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ADP1055 External Synchronization with Spread Spectrum

Dear Sirs

I would like to use ADP1055 with external synchronization clock featured spread spectrum modulation.
For example, LTC6908-1 (Fcenter = 200-400 kHz, ±10% Frequency Spreading).

But I not sure that ADP1055 can support spread spectrum clock on SYNC pin.

Can someone confirm or disprove that, please?

-- Best Regards


  • I read in ADP1055 Data Sheet


    The ADP1055 has a SYNC pin that is used for frequency
    synchronization. The internal digital phase-locked loop (DPLL)
    is capable of determining the master frequency on the SYNC pin
    (f SYNC ) and locking the internal switching frequency to the external
    frequency. The lock or capture range is ±10% of the switching
    frequency, which is programmed using the FREQUENCY_
    SWITCH command (Register 0x33). "

    It seems that ADP1055 can support spread spectrum on the assumption that modulation is not exceed  ±10%.

    Any comments or suggestions?

    -- Regards


  • You are correct. As long as input frequency does not deviate from internal frequency in 0x33 the ADP1055 will track the variation and spectrum of the input frequency.

    May I ask how you are going t generate this spread spectrum waveform and feed it into the SYNC pin of ADP1055?

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