Author Topic: It appears that Jim Williams wasn't a big fan of anti-static mats.  (Read 13446 times)

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Offline JoeNTopic starter

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It appears that Jim Williams wasn't a big fan of anti-static mats.
« on: September 19, 2015, 09:59:14 am »
Should I be?



Have You Been Triggered Today?
 

Offline george graves

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #1 on: September 19, 2015, 10:18:24 am »
I don't know?  Are you as good as Jim Williams?   :-//  Most like not. O0

I've never fried a chip by just handling it - not even when I was working in the dry California Sierra Mountains air.  And that's about as dry as you can get in the summer. Before then I was next to the beach.  And now in Seattle - so you can't even rub a ballon on your hair to make static! 

I run anti-static mats because they are cheap given that if you treat them well, and buy the right type they will last for 10's of years.  With that said, on my main work surface, on top of the mat, I have a Fiskars cutting mat - but I do a lot of micro-scale "manufacturing" - if all I was doing was design, I wouldn't need it I suppose. But as soon as you start making things - you'll destroy any mat.

I was able to buy 60 feet or so of the same stuff Dave uses, but in "no-lead" green color.  It's the same stuff - just the color is to say "NO lead here" in a mixed enviroment.  Yet - I only use lead solder.  Whoops!  IMHO - get the green stuff.  It's really pleasing to the eye.  Was never a fan of the blue stuff. I think I paid $60 shipped for the roll some company was getting rid of - the box had never been open.

BTW - make sure you check the surface hardness.  That's really one of the most important specs IMHO.
« Last Edit: September 19, 2015, 11:01:06 am by george graves »
 

Offline Chris C

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #2 on: September 19, 2015, 10:46:16 am »
Wow!  :o

But maybe an analog engineer's desk isn't the best indication of whether you need an anti-static mat, if you're going to be working with digital.

I've never used an anti-static mat, and never had a problem (yet).  I'm always aware of when myself or the stuff I'm handling may be at different potentials, and equalize them if necessary.  That's the most important thing.

Plus it's a clear day here, and the relative humidity outside is 91%.  Inside, probably around 30%.  That's pretty typical for my locale, and it helps.  The few months of the year the humidity drops enough to accumulate a charge, I crank up a humidifier when working with static sensitive parts.  When working with something known to be very sensitive on a dry day, sometimes I do the fidgety bits in the bathroom, door closed and vent off, and a fine spray of hot water from the showerhead.  But that's rare.

Now if I were to move to a dryer location, I would gear up with a static mat and wrist strap.  Still, there will come a time when you have to work without those niceties, so it's better not to have absolute reliance on them.
 

Offline KJDS

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #3 on: September 19, 2015, 11:29:12 am »
A wooden bench is reasonably static dissapative, so long as it isn't very dry. Metal frames and wooden tops can be better. Plastic topped benches are horrible and really need mats no matter what the humidity.

ESD often just weakens an IC, you may not know if it's damaged unless you spend a good while looking at the silicon under a microscope or you use it for a few years and it dies early. Do you feel lucky?

Offline DimitriP

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #4 on: September 19, 2015, 11:51:03 am »
Should I be?



When you are Jim Williams no one gives two hoots whether you are using a mat or not.
The value of his work was not measured by how many chips he fried (if any, ever)

He also , probably , didn't rub his feet on the carpet before touching the pins of an IC in the dark to see if it will spark, he knew better :)

Only you can decide ...




One of many bench technicians employed  at some ISO certified facility
or a Jim Williams?
 
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Offline Cliff Matthews

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #5 on: September 19, 2015, 02:37:13 pm »
Impressive! That photo's a keeper.  :-+  I see a copper strip running down the wall. I see organized probes, adapters and leads on the drawer handle in front of him.
Maybe he wanted a mat to be installed, but had a messy junior apprentice (like me) always piling up stuff around him..  :palm:
 

Offline Ryano

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #6 on: September 19, 2015, 05:35:47 pm »
The entire bench top might be anti-static as well with no need for a mat. My bench at work is connected via a very large copper wire to ground. Every part of it is anti-static.

Mt home bench has a mat on wood bench top, sitting on a wood floor.
 

