Model 4200A-SCS Parameter Analyzer Reference Manual Section 3: Source-measure hardware4200A-901-01 Rev. C / February 2017 3-7I-Source operation examplesThe next 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 SMUis sourcing 10 mA to the 2 kΩ load, and subsequently measures 20 V. As shown, the load line for2 kΩ intersects the 10 mA current source line at 20 V, which is below the programmed voltage limit.Figure 35: Current source normal operationThe following figure shows what happens if the resistance of the load is increased to 8 kΩ. The DUTload line for 8 kΩ intersects the 40 V voltage compliance limit line, placing the SMU in compliance. Incompliance, the SMU cannot source its programmed current (10 mA). For the 8 kΩ DUT, the SMUonly outputs 5 mA (at the 40 V limit).Figure 36: Current source in complianceNotice that as resistance increases, the slope of the DUT load line increases. As resistanceapproaches infinity (open output), the SMU will source virtually 0 mA at 40 V. However, as resistancedecreases, the slope of the DUT load line decreases. At zero resistance (shorted output), the SMUwill source 10 mA at virtually 0 V.Regardless of the load, voltage will never exceed the programmed compliance of 40 V.
