PS
Pete Stephenson
Thu, Jul 27, 2017 7:31 PM
Hi all,
A few days ago I reported the results from letting a DS3231 RTC run for
a year, and how the chip kept time well within the published specs.
Since I had acquired several DS3231s from dubious sources (Asian vendors
on a major auction site) as part of an RTC module that fits on the
Raspberry Pi's header pins, I was doubtful of the authenticity of the
chips. I decided to sacrifice one in the name of science and decapped it
at home using alternating heat (a lighter) and cold (a glass of cold
water) to embrittle the epoxy casing, then sanded down the back of the
chip on fine-grain sandpaper to expose what I hoped was the back of the
internals (so as not to damage the die itself).
Other than inadvertently sanding through half of the crystal's housing,
thus breaking one of the forks of the crystal, this was a success. (I
was prepared to decap one in acid had my attempt at physically removing
the epoxy package failed.) I slightly scratched the die itself while
separating it from the epoxy, but the die itself is clearly visible.
Based on a sample size of one and the markings on the die itself, it
appears the chip is authentic. The markings on the outside of the epoxy
package look a bit dubious and not like typical Maxim laser-markings, so
it's possible the chip was re-labeled at some point. I'll contact Maxim
to see if they can look up the lot information.
I used my 2 megapixel USB microscope to take some images throughout the
process that you might find interesting. The microscope has limited
resolution, particularly at high magnification, so some of the photos
may not be perfectly clear. I have access to a Zeiss petrographic
microscope at my work and will see if I can get some better images
tomorrow. I'll try to get high-quality images of the whole chip and
stitch them together into a larger composite.
Anyway, the photos are available at http://imgur.com/a/0zudj -- I will
add more photos from the petrographic microscope tomorrow. I focused
mainly on the markings on the die that indicated it was, in fact, a
Maxim chip but if there's any other region of the chip that you'd like
images of, please let me know and I'd be happy to take some more
pictures.
I hope you find this as interesting as I did.
Cheers!
-Pete
--
Pete Stephenson
Hi all,
A few days ago I reported the results from letting a DS3231 RTC run for
a year, and how the chip kept time well within the published specs.
Since I had acquired several DS3231s from dubious sources (Asian vendors
on a major auction site) as part of an RTC module that fits on the
Raspberry Pi's header pins, I was doubtful of the authenticity of the
chips. I decided to sacrifice one in the name of science and decapped it
at home using alternating heat (a lighter) and cold (a glass of cold
water) to embrittle the epoxy casing, then sanded down the back of the
chip on fine-grain sandpaper to expose what I hoped was the back of the
internals (so as not to damage the die itself).
Other than inadvertently sanding through half of the crystal's housing,
thus breaking one of the forks of the crystal, this was a success. (I
was prepared to decap one in acid had my attempt at physically removing
the epoxy package failed.) I slightly scratched the die itself while
separating it from the epoxy, but the die itself is clearly visible.
Based on a sample size of one and the markings on the die itself, it
appears the chip is authentic. The markings on the outside of the epoxy
package look a bit dubious and not like typical Maxim laser-markings, so
it's possible the chip was re-labeled at some point. I'll contact Maxim
to see if they can look up the lot information.
I used my 2 megapixel USB microscope to take some images throughout the
process that you might find interesting. The microscope has limited
resolution, particularly at high magnification, so some of the photos
may not be perfectly clear. I have access to a Zeiss petrographic
microscope at my work and will see if I can get some better images
tomorrow. I'll try to get high-quality images of the whole chip and
stitch them together into a larger composite.
Anyway, the photos are available at http://imgur.com/a/0zudj -- I will
add more photos from the petrographic microscope tomorrow. I focused
mainly on the markings on the die that indicated it was, in fact, a
Maxim chip but if there's any other region of the chip that you'd like
images of, please let me know and I'd be happy to take some more
pictures.
I hope you find this as interesting as I did.
Cheers!
-Pete
--
Pete Stephenson
TP
Trent Piepho
Thu, Jul 27, 2017 7:46 PM
Looks like it still says "DALLAS SEMICONDUCTOR" to the left of Maxim.
Maybe Maxim only wanted to change the mask enough to find some empty
space to sign it?
On Thu, Jul 27, 2017 at 12:31 PM, Pete Stephenson pete@heypete.com wrote:
Hi all,
A few days ago I reported the results from letting a DS3231 RTC run for
a year, and how the chip kept time well within the published specs.
Since I had acquired several DS3231s from dubious sources (Asian vendors
on a major auction site) as part of an RTC module that fits on the
Raspberry Pi's header pins, I was doubtful of the authenticity of the
chips. I decided to sacrifice one in the name of science and decapped it
at home using alternating heat (a lighter) and cold (a glass of cold
water) to embrittle the epoxy casing, then sanded down the back of the
chip on fine-grain sandpaper to expose what I hoped was the back of the
internals (so as not to damage the die itself).
Other than inadvertently sanding through half of the crystal's housing,
thus breaking one of the forks of the crystal, this was a success. (I
was prepared to decap one in acid had my attempt at physically removing
the epoxy package failed.) I slightly scratched the die itself while
separating it from the epoxy, but the die itself is clearly visible.
Based on a sample size of one and the markings on the die itself, it
appears the chip is authentic. The markings on the outside of the epoxy
package look a bit dubious and not like typical Maxim laser-markings, so
it's possible the chip was re-labeled at some point. I'll contact Maxim
to see if they can look up the lot information.
