RoHS => tin whiskers?

I have dialed 9-1-1 twice with my cellphone. The first time was by accident (how the hell does a phone in your pocket choose 9-1-1 over the billion other possibilities anyway?) and the other time (my son and I witnessed a mid-air plane crash

) I told them where I was.

1/3? On a typical TO220 package the pins are at least 1150 um apart. I think you are referring to a SSOP package (350um between the legs).

Hold your horses :-) Meanwhile I've been reading some more on the subject. Tin has been used for centuries already to make all kinds of objects. The tin-whiskers have been studied since the 1940's.

The 2 problems with tin are tin-whiskers and the tin-plague. Tin-plague occurs by using tin below 13 degrees Celcius and can be stopped by adding small amounts of other metals (like bismuth and antimony) to the tin. There are no secrets here.

Tin whiskers are not fully understood yet but it is assumed they are caused by tensions in the material caused by cooling down unevenly, too fast or too slow. Some experimentation with the soldering oven temperature profile should solve the tin whiskers problem. This may imply the oven cannot be used at its fastest speed or some components cannot be placed close together.

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Reply to nico@nctdevpuntnl (punt=.)
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Laptop case.

--
  Keith

Can be. Lead-free bullets are used in many indoor ranges and hunting waterfowl

25479--,00.html

No problems with tin-whiskers either.

--
  Keith

[snip]

Myself, also twice. Witnessed a car crash. The second time was when we were T-boned on Thanksgiving two years ago.

Suppose however that you're on a highway in a strange town... do you really know where you are?

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

[...]

indeed, sorry. I was too lazy to walk to the office and check literature on whiskers growth humidity dependency.

I'm curious which whisker growth we can expect on National's TO220 devices at low RH conditions and >60°C.

Oliver

--
Oliver Betz, Muenchen (oliverbetz.de)

[...]

From the link above: "The smallest gap between leads for any of the TO-220 or TO-263 packages is 457um for the TO-263 9L package". Well, I used only 7 pin TO220 devices so far.

[...]

That's rather hard since you don't have reliable information about the interpretation of accelerated test data and you don't want to wait 10 years for data.

And you don't know each modification of the manufacturer's plating process. And you don't want to qualify every new component this way.

Through-hole TO220 won't be reflowed over the whole lead length in many cases.

Oliver

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Oliver Betz, Muenchen (oliverbetz.de)

accident

them

Begging hte question --

Usually when I am going to a strage town I take my dashboard-top GPS system with me (actually, I always take it with me - it's usually in the trunk). And I have it set to read put lat, long, and altitude above the map.

My wife's new car has an GPS-based audio direction system. You enter a target, and it tells you when to turn. (I like to fool with it by taking slightly different routes.) The first day she got it, she wanted me to drive it to her office and then home, because she had the old car there. She programmed it to go to the office for directions to the office to show it off. After dropping her off, it kept telling me things like "Make a U-turn now!" all the way home.

Others have answered similarly, but I use a Ruger 9mm and wife mate has a little Keltec .380, both with "personal protection" ammo. Not RoHS compliant, I might add.

But with all of the RFID tags on everything, they probably know where we are anyway. Wal-Mart sure does, (assuming you buy things at WM... I don't)

All of the genius of this group should be developing circuits for equipment to burn out the RFID tags in your Gillette razor blades and Michelin tires.

Then you can go to work on countermeasures for traffic cameras that check your speed. Go a few miles an hour over the limit these days and they come to your door.

[snip]

Passive tags can't do more than few feet, at most.

Active tags have more range, but they don't give them away with your razor blades ;-)

Sure. A Hyundai Sonata. Scottsdale officials are sweating this one ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

I doubt thats true. Every metal has 'issues' with crystal alignment, so a lot is known on the subject in general. Take brass for instance. If not properly heat treated after bending thin sheet material, it will get brittle and break.

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Reply to nico@nctdevpuntnl (punt=.)
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Hello Wes,

147mph, wow. I have never gone that fast, around 120mph or 130mph AFAIR, but not in the US and there was no speed limit.

A long time ago I helped design such a camera system but that one was able to work without magnetic strips. They just mounted it on a freeway overpass. Mostly intended to catch tail-gaters though since they were the ones causing the most horrible crashes. The kind of crash where you'd find a car engine severed and a few hundred feet from the car.

--
Regards, Joerg

http://www.analogconsultants.com

Hi Joerg,

I just touched 130-135 in my Camaro on a two-lane not so flat rural road near here. I backed off real quick when the seal between the passenger side window and the top opened up. The blast of air made me think for a moment that one of the t-tops had left the vehicle and I damn near messed my pants. Boys and their toys. [g]

The only camera systems I ever worked on were high-speed motion picture (film) cameras used to document TOW missile firings at Redstone. These things ate 200' of film in a second or two. They were at various vantage points along the range where certain events were supposed to happen and had to be turned on in sequence.

Because they didn't spool up at a constant rate, there was a neon bulb inside that would fire and overexpose a frame or two on command. (I'm dating myself, we didn't have LEDs then [g].) The blink rate on the NE-2 became the event timer when the film was replayed.

Hello Wes,

Nice. A neighbor had one of these, same color. Now he has a truck, 'cause that's man's toy to tool around in out here.

But that's not supposed to happen. A vehicle has to be designed to hold together at its top speed plus some margin.

When I just had my driver license my father let me drive his Chrysler. On the freeway (or in that case autobahn) he said "Well, do you think we'll ever get there at this measly speed?" So, I got her to about

110mph when there was a loud bang. "Oh, the driver side door always pops out a wee bit at that speed". Years later we found out why. They had conveniently placed the battery over one of the frame beams. The occasional drip from there had completely corroded it out at that spot.

--
Regards, Joerg

http://www.analogconsultants.com

No, I'm not kidding. This is a real problem with these morons.

--
  Keith

...or having a heart attack? ...as you've already pointed out.

What's the friggin' problem? Rampant weenieism?

--
  Keith

I guess.

I WANT the EMT's to find me.

Until you've experienced a heart attack you have NO idea.

My wife engineered my survival... the doctors were saying we can try this experimental (at that time) drug called "TPA"... she says, "Go for it, I saw it on PBS!" They asked ME for permission, I said, "Whatever SHE says!"

I immediately felt so good, I said, "Let me outa here!"

Of course they kept me for a week, and then placed a stent.

I was fortunate, no heart muscle damage, because of quick application of the TPA.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

On Mon, 05 Jun 2006 11:01:48 -0400, Greg Neff Gave us:

Raw Tin is crystalline in nature. Therefore "whiskers" will sprout under the right conditions, and atmospheric charge condition may well be that setting.

On Mon, 05 Jun 2006 09:43:15 -0700, Jim Thompson Gave us:

In So. Korea they have had it for a couple years now at least, and EACH kid can turn it off, as well as powering down the phone, as was mentioned.