Tektronix Technical Forums are maintained by community involvement. Feel free to post questions or respond to questions by other members. Should you require a time-sensitive answer, please contact your local Tektronix support center here.

500µs 10mA Pulse for CE breakdown voltage

Models 2601, 2602, 2611, 2612, 2635, 2636
Models 2601A, 2602A, 2611A, 2612A, 2635A, 2636A
Models 2601B, 2602B, 2604B, 2611B, 2612B, 2614B, 2634B, 2635B, 2636B
Post Reply
jaime_g
Posts: 93
Joined: September 23rd, 2014, 6:14 am
Country: United States

500µs 10mA Pulse for CE breakdown voltage

Post by jaime_g » February 24th, 2017, 11:15 am

Dear Forum,

Has anyone tried to configure an SMU2612B to generate a 500µs, 10mA pulse? I have been trying to configure an SMU2612B (with v3.2.2 firmware) to generate a 500µs, 10mA, (55V limit) pulse to measure the CE breakdown voltage of NPN transistor. Maybe I am missing something trivial on how to setup the 2612B. I have include the command string I send to the instrument via a LabVIEW VI.

Code: Select all

reset()
reset()
display.screen = display.SMUB
display.smub.digits = display.DIGITS_4_5
smub.sense = smub.SENSE_REMOTE
smub.measure.nplc = 0.001
smub.source.autorangei = smub.AUTORANGE_OFF
smub.source.rangei = 10e-3
smub.source.leveli = 0
smub.source.limitv = 55
smub.measure.rangev = 55

trigger.timer[1].delay = 200e-6
trigger.timer[1].stimulus = smub.trigger.ARMED_EVENT_ID
trigger.timer[1].count = 1
trigger.timer[1].passthrough = false

trigger.timer[2].delay = 500e-6
trigger.timer[2].stimulus = smub.trigger.ARMED_EVENT_ID
trigger.timer[2].count = 1
trigger.timer[2].passthrough = false

smub.trigger.arm.count = 1
smub.trigger.arm.stimulus = 0
smub.trigger.count = 1

smub.trigger.source.stimulus = 0
smub.trigger.source.action = smub.ENABLE
smub.trigger.source.listi({10e-3})
smub.trigger.source.limitv = 55

smub.trigger.measure.stimulus = trigger.timer[1].EVENT_ID
smub.trigger.measure.action = smub.ENABLE
smub.trigger.measure.v(smub.nvbuffer2)

smub.trigger.endpulse.stimulus = trigger.timer[2].EVENT_ID
smub.trigger.endpulse.action = smub.SOURCE_IDLE

smub.source.output = smub.OUTPUT_ON
smub.trigger.initiate()
waitcomplete()
print(smub.measure.v(smub.nvbuffer2))
smub.source.output = smub.OUTPUT_OFF
See below the oscilloscope trace, the pulse width is almost 4ms instead of 500µs. What gives? Andrea, Kenneth, Brian, any suggestions?

Thanks in advance.

Jaime
Last edited by jaime_g on February 28th, 2017, 11:46 am, edited 2 times in total.

jaime_g
Posts: 93
Joined: September 23rd, 2014, 6:14 am
Country: United States

Re: 500µs 10mA Pulse for CE breakdown voltage

Post by jaime_g » February 24th, 2017, 3:40 pm

SMU2612B 50V-500µs Pulse.png
SMU2612B 50V-500µs Pulse.png (7.11 KiB) Viewed 15558 times
Attachments
SMU2612B 10mA-500µs Pulse.png
SMU2612B 10mA-500µs Pulse.png (7.91 KiB) Viewed 15558 times
Last edited by jaime_g on February 28th, 2017, 11:47 am, edited 3 times in total.

Andrea C
Keithley Applications
Keithley Applications
Posts: 1436
Joined: October 15th, 2010, 10:35 am
Country: United States
Contact:

Re: 2612B 500µs Current Pulse Fail

Post by Andrea C » February 25th, 2017, 9:10 am

The compliance limit is set for 10V, yet your scope traces show 31.2 volts of potential is developed when you force the 1.55mA.
You also are configured to use the remote sense lines. Did you by chance forget to connect the sense HI and LO? That might explain everything.
Please confirm.

jaime_g
Posts: 93
Joined: September 23rd, 2014, 6:14 am
Country: United States

Re: 500µs 10mA Pulse for CE breakdown voltage

Post by jaime_g » February 27th, 2017, 10:41 am

Hi Andrea,

Thanks for your prompt response. The short answer to your query is no. The SMU2612B channel B force and sense leads were connected to the interface test adapter (ITA). However, disregard the code from the post above, it was an oversight on my side. I reviewed the programming commands and found out that the pulse was not being generated properly because the source current level nor the source voltage level was no being initially set to 0. Once this error was fixed the SMU 2612B generated the desired pulse.

I am trying to program an SMU2612B to measure the Collector-Emitter breakdown voltage of an NPN transistor driver. We have two methods that can be used to perform this measurement:
1. Sourcing a 50V, 500µs pulse and measuring the C-E current with the source limit set to 10mA.
2. Sourcing a 10mA, 500µs pulse and measuring the C-E breakdown voltage, in this case the source limit is set to 125V.

The code use to implement the voltage pulse is shown below:

Code: Select all

reset()
display.screen = display.SMUB
display.smub.digits = display.DIGITS_4_5
smub.sense = smub.SENSE_REMOTE
smub.measure.nplc		= 0.001
smub.source.autorangei = smub.AUTORANGE_OFF
smub.source.rangev = 50
smub.source.levelv = 0
smub.source.limiti = 0.01
smub.measure.rangei = 0.001
trigger.timer[1].delay = 0.00072
trigger.timer[1].stimulus = smub.trigger.ARMED_EVENT_ID
trigger.timer[1].count = 1
trigger.timer[1].passthrough = false
smub.trigger.source.listv({50})
smub.trigger.source.limiti = 0.01
smub.trigger.source.stimulus = 0
smub.trigger.arm.count = 1
smub.trigger.source.action = smub.ENABLE
smub.trigger.measure.action = smub.DISABLE
smub.trigger.endpulse.action = smub.SOURCE_IDLE
smub.trigger.endpulse.stimulus = trigger.timer[1].EVENT_ID
smub.trigger.count = 1
smub.source.output = smub.OUTPUT_ON
smub.trigger.initiate()
waitcomplete()
print(smub.measure.i())
smub.source.output = smub.OUTPUT_OFF
Note: In order for the pulse to be at 90% of the its amplitude (45V) for 500µs, the pulse width was set to 720µs.

The oscilloscope trace for the voltage pulse is shown below:
[img]
52520 CE Leakage Current.png
52520 CE Leakage Current.png (10.92 KiB) Viewed 15537 times
[/img]

What I am missing is the appropriate measurement delay command to ensure the current is measured when the pulse is at 50V (~600µs after the pulse is turned on). I would appreciate it if you could give me some ideas on how to synchronize the current measurement correctly. Also, is there a way to speed up the measurement process in the 2612B? Could storing this procedure in the SMU memory affect the programmed pulse width and/or the measurement delay?

Best regards,

Jaime Arevalo

Post Reply

Return to “2600 Series SourceMeter”

Who is online

Users browsing this forum: No registered users and 1 guest