Keithley S530 User Manual

S530 Parametric Test System Test Subroutine Library User's Manual Section 3: Test subroutine library reference
S530-907-01 Rev. A / September 2015 3-43
idss
This subroutine estimates the saturated drain current (I
DSS
) and saturation voltage (V
DSAT
) at forced drain voltage
(V
DSS
) for a metal-semiconductor field effect transistor (MESFET).
Usage
double idss(int d, int g, int s, int sub, double vdss, double idlim, double f,
double *idsat, double *vdsat)
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
vdss
Input
The forced drain voltage, in volts
idlim
Input
Drain current limit, in amperes
f
Input
Fraction of I
DSS
idsat
Output
Target saturation current
vdsat
Output
Saturation voltage
Returns
Output
Measured drain current:
 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)
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
DS
). It also estimates the V
DSAT
by measuring I
DSS
and then
finding the V
DS
that forces a fraction of I
DSS
(usually 0.9).
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

Keithley S530 Specifications

General

Brand	Keithley
Model	S530
Category	Test Equipment
Language	English