Page 1 of 3 123 LastLast
Results 1 to 10 of 21

Thread: ESD questions

  1. #1
    Join Date
    Aug 2016
    Location
    Minsk, Belarus
    Posts
    67

    Default ESD questions

    Hello every one.
    I am just starting with laser diodes and would like some advice on ESD safety with laser diodes. The diodes I got appear to have builtin ESD protection but since each is in the $50-$150 range I would want to be on the safe side and learn from past experiences of others. FYI the diodes are NUBM44, NUGM01, Mitsubishi 500mW.
    Has anyone here killed a diode from ESD? If yes, how did it happen?
    Should I always use an esd wristsraps when soldering diode pins and drivers, or also things down the chain not directly connected to the diodes (PSUs, OEM DACs, etc.?)

  2. #2
    Join Date
    Nov 2008
    Location
    Cleveland Ohio
    Posts
    2,599

    Default

    ALWAYS use esd protection when working on the diodes. I use a clip across the leads when I can. This also keeps heat away from the laser when soldering. I do not suggest sockets though. They are problems. For me I do use a wrist strap. Also make sure to use the lasorbs when you do the design. They make a huge difference in survivability in winter. The built in esd protection is just a bandaid. If you are working with single mode greens be real careful as they are particularity sensitive in my experience.

  3. #3
    Join Date
    Jan 2006
    Location
    Charleston, SC
    Posts
    2,147,489,459

    Default

    Quote Originally Posted by kecked View Post
    If you are working with single mode greens be real careful as they are particularity sensitive in my experience.
    I would say single-mode diodes at any wavelength are quite sensitive. The multi-mode blues are pretty robust, and even the multi-mode reds hold up OK, but the single-mode diodes are far to easy to kill no matter what wavelength they lase at.

    Adam

  4. #4
    Join Date
    Feb 2011
    Location
    New Hampshire
    Posts
    3,513

    Default

    I would also invest in a soldering station ESD pad. These provide a nice surface as well and this is an advantage when dealing with small, pesky parts. I like these.

    https://www.esdmat.com/

    Another reason for a pad is that over time you will accumulate ESD sensitive components (not just laser diodes) and these pads are a good place where you can leave work in progress.

    I swear by Lasorbs. Some of my lasers generate HUGE electrical fields. They would make nice EMP sources and the controllers, timers... would fail regularly until I began to install l Lasorbs across the low voltage input and output terminals.

  5. #5
    Join Date
    Aug 2016
    Location
    Minsk, Belarus
    Posts
    67

    Default

    My guess is the single mode diodes don't have built-in ESD protection to save cost.

    By the way, if my country doesn't have a grounding system, the wall outlet has only two holes(live and neutral) and the third hole (ground) does not exist, can I still make use of an ESD wriststrap?

  6. #6
    Join Date
    Feb 2011
    Location
    New Hampshire
    Posts
    3,513

    Default

    Sure you can. A ground lead in an outlet is literally GROUNDED. Attach the ground lead to a massive conducting system such as metal plumbing and you provide a sink for stray electric charge (electrons) to disperse into.

  7. #7
    Join Date
    Aug 2016
    Location
    Minsk, Belarus
    Posts
    67

    Default

    TY. But what if Im in an apartment on the 7th floor and don't have something like metal plumbing and getting a wire to the Earth on the first floor is problematic?
    Can I attach the wriststrap to a large piece of metal and 'discharge' that metal piece before every usage? If yes, how should I dsicharge such a metal piece?

  8. #8
    Join Date
    Aug 2010
    Location
    London or Spain depending on the weather
    Posts
    1,390

    Default


    @ " But what if Im in an apartment on the 7th floor and don't have something like metal plumbing and getting a wire to the Earth on the first floor is problematic?"
    Then you have a problem.......Check if easier to get to the roof and see if you have screened ariels or comms cables so that you can strap ontothe screening. (also check for drainpipes,lightning conductor etc.
    Cheers
    PS. Where are you ? (update profile to include approx location)

  9. #9
    Join Date
    Feb 2011
    Location
    New Hampshire
    Posts
    3,513

    Default

    Maltes,

    I'm curious about your location as well. I did not know that in some countries a ground is not integral to the electrical service. This brings up a question. Why not? When you look inside electrical service panels (in my country), you will see the two, hot, out of phase leads and a neutral lead that is connected to ground. In theory, neutral IS ground, but to reduce risk and stray currents the neutral is tied locally into plumbing or buried rebar. This costs very little compared to the grid. I'm surprised they did not incorporate it. You might check to see if the service that comes into your apartment enters through a metal conduit. If so, there's your ground.

    https://www.google.com/search?biw=16...MM4W_Xg4JgM%3A

    https://www.google.com/search?biw=16...s+with+ground&

  10. #10
    Join Date
    Aug 2010
    Location
    London or Spain depending on the weather
    Posts
    1,390

    Default

    Many countries have no proper earth connection (most old buildings in Spain don't). Electrical distributors try and put all onus on the clients as far as safety is concerned and corrupt government doesn't help much! A few years ago (probably due to EU rules) ,Spain changed from it being ILLEGAL to tie earth wires to plumbing to OBLIGATORY in one fell swoop. There are NO fuses before the meters and client is responsable for the "acometido" ...wires from street to meter, despite them being BEFORE the meter.Greater than 90% of my elec bill is "standing charge" so consumption is actively encouraged.
    I have had to sink a few copper tubes into my back garden to establish a decent earth here in Catalunya, sojust imagine what Andalucia must be like! Neutral wires in the main three phase distribution system are 1/3rd section of phase wires instead of double,thus assuming well balanced consumption despite different phases supplying different houses/flats etc.

    In UK however earth is obligatory and is everywhere (including old buildings) and neutral is tied to within +/- 10VDC from earth by law!.

    But Spain is different !!!!!! (UK is just "normal).

    Cheers
    Last edited by catalanjo; 09-11-2016 at 07:02.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •