How to design a charge pump for a DLL in .18um technology

Hi,I'm Kashyap, I'm designing an Analog DLL using 0.18 um technology.I'm done with the design of a PFD, but I'm stuck at the design of charge pump.The causes of my worry are:

1.How do you model your charge pump according to the technology you are using, eg. .18 um tech. I mean what calculations are to be made? And how to do them.

2.what are the specifications of a typical charge pump used in a DLL

3. What is the output voltage of charge pump that is required to drive the VCDL.