I want all mosfets work in saturation region

[matin-kh]

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

 

[SIDDHARTHA HAZRA]

Hi mayin-kh,

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

 

[jpanhalt]

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

 

[matin-kh]

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

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

 

[dick_freebird]

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.