I'm looking for a microcontroller which is specified for use in high
temperature environment.
Due to the requirements of our customer automotive parts might not be
appropriate. The application has to work at ambient temperatures of at
least 135 degrees celsius.
Did anybody know whether Microchip (or any other manufacturer) is
offering controllers which are specified up to 150 degrees celsius or
are selected to operate at 135 degrees celsius?
Any hint will be appreciated highly.
Best regards,
M.Schmaeche wrote:
> I'm looking for a microcontroller which is specified for use in high
> temperature environment.
>
> Due to the requirements of our customer automotive parts might not be
> appropriate. The application has to work at ambient temperatures of at
> least 135 degrees celsius.
>
> Did anybody know whether Microchip (or any other manufacturer) is
> offering controllers which are specified up to 150 degrees celsius or
> are selected to operate at 135 degrees celsius?
>
> Any hint will be appreciated highly.
Marc,
I've been using PICs for years at high temp (above 135). Email me
privately and let me know what your project is (if you're a competitor,
my lips are sealed).
> I've been using PICs for years at high temp (above 135). Email me
> privately and let me know what your project is (if you're a competitor,
> my lips are sealed).
I too am looking at using a PIC in a potentially-high-temperature application,
for a boiler-mounted liquid sensor (the PIC will be outside the boiler and
insulated from it, and so 'hopefully' not get over 80c or so, but I'd like
to have some idea that the whole thing isn't going to melt even if ambient
gets excessively hot or if it's placed near a steam vent or something.
part 0 926 bytes I personally have had ceramic (windowed) packages running at 185C at freqencies from 500 KHz to 5MHz. I actually haven't failed any due to temperature response of the micro.
Marc, I was going over temperature specs on various PIC families.
The best I could find was 125C with some 12C5xx and 16C7x parts. The
maximum storage temp was 150C... I also looked at the Motorola 68HCxxx
family and they were 125C.
>Hello to all PICLIST members,
>
>I'm looking for a microcontroller which is specified for use in high
>temperature environment.
>
>Due to the requirements of our customer automotive parts might not be
>appropriate. The application has to work at ambient temperatures of at
>least 135 degrees celsius.
>
>Did anybody know whether Microchip (or any other manufacturer) is
>offering controllers which are specified up to 150 degrees celsius or
>are selected to operate at 135 degrees celsius?
>
>Any hint will be appreciated highly.
>Best regards,
>
>Marc Schmaeche
>
>-----------------------------------------------------------------------
> DESCON Informationssysteme GmbH
>
> Dipl.-Ing. M.Schmaeche Tel.: +49 (0)9131 691145
> ZAM-Anwenderzentrum Nbg. Fax: +49 (0)9131 691166
> Am Weichselgarten 7 E-Mail: msKILLspamzam.nf.fh-nuernberg.de
> 91058 Erlangen, Germany (German/English/Spanish welcome)
>-----------------------------------------------------------------------
>
>
Tom Handley wrote:
>
> Marc, I was going over temperature specs on various PIC families.
> The best I could find was 125C with some 12C5xx and 16C7x parts. The
> maximum storage temp was 150C... I also looked at the Motorola 68HCxxx
> family and they were 125C.
>
From memory, I believe that almost all PICs have versions rated to
125*C. One thing to watch out for: the JW devices are _rated_ to 125,
but not _tested_ at 125. This is not made clear in the specs.
--Matt
Matt, some parts, (ie: 16x84, etc) do not have the "-E" temperature
option which specify 125C operation.
Without knowing the details of the application, I would recommend
isolating the processor from the sensors/actuators. Otherwise, he
will have to use active cooling or look at more `exotic' semiconductor
process', higher costs, and expensive development tools.
>Tom Handley wrote:
>>
>> Marc, I was going over temperature specs on various PIC families.
>> The best I could find was 125C with some 12C5xx and 16C7x parts. The
>> maximum storage temp was 150C... I also looked at the Motorola 68HCxxx
>> family and they were 125C.
>>
>>From memory, I believe that almost all PICs have versions rated to
>125*C. One thing to watch out for: the JW devices are _rated_ to 125,
>but not _tested_ at 125. This is not made clear in the specs.
