ESD Question - Page 1
Forum section: electronics / general

author: SirFatty
author_rank: Newbie
timestamp: May 07, 2014, 12:03:52 pm
content: Hi,New member here... been watching the eevblog for a couple weeks now, very informative. Which leads to this question that doesn't fit into the other forum catagories. I'm in IT (with a EET background), and have assembled hundreds of computers and servers since the 80's. I've always used an ESD mat and wrist strap, mimicking what I witnessed firsthand at the likes of IBM and Dell. But watching videos of people building computers, not a one uses any sort of ESD protection.The question: Am I wasting my time? Is it good enough to simply discharge on the case before handling components?Thanks for any information!-SirFatty

author: Stonent
author_rank: Super Contributor
timestamp: May 07, 2014, 12:38:04 pm
content: I've not had any problems with that, but the two companies that I worked for that did computer repairs for outside customers had antistatic mats on the work benches and floors.Dave's benches have mats on them.

author: david77
author_rank: Frequent Contributor
timestamp: May 07, 2014, 01:23:47 pm
content: That is the problem with ESD: Usually you will not realize that you've been hit by it. Saying things like "I've never had a problem with ESD" is just bullshit, how would you know? That computer might work fine but something fails 6 months down the line, maybe a memory stick. Could very easily have been caused by an ESD event while building the system.The small time corner shop computer shop doesn't usually take any ESD precautions, the proprietors of such establishments most of the time have very little technical knowledge and dismiss ESD as fairy tales. I know one who is like that. He told me once he saw sparks flying from his finger to a processor and that processor still worked and was sold to a customer.I am pretty sure I've had problems with ESD, unexplicable failure of some Atmel chips. After that I did invest in a basic setup: Wrist strap, table mat and ground point.

author: madshaman
author_rank: Frequent Contributor
timestamp: May 07, 2014, 02:55:05 pm
content: I think it depends on how much uncertainty you can live with.I always wear a strap, have *good* anti-static mats on all my work surfaces and run overhead ionisers over both benches.I also don't reuse parts until I have to, any parts left lying on the bench and were used while messing around go into a separate bin which are seen as unreliable/emergency parts.With some silicon however, like 4KV rectifying power diodes, I don't really take too many precautions.I can't prove ESD is what killed them, but I've certainly had a few ICs and discrete transistors go partially dead (i.e. work but can't source rated current, work but have noise or produce distorted waveforms). They go into the absolutely dead parts bin so I can torture them at my will.

author: SirFatty
author_rank: Newbie
timestamp: May 07, 2014, 02:59:10 pm
content: My thoughts are being echo'ed here. I bet the odd BSOD could be related to a RAM module that took a hit.Watch something like this:Makes me cringe... cards lying on a fabric covered table, working with both hands inside the case. With the amount of money these things cost, why risk it?Thanks for the feedback.

author: dexters_lab
author_rank: Unknown
timestamp: May 08, 2014, 02:55:56 pm
content: i think it's good practice to have a mat and strap but i dont always use them for electronicsnever bothered when building PCs, i'm just careful with where i put things

author: scientist
author_rank: Frequent Contributor
timestamp: May 08, 2014, 03:25:57 pm
content: Components in fully populated circuits usually are fine for ESD as the resistors, capacitors, etc. can protect then from any discharge. I recall hearing that on one of Dave's videos, and I've read it elsewhere. I have personally never been able to identify a component as damaged by ESD.

author: Neilm
author_rank: Super Contributor
timestamp: May 08, 2014, 08:20:18 pm
content: A few years ago, I read an article in a trade mag on ESD damage. It was written by a consultant who had been brought into a big company as they found they were getting premature failures of there products. They assumed it was a design flaw as it was usually one component that died.The conclusion was that that the company had bought a few reels of components and the packaging did not comply to standards. As the tape was removed it generated a voltage that caused ESD damage to the component when it was grounded by the the pick and place head. The damage didn't immediately cause it to fail, but the damage was done and propagated when the device was powered (electrons sneaking through).

