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TMS320F28379S: Simultaneous Sampling

Garret Holt
Intellectual 1050 points
Part Number: TMS320F28379S

Hi Team,

I am working with a customer who is targeting synchronously sampling 3 channels differentially for a motor current measuring application. We have a few questions relating to footnote 6 in the datasheet. They interpret this as a contradict synchronous sampling and implies sampling one signal at a time.  They need to measure 3 phase motor currents simultaneously. Is 3 phase simultaneous sampling possible with this device? Are you able to clarify what exactly is meant from foot note 6? I did not have the same interpretation and was hoping that this is a misunderstanding as it  seems like there are enough pins to distribute the 3 simultaneous sampling signals to not cause an issue. Also are we able to quantify footnote 10 which mentions that the max DC code deviation occurs during simultaneous sampling? Appreciate your help with this!

  • 0
    TI__Guru 60865 points

    Hi Garret,

    I/O here refers to digital IOs, not other ADC channels.  You can sample analog channels on separate ADCs simultaneously (up to 4, since there are 4 ADCs) and meet the rated ENOB. 

    You do need to avoid having the ADCs running asynchronously if you are using 16-bit (async. performance = "not supported").  The easiest way to ensure this would be to more-or-less treat the 4 ADCs as a single ADC with 4 simultaneous S+H.

    Footnote 10 is essentially the definition of the parameter since this isn't a standard ADC parameter; the quantification of the max additional deviation due to simultaneous sampling is +/-2 LSBs.