how to design a charge pump pll without resistor?

[xihuwang]

charge pump pll

Hi,every one :
I am designing a charge pump pll. I found the bias current ckt and low pass
filter need resistors , but the process (soi cmos) I use don't provide resistor
device. So my questions are :
How to design the bias and filter ckt without resistgor?
Wheather may I use mos fet woking as resisors ?
Is there any optional structures that need not resistor?

 

[huangjw]

design of charge-pump pll

refer to a jssc paper in 1996, the structure is self-bias