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 08, 2014, 08:51:36 pm
content: Quote from: Neilm on May 08, 2014, 08:20:18 pmAt a company I worked at as an intern, they had some issues with a particular part having an unusually high failure rate. It so happened that I used a piece of the packaging material as a bookmark, then noticed that it collected dust very effectively. Then I rubbed that piece against my shirt and it charged up enough to stick to my hand! Clearly, the supplier of that material had a bad batch lacking whatever is supposed to stop the static.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: May 08, 2014, 09:06:39 pm
content: When dealing with consumer PC and laptop parts: ESD is usually not a huge concern. As long as you don't drag your rubber-soled shoes on a nylon carpet before rubbing your fingers all over a CPU's I/O pins, discharging yourself on the case and/or using an anti-static strap will suffice. If it's good enough for Nvidia employees at an Nvidia partner installing several $1,200 graphics cards in a $5,000 system, it's good enough for your $50 RAM stick in your $500 office PC... Manufacturers realized long ago that $0.02 worth of anti-static measures on their PCBs could save them from $10 thousands in returns from end users.Source: Cooler Master employee, former EVGA employeeWhen dealing with individual ICs... Some basic components are somewhat ESD resistant, but many high-end or esoteric ICs can be very vulnerable to ESD, and a great deal of caution should be taken, including ESD matting, anti-static strap, non-ESD tools, etc.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: May 08, 2014, 09:27:46 pm
content: Just a heads-up: the reason that some larger IT service companies invest in anti-static measures is a combination of factors. The first is that, though PC hardware is largely resistant to ESD damage, it isn't totally immune. A bare Atmel processor handled carelessly by a EE might have a 10% chance of being damaged by ESD; but a computer motherboard with lots of chips, passive components, and ESD protection at critical points might have only a 0.1% chance of being damaged by ESDThis is a more than reasonable figure, as typical PC component return rates are on the order of 1%, and about 40-60% of those are tested as fully functional. So even if ESD accounted for a fifth of all total failures, on top of faulty design, faulty parts, bad solder, failed caps, lightning strikes, and the ever present user error, it would still only effect about 0.1% of products shipped. It's probably much, much lower.This type of failure rate is totally insignificant on a single user scale. It would account for only one in a thousand component failures; and most people do not buy anywhere close to 1,000 computer parts in their entire life. So worrying about ESD as an individual user--beyond easy, common-sense measures like grounding yourself on the case--is a complete waste of time.But, if you're a large IT service provider, system builder, or repair shop, you may handle tens or hundreds of thousands of components (even millions) in a year. In that case the 0.1% becomes significant, and may easily outweigh the cost of thorough ESD protection. Add into that the inflated concern most people have, due to received knowledge from EEs (who have much more legitimate ESD concerns than IT folks, in general), plus the desire to spend budgets and get more nice stuff, and you have lots of large companies investing into ESD protection.And that's fine. But just be aware that for most individual users it's not that huge a concern.Edit: just to be clear, 0.1% of FAILURES. With a typical documented failure rate of 0.5-1%. Which means that the odds of a given PC component being killed by ESD are on the order of 0.001%. This may be higher for certain components (RAM and CPUs might be closer to 0.01-0.1%) and lower for others (power supplies essentially 0%).

author: Neilm
author_rank: Super Contributor
timestamp: May 09, 2014, 08:54:43 pm
content: Chips are the most likely components to be damaged by ESD - after all they are just very small bits of silicone with some impurities.When assembled onto a board, the capacitance of the board, protection circuits etc will reduce the likely-hood of damage. Note the word reduce, not eliminate. A company that worries about its reputation and cares about what it produces will take anti-static precautions. They don't cost a lot and will stop an easily preventable failure.Of course, as the chip die sizes shrink and the operating voltages reduce, the probability of damage increases as there is simply not enough silicone to act as a barrier.