ESD problems

Has anyone had issues with the Propeller and ESD. And what you do to prevent this from killing the chip?

Comments

  • Its a CMOS chip, you always take the normal precautions with all MOS devices or risk destroying them.
    Cold dry air in winter coupled with central heating is a recipe for very large amounts of static electricity
    making damage much more likely. There's nothing special about the Prop, all CMOS chips are vulnerable.

    Use a conductive wrist strap and bench (wood is fine). Do not wear synthetics, cotton/wool only is
    really going to help. Consider ways to humidify the room.

    Never ever touch a chip by its legs until you've grounded yourself to the anti-static packaging it comes
    in - then everything is at the same potential.

    When the air is very dry potentials can rise to many kV on any insulating surface very easily indeed.
  • Thanks for the response. I've had more than my share of Prop chips succumbing to ESD. I am ashamed to say this is my third one that has bit the dust in the same way. Needless to say I will be very careful this time around and hope I have enough in the budget to get serious about ESD protection on my workbench.
  • There is something wrong with your setup as we’ve found the prop chip to be extremely robust.
    Perhaps you can post a pic of your board and the schematic?
    Are you using the DIP or QFP version? Are all power and grounds connected and short? Do you have proper bypass caps?
    Have you tested to see if the dead chips work in rcfast mode (ie a dead PLL)?
    My Prop boards: P8XBlade2, RamBlade, CpuBlade, TriBlade
    Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    Prop Tools (Index) , Emulators (Index) , ZiCog (Z80)
  • Its not really a question of robust, static will destroy any chip if its high enough voltage.

    Protection diodes can only do so much, and are typically designed for a model of a kV or 2 through a
    modest resistance. With dry conditions the voltages typically seen are 10's of kV - just peeling
    sticky tape from a roll can actually generate x-rays due to the massive tribo-electric voltages. No MOS chip
    can handle that.

    The best practice is to always handle components as if they have no protection, so always in anti-static
    conducive bags/foam.
  • I have never had any problems with the Prop chip, and usually disregard all precautions... I do however carefully layout all my PCB's and observe soldering temperatures.

    As an aside, when I was working in the defense industry we had to certify our chips / components and manufacturing procedures were up to standards, extremely high standards, including daily / hourly ESD checks on every piece of equipment and every manufacturing procedure. I would write you up if you had the wrong type of clothing, no wrist / leg straps, not using proper assembly procedures and soldering techniques. The biggest problem was extra "stuff" on the assembly tables: lamps, magnifiers, cleaning rags, smoke removal fans, coffee and cold drink cups, and personal radios and cellphones, believe it or not!

    While we did not use Prop products, we used Atmel chips, the engineers took these chips and used them as coin change and key FOBs for about six months. If the IC pins did not fall off the IC's were put into PCBs - they all worked LOL
  • PropGuy2 wrote: »
    I have never had any problems with the Prop chip, and usually disregard all precautions... I do however carefully layout all my PCB's and observe soldering temperatures.

    +1
    I have worked in (and enforced) well-controlled environments in the past, but my own hobby work bears no resemblance to best practices.

    It would be good to learn how/why you suspect these failures can be attributed to ESD. Is it possible that something else is amiss?
  • hatallica wrote: »
    PropGuy2 wrote: »
    I have never had any problems with the Prop chip, and usually disregard all precautions... I do however carefully layout all my PCB's and observe soldering temperatures.

    +1
    I have worked in (and enforced) well-controlled environments in the past, but my own hobby work bears no resemblance to best practices.

    It would be good to learn how/why you suspect these failures can be attributed to ESD. Is it possible that something else is amiss?

    +1

    I've abused the heck out of the P1 and haven't killed one from ESD yet. I've killed a couple PLLs, fried pins and completely released the magic smoke beyond identification.

    Without seeing anything from your application, it's either a psu issue or a input issue. All prop power pins need to be connected as well as properly bypassed. A well regulated supply, fed into a properly bypassed chip is where most people go wrong.

    The other thing that kills props is voltages > 3.6v. Okay, so there's some wiggle room here but this seems to be the SAFE limit for a few reasons. Anything over this will raise the supply voltage, and this is the way I've fried more chips than I want to admit. Had a few 12v signals get to the propeller pins. bye bye propeller.

    A photo of your bench setup would tell us a lot and help us advise you. It COULD be static, but I doubt it.. Unless you're petting your cat while prototyping, you're probably safe there.
  • The other major killer of Prop chips is inadequate bypassing on the power supply leads. Ideally, each Vdd/Vss pair of leads should have a bypass cap located close to them. Without bypassing, the first thing to go is often the main PLL that drives the system clock. If you can load programs, but they don't run, that's a sign of PLL issues.

    -Phil
    “Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away. -Antoine de Saint-Exupery
  • I have never zapped a prop or the basic stamp or others with ESD. I agree about the dry air etc. but the only time I have a problem with esd is when I am teaching my aircraft mechanic students is when I am at my lab desk which has a steel plate under the formica and I get zapped with 24 vdc grounded. No chips involved just solenoids and relays. Check your desk. If it is not properly insulated it could be a bad day.
    Btw my desk is 20 years old. Have to be careful.
    “Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it.”
    “You only live twice:
    Once when you are born
    And once when you look death in the face”
  • Get rid of carpet under the desk
    “Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it.”
    “You only live twice:
    Once when you are born
    And once when you look death in the face”
  • Coop123 - Any feedback regarding why ESD is suspected? Any thoughts on the responses regarding countermeasures?
  • Coop123 wrote: »
    Thanks for the response. I've had more than my share of Prop chips succumbing to ESD. I am ashamed to say this is my third one that has bit the dust in the same way. Needless to say I will be very careful this time around and hope I have enough in the budget to get serious about ESD protection on my workbench.

    What evidence do you have that this is an ESD problem and why would you jump to that conclusion? For sure there is a problem since you have failures but I've never seen any ESD failures with Props so it seems unlikely. As noted by others, your problems are probably due to another cause however you need to provide some photos and schematics etc if you would like some informed feedback.

    Tachyon Forth - compact, fast, forthwright and interactive
    useforthlogo-s.png
    --->CLICK THE LOGO for more links<---
    P2 +++++ TAQOZ INTRO & LINKS +++++ P2 SHORTFORM DATASHEET
    P1 +++++ Latest Tachyon includes EASYFILE +++++ Tachyon Forth News Blog
    Brisbane, Australia
Sign In or Register to comment.