digital PLL frequency synthesizer

Iam programming the pll through PIC micro controller. i need help in deciding the required phase detector frequency for 10MHz reference frequency.

you sure do! is that all you know so far?

The Ic(PLL400-2200AY) supports 1.5ms to 3ms as settling time. for my required output frequency 2240 MHz it is not locking. so what can i change.

I have option to change in PFD frequency and charge pump current only...........

Plz help in this ..

there is rfmd controller software you can download to drive it. Start with that--usually the software will not let you input invalid register values. If you are using your own controller....it is really easy to get the register values wrong and the unit will simply not work. Also, there are sometimes combinations of frequencies that will never work, and need to be skipped over.
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Since you have a single frequency, you can use 10 MHz or 1 MHz at the PFD detector. If using 10 MHz, you obviously need to set the vco divider to 224, etc. Make sure the external 10 MHz is a big enough signal to drive the chip.