I used my 2 megapixel USB microscope to take some images throughout the
process that you might find interesting. The microscope has limited
resolution, particularly at high magnification, so some of the photos
may not be perfectly clear. I have access to a Zeiss petrographic
microscope at my work and will see if I can get some better images
tomorrow. I'll try to get high-quality images of the whole chip and
stitch them together into a larger composite.
Anyway, the photos are available at http://imgur.com/a/0zudj -- I will
add more photos from the petrographic microscope tomorrow. I focused
mainly on the markings on the die that indicated it was, in fact, a
Maxim chip but if there's any other region of the chip that you'd like
images of, please let me know and I'd be happy to take some more
pictures.
I hope you find this as interesting as I did.
Cheers!
-Pete
--
Pete Stephenson
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Looks like it still says "DALLAS SEMICONDUCTOR" to the left of Maxim.
Maybe Maxim only wanted to change the mask enough to find some empty
space to sign it?
On Thu, Jul 27, 2017 at 12:31 PM, Pete Stephenson <pete@heypete.com> wrote:
> Hi all,
>
> A few days ago I reported the results from letting a DS3231 RTC run for
> a year, and how the chip kept time well within the published specs.
>
> Since I had acquired several DS3231s from dubious sources (Asian vendors
> on a major auction site) as part of an RTC module that fits on the
> Raspberry Pi's header pins, I was doubtful of the authenticity of the
> chips. I decided to sacrifice one in the name of science and decapped it
> at home using alternating heat (a lighter) and cold (a glass of cold
> water) to embrittle the epoxy casing, then sanded down the back of the
> chip on fine-grain sandpaper to expose what I hoped was the back of the
> internals (so as not to damage the die itself).
>
> Other than inadvertently sanding through half of the crystal's housing,
> thus breaking one of the forks of the crystal, this was a success. (I
> was prepared to decap one in acid had my attempt at physically removing
> the epoxy package failed.) I slightly scratched the die itself while
> separating it from the epoxy, but the die itself is clearly visible.
> Based on a sample size of one and the markings on the die itself, it
> appears the chip is authentic. The markings on the outside of the epoxy
> package look a bit dubious and not like typical Maxim laser-markings, so
> it's possible the chip was re-labeled at some point. I'll contact Maxim
> to see if they can look up the lot information.
>
> I used my 2 megapixel USB microscope to take some images throughout the
> process that you might find interesting. The microscope has limited
> resolution, particularly at high magnification, so some of the photos
> may not be perfectly clear. I have access to a Zeiss petrographic
> microscope at my work and will see if I can get some better images
> tomorrow. I'll try to get high-quality images of the whole chip and
> stitch them together into a larger composite.
>
> Anyway, the photos are available at http://imgur.com/a/0zudj -- I will
> add more photos from the petrographic microscope tomorrow. I focused
> mainly on the markings on the die that indicated it was, in fact, a
> Maxim chip but if there's any other region of the chip that you'd like
> images of, please let me know and I'd be happy to take some more
> pictures.
>
> I hope you find this as interesting as I did.
>
> Cheers!
> -Pete
>
> --
> Pete Stephenson
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
PS
Pete Stephenson
Thu, Jul 27, 2017 8:21 PM
On Thu, Jul 27, 2017, at 09:31 PM, Pete Stephenson wrote:
[...]
Based on a sample size of one and the markings on the die itself, it
appears the chip is authentic. The markings on the outside of the epoxy
package look a bit dubious and not like typical Maxim laser-markings, so
it's possible the chip was re-labeled at some point. I'll contact Maxim
to see if they can look up the lot information.
[...]
Hi all,
Quick follow-up: I contacted Maxim to see if the chips were authentic,
and their very pleasant customer support people verified that the
markings and appearance of the chip are consistent with their records
for that year and lot number. That's a good thing.
They also reminded me that they only offer a warranty/guarantee on
products purchased either directly from them or from authorized
resellers. Asian auction-site vendors are not authorized resellers, so
please don't use products from such sources for Serious Business(tm).
Cheers!
-Pete
--
Pete Stephenson
On Thu, Jul 27, 2017, at 09:31 PM, Pete Stephenson wrote:
[...]
> Based on a sample size of one and the markings on the die itself, it
> appears the chip is authentic. The markings on the outside of the epoxy
> package look a bit dubious and not like typical Maxim laser-markings, so
> it's possible the chip was re-labeled at some point. I'll contact Maxim
> to see if they can look up the lot information.
[...]
Hi all,
Quick follow-up: I contacted Maxim to see if the chips were authentic,
and their very pleasant customer support people verified that the
markings and appearance of the chip are consistent with their records
for that year and lot number. That's a good thing.
They also reminded me that they only offer a warranty/guarantee on
products purchased either directly from them or from authorized
resellers. Asian auction-site vendors are not authorized resellers, so
please don't use products from such sources for Serious Business(tm).
Cheers!
-Pete
--
Pete Stephenson
G/
Graham / KE9H
Thu, Jul 27, 2017 8:34 PM
Pete:
If you are concerned about someone copying a chip, you can not rely on the
original manufacturers' markings on the die.
I have experience where the counterfeiter just photocopied the chip layout,
including the original manufacturers marks, and copyright symbol and notice
from the original die.
So, when they copied the die, they really just copied it. Didn't change a
thing. It was not like they redesigned it, or were selling their own design
with equivalent functionality.
--- Graham / KE9H
==
On Thu, Jul 27, 2017 at 2:31 PM, Pete Stephenson pete@heypete.com wrote:
Hi all,
A few days ago I reported the results from letting a DS3231 RTC run for
a year, and how the chip kept time well within the published specs.
