Absolute maximum voltage -- how long can digital chips stand it?

[[email protected]]

I've never been overly impressed with Intersil as a company. There is
certainly no reason for rude support.

I've been getting great support from their FAE. The bad news is that
it's been needed and there isn't much to back it up. There is a 70%
chance that we're going to dump their four-phase boost regulator.

I've worked places where getting a $5 PO through channels was a major
PITA so I would ask for samples of nearly everything on the board. When
I asked Intersil for a sample of a 4000 series CMOS part they responded
that they don't sample those parts, they are well understood. I guess
the effort on their part to sample the device was more than the effort
on my part to get a PO though channels. So I didn't use the part. No
big loss on either side.

We've been getting more samples for our prototypes than my last job
used in most production runs. Intersil isn't an exception; 100 of the
above regulator chipsets and a few hundred LDOs. We have no problems
ordering parts but often they're only available in full reels. It's
easier to just ask for samples. I don't do it for passives (though
our purchasing group will) because I try to make sure they're all on
reels. Passives in cut tape is a PITA and beggars can't be choosers.

On the other hand, some sales folks understand the value of getting a
part in the door at companies. Some companies make parts available in
the schematic capture data base which can make things easier for
engineers. This leads to those parts being designed in more often. So
getting a part into a prototype can lead to sales even if that project
doesn't use it in the end.

I've never used a schematic symbol the manufacturer has provided.
They're ugly (though ours are worse, now). OTOH, I can't figure out
why companies like XFMRS doesn't have 3D models for their parts,
particularly ones like Ethernet connectors.

 

[miso]

Shoot-thru looks like another capacitor; also proportional to f

(number of transitions) and V^2 (impedance of the output devices).


Also proportional to f and V^2. I don't see a V^3 component yet.

If the value of shoot through was independent of supply voltage, then
yeah, you could estimate it as PWM. The the spike level isn't directly
related to V^2 but rather (V-Vt)^2. based on the C T Sah equations.

 

[miso]

I've never been overly impressed with Intersil as a company. There is

certainly no reason for rude support.

Rick

The Intersil of today hardly relates to your grandfather's Intersil.
Look at the history:

http://www.intersil.com/en/about-intersil/history.html

------------------------------------------------------

One of the first semiconductor companies in Silicon Valley, Intersil was
founded in 1967 by Jean Hoerni to produce digital watches. When
microprocessors emerged in the 1970s, Intersil participated with its
12-bit IM6100, which was the first microprocessor produced in CMOS
technology and emulated the DEC PDP-8 instruction set.
Two Different Owners

Intersil was acquired by General Electric in 1980. RCA’s semiconductor
division was also acquired by GE, and the two companies were combined
with GE’s own semiconductor operations.

In 1988, GE’s semiconductor business was acquired by Harris Corporation.
The product lines of Intersil, RCA and GE were combined with those of
Harris and Radiation, Inc. (previously acquired by Harris). In 1999,
Harris spun-off its entire semiconductor division, and Intersil was
re-born as an independent company. In early 2000, Intersil went public
in what was then the largest semiconductor IPO in US history.
-------------------------------------------

I'm not saying they are good, but they have little relevance to the
Intersil of yesteryear. Missing from the Intersil history page is the
revolt of engineers when GE took over. They formed a few start ups in
the valley, with Maxim being the better known of them.

 

[miso]

Just look at how many companies have ISO900x ratings. You can buy fish
from ISO9001 qualified companies.

You know you have a problem when Dilbert is dissing it because Adams
gets his ideas from email from actual engineers. So if Dilbert disses
it, that means your employees think it is bad as well.

http://search.dilbert.com/comic/Iso 9000

The best is Oct 4, 1996. The pointy haired boss says "So you don't care
how bad our internal processes are, as long as they're well documented
and used consistently?"

 

[SoothSayer]

Just look at how many companies have ISO900x ratings. You can buy fish
from ISO9001 qualified companies.

That is because one cannot sell overseas without it. so if one wants
to include that demographic in their sales endeavors, they need to step
to the pump.

You know you have a problem when Dilbert is dissing it because Adams
gets his ideas from email from actual engineers. So if Dilbert disses
it, that means your employees think it is bad as well.

It has evolved over the year.

