• EEVblog #607 – Agilent B2912A Source Measure Unit SMU Teardown


    What’s inside a $13K Agilent Source Measure Unit capable of 15fA and 100nV resolution?
    Plus triaxial cables, and low current measurement connection.
    Data Sheet
    Connection Guide
    Component Datasheets:
    FDS8978 Dual MOSFET
    OPA1611 Audio Opamp
    ISO7240A Isolators
    ADS8202 Diff Amp
    ADS1675 24bit ADC
    30N06 MOSFET

    Forum HERE

    High Resolution Teardown Photos:

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      • Eyal

        Very Nice!
        I have one on my bench waiting for some time to start measuring stuff, and was really nice to see the guts of it! All I had time for was to measure the reverse current of a diode under 200V.
        One thing I learned from that is there is absolutely no correlation whatsoever with the devices that I measured and the datasheet!!!
        A video of it functioning would be really nice, as most people will not see one of these beasts functioning.

        Cheers,
        Eyal

      • TiN

        Lovely SMU.
        Get it working and shoot usage video about shmuuu 🙂 Since you have dual-channel unit, prolly best would be to trace some curves for diodes, LEDs, zener and transistor 🙂 Or make a curve of your uCurrent, voltage to current dependency or something like that.

      • Sebastian

        Hi,
        two comments on this nice insight video.

        I noticed you mentioned the guard to connect to the internal common. Usually in SMU test systems one would have the guard being driven via a buffer directly by the signal voltage. This way there is absolutely no leakage out of the center conductor towards ground, an absolute must for very high precision low current measurements at elevated voltages. That is also the reason why triaxial cables can be quite dangerous to work with if you don’t know your business… there are a lot of different BNC/Triax adapters and some of them expose guard to the outer BNC shield which can be deadly.

        Being a physics scientist myself, I can attest that SMUs are the backbone of research. We rely on them every day, delivering exactly what is displayed and being very versatile when it comes to device characterization. BUT a lot of scientists are really not good electrical engineers and lack an understanding of such devices even though they use them on a daily basis. Just as an example, there was a recent case in the prestigious journal Nature (see http://dx.doi.org/10.1038/nature12589) where experimental errors where exposed and led to the admission of false data interpretation. It basically boiled down to scientists starting to use an SMU just like two independent devices, in this case a current source and a voltage meter. The internal voltage meter is designed to measure a potential that is close to the one put out by the current source… basically some internal diodes prevent large potential differences. One wouldn’t expect it, but a trap for young players and senior scientists as well 😉

      • Chris

        Agilent is really sneaky. They got you to do an hour of free advertising for them. If they produced an hour long video, how many people would watch it? Would someone they hired have seemed trustworthy? How much would the production have cost? A free device to you is a small price to pay. Keep it up.

        • I don’t get to keep these units, they go back to Agilent.
          Yes, they know the game, and I’m happy to play along. I get high tech fodder for my videos and my own curiosity, and they get advertising and views they can’t buy.

      • Murikan320

        All nice and good.

        I was an EE for 25 years.
        Made good money, had fun making hundreds of circuits and black boxes. But, in the end
        I was a hired hand, and nothing I made will be remembered. I realized this and became an artist. I paint now, oil and acrylics.
        My paintings are all over Minneapolis MN, USA.
        These paintings will out live me, while all the work I did as an engineer will end up in a landfill.
        A cautionary tail.

      • Michael K.

        Hi Dave, very nice! I did not even know that triaxial connectors exists ;-). It would be nice to see how some parts correlate to their datasheets.

        • Pierre lavoie

          Yeah could be fun to compare genuine part and crappy copy from ebay!

      • Worf

        Ooh, it’s the Agilent P600 CPU platform development board!

        I actually worked on the software part for that board.

        If it sounds familiar, it’s probably related to the CPU in those Agilent 2000 and 3000 series oscilloscopes, except those weren’t separate boards.

        Heck, even the boot screen is familiar, except the LCD is upside-down (the bar going across the top is the progress bar for Windows CE bootloader startup – it is supposed to be on the bottom running across left-to-right). Obviously the screen is upside down and they’ve just rotated the Agilent logo for this. Hence why the bar is on the top and runs right-to-left.

        Some things never change.

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