Since I had acquired several DS3231s from dubious sources (Asian vendors
on a major auction site) as part of an RTC module that fits on the
Raspberry Pi's header pins, I was doubtful of the authenticity of the
chips. I decided to sacrifice one in the name of science and decapped it
at home using alternating heat (a lighter) and cold (a glass of cold
water) to embrittle the epoxy casing, then sanded down the back of the
chip on fine-grain sandpaper to expose what I hoped was the back of the
internals (so as not to damage the die itself).
Other than inadvertently sanding through half of the crystal's housing,
thus breaking one of the forks of the crystal, this was a success. (I
was prepared to decap one in acid had my attempt at physically removing
the epoxy package failed.) I slightly scratched the die itself while
separating it from the epoxy, but the die itself is clearly visible.
Based on a sample size of one and the markings on the die itself, it
appears the chip is authentic. The markings on the outside of the epoxy
package look a bit dubious and not like typical Maxim laser-markings, so
it's possible the chip was re-labeled at some point. I'll contact Maxim
to see if they can look up the lot information.
I used my 2 megapixel USB microscope to take some images throughout the
process that you might find interesting. The microscope has limited
resolution, particularly at high magnification, so some of the photos
may not be perfectly clear. I have access to a Zeiss petrographic
microscope at my work and will see if I can get some better images
tomorrow. I'll try to get high-quality images of the whole chip and
stitch them together into a larger composite.
Anyway, the photos are available at http://imgur.com/a/0zudj -- I will
add more photos from the petrographic microscope tomorrow. I focused
mainly on the markings on the die that indicated it was, in fact, a
Maxim chip but if there's any other region of the chip that you'd like
images of, please let me know and I'd be happy to take some more
pictures.
I hope you find this as interesting as I did.
Cheers!
-Pete
--
Pete Stephenson
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
Pete:
If you are concerned about someone copying a chip, you can not rely on the
original manufacturers' markings on the die.
I have experience where the counterfeiter just photocopied the chip layout,
including the original manufacturers marks, and copyright symbol and notice
from the original die.
So, when they copied the die, they really just copied it. Didn't change a
thing. It was not like they redesigned it, or were selling their own design
with equivalent functionality.
--- Graham / KE9H
==
On Thu, Jul 27, 2017 at 2:31 PM, Pete Stephenson <pete@heypete.com> wrote:
> Hi all,
>
> A few days ago I reported the results from letting a DS3231 RTC run for
> a year, and how the chip kept time well within the published specs.
>
> Since I had acquired several DS3231s from dubious sources (Asian vendors
> on a major auction site) as part of an RTC module that fits on the
> Raspberry Pi's header pins, I was doubtful of the authenticity of the
> chips. I decided to sacrifice one in the name of science and decapped it
> at home using alternating heat (a lighter) and cold (a glass of cold
> water) to embrittle the epoxy casing, then sanded down the back of the
> chip on fine-grain sandpaper to expose what I hoped was the back of the
> internals (so as not to damage the die itself).
>
> Other than inadvertently sanding through half of the crystal's housing,
> thus breaking one of the forks of the crystal, this was a success. (I
> was prepared to decap one in acid had my attempt at physically removing
> the epoxy package failed.) I slightly scratched the die itself while
> separating it from the epoxy, but the die itself is clearly visible.
> Based on a sample size of one and the markings on the die itself, it
> appears the chip is authentic. The markings on the outside of the epoxy
> package look a bit dubious and not like typical Maxim laser-markings, so
> it's possible the chip was re-labeled at some point. I'll contact Maxim
> to see if they can look up the lot information.
>
> I used my 2 megapixel USB microscope to take some images throughout the
> process that you might find interesting. The microscope has limited
> resolution, particularly at high magnification, so some of the photos
> may not be perfectly clear. I have access to a Zeiss petrographic
> microscope at my work and will see if I can get some better images
> tomorrow. I'll try to get high-quality images of the whole chip and
> stitch them together into a larger composite.
>
> Anyway, the photos are available at http://imgur.com/a/0zudj -- I will
> add more photos from the petrographic microscope tomorrow. I focused
> mainly on the markings on the die that indicated it was, in fact, a
> Maxim chip but if there's any other region of the chip that you'd like
> images of, please let me know and I'd be happy to take some more
> pictures.
>
> I hope you find this as interesting as I did.
>
> Cheers!
> -Pete
>
> --
> Pete Stephenson
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.
>
PS
Pete Stephenson
Fri, Jul 28, 2017 1:21 AM
Graham,
That's very true!
Still, my past experience with copied chips typically involves a
particular type of RS-232-to-TTL serial converter, the MAX3232. I've
found that nearly all of the ones from unauthorized distributors (e.g.
auction site vendors) are fake, even though the package is marked as
being MAX3232. After a few weeks the chips would fail in a way that
they'd pass high currents and get extremely hot.
I did a write-up on those chips at
https://blog.heypete.com/2016/09/11/investigating-fake-max3232-ttl-to-rs-232-chips/
and, after decapuslating them, discovered they were completely different
chips on the inside that were made to function the same way as the
MAX3232 (i.e., they converted RS-232 signals to TTL serial, operated on
the same voltages, had the same pinout, etc.).
In regards to the DS3231, I was concerned that the chip was also a fake
that functioned in the same way as the DS3231, presented the same
registers to the user, etc., but was actually a different design on the
inside. It appears that this is not the case, and in addition to
functioning as advertised, it also is legitimate. If it is a clone, it's
a goood one, but I don't think it is.
Cheers!
-Pete
--
Pete Stephenson
On Thu, Jul 27, 2017, at 10:34 PM, Graham / KE9H wrote:
Pete:
If you are concerned about someone copying a chip, you can not rely on
the
original manufacturers' markings on the die.
