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cdcm7005-sp programming

Sara Caron76
Prodigy 150 points

Hi

I have the spreadsheet for choosing the loop filter components. I am using the passive loop filter topology.

When I look at the datasheet Word 0 asks for the divider M and N (which I guess is P from the  spreadsheet).  Is this correct?

My Fref is 10 MHz

My VCXO is 1200 MHz

Ip =2mA

K= 70000 KHz/V

Divider out is 1 (I want 1.2GHz locked to the 10 MHz)

Any thoughts on Programming. I understand MSB first.

  • 0
    TI__Expert 4415 points
    Hi,

    Divider P and N are separate dividers that are both in the feedback path. The signal returning through VCXO_IN first goes through the P divider which outputs multiple frequencies that are divided down from VCXO_IN. FB_MUX controls which one of these divided down frequencies gets fed back through the N divider and then back to the PFD. The word controlling divider M and N (Word 0) is different from the one controlling P (FB_MUX, word 2). Refer to the Functional Block Diagram (section 9.2, page 19) in the datasheet for more information.