The best is Oct 4, 1996. The pointy haired boss says "So you don't care
how bad our internal processes are, as long as they're well documented
and used consistently?"

It isn't a standard for your processes. It is a standard by which you
declare, document and adhere to your own claimed processes. It is like
this:

"If Johnny is out, how are we going to do the job he was supposed to
have finished by tomorrow, since he is the only one who 'knows how to do
it'?"

The answer to that question should be statistically easier to find in
such a company, under such organization.

So, as long as Johnny's processes are well documented, and there is some
modicum of cross training, the job would get done.

Any specialized assembly procedures, etc.

Of course assembly and other such mfg processes are not the only
disciplines where this streamlines operations. But it can also be done
very poorly. So care must be take when defining things, as well as all
initial start-up implementations so adjustments can be made early on.

Then there are other "douche" type things like "5S", to mop up 'factory
floor' appearances, and even desktops. seems that computers have caused
folks to have extra time, so they waste it by forcing cleaning sessions
upon everyone.

And now everyone walks around reading emails and showing each other
their cell phone videos and pictures. How quaint. A far worse
counter-productivity problem than any organizational program ever was.

 

[LM]

others do, and I'm actually trying to talk them out of it.

The chips are DDR3 DRAM recommended for 1.50V or 1.35V and
rated 1.975V absolute maximum.  A few retail brands of DDR3
modules are sold with recommended voltages of 1.9V - 2.1V,
those recommendations coming from the module marketers, not
the chip makers, and I just want to know how long they'll
likely last.

Overclocking a PC is not electronics. Those RAMs are not supposed to
last while properly designed devices are.

 

[[email protected]]

If the value of shoot through was independent of supply voltage, then
yeah, you could estimate it as PWM. The the spike level isn't directly
related to V^2 but rather (V-Vt)^2. based on the C T Sah equations.

Keep stretching. I'm sure you can move the goalposts further than
that.

 

[[email protected]]

I've yet to
understand what all this ISO9xxx crap accomplished since quality flow is
not standardized to the best of my knowledge. Or if it is, some
companies go beyond the standard. The ISO standards make you document
what you do, but don't specifically say what to do. [My opinion as
someone who never worked in QA.]

You are absolutely right. ISO9000 is more about being able to explain
and justify what you are doing rather than making sure you are doing it
right. There is lots of benefit in that. I was hired by one company
who had hired more engineers in the past year than they had from prior
to that. How do the new hires know how the company is to function? I
don't recall if engineering was ISO9000, technically they were a DOD
outfit and they were just getting their CMMI certification, which is
much similar. In many ways CMMI training is a joke. The CMMI
instructors know the "rules" for CMMI, but can't tell you anything about
how to apply them to your process. In this case we all flailed about
and did a lot of talking in circles. The worst part was in the first
bid I worked on we were adding time to the schedule to make the CMMI
stuff happen and it infuriated the head guy. "If it doesn't save us
time and effort, why are we doing it?" That was a valid point so all
the scheduled time for doing the CMMI stuff was removed along with a
bunch of other fat.

In many ways this company was using the infinite monkey process... but
they did manage to get product out the door. Some of the factory people
were pretty good, but some of them hated engineers. Too bad, I like
working with manufacturing. No point in designing a product only to
have it be hard to make.

Rick

I worked for an electronic manufacturer in the 90s that went ISO9000
while I was there... We had documents for production to refer to
(before and after ISO), but they didn't refer to them much before or
after ISO and didn't seem to do what they were supposed to do. My
impression is that ISO9000 doesn't mean squat. It didn't help
production but we got stuff out the door with or without ISO.

The certification certainly doesn't mean anything. Like many of these
things, ISO9000 is just a set of tools. You can use them to build a
quality system or you can wallpaper a turd with the certificates.
Mostly, I see the latter.

 

[Fred Abse]

I located most bad early RAM chips with a calibrated fingertip.
Cold=dead. Warm=working. Hot=defective.

I once got a Mostek logo burned into a fingertip doing that...

 

[SoothSayer]

I once got a Mostek logo burned into a fingertip doing that...

How funny.

