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.

Display wrong current

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
rlinde
Posts: 8
Joined: December 5th, 2012, 5:55 am
Country: Belgium

Display wrong current

Post by rlinde » February 11th, 2013, 7:01 am

We are currently measuring a low power chip with 2 supplies. The 2600 is providing both voltages and measures both currents. However the instrument displays the wrong current.
This was found by adding a multimeter in series with the supply. Agilent 34411a and 34401a, normal 6-1/2 digit multimeters. Taking the chip out of its reset state sometimes displays the correct current on the 2600, but most of the time one or both current readings are wrong.
The 2600 is in it's power on default state.

Why is the 2600 doing this? How does the measurement principle of a source meter differ from a multimeter?
How can I do reliable measurements with this instrument?

The attached - shows the currents being measured channel B: 19uA on both the source and the multimeter and channel A: 87uA on the multimeter and -7nA on the source meter.
Attachments
IMAG0434ansm.jpg
IMAG0434ansm.jpg (117.45 KiB) Viewed 15806 times

Jane S
Keithley Applications
Keithley Applications
Posts: 114
Joined: November 10th, 2010, 5:45 pm
Country: United States

Re: Display wrong current

Post by Jane S » February 15th, 2013, 3:43 pm

Hello,
Please list your 2600 SMU test conditions, source and measure stimulus per channel, source and measure range on SMU, how you connect to your device, 2W/4W. What is the capacitive load of your device and any other pertinent information.

Also the attached document below, differentiate a DMM from SMU.

Hope this helps!
Attachments
Smu.pdf
SMU Description
(1.15 MiB) Downloaded 1424 times

rlinde
Posts: 8
Joined: December 5th, 2012, 5:55 am
Country: Belgium

Re: Display wrong current

Post by rlinde » February 18th, 2013, 12:41 am

k2602.write("smua.reset()")
k2602.write("smub.reset()")

k2602.write("smua.source.limiti = 0.01")
k2602.write("smub.source.limiti = 0.01")
k2602.write("smub.source.levelv = 3.3")
k2602.write("smua.source.levelv = 3.3")
k2602.write("display.smua.measure.func = display.MEASURE_DCAMPS")
k2602.write("display.smub.measure.func = display.MEASURE_DCAMPS")
k2602.write("smua.source.output = smua.OUTPUT_ON")
k2602.write("smub.source.output = smub.OUTPUT_ON")

The range is the 'reset default' or AUTO.

The expected currents are +/-19uA and 70-90uA.
Connection is 2 wire.
Capacitance is cabling, one 100nF decoupling capacitor and the dut.
Attachments
k2600.jpg
k2600.jpg (60.48 KiB) Viewed 15779 times

rlinde
Posts: 8
Joined: December 5th, 2012, 5:55 am
Country: Belgium

Re: Display wrong current

Post by rlinde » March 27th, 2013, 10:20 am

Thanks to the Belgian representative.

The output started to oscillate and some noise on the supply could be observed with the oscilloscope.
k2602.write("smua.source.highc = smua.ENABLE")
k2602.write("smub.source.highc = smua.ENABLE")
Putting the device in 'high capacitance' mode solves the problem.

Post Reply

Return to “2600 Series SourceMeter”

Who is online

Users browsing this forum: Bing [Bot] and 7 guests