Idss - Keithley S530 User Manual

S530 Parametric Test System Test Subroutine Library User's Manual

idss

This subroutine estimates the saturated drain current (I
(V ) for a metal-semiconductor field effect transistor (MESFET).
DSS
Usage
double idss(int d, int g, int s, int sub, double vdss, double idlim, double f,
double *idsat, double *vdsat)
d
g
s
sub
vdss
idlim
f
idsat
vdsat
Returns
Details
This subroutine measures the drain current of a field effect transistor (FET) when the gate is shorted
to the source at a specified drain voltage (V
finding the V
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 f parameter is normally set to 0.9.
A delay is included in the idss subroutine; this delay is the calculated time required for stable forcing
of drain current with a 30 V voltage limit.
Source-measure units (SMUs)

SMU1: Forces vdss, programmable current limit, measures idss
S530-907-01 Rev. A / September 2015
Input The drain pin of the device
Input The gate pin of the device
Input The source pin of the device
Input The substrate pin of the device
Input The forced drain voltage, in volts
Input Drain current limit, in amperes
Input
Fraction of I
Output Target saturation current
Output Saturation voltage
Output Measured drain current:



that forces a fraction of I
DS
) and saturation voltage (V
DSS
DSS
0.0 = If f  0.0 or > 1.0
2.0E+21 = If measured vdsat is within 98 % of the gate voltage
limit
4.0E+21 = If idss is within 98 % of specified drain current limit
(idlim)
). It also estimates the V
DS
(usually 0.9).
DSS
Section 3: Test subroutine library reference
) at forced drain voltage
DSAT
by measuring I
DSAT
and then
DSS
3-43