Keithley 6487 Reference Manual

G-18 Applications Guide Model 6487 Reference Manual
Applications
Diode leakage current
Figure G-14 shows how to measure the leakage current for a diode. By sourcing a positive
voltage, the leakage current through the diode will be measured. Note that if you source a
negative voltage, you will forward bias the diode. Resistor R is used to limit current in the
event that the diode shorts out or it becomes forward biased. Select a value of R that will
limit current to 20mA or less.
A profile for leakage current can be developed by measuring current at various voltage
levels. For example, program the voltage source to sweep voltage from 1 to 10V in 1V
steps. The Model 6487 performs a current measurement on each voltage step. To ensure
that the voltage is settled before each current measurement, you can program the
Model 6487 for a delay. For example, if you program the Model 6487 for a one second
delay, each measurement will be performed after the voltage step is allowed to settle for
one second. The current measurements are stored in the buffer.
klqb Buffer and voltage sweep operation are covered in Section 6.
Figure G-14
Connections; diode leakage current test
klqb The details on “Typical range change transients,” page G-12 may be particu-
larly relevant to this application
A
+
-
6487
V-Source
6487
Picoammeter
Metal
Shield
HI
LO
HI
LO
R
Diode
Equivalent Circuit

Keithley 6487 Specifications

General

Type	Picoammeter/Voltage Source
Current Measurement Range	20 fA to 20 mA
Interfaces	GPIB, RS-232
Voltage Burden	< 200 µV
Input Impedance	>10^14 Ω
Power	100 V / 120 V / 220 V / 240 V
Basic Current Measurement Accuracy	0.4%