I have experience where the counterfeiter just photocopied the chip
layout,
including the original manufacturers marks, and copyright symbol and
notice
from the original die.
So, when they copied the die, they really just copied it. Didn't change a
thing. It was not like they redesigned it, or were selling their own
design
with equivalent functionality.
--- Graham / KE9H
==
On Thu, Jul 27, 2017 at 2:31 PM, Pete Stephenson pete@heypete.com
wrote:
Hi all,
A few days ago I reported the results from letting a DS3231 RTC run for
a year, and how the chip kept time well within the published specs.
Since I had acquired several DS3231s from dubious sources (Asian vendors
on a major auction site) as part of an RTC module that fits on the
Raspberry Pi's header pins, I was doubtful of the authenticity of the
chips. I decided to sacrifice one in the name of science and decapped it
at home using alternating heat (a lighter) and cold (a glass of cold
water) to embrittle the epoxy casing, then sanded down the back of the
chip on fine-grain sandpaper to expose what I hoped was the back of the
internals (so as not to damage the die itself).
Other than inadvertently sanding through half of the crystal's housing,
thus breaking one of the forks of the crystal, this was a success. (I
was prepared to decap one in acid had my attempt at physically removing
the epoxy package failed.) I slightly scratched the die itself while
separating it from the epoxy, but the die itself is clearly visible.
Based on a sample size of one and the markings on the die itself, it
appears the chip is authentic. The markings on the outside of the epoxy
package look a bit dubious and not like typical Maxim laser-markings, so
it's possible the chip was re-labeled at some point. I'll contact Maxim
to see if they can look up the lot information.
I used my 2 megapixel USB microscope to take some images throughout the
process that you might find interesting. The microscope has limited
resolution, particularly at high magnification, so some of the photos
may not be perfectly clear. I have access to a Zeiss petrographic
microscope at my work and will see if I can get some better images
tomorrow. I'll try to get high-quality images of the whole chip and
stitch them together into a larger composite.
Anyway, the photos are available at http://imgur.com/a/0zudj -- I will
add more photos from the petrographic microscope tomorrow. I focused
mainly on the markings on the die that indicated it was, in fact, a
Maxim chip but if there's any other region of the chip that you'd like
images of, please let me know and I'd be happy to take some more
pictures.
I hope you find this as interesting as I did.
Cheers!
-Pete
--
Pete Stephenson
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
Graham,
That's very true!
Still, my past experience with copied chips typically involves a
particular type of RS-232-to-TTL serial converter, the MAX3232. I've
found that nearly all of the ones from unauthorized distributors (e.g.
auction site vendors) are fake, even though the package is marked as
being MAX3232. After a few weeks the chips would fail in a way that
they'd pass high currents and get extremely hot.
I did a write-up on those chips at
<https://blog.heypete.com/2016/09/11/investigating-fake-max3232-ttl-to-rs-232-chips/>
and, after decapuslating them, discovered they were completely different
chips on the inside that were made to function the same way as the
MAX3232 (i.e., they converted RS-232 signals to TTL serial, operated on
the same voltages, had the same pinout, etc.).
In regards to the DS3231, I was concerned that the chip was also a fake
that functioned in the same way as the DS3231, presented the same
registers to the user, etc., but was actually a different design on the
inside. It appears that this is not the case, and in addition to
functioning as advertised, it also is legitimate. If it is a clone, it's
a goood one, but I don't think it is.
Cheers!
-Pete
--
Pete Stephenson
On Thu, Jul 27, 2017, at 10:34 PM, Graham / KE9H wrote:
> Pete:
>
> If you are concerned about someone copying a chip, you can not rely on
> the
> original manufacturers' markings on the die.
>
> I have experience where the counterfeiter just photocopied the chip
> layout,
> including the original manufacturers marks, and copyright symbol and
> notice
> from the original die.
>
> So, when they copied the die, they really just copied it. Didn't change a
> thing. It was not like they redesigned it, or were selling their own
> design
> with equivalent functionality.
>
> --- Graham / KE9H
>
> ==
>
>
>
> On Thu, Jul 27, 2017 at 2:31 PM, Pete Stephenson <pete@heypete.com>
> wrote:
>
> > Hi all,
> >
> > A few days ago I reported the results from letting a DS3231 RTC run for
> > a year, and how the chip kept time well within the published specs.
> >
> > Since I had acquired several DS3231s from dubious sources (Asian vendors
> > on a major auction site) as part of an RTC module that fits on the
> > Raspberry Pi's header pins, I was doubtful of the authenticity of the
> > chips. I decided to sacrifice one in the name of science and decapped it
> > at home using alternating heat (a lighter) and cold (a glass of cold
> > water) to embrittle the epoxy casing, then sanded down the back of the
> > chip on fine-grain sandpaper to expose what I hoped was the back of the
> > internals (so as not to damage the die itself).
> >
> > Other than inadvertently sanding through half of the crystal's housing,
> > thus breaking one of the forks of the crystal, this was a success. (I
> > was prepared to decap one in acid had my attempt at physically removing
> > the epoxy package failed.) I slightly scratched the die itself while
> > separating it from the epoxy, but the die itself is clearly visible.
> > Based on a sample size of one and the markings on the die itself, it
> > appears the chip is authentic. The markings on the outside of the epoxy
> > package look a bit dubious and not like typical Maxim laser-markings, so
> > it's possible the chip was re-labeled at some point. I'll contact Maxim
> > to see if they can look up the lot information.
