to be matched; it really is a switched-capacitor circuit where settling time, source impedance, source bandwidth, the ADC input model, and the acceptable settling error need to be considered. 

  • 0 in reply to Devin Cottier
    TI__Genius 9955 points

    Devin,

    Thank you for the help.