Programming instructions

N-Channel & P-Channel GaAsFET
 National Instruments Corporation 4-21 Multisim Component Reference Guide
4.12 N-Channel & P-Channel GaAsFET
This component is a high-speed field-effect transistor that uses gallium arsenide (GaAs) as the
semiconductor material rather than silicon. It is generally used as a very high frequency
amplifier (into the gigahertz range). A GaAsFET consists of a length of n-type or p-type
doped GaAs called the channel. The ends of the channel are called the source and the drain.
The terminal with the arrowhead represents the gate. GaAsFETs are used in microwave
applications.
4.12.1 Model and Characteristic Equations
The GaAsFET component is based on the Statz model.
where:
V
gs
= gate-source voltage
V
ds
= drain-source voltage
V
TO
= threshold voltage; equivalent to the gate-source cutoff voltage
a = saturation voltage
b = transconductance
l = channel-length modulation
Id = drain to source current
()
()
()
=
1+ V V V 0
for
for
ds gs TO
Id
VV
V
VV
gs TO
ds
gs TO
0
11
3
1
2
3
VV 0
gs TO
−<
∗∗∗−∗
−−∗












+∗ −
−≥







βλ
α
β
ComponentRef.book Page 21 Thursday, December 7, 2006 10:12 AM