> >
> > I used my 2 megapixel USB microscope to take some images throughout the
> > process that you might find interesting. The microscope has limited
> > resolution, particularly at high magnification, so some of the photos
> > may not be perfectly clear. I have access to a Zeiss petrographic
> > microscope at my work and will see if I can get some better images
> > tomorrow. I'll try to get high-quality images of the whole chip and
> > stitch them together into a larger composite.
> >
> > Anyway, the photos are available at http://imgur.com/a/0zudj -- I will
> > add more photos from the petrographic microscope tomorrow. I focused
> > mainly on the markings on the die that indicated it was, in fact, a
> > Maxim chip but if there's any other region of the chip that you'd like
> > images of, please let me know and I'd be happy to take some more
> > pictures.
> >
> > I hope you find this as interesting as I did.
> >
> > Cheers!
> > -Pete
> >
> > --
> > Pete Stephenson
> > _______________________________________________
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> > mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
G/
Graham / KE9H
Fri, Jul 28, 2017 1:53 AM
Yes, I doubt that the volume on a specialty chip like the DS3231 is high
enough to attract the counterfeiters.
RS-232 chips and the FTDI USB to serial chips, and consumer FM tuner and
audio amplifier chips, is another story.
My experience was with a proprietary full custom IC that totally
implemented a 'pager' in a single IC package. The Chinese apparently wanted
to get into the the paging business, at the time. Of course, the
cellphones have now totally eaten the pager business, globally.
--- Graham
==
On Thu, Jul 27, 2017 at 8:21 PM, Pete Stephenson pete@heypete.com wrote:
Graham,
That's very true!
Still, my past experience with copied chips typically involves a
particular type of RS-232-to-TTL serial converter, the MAX3232. I've
found that nearly all of the ones from unauthorized distributors (e.g.
auction site vendors) are fake, even though the package is marked as
being MAX3232. After a few weeks the chips would fail in a way that
they'd pass high currents and get extremely hot.
I did a write-up on those chips at
<https://blog.heypete.com/2016/09/11/investigating-fake-
max3232-ttl-to-rs-232-chips/>
and, after decapuslating them, discovered they were completely different
chips on the inside that were made to function the same way as the
MAX3232 (i.e., they converted RS-232 signals to TTL serial, operated on
the same voltages, had the same pinout, etc.).
In regards to the DS3231, I was concerned that the chip was also a fake
that functioned in the same way as the DS3231, presented the same
registers to the user, etc., but was actually a different design on the
inside. It appears that this is not the case, and in addition to
functioning as advertised, it also is legitimate. If it is a clone, it's
a goood one, but I don't think it is.
Cheers!
-Pete
--
Pete Stephenson
On Thu, Jul 27, 2017, at 10:34 PM, Graham / KE9H wrote:
Pete:
If you are concerned about someone copying a chip, you can not rely on
the
original manufacturers' markings on the die.
I have experience where the counterfeiter just photocopied the chip
layout,
including the original manufacturers marks, and copyright symbol and
notice
from the original die.
So, when they copied the die, they really just copied it. Didn't change a
thing. It was not like they redesigned it, or were selling their own
design
with equivalent functionality.
--- Graham / KE9H
==
On Thu, Jul 27, 2017 at 2:31 PM, Pete Stephenson pete@heypete.com
wrote:
Hi all,
A few days ago I reported the results from letting a DS3231 RTC run for
a year, and how the chip kept time well within the published specs.
Since I had acquired several DS3231s from dubious sources (Asian
on a major auction site) as part of an RTC module that fits on the
Raspberry Pi's header pins, I was doubtful of the authenticity of the
chips. I decided to sacrifice one in the name of science and decapped
at home using alternating heat (a lighter) and cold (a glass of cold
water) to embrittle the epoxy casing, then sanded down the back of the
chip on fine-grain sandpaper to expose what I hoped was the back of the
internals (so as not to damage the die itself).
Other than inadvertently sanding through half of the crystal's housing,
thus breaking one of the forks of the crystal, this was a success. (I
was prepared to decap one in acid had my attempt at physically removing
the epoxy package failed.) I slightly scratched the die itself while
separating it from the epoxy, but the die itself is clearly visible.
Based on a sample size of one and the markings on the die itself, it
appears the chip is authentic. The markings on the outside of the epoxy
package look a bit dubious and not like typical Maxim laser-markings,
it's possible the chip was re-labeled at some point. I'll contact Maxim
to see if they can look up the lot information.
I used my 2 megapixel USB microscope to take some images throughout the
process that you might find interesting. The microscope has limited
resolution, particularly at high magnification, so some of the photos
may not be perfectly clear. I have access to a Zeiss petrographic
microscope at my work and will see if I can get some better images
tomorrow. I'll try to get high-quality images of the whole chip and
stitch them together into a larger composite.
Anyway, the photos are available at http://imgur.com/a/0zudj -- I will
add more photos from the petrographic microscope tomorrow. I focused
mainly on the markings on the die that indicated it was, in fact, a
Maxim chip but if there's any other region of the chip that you'd like
images of, please let me know and I'd be happy to take some more
pictures.
I hope you find this as interesting as I did.
Cheers!
-Pete
--
Pete Stephenson
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
Yes, I doubt that the volume on a specialty chip like the DS3231 is high
enough to attract the counterfeiters.
RS-232 chips and the FTDI USB to serial chips, and consumer FM tuner and
audio amplifier chips, is another story.
My experience was with a proprietary full custom IC that totally
implemented a 'pager' in a single IC package. The Chinese apparently wanted
to get into the the paging business, at the time. Of course, the
cellphones have now totally eaten the pager business, globally.
