EE PRO for TI-89, 92 Plus
Equations - Solid State Devices
98
an output voltage of 3.0_ V find the output high voltage, the input high voltage, and the threshold of the load
device. Assume a input voltage of 2.5_V.
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Solution -
Use Equations 27.11.1-27.11.4 and 27.11.6-17.11.7 to get a complete solution to the problem on hand.
Select these by highlighting each equation and pressing the
¸
key. Press
„
to display the input screen, enter all
the known variables and press
„
to solve the equation. The computed results are shown in the screen displays above.
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27.12 MOS Inverter (Depletion Load)
This section lists the design equations for a MOS inverter with a depletion load.
The first two equations compute device constants kL and kD for the load and the driver transistors in terms of their
geometries WD, WL, LD, and LL.
kL
n Cox WL
LL
=
⋅
⋅
µ
Eq. 27.12.1
kD
n Cox WD
LD
=
⋅
⋅
µ
Eq. 27.12.2
At the output low and output high, VOL and VOH, the driver is in the linear region while the load device is saturated.
The next equation finds the threshold voltage VTL for the load device in terms of its zero bias threshold VTL0, Fermi
potential
φφ
F, and body coefficient
γγ
.
kD
VOH VT
VOL VOL
kL
VTL
2
2
0
2
2
2
⋅
−
⋅
−
=
⋅
b
g
c
h
Eq. 27.12.3
VTL
VTL
Vo
F
F
=
+ ⋅
+ ⋅
−
⋅
0
2
2
γ
φ
φ
d
i
Eq. 27.12.4