T
tiger66
- Jan 1, 1970
- 0
Hi All
I am a bit confused with the differential input amplifier concept, I
hope experts out there can give me some assistant.
For the differential input amplifier to achieve the max dc gain, does
the Vin- and Vin+'s dc voltage must be zero?
I uses the netlist below for implementing my 2 stage amplifier, it
seems that both Vin- and Vin+ equals to 0V gives me the highest dc
gain (64dB)
If Vin- and Vin+ all equals to zero, does that mean there is no input-
offset voltage?
Finally, I am just wondering, does the max and min output voltage of
the 2 stage amplifier depend only on VDD and Vss values respectively?
I simulated the .dc response and the plot shows that the max output
voltage is 2.5V and the min is -2.5V which are VDD and Vss. So, do VDD
and Vss control the output voltage or is it just a coincident?
I would be really appreciate if someone could clarify my questions
above.
Thanks
*Netlist:
VDD 1 0 DC 2.5
Vss 7 0 DC -2.5
VbiasQ5 2 0 DC 1.5
*
Mp5 8 2 1 1 p1 W=200u L=1.2u
+AD=840p AS=840P PD=210u PS=210u
Mp1 10 9 8 1 p1 W=200u L=1.2u
+AD=840p AS=840P PD=210u PS=210u
Mp2 12 11 8 1 p1 W=200u L=1.2u
+AD=840p AS=840P PD=210u PS=210u
Mn3 10 10 7 7 n1 W=100u L=1.2u
+AD=420p AS=420P PD=110u PS=110u
Mn4 12 10 7 7 n1 W=100u L=1.2u
+AD=420p AS=420P PD=110u PS=110u
Mp6 13 2 1 1 p1 W=200u L=1.2u
+AD=840p AS=840P PD=210u PS=210u
Mn7 13 12 7 7 n1 W=200u L=1.2u
+AD=840p AS=840P PD=210u PS=210u
CL 13 0 .5PF
* simple compensation network
*Cc 15 13 ?? pF
*Rc 12 15 1
*
VINL 9 0 dc 0
VINH 11 0 dc 0 ac 1
*
*.op
..dc Vinh -2.5 2.5 .0001
*.ac dec 20 1 1G
*.TRAN 0.001m 20m
..TEMP 27.0
*
* Microwind 0.6 micron foundry level 3 models
*n-mos model
..MODEL N1 NMOS LEVEL=3 VTO=0.80 U0=600 TOX=15.0E-9
+LD =0.010U THETA=0.200 GAMMA=0.700
+PHI=0.700 KAPPA=0.010 VMAX=130.00K
+CGSO=100.0p CGDO=100.0p
+CGBO= 60.0p CJSW=240.0p
*p-mos model
..MODEL P1 PMOS LEVEL=3 VTO=-0.80 U0=200 TOX=15.0E-9
+LD =-0.050U THETA=0.200 GAMMA=0.450
+PHI=0.700 KAPPA=0.040 VMAX=100.00K
+CGSO=100.0p CGDO=100.0p
+CGBO= 60.0p CJSW=240.0p
..END
I am a bit confused with the differential input amplifier concept, I
hope experts out there can give me some assistant.
For the differential input amplifier to achieve the max dc gain, does
the Vin- and Vin+'s dc voltage must be zero?
I uses the netlist below for implementing my 2 stage amplifier, it
seems that both Vin- and Vin+ equals to 0V gives me the highest dc
gain (64dB)
If Vin- and Vin+ all equals to zero, does that mean there is no input-
offset voltage?
Finally, I am just wondering, does the max and min output voltage of
the 2 stage amplifier depend only on VDD and Vss values respectively?
I simulated the .dc response and the plot shows that the max output
voltage is 2.5V and the min is -2.5V which are VDD and Vss. So, do VDD
and Vss control the output voltage or is it just a coincident?
I would be really appreciate if someone could clarify my questions
above.
Thanks
*Netlist:
VDD 1 0 DC 2.5
Vss 7 0 DC -2.5
VbiasQ5 2 0 DC 1.5
*
Mp5 8 2 1 1 p1 W=200u L=1.2u
+AD=840p AS=840P PD=210u PS=210u
Mp1 10 9 8 1 p1 W=200u L=1.2u
+AD=840p AS=840P PD=210u PS=210u
Mp2 12 11 8 1 p1 W=200u L=1.2u
+AD=840p AS=840P PD=210u PS=210u
Mn3 10 10 7 7 n1 W=100u L=1.2u
+AD=420p AS=420P PD=110u PS=110u
Mn4 12 10 7 7 n1 W=100u L=1.2u
+AD=420p AS=420P PD=110u PS=110u
Mp6 13 2 1 1 p1 W=200u L=1.2u
+AD=840p AS=840P PD=210u PS=210u
Mn7 13 12 7 7 n1 W=200u L=1.2u
+AD=840p AS=840P PD=210u PS=210u
CL 13 0 .5PF
* simple compensation network
*Cc 15 13 ?? pF
*Rc 12 15 1
*
VINL 9 0 dc 0
VINH 11 0 dc 0 ac 1
*
*.op
..dc Vinh -2.5 2.5 .0001
*.ac dec 20 1 1G
*.TRAN 0.001m 20m
..TEMP 27.0
*
* Microwind 0.6 micron foundry level 3 models
*n-mos model
..MODEL N1 NMOS LEVEL=3 VTO=0.80 U0=600 TOX=15.0E-9
+LD =0.010U THETA=0.200 GAMMA=0.700
+PHI=0.700 KAPPA=0.010 VMAX=130.00K
+CGSO=100.0p CGDO=100.0p
+CGBO= 60.0p CJSW=240.0p
*p-mos model
..MODEL P1 PMOS LEVEL=3 VTO=-0.80 U0=200 TOX=15.0E-9
+LD =-0.050U THETA=0.200 GAMMA=0.450
+PHI=0.700 KAPPA=0.040 VMAX=100.00K
+CGSO=100.0p CGDO=100.0p
+CGBO= 60.0p CJSW=240.0p
..END