Keithley S530, Руководство пользователя

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Section 3: Test subroutine library reference S530 Parametric Test System Test Subroutine Library User's Manual
3-76 S530-907-01 Rev. A / September 2015
vtext2
This subroutine estimates the extrapolated gate-source threshold voltage of a metal-oxide field-effect transistor
(MOSFET) using a modified version of the
vtext
subroutine method.
Usage
double vtext2(int d , int g , int s , int sub , char type , double vlow , double vhigh ,
double vds , double vbs , double ithr , double vstep , int npts , double *slope , int
*kflag )
d
Input The drain pin of the device
g
Input The gate pin of the device
s
Input The source pin of the device
sub
Input The substrate pin of the device
type
Input Type of transistor:
"N"
or
"P"
vlow
Input
The start of the gate-source voltage (V
GS
) binary search, in volts
vhigh
Input
The end of the V
GS
binary search, in volts
vds
Input Drain voltage, in volts
vbs
Input Substrate bias, in volts
ithr
Input
Drain-source trigger current (I
DS
), in amperes
vstep
Input
V
GS
step size, in volts
npts
Input The number of points in the sweep
slope
Output
The calculated transconductance (g
m
)
kflag
Output Return status flag:

0 = Normal operation

1 = The
ithr
parameter is too high; indicates that the
vlow
parameter is above the voltage threshold (V
T
) and the slope is
constantly decreasing

2 = Did not find peak slope; indicates that the
vhigh
parameter
was below V
T
(maximum slope was the last value)

3 = Binary search on V
GS
failed; may indicate that the
vlow
and
vhigh
parameters were below V
T
and the device never turned on

4 = The
type
parameter was not specified as "N" or "P"

5 = V
GS
step size is 0.0
Returns Output The estimated threshold voltage
Details
This subroutine is a modified version of the vtext (on page 3-73) subroutine. The differences are:

All setup parameters must have the correct sign (polarity)

An initial binary search is done with LPTLib
trigi
and
searchv
subroutines

The I
DS
-V
GS
data is measured at one time (LPTLib
sweepv
,
smeasi
)

The
vlow
parameter must be algebraically smaller than the
vhigh
parameter