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Good day everybody,
I'm using National Instrument's Multisim 10 to design and simulate a fully differntial telescopic op amp. The design picture, Problem source, design details and simulation files are associated.
The problem is that I can't get the NMOS telesdcopic transistors to work in saturation, the entire biasing voltage is distributed on the PMOS transistors.
Plz help if anybody knows where's the problem.
Design details
Currents in P, NMOS current mirrors are 0.17 mA each. Currents in differential branches are 1.5 mA each.
Mb2: (PMOS current mirror 2N6804)
L=1u W=118.5u
* RS=0 RD=0 LD=0 CBD=0 CBS=0 CGBO=0
.MODEL MM PMOS LEVEL=1 IS=1e-32
+VTO=-0.7 LAMBDA=0.1KP=3.555m
+CGSO=3.44747e-06 CGDO=1e-11
.
L=1u W=118.5u
* RS=0 RD=0 LD=0 CBD=0 CBS=0 CGBO=0
.MODEL MM PMOS LEVEL=1 IS=1e-32
+VTO=-0.7 LAMBDA=0.1KP=3.555m
+CGSO=3.44747e-06 CGDO=1e-11
.
M5-7 (PMOS telescopic 2N6804)
M1 9 7 8 8 MM L=1u W=1111u
* RS=0 RD=0 LD=0 CBD=0 CBS=0 CGBO=0
.MODEL MM PMOS LEVEL=1 IS=1e-32
+VTO=-0.7 LAMBDA=0.1KP=33.33m
+CGSO=3.44747e-06 CGDO=1e-11
M1 9 7 8 8 MM L=1u W=1111u
* RS=0 RD=0 LD=0 CBD=0 CBS=0 CGBO=0
.MODEL MM PMOS LEVEL=1 IS=1e-32
+VTO=-0.7 LAMBDA=0.1KP=33.33m
+CGSO=3.44747e-06 CGDO=1e-11
M1-4: (NMOS telescopic 2N7000)
Cgs 2 3 12.3E-12
Cgd1 2 4 27.4E-12
Cgd2 1 4 6E-12
M1 1 2 3 3 MOST1 W=2.5m L=2u
M2 4 2 1 3 MOST2 W=2.5m L=2u
D1 3 1 Dbody
.MODEL MOST1 NMOS(Level=3 Kp=75m W=2.5m L=2u Rs=20m Vto=0.7 Rd=1.186)
.MODEL MOST2 NMOS(VTO=-0.7 Kp=75m W=2.5m L=2u Rs=20m)
.MODEL Dbody D(Is=125f N=1.023 Rs=1.281 Ikf=18.01 Cjo=46.3p M=.3423
+ Vj=.4519 Bv=60 Ibv=10u Tt=161.6n)
Cgs 2 3 12.3E-12
Cgd1 2 4 27.4E-12
Cgd2 1 4 6E-12
M1 1 2 3 3 MOST1 W=2.5m L=2u
M2 4 2 1 3 MOST2 W=2.5m L=2u
D1 3 1 Dbody
.MODEL MOST1 NMOS(Level=3 Kp=75m W=2.5m L=2u Rs=20m Vto=0.7 Rd=1.186)
.MODEL MOST2 NMOS(VTO=-0.7 Kp=75m W=2.5m L=2u Rs=20m)
.MODEL Dbody D(Is=125f N=1.023 Rs=1.281 Ikf=18.01 Cjo=46.3p M=.3423
+ Vj=.4519 Bv=60 Ibv=10u Tt=161.6n)
M9: (current source NMOS 2N7000)
Cgs 2 3 12.3E-12
Cgd1 2 4 27.4E-12
Cgd2 1 4 6E-12
M1 1 2 3 3 MOST1 W=0.8m L=2u
M2 4 2 1 3 MOST2 W=0.8m L=2u
D1 3 1 Dbody
.MODEL MOST1 NMOS(Level=3 Kp=24m W=0.8m L=2u Rs=20m Vto=0.7 Rd=1.186)
.MODEL MOST2 NMOS(VTO=-0.7 Kp=24m W=0.8m L=2u Rs=20m)
.MODEL Dbody D(Is=125f N=1.023 Rs=1.281 Ikf=18.01 Cjo=46.3p M=.3423
+ Vj=.4519 Bv=60 Ibv=10u Tt=161.6n)
Cgs 2 3 12.3E-12
Cgd1 2 4 27.4E-12
Cgd2 1 4 6E-12
M1 1 2 3 3 MOST1 W=0.8m L=2u
M2 4 2 1 3 MOST2 W=0.8m L=2u
D1 3 1 Dbody
.MODEL MOST1 NMOS(Level=3 Kp=24m W=0.8m L=2u Rs=20m Vto=0.7 Rd=1.186)
.MODEL MOST2 NMOS(VTO=-0.7 Kp=24m W=0.8m L=2u Rs=20m)
.MODEL Dbody D(Is=125f N=1.023 Rs=1.281 Ikf=18.01 Cjo=46.3p M=.3423
+ Vj=.4519 Bv=60 Ibv=10u Tt=161.6n)
Mb1: (NMOS current mirror 2N7000)
Cgs 2 3 12.3E-12
Cgd1 2 4 27.4E-12
Cgd2 1 4 6E-12
M1 1 2 3 3 MOST1 W=45.33u L=2u
M2 4 2 1 3 MOST2 W=45.33u L=2u
D1 3 1 Dbody
.MODEL MOST1 NMOS(Level=3 Kp=1.36m W=45.33u L=2u Rs=20m Vto=0.7 Rd=1.186)
.MODEL MOST2 NMOS(VTO=-0.7 Kp=1.36m W=45.33u L=2u Rs=20m)
.MODEL Dbody D(Is=125f N=1.023 Rs=1.281 Ikf=18.01 Cjo=46.3p M=.3423
+ Vj=.4519 Bv=60 Ibv=10u Tt=161.6n)Cgs 2 3 12.3E-12
Cgd1 2 4 27.4E-12
Cgd2 1 4 6E-12
M1 1 2 3 3 MOST1 W=45.33u L=2u
M2 4 2 1 3 MOST2 W=45.33u L=2u
D1 3 1 Dbody
.MODEL MOST1 NMOS(Level=3 Kp=1.36m W=45.33u L=2u Rs=20m Vto=0.7 Rd=1.186)
.MODEL MOST2 NMOS(VTO=-0.7 Kp=1.36m W=45.33u L=2u Rs=20m)
.MODEL Dbody D(Is=125f N=1.023 Rs=1.281 Ikf=18.01 Cjo=46.3p M=.3423
