i am designing cascoded amplifier using MOSFET, there i am facing this problem (saturation)...mathematically i calculate that my all transistor are in saturation but when i run it on mentrographics using eldo (TSMC 0.18), it shows different result...............this is my problem brother.........
saturation is by definition when Vdsat<Vds.
This said, in many cases Vds is dependent on the circuit itself. So, if you post your circuit with annotated operating point, may be someone will tell you what is going wrong.