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ADC12020: Maximum clock frequency worse at 25C vs. over full temp range?

david royle
Intellectual 440 points
Part Number: ADC12020

Sheet 8, Maximum clock frequency:

25C typical 20MHz

Over temperature 30MHz

Are these reversed? All other 25C specs are better than over-temp specs (as we would expect).

  • 0
    TI__Mastermind 22030 points

    Hi David,

    My understanding from reading this datasheet is the typical application sample rate for this ADC is 20MSPS - the 25C is just how this device was characterized in 2003.

    My guess is the performance the bolded text was not intended to specify the performance at a specific temperature, but rather to refer to the maximum limit of the specification, regardless of temperature (as the bolded text applies for the device under Tj=Tmin to Tmax). This means that the maximum sample rate for this device is 30MSPS. Below is a snippet from the Application Information section on page 17 confirming my understanding.

    Regards, Chase

  • 0 in reply to Chase W
    Intellectual 440 points

    Exactly my question. if 30MSPS is maximum limit regardless of temp, then where is 20MSPS coming from? 20MSPS is how the part is described at the top of the first page of the datasheet.

    It would make sense if it were reversed, that you could get 30MSPS at 25C but only guaranteed 20 over temp.

  • +1 in reply to david royle
    TI__Mastermind 22030 points

    David,

    Unfortunately, there is nobody on our team who helped to characterize this part to ask. I imagine it is because there is also a 40MSPS device in the family and placing this device at 30MSPS with a similar power consumption is not good enough of a differentiation from a marketing view. This device may have been advertised at 20MSPS since more customers were interested in using this at 20MSPS and gaining lower power consumption versus a higher power consumption at 30MSPS. I agree that this is very strange, but all signs are pointing towards this device operating at 30MSPS maximum. 

    Thanks, Chase