--- Graham
==
On Thu, Jul 27, 2017 at 8:21 PM, Pete Stephenson <pete@heypete.com> wrote:
> Graham,
>
> That's very true!
>
> Still, my past experience with copied chips typically involves a
> particular type of RS-232-to-TTL serial converter, the MAX3232. I've
> found that nearly all of the ones from unauthorized distributors (e.g.
> auction site vendors) are fake, even though the package is marked as
> being MAX3232. After a few weeks the chips would fail in a way that
> they'd pass high currents and get extremely hot.
>
> I did a write-up on those chips at
> <https://blog.heypete.com/2016/09/11/investigating-fake-
> max3232-ttl-to-rs-232-chips/>
> and, after decapuslating them, discovered they were completely different
> chips on the inside that were made to function the same way as the
> MAX3232 (i.e., they converted RS-232 signals to TTL serial, operated on
> the same voltages, had the same pinout, etc.).
>
> In regards to the DS3231, I was concerned that the chip was also a fake
> that functioned in the same way as the DS3231, presented the same
> registers to the user, etc., but was actually a different design on the
> inside. It appears that this is not the case, and in addition to
> functioning as advertised, it also is legitimate. If it is a clone, it's
> a goood one, but I don't think it is.
>
> Cheers!
> -Pete
>
> --
> Pete Stephenson
>
> On Thu, Jul 27, 2017, at 10:34 PM, Graham / KE9H wrote:
> > Pete:
> >
> > If you are concerned about someone copying a chip, you can not rely on
> > the
> > original manufacturers' markings on the die.
> >
> > I have experience where the counterfeiter just photocopied the chip
> > layout,
> > including the original manufacturers marks, and copyright symbol and
> > notice
> > from the original die.
> >
> > So, when they copied the die, they really just copied it. Didn't change a
> > thing. It was not like they redesigned it, or were selling their own
> > design
> > with equivalent functionality.
> >
> > --- Graham / KE9H
> >
> > ==
> >
> >
> >
> > On Thu, Jul 27, 2017 at 2:31 PM, Pete Stephenson <pete@heypete.com>
> > wrote:
> >
> > > Hi all,
> > >
> > > A few days ago I reported the results from letting a DS3231 RTC run for
> > > a year, and how the chip kept time well within the published specs.
> > >
> > > Since I had acquired several DS3231s from dubious sources (Asian
> vendors
> > > on a major auction site) as part of an RTC module that fits on the
> > > Raspberry Pi's header pins, I was doubtful of the authenticity of the
> > > chips. I decided to sacrifice one in the name of science and decapped
> it
> > > at home using alternating heat (a lighter) and cold (a glass of cold
> > > water) to embrittle the epoxy casing, then sanded down the back of the
> > > chip on fine-grain sandpaper to expose what I hoped was the back of the
> > > internals (so as not to damage the die itself).
> > >
> > > Other than inadvertently sanding through half of the crystal's housing,
> > > thus breaking one of the forks of the crystal, this was a success. (I
> > > was prepared to decap one in acid had my attempt at physically removing
> > > the epoxy package failed.) I slightly scratched the die itself while
> > > separating it from the epoxy, but the die itself is clearly visible.
> > > Based on a sample size of one and the markings on the die itself, it
> > > appears the chip is authentic. The markings on the outside of the epoxy
> > > package look a bit dubious and not like typical Maxim laser-markings,
> so
> > > it's possible the chip was re-labeled at some point. I'll contact Maxim
> > > to see if they can look up the lot information.
> > >
> > > I used my 2 megapixel USB microscope to take some images throughout the
> > > process that you might find interesting. The microscope has limited
> > > resolution, particularly at high magnification, so some of the photos
> > > may not be perfectly clear. I have access to a Zeiss petrographic
> > > microscope at my work and will see if I can get some better images
> > > tomorrow. I'll try to get high-quality images of the whole chip and
> > > stitch them together into a larger composite.
> > >
> > > Anyway, the photos are available at http://imgur.com/a/0zudj -- I will
> > > add more photos from the petrographic microscope tomorrow. I focused
> > > mainly on the markings on the die that indicated it was, in fact, a
> > > Maxim chip but if there's any other region of the chip that you'd like
> > > images of, please let me know and I'd be happy to take some more
> > > pictures.
> > >
> > > I hope you find this as interesting as I did.
> > >
> > > Cheers!
> > > -Pete
> > >
> > > --
> > > Pete Stephenson
> > > _______________________________________________
> > > time-nuts mailing list -- time-nuts@febo.com
> > > To unsubscribe, go to https://www.febo.com/cgi-bin/
> > > mailman/listinfo/time-nuts
> > > and follow the instructions there.
> > >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.
>
PS
Pete Stephenson
Fri, Jul 28, 2017 11:05 PM
On Thu, Jul 27, 2017, at 09:31 PM, Pete Stephenson wrote:
[snip]
Anyway, the photos are available at http://imgur.com/a/0zudj -- I will
add more photos from the petrographic microscope tomorrow. I focused
mainly on the markings on the die that indicated it was, in fact, a
Maxim chip but if there's any other region of the chip that you'd like
images of, please let me know and I'd be happy to take some more
pictures.
Hi all,
Just a quick update: I was able to look at the DS3231 at work at the
quality of the (very expensive) Zeiss microscope is dramatically better
than my $20 USB microscope at home. No surprise.
