2600S-901-01 Rev. C / January 2008
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Series 2600 System SourceMeter® Instruments Reference Manual
Section 3: DUT Test Connections
Output-off states
When a SMU is turned off, it may not be completely isolated from the external circuit that it is
connected to. There are three output-off states for a Series 2600 SMU: Normal, High Impedance
or zero. For the Models 2602, 2612, and 2636, each SMU channel can have its own unique
output-off state.
Normal output-off state
For the normal output-off state (which is the default setting), the SMU will source 0V. When
running firmware version earlier than 1.2.0, current compliance will set to 10% full scale of the
present current range, or 100µA (whichever is smaller). When running firmware version 1.2.0 or
later, current compliance determined by the
smuX.source.offlimiti
command (default 1mA)
will be used. Therefore, the SMU may source or sink a very small amount of power. In most cases,
this source or sink power level is not significant.
High-impedance output-off state
For the high-impedance output-off state, the output relay opens when the output is turned off. This
disconnects external circuitry from the input/output of the SMU. To prevent excessive wear on the
output relay, do not use this output off state for tests that turn the output off and on frequently.
Zero output-off state
When in this output-off state, the SourceMeter is configured as follows:
When the V-Source is the selected source:
• The programmed V-Source value remains on the display.
• Internally, the V-Source is set to 0V.
• The current compliance setting remains the same as the output-on value. Real compliance
detection remains active.
• Measurements are performed and displayed.
When the I-Source is the selected source:
• The programmed I-Source value remains on the display.
• Internally, the V-Source is selected and set to 0V.
• Current compliance is set to the programmed Source I value or to 10% full scale of the
present current range, whichever is greater.
• Measurements are performed and displayed.
While in the zero output-off state, the SourceMeter can be used as an I-Meter since it will output
0V, but measure current.
Selecting the Output-off state
Output-off state menu
The OUTPUT configuration menu can be accessed by pressing the CONFIG key and then the
appropriate OUTPUT ON/OFF key. In the configuration menu, select OFF STATE to display the
OUTPUT OFF STATE menu.