Offline sarepairman2

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #7 on: September 19, 2015, 06:00:11 pm »
I like the antistatic rubber mat because it is extremely durable and the table underneath survived. My mat looks like it has seen better days lol... its ALL fucked up
 

Offline electr_peter

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #8 on: September 19, 2015, 06:34:47 pm »
What are you talking about? Of course, Jim Williams used antistatic mat - just look at all those wire nests and copper clad boards (= antistatic mats) on his desk.
Conventional rubber antistatic mats are only suited for needs of common folk here (with semi-clean desk and plastic items), not for masters like Jim.
 

Offline george graves

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #9 on: September 20, 2015, 10:11:58 am »
The value of his work was not measured by how many chips he fried (if any, ever)

I'm sure he fried a metric-shit-load. 

Offline DimitriP

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #10 on: September 20, 2015, 11:55:02 am »
The value of his work was not measured by how many chips he fried (if any, ever)

I'm sure he fried a metric-shit-load.

Grounded soldering iron is as far as I will go.
If a monstrously messy bench was good enough for him, it's good enough for me.
   If three 100  Ohm resistors are connected in parallel, and in series with a 200 Ohm resistor, how many resistors do you have? 
 

Offline Marco

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #11 on: September 20, 2015, 12:27:38 pm »
Should I be?

With small signal/rf mosfets with unprotected gates, yes.
 

Offline con-f-use

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #12 on: September 20, 2015, 12:29:11 pm »
I'd suspect, that Mr. Williams did the gross of his work before the advent of small package SMDs. I'd say, ESD isn't that much of an issue with robust old through holes.
 

Offline AF6LJ

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #13 on: September 20, 2015, 12:36:51 pm »
I have seen garbaged up benches before, even had a few myself but NEVER that bad.
Sue AF6LJ
 

Offline Nerull

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #14 on: September 21, 2015, 12:51:10 am »
Wow!  :o

But maybe an analog engineer's desk isn't the best indication of whether you need an anti-static mat, if you're going to be working with digital.

I've never used an anti-static mat, and never had a problem (yet).  I'm always aware of when myself or the stuff I'm handling may be at different potentials, and equalize them if necessary.  That's the most important thing.

Plus it's a clear day here, and the relative humidity outside is 91%.  Inside, probably around 30%.  That's pretty typical for my locale, and it helps.  The few months of the year the humidity drops enough to accumulate a charge, I crank up a humidifier when working with static sensitive parts.  When working with something known to be very sensitive on a dry day, sometimes I do the fidgety bits in the bathroom, door closed and vent off, and a fine spray of hot water from the showerhead.  But that's rare.

Now if I were to move to a dryer location, I would gear up with a static mat and wrist strap.  Still, there will come a time when you have to work without those niceties, so it's better not to have absolute reliance on them.

I'm kind of amazed at the effort people will put into avoiding basic precautions. At some point it becomes easier just to get a mat.

I have a mat cause its pretty cheap, its nice to work on, protects the desktop, keeps parts from sliding around, and I don't feel like messing with a dehumidifier or building circuits in the shower just so I can brag about not using a mat.

Looking at that desk, I would be surprised if he ever saw the same IC twice, so it probably didn't matter if he fried them. Once used, they just became a new layer of desktop...
« Last Edit: September 21, 2015, 12:56:11 am by Nerull »
 

Offline rs20

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #15 on: September 21, 2015, 01:03:51 am »
I've never fried a chip by just handling it - not even when I was working in the dry California Sierra Mountains air.

So, discussion of ESD aside, you've never had a chip fail, ever? Not once? Because I'm curious to know how you established with 100% confidence that none of those chips that have failed on you didn't have a little bit of latent ESD damage contributing to their ultimate failure mode.

One of the greatest fallacies to do with ESD is the idea that it's black-and-white: the idea that ESD damage either totally bricks the chip, or the chip is perfectly fine. That is nonsense. ESD can make one I/O pin a little bit leaky; create a slight fault in a MOSFET that only truly fails when it's pushed to 50% of design load; lead to destructive latchup in an otherwise nominally safe situation; push a voltage reference slightly outside of spec or cause it to drift over time; etc bla bla bla. See one of Dave's recent videos where he put 10V into a 5V part and it end up kinda working, but outside of spec. Not ESD per se, but the same story. With all that in mind, confidently asserting that you've never caused ESD damage to any chip is, well... brave.

Now of course, you used the word "fried", so you might argue that you're not claiming not to have caused damaged. That'd be beside the point  :)
 

Offline bitseeker

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #16 on: September 21, 2015, 02:39:31 am »
Should I be?



