Transcript Lab 2 Pictures

Amplification
Rd
ID
ID
Vds
Vgs
 V gs
ID
Slope
gm 
Small Rd
V dd / R d
Id
Q point
 V gs
Large
Rd
Q point
Id
Id
 V ds
Vt
Vgs
V knee
V dd
Vds
 V ds   R d  I d
  g m R d  V gs
© Bob York
Power Dissipation
ID
P  Pm ax
Imax
Rd
ID
Vds
P  V ds I d  Pm ax
Vgs
Vmax
© Bob York
Vds
CD4007
CD4007 n-Ch
2.5
* Typical - Typical Condition
.model MbreakND NMOS
+ Level=1 Gamma= 0 Xj=0
+ Tox=1200n Phi=.6 Rs=0
Kp=111u Vto=2.0 Lambda=0.01
+ Rd=0
Cbd=2.0p Cbs=2.0p Pb=.8 Cgso=0.1p
+ Cgdo=0.1p Is=16.64p N=1
1/2
* CD4007 NMOS and PMOS transistor SPICE models
I d [mA]
Sqrt(Id),
mA^0.5
0.25
0.20
2.0
0.15
0.10
1.5
0.05
0.00
1.0
0.8
1
1.2
0.5
0.0
0
1
2
3
Vgs, Volts
*The default W and L is 30 and 10 um respectively and AD and AS
*should not be included.
Id, mA
4
5
4
5
CD4007 N-ch
6
.model MbreakPD PMOS
+ Level=1 Gamma= 0 Xj=0
+ Tox=1200n Phi=.6 Rs=0
Kp=55u Vto=-1.5 Lambda=0.04
+ Rd=0
Cbd=4.0p Cbs=4.0p Pb=.8 Cgso=0.2p
+ Cgdo=0.2p Is=16.64p N=1
*The default W and L is 60 and 10 um respectively and AD and AS
*should not be included.
1.4
5
Vt  1V
4
K n  0.4mA/V
Data
2
Model
3
2
1
0
0
© Bob York
1
2
3
Vgs, Volts
2N7000
From DataSheet: (~2.5um technology)
*2N7000 SPICE MODEL
*
.MODEL 2N7000 NMOS (LEVEL=3 RS=0.205
NSUB=1.0E15
+DELTA=0.1
KAPPA=0.0506 TPG=1
CGDO=3.1716E-9
+RD=0.239
VTO=1.000
VMAX=1.0E7
ETA=0.0223089
+NFS=6.6E10 TOX=1.0E-7 LD=1.698E-9
UO=862.425
+XJ=6.4666E-7 THETA=1.0E-5 CGSO=9.09E-9
L=2.5E-6
+W=0.8E-2)
.ENDS
*
For large currents, Id-Vgs is approximately linear (dotted line)
For small currents (<100mA) the behavior is parabolic
© Bob York
2N7000
2N7000
120
10
9
8
7
6
5
4
3
2
1
0
Vt  2.35V
100
Id, mA
I d [mA]
Sqrt(Id),
mA^0.5
1/2
2N7000
Subthreshold
currents
K n  220mA/V
2
Data
Model
80
60
40
20
0
1.5
2.0
2.5
2.2
3.0
2.4
Vgs, Volts
2N7000
100
1
1.0
2.0
3.0
4.0
Id, mA
10
Id, mA
3.2
120
100
80
60
40
0.01
20
0.001
0
Vgs, Volts
© Bob York
3.0
2N7000
1000
0.1
2.6
2.8
Vgs, Volts
2.2
2.4
2.6
2.8
Vgs, Volts
3.0
3.2
2N7000
Pdiss=400mW
© Bob York
Measuring Parameters gm, Vt
This is a simple method for estimating device parameters
Vdd
• Use diode-connected device (forces operation in saturation)
• With an ammeter, vary the supply voltage until the desired
bias current is achieved, and record the gate voltage Vgs
A
• Adjust Vdd so that Vgs changes by a small amount (say 50mV),
and record the resulting change in current
gm 
Vout
Id
 V gs
• Continue varying the gate voltage until the current increases
by a factor of 4. If the device follows a parabolic law, this
means that the (Vgs-Vt) must have changed by a factor of 2
I d 1  K n V gs1  V t 
2
I d 2  4 I d 1  K n V gs 2  V t 
r 
2
Id 2
Id1
For r = 2:
© Bob York
Vt 
rV gs 1  V gs 2
r 1
V t  2V gs 1  V gs 2
Common Source Amps
Vdd
Rg1
Vdd
Rd
∞
∞
Rd
Rg1
∞
Rgen
Vout
Vin
∞
Vout
RL
Vgen
Rg2
Rg2
Rgen
Vin
Rin
© Bob York
vin
gmvin
Rout
Vout
Vgen
Rin
vin
gmvin
Rout
RL
Lab Circuits
+10 V
+10 V
220 Ω
100 kΩ
Vin
100 kΩ
220 Ω
10 μF
Vout
Vin
10 μF
10 μF
10 μF
10 kΩ
10 kΩ
Rg1
Vout
Rg1
100 Ω
10 μF
© Bob York
Common Source Amplifier
Vdd
Rg1
Rsig
Rd
∞
∞
Vout
RL
Vsig
Rg2
Rs
© Bob York
∞
Common Gate Amplifier
Vdd
Rd
∞
∞
G
Vout
D
gmvgs
1/gm
S
D
1/gm
gmvin
vin
∞
S
Vin
G
Id
Vin
1/gm
vin
gmvin
R in  1 / g m
Rd
Vout
R out  R d
© Bob York
Av 
Vout
V in
 g m Rd
Common-Gate Amplifier
Vdd
Rg1
Rg2
Rd
∞
Vout
∞
RL
∞
Rgen
Vgen
Rs
R in  R s
Rgen
Vgen
© Bob York
Rin
1 gm  1 gm
R out  R d
vin
gmvin
Rout
RL
Av 
Vout
V in
 g m  Rout
RL 
Lab experiment
+10 V
220 Ω
10 μF
Rg1
10 μF
100 kΩ
10 kΩ
Vin
Rs
100 μF
© Bob York
100 Ω
Vout
Source Follower
Vdd
Rg1
Rgen
Rd
∞
∞ Vout
Vgen
Rg2
Rs
RL
© Bob York
CS Resistive Feedback
Rf
Vdd
Vdd
Rd
Id
∞
Vout
∞
∞
Vin
© Bob York
RL
Vin
Rg
Vin
∞ Vout
Rf
vgs
Rgen
gmvgs
Rout
Vout
Vgen
Rg
vgs
gmvin
RL
CD4007
VDD
14
1
P
P
2
13
3
12
4
P
11
N
5
VSS
© Bob York
2
13
1
6
3
11
10
8
5
7
4
12
10
6
7
14
N
N
9
8
9
Active Loading
Vdd
Vdd
Q2
Q3
C2
Rf
C1
Q4
Q1
Vin
© Bob York
Vout
RL