kindly help me in designing pll

we have a problem in designing PLL (Phase locked loop).. please help us......

That's a little like saying "please help me design an amplifier". There are many types of PLLs. What do you need the PLL to do?

The useful things to tell us about the PLL so that we can help would include:
- is the PLL for generating an AC waveform, or is it for demodulating FM from a carrier or is it for detecting a tone?
- what is the output or input frequency?
- are you trying to work with a specific IC or can we recommend one for you?