Electrostatic Discharge (ESD) - a lost topic?
Mar 4, 2006 at 8:49 PM Thread Starter Post #1 of 25

GeekGirl

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I was wondering why I have not seen any discussions mentioning the risk of ESD (ElectroStatic Discharge) and proper handling procedures? Any semiconductor is affected, not just op-amps.It might be helpful if the risks of ESD and the awareness of proper handling procedures were emphasized, especially to beginners.

ESD failure is more than "zapping" the chip. It can also be a partial failure that is very subtle to detect, e.g. degradation in performance. A part affected by ESD must be replaced. The only prevention is the observance of proper handling techniques.

I don't want to scare anyone, but this is a "proper parts handling technique" topic that should be taught right after learning to solder and basic measurement techniques. The most important point is to understand what causes it and to be aware of how to prevent it. I'd like to offer some tutorial information:

Fundmentals of the history and background of ESD, including the tribolelectric effect: http://www.esda.org/basics/part1.cfm (parts 2 through 6 also apply)

Texas Instrument's Application Note on ESD, including some basic information on the proper setup of an ESD safe workbench. Intended for industry, so a home workbench will probably not have all of the safeguards in place. "Electrostatic Discharge (ESD) Application Report" http://focus.ti.com/docs/apps/catalo...ctName=ssya008 (app note ssya008)

Another TI application note, from a more technical perspective. Includes models and failure modes. "Electrostatic Discharge" http://focus.ti.com/docs/apps/catalo...ctName=ssya010 (app note ssya010)

From Analog Devices: "Electrically Induced Damage to Standard Linear Integrated Circuits: The Most Common Causes and the Associated Fixes to Prevent Reoccurrence Application Note (AN-397)"
http://search.analog.com/search/defa...n-397&local=en
 
Mar 4, 2006 at 9:26 PM Post #2 of 25

amb

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MOS-based parts are more prone to ESD damage than the typical opamps we use. It's theoretically possible to damage them, but I haven't had such a problem in many years of playing with these devices. It's still prudent to keep them in anti-static bag/foam before installation on a pcb, and don't walk around while handling them, etc. You can get really pedantic and use grounded wrist straps, work surface and soldering equipment, but that is mostly unnecessary.
 
Mar 5, 2006 at 12:41 AM Post #3 of 25

Garbz

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Many parts we use here are pretty immune. I must admit the only thing i've remotely taken care of is a IRF610 when assembling an amp and only because someone else fried it. Many chips we use are either ludicrously cheap like 74HC series chips, or are not affected by ESD like the MAX debouncers I use. Even very small parts like S/PDIF Receivers and DAC chips I have been unable to break thus far.
 
Mar 5, 2006 at 5:44 AM Post #4 of 25

Whitebread

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I'm always getting shocked or shocking someone, I think I have charge imbalance written on my forehead............
 
Mar 5, 2006 at 7:41 AM Post #5 of 25

Twombly

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Quote:

Originally Posted by Whitebread
I'm always getting shocked or shocking someone, I think I have charge imbalance written on my forehead............


Maybe it's a sign of a budding mutant superpower.
eek.gif
 
Mar 5, 2006 at 7:42 AM Post #6 of 25

Twombly

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Quote:

Originally Posted by Garbz
Many parts we use here are pretty immune. I must admit the only thing i've remotely taken care of is a IRF610 when assembling an amp and only because someone else fried it. Many chips we use are either ludicrously cheap like 74HC series chips, or are not affected by ESD like the MAX debouncers I use. Even very small parts like S/PDIF Receivers and DAC chips I have been unable to break thus far.


In a professional environment, wouldn't it be better to have a grounding strap just in case?
 
Mar 5, 2006 at 1:58 PM Post #7 of 25

tangent

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In NM, the low humidity makes for lots more static than most other places in the US. To avoid problems, I habitually touch something grounded before handling semiconductors of any sort. I've gotten so much into this habit that I will actually look around for something to ground myself on before I accept a PC video card handed to me by someone. My electronics work table has an antistatic rolly-chair mat in front of it, and even then, I periodically re-ground myself while working. I welcome sparks big enough to feel: they validate my habit.

I own antistatic wrist straps (2!) but I never use them. If I've ever killed a chip with static, I never twigged to it.
 