The layers and layers of circuit boards with their myriad components provide plenty of places for static to go. :-DD
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Offline AF6LJ

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #17 on: September 23, 2015, 03:32:53 pm »
There comes a point when a cluttered workstation becomes less and less productive.
I can see he reached that point four layers ago.
Sue AF6LJ
 

Offline rsjsouza

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #18 on: September 23, 2015, 04:32:26 pm »
I'd suspect, that Mr. Williams did the gross of his work before the advent of small package SMDs. I'd say, ESD isn't that much of an issue with robust old through holes.
That is not true. The initial CD4k series of devices of early 70s were terribly sensitive before the industry started adopting protection diodes - not to mention the early mosfets mentioned by Marco. Being fully bipolar, early TTLs were a bit more robust but still could be fried.

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Offline Tomorokoshi

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #19 on: September 23, 2015, 04:36:30 pm »
"Now where did I put that resistor..."
 

Offline krivx

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #20 on: September 23, 2015, 04:42:19 pm »
W can't see the floor. That could be an ESD safe environment if he is wearing ESD safe shoes, like is standard in cleanrooms.
 

Offline AF6LJ

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #21 on: September 23, 2015, 05:07:25 pm »
W can't see the floor. That could be an ESD safe environment if he is wearing ESD safe shoes, like is standard in cleanrooms.
Maybe it is concrete and he is barefoot.
Sue AF6LJ
 

Offline free_electron

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #22 on: September 23, 2015, 05:21:26 pm »
jim wandered around in shorts and birkenstocks...

but : jim did a lot of very low current stuff. antistatic mats caus eleakage. that why his boards almost always sit clamped in a panavise and use dead bug construction.
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Offline SeanB

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #23 on: September 23, 2015, 05:25:26 pm »
He did not have to worry about it. Remember these were all new design chips, fresh from a fab line or developed in house, and he was doing both application notes and reference designs for them. Single circuit, or a few dozen iterations till it did as desired, or blew up the chip by accident. Then it was written up on paper as a design, had some drawings done ( photos as well in many cases, and scope polaroid shots for those which needed it) and then was sent off to a draughtsman to produce a proof set of application notes to be included in a library.

If he did more than 3 of the same circuit it would be considered a lot, though he probably did do at least 2 of all, just so he could characterise after the initial very dead bug work, then have one good enough to show off in the application note as a design reference layout.
 

Offline mzzj

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #24 on: September 24, 2015, 07:50:35 am »
I'd suspect, that Mr. Williams did the gross of his work before the advent of small package SMDs. I'd say, ESD isn't that much of an issue with robust old through holes.
Quite opposite. He probably has had experience with everything starting from ancient cmos chips without any protection diodes.  SMD vs trough hole has not much to do with it.
Nowadays only small rf fets are  really sensitive, pretty much all logic chips are protected at some level.

some fiqures for esd sensitivity:
ancient cmos logic, rf fet's   10...100V
modern HCMOS 2000-3000V
 

Offline oldway

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #25 on: September 24, 2015, 08:23:16 am »
There are many tricks that avoid burning sensitive components by ESD.
Touch a ground connection before touching the component to eliminate electrostatic voltage is one of them.
First touching the power supply rail of a circuit or a non-sensitive connection of the component before touching a sensitive one is another.
Jim Williams knew this stuffs and definitely used them.
I wonder that beginners come dare criticize Jim Williams ... the day they only have one tenth of the experience of Jim Williams, they might be able to afford to come criticize. :scared:
 

Offline nbritton

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #26 on: September 24, 2015, 08:38:36 am »
In the 18 years I've been working as a computer professional I've never once used an ESD wrist strap or mat. However, I always ground myself to an earth referenced ground source prior to handling components, i.g. by touching the bare metal of a computer chassis, server rack, metal junction box, water pipe, etc.
 

Offline GNU_Ninja

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #27 on: September 24, 2015, 09:05:16 am »
There comes a point when a cluttered workstation becomes less and less productive.
I can see he reached that point four layers ago.

That ain't just a cluttered workstation its 'The Singularity'. That seemingly chaotic mess of components probably achieved true sentience FROM an accidental static discharge  ;)
« Last Edit: September 24, 2015, 09:08:20 am by GNU_Ninja »
 

Offline TheBay

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #28 on: September 24, 2015, 11:12:13 am »
I touched a leg on an IC and the centre blew out of it across the room once!
 

Offline mikerj

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #29 on: September 24, 2015, 11:43:50 am »
I touched a leg on an IC and the centre blew out of it across the room once!

