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HMC807 - Ring Oscillator frequency / Digital Lock Detect window


I'm wondering what is the frequency of the HMC807 internal ring oscillator?

In the "pll_operating_guide_mwave_vcos.pdf" for the HMC807 it says the digital lock detect window length depends on following bits configured in the register 0x07 / LKD/SCP:

[16:14] oneshot_duration

[18:17] ringosc_cfg

Is there a table available for the HMC807 like in the HMC704 datasheet?

Thank you very much!

Best regards, Herbert

  • Hi Herbert,

    I'm not sure of the frequency of the ring oscillator but it isn't essential to know this in order to derive the proper LD window. I'm attaching an FAQ that outlines exactly how to use LD for a PLL that is similar to that in the HMC807. The PLL in the HMC807 is different than the HMC704 for which the table you are referencing was provided. Using the example in the attached FAQ at 5GHz these differences result in a LD window that is roughly twice that of what is required for the HMC807. 

    Hope this helps,