gm-constant bias problem

[chunlee]

Hi,

I'm try to design a gm-constant bias circuit. However, when i do transient simulation for different process corner, i found that the current in the circuit will oscillate. How can i make the circuit become more stable for different process corner?

Thanks,
Chun Lee

 

[ericliu]

If you use HSPICE to see the simulation result of the current in the circuit, you should set "method=gear" in ".options" to avoid the current oscillation.

 

[iocx]

Can you give your gm-constant bias circuit diagram and simulation results? Do you simulate gm-constant bias circuit alone or with other component?

 

[chunlee]

Hi ericliu,

May i know what is the purpose to set "method=gear" in ".options? which one will represent the real enviroment?

My gm-constant bias design is based on conventional circuit design, you can find it in any analog circuit design reference book.

Regards,
chun lee