Model 4200A-SCS Source-Measure Unit (SMU) User's Manual
Section 5: Source-measure concepts
4200A-SMU-900-01 Rev. A December 2020
5-19
Notice that as resistance decreases, the slope of the DUT load line increases. As resistance
approaches infinity (open output), the SMU will source about 50 V at 0 mA. However, as resistance
decreases, the slope of the DUT load line increases. At zero resistance (shorted output), the SMU will
source virtually 0 V at 5 mA.
Regardless of the load, current never exceeds the programmed compliance of 5 mA.
Figure 92: Voltage source in compliance
Source I measure I and source V measure V
The SMU can measure the function it is sourcing. When sourcing a voltage, you can also measure
voltage. However, if you are sourcing current, you can also measure the output current. For these
measure source operations, the measure range is always the same as the source range.
This feature is valuable when operating with the source in compliance, or when additional overall
accuracy is desired. When in compliance, the programmed source value is not reached. Thus,
measuring the source lets you measure the actual output voltage.
Sweep concepts
Although the SMU can be used for static source or measure operation, SMU operation usually
consists of a series of source-delay-measure (SDM) cycles (see the following figure) as part of a
sweep (refer to
(on page 5-20)).