>--Matt
>
>
Tom Handley wrote:
>
> Matt, some parts, (ie: 16x84, etc) do not have the "-E" temperature
> option which specify 125C operation.
>
I've always stayed away from EEPROM and flash based devices because they
don't have that all-important (to me) higher temperature spec - if they
did, I would have moved to the 'HC11 (from the RCA 1805) about a decade
ago. Until MChip came along, there were no really good fully-static
CMOS uP or uC around.
Saying that though, I distinctly remember eating my words on this list a
few months ago when I said that the 16x84 didn't come in an extended
range version. But I'm _sure_ the data book doesn't lie when it only
gives part numbers for commercial and industrial versions of the 16x84.
I guess that I could go check the list archives - but I just spent a
couple of hours there yesterday looking for read-modify-write stuff.
Maybe later.
> One thing to watch out for: the JW devices are _rated_ to 125,
> but not _tested_ at 125. This is not made clear in the specs.
This is a funny distinction. Surely JW devices come from the same
batches as OTPs? Now, how do they test devices? You can't test an OTP
device by programming it and running a program, can you? Only by
sampling, because then you've cooked it. Unless you "sample" test by
making QTP (note: I didn't say OTP that time!) devices for orders and
testing them, but then you have to know what the program is supposed to
do to see whether it is actually working or not.
What am I rambling about? Just seems to me that only JW devices could
be fully tested and characterised prior to shipment so whatever testing
OTPs get, it must be to a lesser spec anyway. Have I missed something?
At 07:59 AM 2/7/98 +1000, Paul Webster wrote:
> This is a funny distinction. Surely JW devices come from the same
>batches as OTPs? Now, how do they test devices? You can't test an OTP
>device by programming it and running a program, can you? Only by
>sampling, because then you've cooked it. Unless you "sample" test by
>making QTP (note: I didn't say OTP that time!) devices for orders and
>testing them, but then you have to know what the program is supposed to
>do to see whether it is actually working or not.
>
> What am I rambling about? Just seems to me that only JW devices could
>be fully tested and characterised prior to shipment so whatever testing
>OTPs get, it must be to a lesser spec anyway. Have I missed something?
>
I guess I ought to know this but I never really found out: do companies
making regular commercial grade components usually test each component in
some way??! I never exepected that, I always thought that components for
non-critical applications (i.e. consumer electronics) were only spot
checked. I could understand maybe testing each one of the industrial or
aerospace/military versions for saftey's sake (although, you would also
expect the final equipment manufacturer to test each final device under
these circumstances).
Sean
+--------------------------------+
| Sean Breheny |
| Amateur Radio Callsign: KA3YXM |
| Electrical Engineering Student |
+--------------------------------+
Fight injustice, please look at http://homepages.enterprise.net/toolan/joanandrews/
> I guess I ought to know this but I never really found out: do companies
> making regular commercial grade components usually test each component in
> some way??! I never exepected that, I always thought that components for
> non-critical applications (i.e. consumer electronics) were only spot
> checked. I could understand maybe testing each one of the industrial or
> aerospace/military versions for saftey's sake (although, you would also
> expect the final equipment manufacturer to test each final device under
> these circumstances).
In many cases, testing individual devices merely to see if they meet cust-
omer specifications is not terribly useful; a crate of devices that happen
to "barely" meet specs may turn into half a crate of devices that fail in
use. Instead, it's desirable to determine what types of defects or modes
of failure exist, and then to work at identifying/preventing those.
My impression of normal silicon manufacturing processes is that devices are
at minimum somehow checked to ensure that no stray dust particle has prod-
uced a crater or mountain somewhere. While chips are always made in clean
room conditions, even a room with one particle for every thousand liters of
air will have a few dust particles that may land somewhere and wreak havoc
on one chip on one wafer without affecting anything else; even if 99.99% of
parts don't have such defects, most customers would like another nine at
the end of that.
For (E)PROM devices, my impression is that many such devices, even OTPROM's,
are indeed programmed and tested before packaging; until the wafer has been
sealed in the expoxy, there's nothing to prevent its erasure. If the dev-
ices program and operate correctly at various extremes of temperature and
radiation exposure, they are very unlikely to fail in the field; my imp-
ression is that all shipped Microchip EPROM-related products are tested for
data retention at moderately high temperatures, and that some "sacrificial"
units from each batch are tested at excessive temperatures.