I got myself a permanent "Rubber Powder Tattoo' under the skin of my
finger by accidentally touching a moving, aged V-belt edge. It sliced me
open like a surgeon's blade. I was unable to wash the rubber powder
infusion out, so it healed in place, becoming a permanent 'pigmentation
adjustment'. Probably loaded up with PCBs knowing my luck.

 

[TheQuickBrownFox]

Then your finger was out of calibration. You should be able to sense
the heat before you touch the chip.

"Lunar Lander" Upright Arcade video game by Cinematronics, 1979.

Your vertical velocity is important as you touch down.

 

[rickman]

I've never used a schematic symbol the manufacturer has provided.
They're ugly (though ours are worse, now). OTOH, I can't figure out
why companies like XFMRS doesn't have 3D models for their parts,
particularly ones like Ethernet connectors.

That's not what I'm talking about. I mean once a component user has
added the part to their data base, it is much easier to use logistically
speaking. The company has given it an internal part number and ordering
is easier. Of course it is also easier for engineering to use it as well.

Rick

 

[rickman]

It's from physical chemistry, was discovered long before electronics,
and works just fine.

<http://en.wikipedia.org/wiki/Arrhenius_equation>

Joe Gwinn

Yes, I am often offline when I post so I can't look up things on the
Internet, *but* I have a wikireader which includes the entry on the
Arrhenius equation (how do you think I spelled it right?) So you just
gave me a link to the text I was quoting in my post.

The Arrhenius equation does not give you a doubling of the failure rate
for a 10°C rise unless you have *just* the right constants in it. Where
did those constants come from? My point is that I think this rule of
thumb is just that, a rough approximation and is nothing like exact.

BTW, I passed P-chem.

Rick

 

[rickman]

I worked for an electronic manufacturer in the 90s that went ISO9000
while I was there... We had documents for production to refer to
(before and after ISO), but they didn't refer to them much before or
after ISO and didn't seem to do what they were supposed to do. My
impression is that ISO9000 doesn't mean squat. It didn't help
production but we got stuff out the door with or without ISO.

None of this stuff helps if it is just given lip service. I think that
is what happens mostly. The point is supposed to be documentation so
that you know how you are supposed to be doing your job. If you change
the way you do it, that's fine, but document that so the next guy can do
it the same way.

It's not rocket science, it's just a matter of saying what you are doing
and then doing what you say you are doing.

Rick

 

[[email protected]]

That's not what I'm talking about. I mean once a component user has
added the part to their data base, it is much easier to use logistically
speaking. The company has given it an internal part number and ordering
is easier. Of course it is also easier for engineering to use it as well.

The point is that the manufacturer's schematic symbols are universally
*ugly*. I wouldn't use them on a bet.

As far as the user adding parts to their database, that only happens
in a really small company (or a very independent lab in a larger one).
There is no way a database admin for a large company is just going to
take whatever they're given by a user. The schematic capture database
isn't in the driver's seat, either.

 

[[email protected]]

None of this stuff helps if it is just given lip service. I think that
is what happens mostly. The point is supposed to be documentation so
that you know how you are supposed to be doing your job. If you change
the way you do it, that's fine, but document that so the next guy can do
it the same way.

Exactly. Add to that, the process feedback portion is supposed to be
functional too. ISO-9000 isn't a bad system at all, though I've never
seen it implemented in any sane (or useful) manner. "Lip service" is
being nice.

It's not rocket science, it's just a matter of saying what you are doing
and then doing what you say you are doing.

....and then measuring the results, as a feedback to the process.

 

[[email protected]]

You are hard to talk to.

Only by pig-headed morons.

As an engineer in a company of some 1500
employees, I would add the part to the schematic database. Purchasing
would add their info to it and it could then be used by anyone in the
company. I never said anything about the manufacturer's components.

Purchasing uses the engineering databases? Your company is out of
control! It should be the other way around.

You don't buy components from a manufacturer? The discussion *did*
include taking the manufacturer's data, which I replied that only an
idiot would do such. They're universally *ugly*. You can continue
down that thread if you want but perhaps you should learn to read,
first.

But mostly I was referring to the fact that once the part has been used,
regardless of the mechanism, samples in a prototype or a production run,
it is in the company and has been entered into the systems, so it shows
up internally for others to use. That doesn't matter what size the
company is.

How do you resolve conflicts? This is *NOT* as small of a problem as
you pretend.