Section 6: Characterization of power discretes
Model 2651A High Power System SourceMeter® Instrument User's Manual
When the configured trigger model of the Model 2651A is initiated, the following occurs:
1. The source-measure unit (SMU) trigger model passes through the Arm Layer, enters the Trigger
Layer, then outputs the ARMED event trigger.
2. The ARMED event trigger triggers TSP-Link
®
trigger 1, which outputs a trigger on TSP-Link line 1.
This trigger is meant to tell the Series 2600A that it should step the gate SMU.
3. The SMU trigger model continues until it reaches the Source Event and then pauses and waits for
an event trigger.
4. A trigger comes back on TSP-Link trigger 1, indicating that the gate step is complete. An event
trigger is output from TSP-Link trigger 1 and input to timer 1.
5. Timer 1 receives the event trigger and begins its countdown while simultaneously passing the
event trigger.
6. The SMU Source Event Detector receives the event trigger from timer 1, sets the SMU output to
the pulse level, waits for a programmed source delay (if any), and outputs the
SOURCE_COMPLETE event to timer 2.
7. Timer 2 receives the SOURCE_COMPLETE event trigger and begins its countdown.
8. The SMU trigger model moves to the Measure Event, where it waits for a programmed measure
delay (if any), then takes a measurement.
9. The SMU trigger model moves to the End Pulse Event, where it stops and waits for an event
trigger from timer 2.
10. The timer 2 countdown expires and outputs an event trigger to the SMU End Pulse Event.
11. The End Pulse Event Detector receives the event trigger from timer 2, sets the SMU output to the
bias level, and then continues.
12. The trigger model checks the current Trigger Layer iteration number against the trigger count.
•
If the iteration number is less than the trigger count, the trigger model stays in the trigger layer and
wraps around to the Source Event, where it waits again for an event trigger from timer 1 (as it did in step
3). This time, however, timer 2 will not receive an event trigger from TSP-Link trigger 1. Despite this, the
trigger model will continue running because the timer 1 count was set to one less than the trigger count.
Therefore, timer 1 will continue outputting event triggers while the trigger model is in the Trigger Layer,
outputting one trigger event every time the countdown expires. The trigger model continues as
described in step 6.
•
If the iteration number is greater than the trigger count, the SMU trigger model exits the Trigger Layer
and goes into the Arm Layer.
13. Upon entering the Arm Layer, the SMU trigger model outputs the SWEEP_COMPLETE event
trigger.
14. TSP-Link trigger 2 receives the SWEEP_COMPLETE event trigger and outputs a trigger on TSP-
Link line 2. This trigger is meant to signal the Series 2600A that it is acceptable to continue, and it
no longer needs to hold the current gate level.
15. The trigger model checks the current Arm Layer iteration number against the arm count.
•
If the iteration number is less than the arm count, the trigger model stays in the Arm Layer and begins
the entire process again from step 1.
•
If the iteration number is greater than the arm count, the trigger model continues, exits the Arm Layer,
and returns to an iIdle state.
6-8
2651A-900-01 Rev. A / March 2011
