Keithley 2651A Reference Manual page 73

Model 2651A High Power System SourceMeter® Instrument Reference Manual
SourceMeter instrument configuration
Source voltage with extended current using parallel
SMUs
SMU 1
For all configurations
Combining channels in series to output higher voltage
Channels in series cause hazardous voltage (>30 V RMS, 42 V peak) to be present and
accessible at the Model 2651A output connector. A safety shield must be used whenever
hazardous voltages will be present in the test circuit. To prevent electrical shock that could
cause injury or death, NEVER use the Model 2651A in a test circuit that may contain
hazardous voltages without a properly installed and configured safety shield.
2651A-901-01 Rev. A / March 2011
HI HI
+
_
LO LO
Guidelines
Maximum Pulsed Signal Levels for Model 2651A:
36 V with 95 A compliance
SMU 1 configuration:
Output-off mode:
smuX.source.offmode = smuX.OUTPUT_NORMAL
Output-off function:
smuX.source.offfunc = smuX.OUTPUT_DCVOLTS
SMU 2
Normal output-off current limit:
smuX.source.offlimiti = 1e-3 (default)
The current compliance of SMU 1 (V-source) must be 10% greater
than that maximum programmed current of SMU 2 (I-source)
Current compliance limit (maximum):
smuX.trigger.source.limiti = 50
SMU 2 configuration:
Output-off mode:
smuX.source.offmode = smuX.OUTPUT_NORMAL
Output-off function:
smuX.source.offfunc = smuX.OUTPUT_DCAMPS
Normal output-off voltage limit (40 V maximum):
smuX.source.offlimitv = 40
The voltage compliance of SMU 2 (I-source) must be 10% greater
than the maximum programmed voltage of SMU 1 (V-source).
Voltage compliance limit (maximum):
smuX.trigger.source.limitv = 40
• When combining Model 2651A SMUs, restrict operation to
pulse only
• For comparable rise times, the source range and level of
SMU 1 must match the source range and level of SMU 2
•
The programmed current and voltage levels for both SMUs
must fall within the same pulse region. See the figure titled
"SMU pulse regions when combining SMUs" for a definition of
pulse regions (earlier in this topic)
• Placing two voltage sources in parallel is not recommended
•
Placing two current sources in series is not recommended
•
Think carefully about the appropriate output-off mode
(smuX.source.offmode) and output-off function
(smuX.source.offfunc) whenever changes are made to the
source function. The alternative is to always use the high
impedance output-off mode (smuX.source.offmode =
smuX.OUTPUT_HIGH_Z).
WARNING
Section 2: General operation
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