Section 5: Source-measure concepts
Model 4200A-SCS Source-Measure Unit (SMU) User's Manual
5-16
4200A-SMU-900-01 Rev. A December 2020
I-Source operation examples
The following figures show operation examples for resistive loads that are 2
kΩ and 8 kΩ, respectively.
For these examples, the SMU is programmed to source 10 mA and limit (compliance) 40 V. The SMU
is sourcing 10 mA to the 2
kΩ load, and subsequently measures 20 V. As shown, the load line for
2
kΩ intersects the 10 mA current source line at 20 V, which is below the programmed voltage limit.
Figure 87: Current source normal operation
The following figure shows what happens if the resistance of the load is increased to 8
kΩ. The DUT
load line for 8
kΩ intersects the 40 V voltage compliance limit line, placing the SMU in compliance. In
compliance, the SMU cannot source its programmed current (10 mA). For the 8
kΩ DUT, the SMU
only outputs 5 mA (at the 40 V limit).
Figure 88: Current source in compliance