Once devices have been tested on the wafer, they are placed into either plas-
tic of ceramic packages. My impression is that when Microchip says that the
JW parts are characterized but not tested at extreme temperatures, what they
mean is:
(1) All their parts are tested at temperatures somewhat outside the operating
range specification; the sacrificial parts are tested outside the "absol-
ute" specification. The wafers themselves do not fail under such abuse.
(2) The plastic-cased parts will suffer package-related failure at temperature
extremes which the ceramic cases can survive. Microchip does not, how-
ever, test individual parts to ensure full-range temperature reliability
after they are packaged. While Microchip does not expect /JW packages to
fail due to temperature extremes, it is possible that, e.g., thermal exp-
ansion and contraction could weaken one of the die bonds.
(3) Exposing individual parts to temperature extremes significantly outside
rated specifications may degrade their long-term reliability. It would
not make sense for Microchip to take years off the lives of their parts
by exposing them all to extreme temperatures even if they'd found that
most parts treated that way would suffer little if any apparent damage.
Note that these are only my impressions; since I don't work at Microchip
anything above may or may not be right, and should be taken with 4 grains
of salt and 2 grains of oregano.
Wow! I never expected that the manufacturing process for each individual
chip involved so much testing! Is this, then, a major or maybe THE major
share of the price of the IC? It would seem to me to be a fairly expensive
undertaking. Also, in a typical consumer electronic device (take a
microwave oven, TV, or clock, for example), is the initial failure rate
less than 99.99% ??! Again, this is news to me. As a first year EE student
and an avid electronics hobbyist, I have never had any of my designs go
into production, but have considered trying several times. I guess that
this is the reason why I am unfamiliar with the expectations of
manufactured devices. It just seems that in my experience, I have seen at
least several of the applicances which I have purchased fail prematurely or
never work. If the rate were really 99.99%, I must be very unlucky. Then
again, we engineers are especially cursed by murphy, right :)
>In many cases, testing individual devices merely to see if they meet cust-
>omer specifications is not terribly useful; a crate of devices that happen
>to "barely" meet specs may turn into half a crate of devices that fail in
>use. Instead, it's desirable to determine what types of defects or modes
>of failure exist, and then to work at identifying/preventing those.
>
>My impression of normal silicon manufacturing processes is that devices are
>at minimum somehow checked to ensure that no stray dust particle has prod-
>uced a crater or mountain somewhere. While chips are always made in clean
>room conditions, even a room with one particle for every thousand liters of
>air will have a few dust particles that may land somewhere and wreak havoc
>on one chip on one wafer without affecting anything else; even if 99.99% of
>parts don't have such defects, most customers would like another nine at
>the end of that.
>
>For (E)PROM devices, my impression is that many such devices, even OTPROM's,
>are indeed programmed and tested before packaging; until the wafer has been
>sealed in the expoxy, there's nothing to prevent its erasure. If the dev-
>ices program and operate correctly at various extremes of temperature and
>radiation exposure, they are very unlikely to fail in the field; my imp-
>ression is that all shipped Microchip EPROM-related products are tested for
>data retention at moderately high temperatures, and that some "sacrificial"
>units from each batch are tested at excessive temperatures.
>
>Once devices have been tested on the wafer, they are placed into either plas-
>tic of ceramic packages. My impression is that when Microchip says that the
>JW parts are characterized but not tested at extreme temperatures, what they
>mean is:
>
>(1) All their parts are tested at temperatures somewhat outside the operating
> range specification; the sacrificial parts are tested outside the "absol-
> ute" specification. The wafers themselves do not fail under such abuse.
>
>(2) The plastic-cased parts will suffer package-related failure at
> extremes which the ceramic cases can survive. Microchip does not, how-
> ever, test individual parts to ensure full-range temperature reliability
> after they are packaged. While Microchip does not expect /JW packages to
> fail due to temperature extremes, it is possible that, e.g., thermal exp-
> ansion and contraction could weaken one of the die bonds.
>
>(3) Exposing individual parts to temperature extremes significantly outside
> rated specifications may degrade their long-term reliability. It would
> not make sense for Microchip to take years off the lives of their parts
> by exposing them all to extreme temperatures even if they'd found that
> most parts treated that way would suffer little if any apparent damage.
