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CCS/CC430F5135: Issue of communication while using crystal of different make but all the specifications and frequency are same.

Part Number: CC430F5135

Tool/software: Code Composer Studio

Hello All,

I am working on CC430F5135 RF based controller part, in this I am facing the issue of communication while using the RF crystal(26.000MHz) of different make but having the all other specifications are same and also the loading capacitors are same. But in case of same make (manufacturer) it works very fine. Please give me a guidance for this issue because it will create problem in our production.

Thanks in advance.

Regards,

Avinash T.  

  • Hi,

    There are several cheap manufactures of poor crystals available and these should be avoided. Cheaper crystals have a high level of spurs that will also be reflected onto the RF path. Usually, fundamental mode crystals are required to have only one resonance frequency. All other resonance frequencies, also know as spurious modes, needs to be well attenuated. If not, the oscillator will produce a mix of frequencies. This leads to high spurious output levels and wrong reference frequency, both which are detrimental RF systems.

    The crystal must maintain a ratio > 10 of the motional resistance of the spurious mode to the motional resistance of the fundamental mode.

    Regards,
    Richard
  • Hello Richard,

    Can you please tell me 2-3 manufacturer for crystal, so that I can try this on my board.

    Regards,

    Avinash T.

  • Hi,

    Recommend to use the same crystal as used in the reference design since this has been thoroughly tested.

    I only have two crystal part numbers from NDK:

    NDK: NX3225GA, EXS00A-CG01972

    NDK: AT-41CD2 26 MHz EXS00A-02094

    Regards,
    Richard

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