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LMX2820: Issue with ACAL_CMP_DLY configuration for LMX2820

Mark
Prodigy 97 points

Part Number: LMX2820
Other Parts Discussed in Thread: LMX2594,

Tool/software:

Hi,

I am currently working with the LMX2820 and have encountered an issue while configuring the R6 register. I am unsure about how to set the value for ACAL_CMP_DLY. The relevant content in the LMX2820 datasheet is relatively brief. For reference, I checked the LMX2594 datasheet, which provides a more detailed explanation of ACAL_CMP_DLY. However, I still have the following questions:

(1) Based on the description in the LMX2594 datasheet, reducing the value of ACAL_CMP_DLY can shorten the VCO calibration time. However, why does it state that "if calibration time is a concern, ACAL_CMP_DLY should be ≥ 25 rather than ≤ 25"?

(2) For LMX2820, can the ACAL_CMP_DLY setting be directly referenced from the LMX2594 configuration?

Specifically, is the minimum allowed value 10 in all cases? Additionally, to achieve the best and repeatable VCO phase noise performance, is the formula for calculating the minimum ACAL_CMP_DLY value also "ACAL_CMP_DLY > Fsmclk / 10MHz"?

Thank you in advance for your help and insights!

Best regards,

Mark