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HMC440 eval module with loop filter components?

Category: Hardware
Product Number: EVAL-HMC440QS16G

Hi,

I refer to the schematic diagram of the EVAL-HMC440QS16G below:

Could you please clarify if the components R1, R3, C5 and C6 parts of the loop filter?

This is confusing to me as the schematic derived from ADIsimPLL as below seems to be that R1 and R3  (from the eval board) are R1a and R1c respectively.

2. Are the caps C5 and C6 in the schematic of the EVAL-HMC440QS16G part of the loop filter? I note also that these components are present as C1a and C1b in the schematic from ADIsimPLL.

3. To use the EVAL-HMC440QS16G in a test setup, I plan to make a loop filter based on the LT6200 opamp based on the results from ADIsimPLL above. Do I need to replace/change R2 and R4 from 4.3 to 20Ohm?

3b. Do I need to change C5 and C6 from 1000pF to 31.8pF? 

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  • Hi Obabarin,

    Could you please clarify if the components R1, R3, C5 and C6 parts of the loop filter?

    Yes these components are considered to be an extension of the loop filter. 

    3. To use the EVAL-HMC440QS16G in a test setup, I plan to make a loop filter based on the LT6200 opamp based on the results from ADIsimPLL above. Do I need to replace/change R2 and R4 from 4.3 to 20Ohm?

    We recommend you swap the components to match the values on the ADISIMPLL, since you are introducing an active loop filter which is not captured in the actual PCB layout.

    Hope this helps.

    Jude

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  • Hi Obabarin,

    Could you please clarify if the components R1, R3, C5 and C6 parts of the loop filter?

    Yes these components are considered to be an extension of the loop filter. 

    3. To use the EVAL-HMC440QS16G in a test setup, I plan to make a loop filter based on the LT6200 opamp based on the results from ADIsimPLL above. Do I need to replace/change R2 and R4 from 4.3 to 20Ohm?

    We recommend you swap the components to match the values on the ADISIMPLL, since you are introducing an active loop filter which is not captured in the actual PCB layout.

    Hope this helps.

    Jude

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