>
>Note that these are only my impressions; since I don't work at Microchip
>anything above may or may not be right, and should be taken with 4 grains
>of salt and 2 grains of oregano.
>
+--------------------------------+
| Sean Breheny |
| Amateur Radio Callsign: KA3YXM |
| Electrical Engineering Student |
+--------------------------------+
Fight injustice, please look at http://homepages.enterprise.net/toolan/joanandrews/
I used to work at a semiconductor factory, and I can tell you that most (if
not all) semiconductors, from a simple diode up to a microprocessor are
extensively tested during most phases of manufacturing. In this way, by
rejecting bad units in early stages of manufacture materials and work is
saved. What good would it be to assemble a bad chip and at the end of the
process find out it is bad?
And failure rates are usually measured in ppms (parts per million). In the
plant I worked a goal was 100ppm, and we were actually doing about
180-250ppms.
At 10:45 PM 02/07/98 -0500, you wrote:
>Wow! I never expected that the manufacturing process for each individual
>chip involved so much testing! Is this, then, a major or maybe THE major
>share of the price of the IC? It would seem to me to be a fairly expensive
>undertaking. Also, in a typical consumer electronic device (take a
>microwave oven, TV, or clock, for example), is the initial failure rate
>less than 99.99% ??! Again, this is news to me. As a first year EE student
>and an avid electronics hobbyist, I have never had any of my designs go
>into production, but have considered trying several times. I guess that
>this is the reason why I am unfamiliar with the expectations of
>manufactured devices. It just seems that in my experience, I have seen at
>least several of the applicances which I have purchased fail prematurely or
>never work. If the rate were really 99.99%, I must be very unlucky. Then
>again, we engineers are especially cursed by murphy, right :)
>
>Sean
>
Sean;
Don't forget that if you have ten parts, each with a reliability of 0.999,
then the system has a reliability of 0.99 to the fifth power, or 0.990.
Thus a system with a a lot of parts can end up with low reliability very
quickly. This is of course a simplified version.
>At 10:45 PM 02/07/98 -0500, you wrote:
>>Wow! I never expected that the manufacturing process for each individual
>>chip involved so much testing! Is this, then, a major or maybe THE major
>>share of the price of the IC? It would seem to me to be a fairly expensive
>>undertaking. Also, in a typical consumer electronic device (take a
>>microwave oven, TV, or clock, for example), is the initial failure rate
>>less than 99.99% ??! Again, this is news to me. As a first year EE student
>>and an avid electronics hobbyist, I have never had any of my designs go
>>into production, but have considered trying several times. I guess that
>>this is the reason why I am unfamiliar with the expectations of
>>manufactured devices. It just seems that in my experience, I have seen at
>>least several of the applicances which I have purchased fail prematurely or
>>never work. If the rate were really 99.99%, I must be very unlucky. Then
>>again, we engineers are especially cursed by murphy, right :)
>>
>>Sean
>>
>Sean;
>Don't forget that if you have ten parts, each with a reliability of 0.999,
>then the system has a reliability of 0.99 to the fifth power, or 0.990.
>Thus a system with a a lot of parts can end up with low reliability very
>quickly. This is of course a simplified version.
>
>
>Mark Walter
>
Mark, Morgan, and others,
Thanks for the reminder. I have to remember to engage brain before engaging
mouth (or hands, in this case). I would say, though, that there are some
components which are MUCH more likely to fail than others (i.e., I wouldn't
think that a resistor with very little current running thru it would be
likely to fail, etc.) and therefore, even though there are 1000 components
in a device, maybe only 100 of them realisitically contribute significantly
to the failure rate of the device. OF course, as you pointed out, there
could be problems with soldering, too.