Mar 5, 2006 at 2:23 PM Post #8 of 25

Garbz

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Quote:

Originally Posted by Twombly
In a professional environment, wouldn't it be better to have a grounding strap just in case?


In a professional environment by all means. This is quite different from the hobbiest attitude I put towards my response. I don't handle enough semiconductors in a day to warrent proper ESD safety, and at the same time I work on the spot and don't move around a lot so static buildup is also reduced.

In a professional environment where such devices are handled on an hourly basis and movement is required around a lab or office, prevention of ESD could or rather should be adhered to as religiously as occupational health and saftey.
 
Mar 5, 2006 at 4:28 PM Post #9 of 25

Whitebread

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Quote:

Originally Posted by Twombly
Maybe it's a sign of a budding mutant superpower.
eek.gif



I afraid so, it all started a few months ago........................... I'm mutating.
 
Mar 5, 2006 at 6:27 PM Post #10 of 25

GeekGirl

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I practice the black art of RF engineering, where mastery of the dark side is the key to success
evil_smiley.gif
. In this world, ESD is part of basic training. I'm in the parts selection phase of building a PPAv2 (ordering is next) and noticed that the topic of ESD was not (seriously) discussed anywhere in these forums. I was wondering why, since it's very important in what I do- why not in audio?

Garbz parallels my experience. Where I work, ESD is treated as seriously as occupational health and safety. At home, however, I use tangent's techniques for grounding. Never used a ground strap, but am continually maintaining a grounded connection to whatever I'm working on. A technique I use for the PC is to keep the card in its ESD bag and place it on the chassis. Then, I ground myself to the PC chassis (the chassis, part, and myself are now common potential) and install the card. It's a matter of being aware of relative charges between the objects.

One comment about ground straps: They're not like wrist bands worn like jewelry. They must have perfect contact with your skin at all times in order to be effective. After a while of prolonged use, this is no longer the case. Hence, the reason for alternative techniques that prove better in practice - but don't do this at work.
biggrin.gif
 
Mar 5, 2006 at 6:56 PM Post #11 of 25

mono

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In an ideally safe world, there are myriad numbers of things that are best practices, most safe, most cautious, most (anal to the nth degree).

Some highly integrated or high cost items are worth the extra care in handling... for example an expensive computer video card. Others aren't, depending on the susceptibility the environment has on building the ES charges.

IOW, it is not reasonable to do "everything" in life the safest way possible. It can be argued as a singular, general rule but then for puroses of practicality it would be unreasonable to do this for only low-cost DIY audio projects.

IMO, it's all relative. If I'd been walking around discharging through many things I'd touched in an environment then I'd be taking the extra effort for ESD precautions. In other environments, my personal choice is to not bother, and in not bothering I accept that eventually some part may be damaged. You might see it as reckless but in retrospect it hasn't been, since my habits would have changed quickly enough if the parts had been damanged. I have not been building DIY audio projects for very long but have been handling other electronics parts for many years and mostly see wrist-straps as unnecessary for the projects here, and indeed, you seldom see mention of them because most people do not find they need them.
 
Mar 5, 2006 at 7:49 PM Post #12 of 25

Twombly

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Quote:

Originally Posted by Garbz
In a professional environment by all means. This is quite different from the hobbiest attitude I put towards my response. I don't handle enough semiconductors in a day to warrent proper ESD safety, and at the same time I work on the spot and don't move around a lot so static buildup is also reduced.

In a professional environment where such devices are handled on an hourly basis and movement is required around a lab or office, prevention of ESD could or rather should be adhered to as religiously as occupational health and saftey.



Apologies. When you said "we use here" I assumed you were talking about you place of employment and not this forum.
 
Mar 5, 2006 at 10:53 PM Post #13 of 25

Garbz

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Lol I should have worded it differently. We as in the general head-fiers. Not the head-fiers who go out and build complex DACs, but the ones who typically only come in contact with CMoys, PIMETAs etc. The only part handled here that can die is the opamps.
 
Mar 5, 2006 at 11:34 PM Post #14 of 25

Whitebread

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Not wearing socks on carpet and taking off the fleece seems to keep me nearly neutral.
 
Mar 5, 2006 at 11:40 PM Post #15 of 25

Twombly

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I hope you're not taking off the fleece while working.
 

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