Did you touch it with a big capacitor charged to 400v? :D
 

Offline GNU_Ninja

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #30 on: September 24, 2015, 12:11:25 pm »
I touched a leg on an IC and the centre blew out of it across the room once!

One of the service technicians where I work is like that; I swear the bloke's a walking bloody Van de Graaff Generator. Which is weird, because company policy requires us all to wear anti-static shoes and whatnot. We call him Dr Doom. I suppose some people are more prone to 'charging up' :)
 

Offline oldway

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #31 on: September 24, 2015, 12:14:07 pm »
I touched a leg on an IC and the centre blew out of it across the room once!
Don't do this with the leg of an IC  :-DD
 

Offline SeanB

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #32 on: September 24, 2015, 12:26:55 pm »
I touched a leg on an IC and the centre blew out of it across the room once!

One of the service technicians where I work is like that; I swear the bloke's a walking bloody Van de Graaff Generator. Which is weird, because company policy requires us all to wear anti-static shoes and whatnot. We call him Dr Doom. I suppose some people are more prone to 'charging up' :)

I will bet that he does not have working sweat glands in his feet, and thick calluses there as well. Dry skin is a pretty good insulator. I will guess he also does not use fabric softener on his clothes either, which would make them static dissipative.
 

Offline Howardlong

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #33 on: September 24, 2015, 12:38:44 pm »
The use ESD straps and other similar paraphernalia such as clean room attire is as much to do with the psychology of the situation as it is physical protection of devices.

If you're making that effort, then instinctively you will take more care.

We've had this discussion many times on eevblog, and there will be differing opinions based on differing experiences. My own is that I have suspected lack of protection on a few occasions, but never been able to prove it as such, with eventual evidence usually pointing elsewhere. The last time was on an RF LNA device whose noise figure significantly degraded, and the production yield problem still continued despite some quite draconian additional ESD controls. In that RF LNA yield problem, almost certainly it was due to secondary reflow (rather than ESD) during some post-assembly rework that was required in that area of the board. Once the board design had been updated to avoid the rework, the yield problem stopped.

I'm not saying that ESD is never a problem, far from it, I'm just saying that one should keep an open mind when problems arise rather than immediately blaming ESD. Pretty much every time I blow up a device I can pretty much guarantee the evidence will point to this operator's error and nothing to do with ESD, but human nature is such that it doesn't stop me thinking it might be.
« Last Edit: September 24, 2015, 12:42:49 pm by Howardlong »
 

Offline Cubdriver

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #34 on: September 24, 2015, 03:46:58 pm »
Should I be?



The layers and layers of circuit boards with their myriad components provide plenty of places for static to go. :-DD

Jim's bench was a giant MAZE for static.  It would get into the piles and wander aimlessly, lost forever never to be heard from again.

-Pat
If it jams, force it.  If it breaks, you needed a new one anyway...
 

Offline Cliff Matthews

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #35 on: September 24, 2015, 06:14:55 pm »
I wonder that beginners come dare criticize Jim Williams ... the day they only have one tenth of the experience of Jim Williams, they might be able to afford to come criticize. :scared:
Agreed! We should put this thread to rest folks...

Jim's bibliography is on Wiki and expanded at http://web.mit.edu/klund/www/jw/jwbib.pdf  + EDN contributions http://www.edn.com/collections/4374116/Jim-Williams-contributions-to-EDN
 

Offline AF6LJ

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #36 on: September 24, 2015, 06:19:01 pm »
I wonder that beginners come dare criticize Jim Williams ... the day they only have one tenth of the experience of Jim Williams, they might be able to afford to come criticize. :scared:
Agreed! We should put this thread to rest folks...

Jim's bibliography is on Wiki and expanded at http://web.mit.edu/klund/www/jw/jwbib.pdf  + EDN contributions http://www.edn.com/collections/4374116/Jim-Williams-contributions-to-EDN

Oh Please;
I am no beginner by any stretch, respect where it is deserved, but a mess is a mess.
This guy's lab looks like a Tweaker's garage.
Sue AF6LJ
 

Offline Cliff Matthews

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #37 on: September 24, 2015, 06:24:54 pm »
Oh Please;
I am no beginner by any stretch, respect where it is deserved, but a mess is a mess.
This guy's lab looks like a Tweaker's garage.
Opinions (or legacies) should never be formed from just one angle.
 