Thanks again,
Sean
+--------------------------------+
| Sean Breheny |
| Amateur Radio Callsign: KA3YXM |
| Electrical Engineering Student |
+--------------------------------+
Fight injustice, please look at http://homepages.enterprise.net/toolan/joanandrews/
John Payson <RemoveMEsupercatTakeThisOuTMCS.NET> wrote:
> In many cases, testing individual devices merely to see if they meet cust-
> omer specifications is not terribly useful; a crate of devices that happen
> to "barely" meet specs may turn into half a crate of devices that fail in
> use. Instead, it's desirable to determine what types of defects or modes
I might disagree, depending on what you mean by "'barely' meet specs". If the
device is rigourously tested and meets all the specs over the entire rated
temperature, voltage, and frequency ranges, but doesn't have much margin at
85C, 3.0V, and 20 MHz, that doesn't seem like a problem. But if it is only
tested at typical conditions (say 25C, 5.0V, 4 MHz), and has little margin
there, it sounds like big trouble.
I thought there was a famous case (urban legend?) where mil-spec testing
of drams was so harsh that it would leave the chips partially damaged, so
even the parts that passed testing would then have a lower overall
reliability than off-the-shelf (1/10 the price) commerical chips...
> I used to work at a semiconductor factory, and I can tell you that most (if
> not all) semiconductors, from a simple diode up to a microprocessor are
> extensively tested during most phases of manufacturing. In this way, by
> rejecting bad units in early stages of manufacture materials and work is
> saved. What good would it be to assemble a bad chip and at the end of the
> process find out it is bad?
> And failure rates are usually measured in ppms (parts per million). In the
> plant I worked a goal was 100ppm, and we were actually doing about
> 180-250ppms.
>
>
> Gabriel
> TGO
>
> {Original Message removed}
Basically what he said is that if you control your manufacturing
processes carefully, then it should not be neccessary to test at all.
The policy is "let the customer test it for you, and if he complains
then you just replace it". So it is very likely that the failure rate
of new goods could be much worse than 99.99%.
If your failure rate goes up too high, it is no longer ecconomically
feasible to let the customer do your testing.
> Basically what he said is that if you control your manufacturing
> processes carefully, then it should not be neccessary to test at all.
> The policy is "let the customer test it for you, and if he complains
> then you just replace it". So it is very likely that the failure rate
> of new goods could be much worse than 99.99%.
>
> If your failure rate goes up too high, it is no longer ecconomically
> feasible to let the customer do your testing.
I agree. I'm just quoting what the supposedly expert said about what the
world trends are.
Rgds
Werner
--
Werner Terreblanche users.iafrica.com/w/we/wernerte/index.htm EraseMEwterrebplessey.co.za (work) OR RemoveMEwernerteEraseMEEraseMEiafrica.com (home)
Plessey SA, PO Box 30451,Tokai 7966, Cape Town, South Africa
or at home : Suite 251, PostNet X5061, Stellenbosch, 7599
Tel +27 21 7102251 Fax +27 21 7102886 Home +27 21 8523249
------------------------------------------------------------
John Payson wrote:
>
> > I guess I ought to know this but I never really found out: do companies
> > making regular commercial grade components usually test each component in
> > some way??! I never exepected that, I always thought that components for
> > non-critical applications (i.e. consumer electronics) were only spot
> > checked. I could understand maybe testing each one of the industrial or
> > aerospace/military versions for saftey's sake (although, you would also
> > expect the final equipment manufacturer to test each final device under
> > these circumstances).
>
> In many cases, testing individual devices merely to see if they meet cust-
> omer specifications is not terribly useful;
<Lots of interesting stuff snipped>
I would expect that for the OTP parts there is wafer testing, combined
with some kind of statistical quality control.
It is possible to estimate the upper and lower limits of reliability
given a random sample of devices to test. I can't remember the details
but I'm sure any undergraduate stats textbook can provide them.
I would expect the JW parts to undergo more stringent testing because
they are expected to work over the full operating range. In addition, if
I worked for Microchip, I would make damn sure the development chips
worked since one dud one could cancel a project using thousands of OTP
parts.
Just a few monday morning thoughts (before my brain gets started |-)
I know this was a quote by someone not on the list, but I must
add, how can one keep their manufacturing processes under control
(carefully or otherwise) without some kind of testing?
Matt
On Sun, 8 Feb 1998, William Chops Westfield wrote:
> Basically what he said is that if you control your manufacturing
> processes carefully, then it should not be neccessary to test at all.
> The policy is "let the customer test it for you, and if he complains
> then you just replace it". So it is very likely that the failure rate
> of new goods could be much worse than 99.99%.
