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TMS320F28035: What clock accuracy can I expect?

Devon Curry
Prodigy 470 points
Part Number: TMS320F28035


I have a customer who is looking for assistance with the following information:

1) Is it possible to get within +/- 1%
2) What can be expected for clock accuracy?

  • 0
    TI__Guru 60865 points
    Hi Devon,

    If you use an external XTAL or clock source, the accuracy will be limited by that source. An XTAL should be able to easily meet 1% accuracy.

    If you use the internal oscillator on the device, the accuracy over operating conditions is approximately 5%. Most of this is due to temperature variation. See Figure 5-9. "Zero-Pin Oscillator Frequency Movement With Temperature" in the datasheet.

    When using the internal oscillator, we also have software compensation libraries to use the internal temperature sensor to compensate for oscillator temperature drift. This will typically result in better than 1% accuracy across temperature.
  • 0 in reply to Devin Cottier
    Prodigy 10 points
    When using the compensation libraries, is there a max/min clock accuracy across temperature?
  • 0 in reply to Josh Matthews
    TI__Guru 60865 points
    Hi Josh,

    This isn't something we can test in production on every part, so we don't have a guaranteed specification in the datasheet.

    From bench characterization of split-lot units, we saw a worst case error slightly below 1% across temperature and the worst case occurs near minimum temperature (-40 C).