Offline AF6LJ

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #38 on: September 24, 2015, 07:48:23 pm »
Oh Please;
I am no beginner by any stretch, respect where it is deserved, but a mess is a mess.
This guy's lab looks like a Tweaker's garage.
Opinions (or legacies) should never be formed from just one angle.

Okay It looks less like a Tweaker's garage but still looks like a disaster.

I guess part of my problem might be I never saw anybody who blazed a trail in this industry that was worth idolizing. There are a couple of people who I hold in high respect but they are still made of the same clay as the rest of us.

And No I don't even believe in String Theory, Has not been proven yet.
Sue AF6LJ
 

Offline DimitriP

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #39 on: September 24, 2015, 07:56:05 pm »
Quote
I guess part of my problem might be I never saw anybody who blazed a trail in this industry that was worth idolizing. There are a couple of people who I hold in high respect but they are still made of the same clay as the rest of us.

Sometimes you have to be your own hero.
A mirror helps.
   If three 100  Ohm resistors are connected in parallel, and in series with a 200 Ohm resistor, how many resistors do you have? 
 

Offline nitro2k01

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #40 on: September 24, 2015, 08:03:54 pm »
Opinions (or legacies) should never be formed from just one angle.
So, is that a mat of some kind on his bench, or is it just the laminate starting to come off from the tabletop surface?  :-//
Whoa! How the hell did Dave know that Bob is my uncle? Amazing!
 

Offline AF6LJ

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #41 on: September 24, 2015, 09:12:20 pm »
Quote
I guess part of my problem might be I never saw anybody who blazed a trail in this industry that was worth idolizing. There are a couple of people who I hold in high respect but they are still made of the same clay as the rest of us.

Sometimes you have to be your own hero.
A mirror helps.
I agree. :)
Sue AF6LJ
 

Offline Bud

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #42 on: September 25, 2015, 04:51:51 am »
Did the poor guy have only one pair of shorts?
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Offline oldway

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #43 on: September 25, 2015, 06:06:34 am »
Those who knew the analog electronics era know it was not enough to be a genius to do what Jim Williams did: it was also necessary to have some artistic side.

From a same diagram, a circuit could work or not depending on the person who make it.
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Offline george graves

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #44 on: November 20, 2015, 12:55:17 pm »
From a same diagram, a circuit could work or not depending on the person who make it.

Well, that's a new one.  Almost a Jim Willams' religion...

Offline TheUnnamedNewbie

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #45 on: November 20, 2015, 01:46:02 pm »
Having been on a company tour at a facility that focuses on ESD protective IP blocks I thought this might be a good place to shared what I have learned/heard there. Some of this stuff will likely be obvious, others I might have misinterpreted/misheard, but here goes anyways:

There are three main models for ESD:
  • Human Body Model (HBM): A person acts as a capacitor with a relatively large (few kOhms IIRC) resistance.
  • Machine Model (MM): Smaller capacitance as the HBM, but no resistance (machines are usually made out of metals and/or other conductive materials)
  • Charged Device Model (CDM): Charge is accumulated within/on the device itself. The charge is dissipated as soon as one of the pins finds a path to ground. I don't know if this is very common still, but the model was designed back when DIP packages were common in pick and place machines, and the machine vibrated them inside tubes. As soon as the device contacted any metal, it discharged potentially ruining your device.

*The ones we actually come in contact with most is similar to the HBM model. Usually we are dealing with a few KV of potential buildup, ratings go up to 20kV or even 50kV (important for situations where you have exposed contacts on a consumer product, like bus connectors, headphone jacks, ...). Discharge times are on the order of hundreds of nanoseconds (compared to a tens nanoseconds in the MN and sub-nanosecond pulses in the CDM models).

I was told that in "the olden days" (I'm 21 years old and thus haven't a clue if this is correct - feel free to point out any bs written here) ESD was a lot less of an issue. Discretes are less sensitive to ESD because the length of leads and the amount of PCB tracks alone form enough of an inductor to stop a lot of the current spikes. They are built at larger scales with thicker insulating layers and more surface area to dissipate the energy over. And the components were usually designed with higher voltages to begin with.

ESD becomes a more significant issue as you move down process nodes. A bigger FET, rated for higher voltage operation has a lot more space to dissipate the energy provided by the ESD. I don't remember exact numbers, but the oxide layer in 18nm FETs will have to deal with 50MV/cm (since they are so thin) during normal operation (1-3 volts DC). if they are hit by an ESD discharge at a few kV, this goes well into the GV/cm ranges. Larger and more powerful devices are a lot less sensitive since they have thicker oxide layers and larger areas for the currents to flow through once discharge does take place.