>
> If your failure rate goes up too high, it is no longer ecconomically
> feasible to let the customer do your testing.
>
> BillW
>
/*****************************************/
/* Matt Calder, Dept. of Statistics, CSU */
/* http://www.stat.colostate.edu/~calder */
/*****************************************/
I took a look at the reliability document (just a glance, really) and it
appears that I may be partially right, they only test a certain segment of
most of their devices. They have large tables detailing the different tests
that are performed and only a few are performed on 100% of devices.
Sean
+--------------------------------+
| Sean Breheny |
| Amateur Radio Callsign: KA3YXM |
| Electrical Engineering Student |
+--------------------------------+
Fight injustice, please look at http://homepages.enterprise.net/toolan/joanandrews/
Whoops..sent this only privately to Paul. Microchip won't see it there.
Paul B. Webster VK2BZC wrote:
>
> Matt Bonner wrote:
>
> > One thing to watch out for: the JW devices are _rated_ to 125,
> > but not _tested_ at 125. This is not made clear in the specs.
>
> This is a funny distinction. Surely JW devices come from the same
> batches as OTPs? Now, how do they test devices? You can't test an OTP
> device by programming it and running a program, can you? Only by
> sampling, because then you've cooked it. Unless you "sample" test by
> making QTP (note: I didn't say OTP that time!) devices for orders and
> testing them, but then you have to know what the program is supposed to
> do to see whether it is actually working or not.
>
> What am I rambling about? Just seems to me that only JW devices could
> be fully tested and characterised prior to shipment so whatever testing
> OTPs get, it must be to a lesser spec anyway. Have I missed something?
>
I was told this by a MChip FAE at a MChip seminar (after using the JW
device at high temp for a couple of years). My first thought was that
he hadn't recovered from the sixties. I guess what the specs all come
down to is butt-covering - but to be fair, maybe what he meant was that
the screening procedures are different for JWs. What he did do,
however, was to challenge me to find _anywhere_ in the data book that
said the JW was spec'ed to 125. He said that you have to go to an
E-suffix part for that.
Microchip, can you clarify this? Brian Boles...I know you're watching.
> What he did do, however, was to challenge me to find
> _anywhere_ in the data book that said the JW was
> spec'ed to 125. He said that you have to go to an
> E-suffix part for that.
Ahhh, now this is an interesting question...
Take a datasheet at random. Say PIC16C71x. And
look at section 11.0 'Absolute Maximum Ratings'.
Note the first line:
"Ambient termperature under bias .... -55 to +125C"
This section does _not_ distinguish between
different versions of the chips; neither oscillator
type nor package type. Therefore, any 16C71x is
"spec'd" to operate up to +125C, including a JW
packaged chip.
The following sections then give extensive DC and
AC characteristics. These sections _do_ distinguish
between different versions of the chip; specifically
between commercial, industrial, and extended temp-
erature ranges. Therefore, the characteristics of
a JW packaged chip at +125C are only "spec'd" if
that JW packaged chip is an extended temperature
type.
So (for example):
1. A 16C710/JW is spec'd to operate at +125C.
2. A 16C710E/JW is spec'd to have certain DC
and AC characteristics at +125C.
So I believe the answer to your Microchip FAE is
that the datasheet DOES spec a JW packaged part
to operate at +125C (but with undefine charac-
teristics unless it is ALSO an extended temp-
erature version).
>At 10:45 PM 02/07/98 -0500, you wrote:
>>Wow! I never expected that the manufacturing process for each individual
>>chip involved so much testing! Is this, then, a major or maybe THE major
>>share of the price of the IC? It would seem to me to be a fairly expensive
>>undertaking.
Yes - this is why chips with A/D converters and the like are expensive
- analog is harder/slower to test.
Test time, die size (small chips = more per wafer) and packaging
(fewer pins/less plastic = cheaper) are the major factors in chip
cost.
____ ____
_/ L_/ Mike Harrison / White Wing Logic / .....wwlRemoveMEnetcomuk.co.uk _/ L_/
_/ W_/ Hardware & Software design / PCB Design / Consultancy _/ W_/
/_W_/ Industrial / Computer Peripherals / Hazardous Area /_W_/
zam.nf.fh-nuernberg.de
