EE PRO for TI-89, 92 Plus
Equations - Solid State Devices
101
constant
ε
s, Nd, Vbi, and the drain saturation voltage VDsat. The last two equations display the relationship for drain
voltage and drain current upon saturation.
ID
q Z
n Nd b
L
VDD
Vbi Vp
VDD Vbi VG
Vbi Vp
Vbi VG
Vbi Vp
= ⋅ ⋅ ⋅ ⋅
⋅ ⋅
− ⋅
−
⋅
+
−
−
F
HG
I
KJ
−
−
−
F
HG
I
KJ
F
H
G
I
K
J
F
H
GG
I
K
JJ
2
2
3
1 5
1 5
µ
b
g
.
.
Eq. 27.14.1
IDsat
q Z n Nd b
L
VDsat
Vbi Vp
VDD Vbi VG
Vbi Vp
Vbi VG
Vbi Vp
= ⋅ ⋅ ⋅ ⋅ ⋅ ⋅
− ⋅
−
⋅
+
−
−
F
HG
I
KJ
−
−
−
F
HG
I
KJ
F
H
G
I
K
J
F
H
GG
I
K
JJ
2
2
3
15
15
µ
b
g
.
.
Eq. 27.14.2
b
s
q Nd
Vbi VDsat VG
=
⋅
⋅
⋅
+
−
2 0
ε ε
1
6
when VG
Vp and VDsat
Vbi Vp
<
<
−
R
S
T
U
V
W
l
q
2
3
(
)
Eq. 27.14.3
VDsat
VG Vp
=
−
when VG
Vp and VDsat
Vbi Vp
>
>
−
R
S
T
U
V
W
l
q
2
3
(
)
Eq. 27.14.4
IDsat
ID
VG
Vp
=
⋅ −
F
HG
I
KJ
0 1
2
Eq. 27.14.5
Example 27.14 -
Find the saturation current when the drain current at zero bias is 12.5
µ
A, the gate voltage is 5 V,
and the Pinchoff voltage is 12 V.
Entered Values
Calculated Results
Solution -
Use the third equation to solve this problem. Select the equation by highlighting and pressing the
¸
key. Press
„
to display the input screen, enter all the known variables and press
„
to solve the equation. The
computed result is shown in the screen display above.
-PQYP8CTKCDNGUD
A
µ
ε
U
0F
'AEO@
8DK
A8
8)
A8
%QORWVGF4GUWNVU
8&UCV
A8