Unfortunately, due to the ancient Canon camera attached to the
microscope not being compatible with Windows 7 or Linux, I was unable to
get any high-quality photos at this time. The camera is normally used in
tethered mode with no CF card, with the camera connected to the user's
laptop. Most of my colleagues use Macs, which evidently do work with it
but I wasn't able to ask any of them today before they all left. I've
ordered a CF-to-SD adapter that should allow me to take photos without
any issues, but it will be a few weeks until it arrives. Once it's
arrived, I'll take some more photos of the chip and let people know.
I've taken a few photos with my smartphone through the microscope's
eyepiece, but they turned out quite poorly as you can see below. When
viewed directly via the eyepiece, the appearance of the chip is quite
stunning.
On a related note, the reflected differential interference contrast
(DIC) filters on the microscope make looking at multi-layer chips
dramatically more clear and interesting. Compare
http://imgur.com/7nuTooL , which was taken with with no optical
filtering using standard reflected light illumination and
http://imgur.com/P6HL9MB which was taken of a different area of the chip
using reflected DIC. The colors are different, of course, but the
contrast between elements of the chip is much improved.
If anyone has any chips they'd like me to examine under the microscope,
let me know and I'd be happy to do so.
Cheers!
-Pete
--
Pete Stephenson
On Thu, Jul 27, 2017, at 09:31 PM, Pete Stephenson wrote:
[snip]
> Anyway, the photos are available at http://imgur.com/a/0zudj -- I will
> add more photos from the petrographic microscope tomorrow. I focused
> mainly on the markings on the die that indicated it was, in fact, a
> Maxim chip but if there's any other region of the chip that you'd like
> images of, please let me know and I'd be happy to take some more
> pictures.
Hi all,
Just a quick update: I was able to look at the DS3231 at work at the
quality of the (very expensive) Zeiss microscope is dramatically better
than my $20 USB microscope at home. No surprise.
Unfortunately, due to the ancient Canon camera attached to the
microscope not being compatible with Windows 7 or Linux, I was unable to
get any high-quality photos at this time. The camera is normally used in
tethered mode with no CF card, with the camera connected to the user's
laptop. Most of my colleagues use Macs, which evidently do work with it
but I wasn't able to ask any of them today before they all left. I've
ordered a CF-to-SD adapter that should allow me to take photos without
any issues, but it will be a few weeks until it arrives. Once it's
arrived, I'll take some more photos of the chip and let people know.
I've taken a few photos with my smartphone through the microscope's
eyepiece, but they turned out quite poorly as you can see below. When
viewed directly via the eyepiece, the appearance of the chip is quite
stunning.
On a related note, the reflected differential interference contrast
(DIC) filters on the microscope make looking at multi-layer chips
dramatically more clear and interesting. Compare
http://imgur.com/7nuTooL , which was taken with with no optical
filtering using standard reflected light illumination and
http://imgur.com/P6HL9MB which was taken of a different area of the chip
using reflected DIC. The colors are different, of course, but the
contrast between elements of the chip is much improved.
If anyone has any chips they'd like me to examine under the microscope,
let me know and I'd be happy to do so.
Cheers!
-Pete
--
Pete Stephenson
PS
Pete Stephenson
Sat, Jul 29, 2017 6:32 PM
On Thu, Jul 27, 2017, at 09:46 PM, Trent Piepho wrote:
Looks like it still says "DALLAS SEMICONDUCTOR" to the left of Maxim.
Maybe Maxim only wanted to change the mask enough to find some empty
space to sign it?
It does indeed say "DALLAS SEMICONDUCTOR".
I managed to get some high-quality photos using the microscope's
on-board camera and have updated the photo album at
https://imgur.com/a/0zudj with the newest ones (they're the
all-rectangular photos below the two circular photos). There's some
high-resolution composite images.
Some things I found interesting:
-
There's a section just above the "Maxim" part that has several
snippets of text ("17A3", "16A3", etc.). In normal light, each of these
bits of text is a different color, where the colors correspond to
different layers of the chip. Each bit of text has a different depth of
focus, indicating they're physically closer or further from the lens.
Does anyone know what material the colors might correspond to?
-
There's several square grids of circles-in-squares circuit elements. I
have no idea what these are.
-
I find it remarkable that this circuit can operate on less than a
microamp during normal usage, including temperature conversion.
The DS3231 has on-board temperature monitoring to correct the crystal
frequency: is this something where they would have bothered putting a
separate sensor next to the crystal itself, or are the die and the
crystal are close enough and in the same package that they could use an
on-die sensor like a diode and call that "good enough"?
Cheers!
-Pete
--
Pete Stephenson
On Thu, Jul 27, 2017, at 09:46 PM, Trent Piepho wrote:
> Looks like it still says "DALLAS SEMICONDUCTOR" to the left of Maxim.
> Maybe Maxim only wanted to change the mask enough to find some empty
> space to sign it?
It does indeed say "DALLAS SEMICONDUCTOR".
I managed to get some high-quality photos using the microscope's
on-board camera and have updated the photo album at
https://imgur.com/a/0zudj with the newest ones (they're the
all-rectangular photos below the two circular photos). There's some
high-resolution composite images.
Some things I found interesting:
- There's a section just above the "Maxim" part that has several
snippets of text ("17A3", "16A3", etc.). In normal light, each of these
bits of text is a different color, where the colors correspond to
different layers of the chip. Each bit of text has a different depth of
focus, indicating they're physically closer or further from the lens.
Does anyone know what material the colors might correspond to?
- There's several square grids of circles-in-squares circuit elements. I
have no idea what these are.
- I find it remarkable that this circuit can operate on less than a
microamp during normal usage, including temperature conversion.
