I am using ADF9010 to build an UHF RFID reader. I build the PCB board by myself. There is a problem in using the internal charge pump to tune the internal VCO. Basically, what i have found is that my VCO is always output 810MHz, and it cannot be tunned. I can turn the VCO off by writing the register. I found the problem is caused by the charge pump output. There is no current and voltage coming out from the charge pump pin. I checked the Vp pin which is the power supply for charge pump and I also checked the Rset pin. They seem to be ok.
Are there any other factors can cause this problem?