Keithley S530 User Manual page 80

Section 3: Test subroutine library reference
Details
This subroutine estimates the "pinch-off" voltage for a MESFET at a specified drain voltage and
fraction of I
DSS
"pinch-off current" (ip). The ip output parameter is normally described as a fraction of I
0.02 of I ). The trigger and search routines are used to find the V
DSS
drain-source current (I
If a positive substrate pin is specified, the substrate is grounded. If a positive substrate pin is not
specified, the substrate is left floating.
The factor for I
This subroutine does not call the idss subroutine.
Source-measure units (SMUs)

SMU1: Forces V

SMU2: Searches V
Example
result = vp(d, g, s, sub, vdss, idlim, factor, v1, v2, &idss, &ip, &iflag)
Schematic
3-68
. First, it measures I , and then searches for a gate voltage that achieves a targeted
DSS
) value (ip).
DS
is normally 0.02.
DSS
, programmable current limit, sets trigger on I
DS
, default current limit
GS
S530 Parametric Test System Test Subroutine Library User's Manual
DSS
that forces the targeted
GS
* factor)
(I = I
P P DSS
S530-907-01 Rev. A / September 2015
(usually