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TM4C1290NCPDT: clock input spec

Aaron Spaete
Expert 4647 points

Part Number: TM4C1290NCPDT

Team, 

My customer had the following question regarding use of TM4C1290NCPDT with an external clock that's slightly outside of specification.

The MCU will be used in two different types of Active Antennas. We are currently using a 13MHz clock on the design but it has been giving us many issues with spur appearing at our RF band. We have evaluated the all clock options from 5MHz to 25MHz and unfortunately all these frequencies will have harmonics that falls in our band.  We experimented with use of 26MHz with this MCU and it seems to work very well for us at our frequency band.

Can you help connect us with anyone at TI that can help us understand the impact of using 26MHz with this MCU or is there any possibility that can be acceptable.

Regards,

Aaron

  • 0
    TI__Guru**** 191886 points

    HI Aaron,

    Aaron Spaete said:

    Can you help connect us with anyone at TI that can help us understand the impact of using 26MHz with this MCU or is there any possibility that can be acceptable.

    No, it is not acceptable to exceed the spec which is 25Mhz. The device is only tested/qualified to the maximum limit as stated. Beyond the spec, we cannot guarantee no failures due to variations of different process corners, temperatures and voltages. What is the RF band range  (MF, HF, VHF and etc) you have problem with? Can you not use filter to remove the unwanted harmonics? Again, we cannot guarantee any operations that are outside of the spec. Sorry.