Section 7: Increasing SMU current sourcing ability Model 2651A High Power System SourceMeter® Instrument User's Manual
To avoid device self-heating, this test is usually performed using pulsed measurements. This method
pulses current across the device for a short duration. During this pulse (after the pulse has settled),
the voltage is measured. The duration of the pulse and the duty cycle in which the pulses are applied
to the device are controlled, minimizing self-heating. A single Model 2651A High Power System
SourceMeter
®
Instrument can pulse-measurement test with precision timing at currents up to 50 A
and pulse widths as low as 100 µs.
To increase the pulse output, you can combine two Model 2651A High Power System SourceMeter
®
Instruments to output a pulse that is greater than that of a single Model 2651A. This example
demonstrates how to perform an Rds(on) sweep up to 100 A using two Model 2651A High Power
System SourceMeter
®
Instruments.
Combining SMUs to increase current sourcing capability
CAUTION
Carefully consider and configure the appropriate output-off state, source, and compliance levels
before connecting the Model 2651A High Power System SourceMeter
®
Instrument to a device that
can deliver energy (for example, other voltage sources, batteries, capacitors, solar cells, or other
Series 2600A System SourceMeter
®
instruments). Program recommended instrument settings before
making connections to the device. Failure to consider the output-off state, source, and compliance
levels may result in damage to the instrument or to the device under test (DUT).
To combine two Model 2651A High Power System SourceMeter
®
Instruments to output a pulse that is
greater than that of a single instrument, the current sources are connected in parallel. This delivers
the sum of the currents to the DUT, which allows a sweep of the DUT up to 100 A. The following
figure illustrates this principle of combining current sources.
Figure 23: Sum of parallel current sources
DUT
I
1
I
1
+I
2
I
2
Because each Model 2651A can produce up to 50 A, placing the instruments in parallel can deliver up
to 100 A. In this example, we will sweep the DUT using each Model 2651A to source exactly half of
the desired total current level for each point in the sweep.
7-2
2651A-900-01 Rev. A / March 2011
