I want all mosfets work in saturation region

Hi every one.
I want to simulate a circuit in Hspice which I don't know their w/l value I work with it and I could calculate some of the w/l in paper but for some parts like mirror currents I don't have any w/l and i just Initialized them in a way that my IC have little area but 2 of my transistors work in linear region and when i change the w/l other transistors work in a bad way as there are a lot of transistors and i can't calculate them manually is there any way that i use that all my transistors work in saturation region i mean Hspice or other softwares have any option to optimize it??
with best regards

Hi mayin-kh,

Can you post the picture of your circuit along with the sizing of the transistors that you have kept.

Do you mean "saturated" or "fully on?" Checkout the section on mosfet characterization in this application note: https://www.fairchildsemi.com/an/AN/AN-558.pdf
Most application notes will have similar information. That one just happened to be handy.


JOhn

SIDDHARTHA HAZRA said:

Can you post the picture of your circuit along with the sizing of the transistors that you have kept.

Click to expand...

hi
yes this is a part of my code in hspice:

M1 vout1 vin+ 1 1 NMOS W=10u L=0.5u m=1
M2 vout2 vin- 1 1 NMOS W=10u L=0.5u m=1
M3 vout1 vin- 2 2 NMOS W=10u L=0.5u m=1
M4 vout2 vin+ 2 2 NMOS W=10u L=0.5u m=1
M5 3 vcn 5 5 PMOS W=10u L=0.5u m=.5
M6 4 vcp 5 5 PMOS W=10u L=0.5u m=.5
M17 5 vb vdd vdd PMOS W=5u L=1u m=1
M7 1 3 GND GND NMOS W=1u L=0.6u m=1
M8 3 3 GND GND NMOS W=1u L=0.6u m=1
M9 2 4 GND GND NMOS W=1u L=0.6u m=1
M10 4 4 GND GND NMOS W=1u L=0.6u m=1
M11 6 6 vdd vdd PMOS W=1u L=2u m=.5
M12 vcp 6 vdd vdd PMOS W=1u L=2u m=.5
M13 7 8 vdd vdd PMOS W=1u L=2u m=.5
M14 8 8 vdd vdd PMOS W=1u L=2u m=.5
M15 vcn 7 GND GND NMOS W=1u L=.5u m=6
M16 7 7 GND GND NMOS W=1u L=.5u m=6

Q1 6 vctrl GND T2n2222a
Q2 8 vctrl GND T2n2222a

.Model T2n2222a NPN LEVEL=1 ISS= 0. XTF= 1 NS = 1.00000
+ CJS= 0 VJS= 0.5 PTF= 0 MJS= 0 EG = 1.10000 AF = 1 ITF= 0.5
+VTF= 1 BR = 40 IS = 1.6339e-14 VAF= 103.40529 VAR= 17.77498
+IKF= 1 NE = 1.31919 IKR= 1 ISC= 3.6856e-13 NC = 1.10024 IRB= 4.3646e-05
+NF = 1.00531 NR = 1.00688 RBM= 1.0000e-02 RB = 71.82988 RC = 0.42753
+RE = 3.0503e-03 MJE= 0.32339 MJC= 0.34700 VJE= 0.67373 VJC= 0.47372
+ TF = 9.693e-10 TR = 380.00e-9 CJE= 2.6734e-11 CJC= 1.4040e-11 FC = 0.950
+XCJC= 0.94518View attachment mm018.txt
View attachment mm018.txt

thanks

You would like all transistors to work there but you don't
get to say. An input or output device that must approach
the rails is going to disregard your wishes.