Fabs are another place where ESD can be a very significant risk. The air is so clean and pure, and exists almost only of non-polar molecules which have a lot harder time dissipating even the smallest amount of charge. The mere action of putting on bondwires can destroy IC's.

The most sensitive components are things like powerfull processors and FPGA's which end up using a very small nodes. Really sensitive components often have ESD protection internal to them.

Analog components are often a lot stronger anyways. RF stuff is an exception to this, and often can't be protected either (because the protection circuitry would just ruin the RF performance), which is why, as mentioned here, these are most prone to being damaged.

Oh, just a little afterthought: The reason most power components (like say discretes and 74 logic) don't seem to break is because they seldom fully fail: they just get damaged reducing performance (most often the leakagecurrent into the source because a "damaged" path has formed through the source oxide) and/or reliability. You might just not realize because your prototype has to work only once or you are using over-rated components anyways. You could for instance have ruined the Rds(on) causing higher temperatures, making the component die once the product is actually pushed to it's limits.

Hope I didn't mess up to bad...
Parts with a * have been added after I taken some time to read and think about my post.
« Last Edit: November 20, 2015, 05:13:39 pm by TheUnnamedNewbie »
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Offline AF6LJ

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #46 on: November 20, 2015, 01:58:22 pm »
 Good job in explaining that.  :-+ :-+
I had ESD training back in the "Olden Days",
Latent ESD damage would sometimes show up as a failure in HT burn-in after the product is built and a day away from final QC acceptance.

Microwave semiconductors have historically came with static damage warnings.

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Offline rsjsouza

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #47 on: November 20, 2015, 05:00:24 pm »
TheUnnamedNewbie, thanks for sharing the information. One detail:

I was told that in "the olden days" (I'm 21 years old and thus haven't a clue of this is correct - feel free to point out any bs written here) ESD was a lot less of an issue. Discretes are less sensitive to ESD because the length of leads and the amount of PCB tracks alone form enough of an inductor to stop a lot of the current spikes. They are built at larger scales with thicker insulating layers and more surface area to dissipate the energy over. And the components were usually designed with higher voltages to begin with.

That would depend on the technology referenced. Despite the nodes were larger in size, there were a lot of pure bipolar devices (ICs, BJT and J-FET transistors, diodes) that were naturally less susceptible to ESD due to their physical construction. The original DTL, RTL, TTL, DCTL, ECL and a few other "soup letter" devices are purely bipolar.

However, MOS (Metal-Oxide Semiconductor) started to gain popularity (early to mid 1970's) and its main feature is a terminal fully isolated from the substrate through a very thin coating of Silicon Dioxide (SiO2).  This increased the susceptibility of this terminal (called gate) to ESD, given that discharges were enough to pierce through the glass. This problem started to appear to both discrete MOS field effect transistors (MOSFETs) and IC's (Complementary MOS or C-MOS), but other technologies followed through.

With the experience accumulated in the field after the wider adoption of MOS devices, the IC manufacturers started to integrate (relatively) beefy junction diodes to the input pins - all this to provide a path of lower resistance to ground and prevent the piercing of the gate terminal.

There are several limitations in integrating this diode, but it helped improve the robustness of the gate piercing. However, other problems started to become more significant as the technology nodes were reduced in size - one of them is the width of the wiring inside an IC. ESD failures started to cause enough current density that wires simply vapourized and disconnected parts of the circuit. That is also behind AF6LJ's remark about microwave semiconductors always being susceptible - their dimensions were always smaller.

That (and perhaps other reasons I don't remember here) still make ESD an important matter until today.
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Offline TheUnnamedNewbie

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #48 on: November 20, 2015, 05:10:45 pm »
However, other problems started to become more significant as the technology nodes were reduced in size - one of them is the width of the wiring inside an IC. ESD failures started to cause enough current density that wires simply vapourized and disconnected parts of the circuit.


I remember them talking about that failure mode, they said it gave a very distinct and audible click when it happened.
The best part about magic is when it stops being magic and becomes science instead

"There was no road, but the people walked on it, and the road came to be, and the people followed it, for the road took the path of least resistance"
 

Offline timofonic

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #49 on: November 20, 2015, 06:10:51 pm »
However, other problems started to become more significant as the technology nodes were reduced in size - one of them is the width of the wiring inside an IC. ESD failures started to cause enough current density that wires simply vapourized and disconnected parts of the circuit.


