AnsweredAssumed Answered

ADRF6750 divider didn't work

Question asked by JaeKyung on Feb 25, 2016
Latest reply on Feb 26, 2016 by LKelly

Hi,

 

I designed ADRF6750 b'd.

 

When first time, I feed 10 MHz reference clock and 1200 MHz RF clock. It work very well.

 

Now I want re-use this b'd for 54 MHz reference clock and 1200 MHz RF clock. But, it didn't work.

 

"didn't work" mean pll LOCKDET pin hold low and LOMON out (in spite of LOMON out disable) 1715 MHz

 

I tested some configuration, as following,

 

(1) ref:10MHz, doubler enable, divider disable, r-counter 1 (PFD=20MHz) It work well.

(2) ref:10MHz, doubler disable, divider disable, r-counter 1 (PFD=10MHz) It work well.

(3) ref:20MHz, doubler disable, divider disable, r-counter 1 (PFD=20MHz) It work well.

(4) ref:20MHz, doubler disalble, divider enable, r-counter 1 (PFD=10MHz) It didn't work.

 

When divider enable only, didn't work.

 

Divider disable, r-counter 2, r-counter enable register set is not work too.

 

Help me.

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