I remember them talking about that failure mode, they said it gave a very distinct and audible click when it happened.
I would love to see a video of that!
 

Offline G0HZU

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #50 on: November 20, 2015, 08:54:35 pm »
I've seen that first image of Jim's bench a few times now.

I'll dare to make a few comments... :)

He doesn't have a megadigit bench DMM anywhere in sight and the items that look like DMMs seem to be stacked on top of power supplies (that act as a heat source).

So it does make you wonder why so many newbies on this forum seem to think they 'need' a super accurate/stable megadigit DMM. Maybe they are doing stuff that is at a higher level than Jim?

Also, I think a couple of low level shelves would have helped a lot. Also a deeper bench. I also suspect that the photo was taken at 'peak/critical mess' during a particularly busy time.

I am definitely a fan of ESD mats but this is mainly because a good one will act as a nice grippy and pliable surface to work on that is fairly tolerant of abuse from a soldering iron. I really like the old sky blue ones from Farnell. I suspect that these are now obsolete but they are really nice to work on and I also like the colour. Many years ago I used to just work on a wooden bench but because wood is relatively hard and smooth it's really easy for stuff to bounce and slide off the desk if mishandled.
 

Offline AF6LJ

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #51 on: November 20, 2015, 08:57:17 pm »
I have one of those sky blue mats, and I love it.
Sue AF6LJ
 

Offline G0HZU

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #52 on: November 20, 2015, 09:22:43 pm »
I have one of those sky blue mats, and I love it.

I tried to buy another one a few years ago but ended up going for a couple green mats made by Multicomp. I use these as a work surface on a couple of desks. They stank of rubber so badly I had to put them in with the boiler to try and age the smell out of them. It took several months before I could have them in my workroom.

Modern mats probably work a lot better as ESD mats but they feel cold and clammy compared to those old sky blue mats. I still have a sky blue one on my main workbench but it's covered in battle scars. Mostly inflicted with soldering irons, heat guns and scalpels :)
 

Offline AF6LJ

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #53 on: November 20, 2015, 09:27:51 pm »
I got my mat from a friend who had a half dozen two meter mats rolled up in his garage.
Already aged and a little 409 and some elbow grease took the garage smell out of it.
Sue AF6LJ
 

Offline AF6LJ

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #54 on: November 20, 2015, 09:29:31 pm »
As a side note, my favorite work surface, static free Indoor/Outdoor carpet on a metal desk.
Dark Green is the preferred color.
Sue AF6LJ
 

Offline G0HZU

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #55 on: November 20, 2015, 09:42:59 pm »
I like the sky blue colour for several reasons.

I find the colour to be welcoming and soothing. It also looks good as a background colour against typical RF based stuff. eg gold, copper and silver (and also those little wooden boxes full of RF goodies) look really good to me when set against a sky blue background. It does show the muck easily though.

By contrast, I find the darker and more intense colours used in modern mats to be either too gloomy or too harsh on the eyes.


« Last Edit: November 20, 2015, 10:45:30 pm by G0HZU »
 

Offline basinstreetdesign

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #56 on: November 24, 2015, 08:30:11 am »
I have a blue one and I love it.  But its there not for what I know would happen if I had carpet on the floor but for what I cant predict like forgetting I was wearing the wrong sweater on a dry day before plopping into the chair at the bench.

I also use grounded soldering irons but will unplug it from the station if I need to change a connection on a powered-up rig especially if it takes some time to cycle the power on it. ;)
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Offline AF6LJ

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #57 on: November 24, 2015, 04:32:51 pm »
I have a blue one and I love it.  But its there not for what I know would happen if I had carpet on the floor but for what I cant predict like forgetting I was wearing the wrong sweater on a dry day before plopping into the chair at the bench.

I also use grounded soldering irons but will unplug it from the station if I need to change a connection on a powered-up rig especially if it takes some time to cycle the power on it. ;)

I like that, it looks really nice.
Sue AF6LJ
 

Offline Seekonk

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Re: It appears that Jim Williams wasn't a big fan of anti-static mats.
« Reply #58 on: November 24, 2015, 05:02:28 pm »
Many years ago I remember talking with thr president of a fairly well known company and he said he never had problems with static until he implemented anti static procedures.
 


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