The DS3231 has on-board temperature monitoring to correct the crystal
frequency: is this something where they would have bothered putting a
separate sensor next to the crystal itself, or are the die and the
crystal are close enough and in the same package that they could use an
on-die sensor like a diode and call that "good enough"?
Cheers!
-Pete
--
Pete Stephenson
AK
Attila Kinali
Sun, Jul 30, 2017 9:15 AM
- There's several square grids of circles-in-squares circuit elements. I
have no idea what these are.
If you look closely, these are actually suqares-in-squares.
I am not sure, but my guess would be that these are the
capacitor banks for the correction of the oscillator frequency.
- I find it remarkable that this circuit can operate on less than a
microamp during normal usage, including temperature conversion.
That's not so remarkable. If you make the transistors long, then
you get very low leakage. Couple that with small clock frequency
and you use very little current. Modern ICs only use so much current
because they have so many transistors, which are also optimized
for being fast, rather then low leakage.
The DS3231 has on-board temperature monitoring to correct the crystal
frequency: is this something where they would have bothered putting a
separate sensor next to the crystal itself, or are the die and the
crystal are close enough and in the same package that they could use an
on-die sensor like a diode and call that "good enough"?
My guess would be that it's a PN-junction or a bandgap temperature
sensor somewhere on the chip. Adding another part increases the cost
of production quite considerably.
Attila Kinali
--
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering. -- The Doctor
On Sat, 29 Jul 2017 20:32:30 +0200
Pete Stephenson <pete@heypete.com> wrote:
> - There's several square grids of circles-in-squares circuit elements. I
> have no idea what these are.
If you look closely, these are actually suqares-in-squares.
I am not sure, but my guess would be that these are the
capacitor banks for the correction of the oscillator frequency.
> - I find it remarkable that this circuit can operate on less than a
> microamp during normal usage, including temperature conversion.
That's not so remarkable. If you make the transistors long, then
you get very low leakage. Couple that with small clock frequency
and you use very little current. Modern ICs only use so much current
because they have so many transistors, which are also optimized
for being fast, rather then low leakage.
> The DS3231 has on-board temperature monitoring to correct the crystal
> frequency: is this something where they would have bothered putting a
> separate sensor next to the crystal itself, or are the die and the
> crystal are close enough and in the same package that they could use an
> on-die sensor like a diode and call that "good enough"?
My guess would be that it's a PN-junction or a bandgap temperature
sensor somewhere on the chip. Adding another part increases the cost
of production quite considerably.
Attila Kinali
--
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering. -- The Doctor
PS
Pete Stephenson
Sun, Jul 30, 2017 10:23 AM
On Sun, Jul 30, 2017, at 11:15 AM, Attila Kinali wrote:
- There's several square grids of circles-in-squares circuit elements. I
have no idea what these are.
If you look closely, these are actually suqares-in-squares.
I am not sure, but my guess would be that these are the
capacitor banks for the correction of the oscillator frequency.
True, the larger ones are squares-in-squares, but the smaller ones to
the left look like circles-in-octagons, but I find it hard to see the
details of the smaller features.
Either way, I should probably stare less through microscope eyepieces.
It seems to stress the eyes a bit.
- I find it remarkable that this circuit can operate on less than a
microamp during normal usage, including temperature conversion.
That's not so remarkable. If you make the transistors long, then
you get very low leakage. Couple that with small clock frequency
and you use very little current. Modern ICs only use so much current
because they have so many transistors, which are also optimized
for being fast, rather then low leakage.
Good point! I admit the details of optimizing transistors for different
purposes is beyond my ken, and I appreciate the insight.
The DS3231 has on-board temperature monitoring to correct the crystal
frequency: is this something where they would have bothered putting a
separate sensor next to the crystal itself, or are the die and the
crystal are close enough and in the same package that they could use an
on-die sensor like a diode and call that "good enough"?
My guess would be that it's a PN-junction or a bandgap temperature
sensor somewhere on the chip. Adding another part increases the cost
of production quite considerably.
Indeed. At first glance, I was surprised not to see tiny discrete
capacitors within the chip package itself, as I assumed (incorrectly)
that getting sufficient capacitance to steer a crystal a little would
require larger capacitors than could be easily put on a die, but then I
remembered that each LSB in the aging register only changes the
frequency by 0.1ppm at 25C, so that wouldn't need a large amount of
capacitance.
As you say, minimizing part count keeps the price down and makes the
design simpler.
Cheers!
-Pete
--
Pete Stephenson
On Sun, Jul 30, 2017, at 11:15 AM, Attila Kinali wrote:
> On Sat, 29 Jul 2017 20:32:30 +0200
> Pete Stephenson <pete@heypete.com> wrote:
>
> > - There's several square grids of circles-in-squares circuit elements. I
> > have no idea what these are.
>
> If you look closely, these are actually suqares-in-squares.
> I am not sure, but my guess would be that these are the
> capacitor banks for the correction of the oscillator frequency.
True, the larger ones are squares-in-squares, but the smaller ones to
the left look like circles-in-octagons, but I find it hard to see the
details of the smaller features.
Either way, I should probably stare less through microscope eyepieces.
It seems to stress the eyes a bit.
> > - I find it remarkable that this circuit can operate on less than a
> > microamp during normal usage, including temperature conversion.
>
> That's not so remarkable. If you make the transistors long, then
> you get very low leakage. Couple that with small clock frequency
> and you use very little current. Modern ICs only use so much current
> because they have so many transistors, which are also optimized
> for being fast, rather then low leakage.
Good point! I admit the details of optimizing transistors for different
purposes is beyond my ken, and I appreciate the insight.
> > The DS3231 has on-board temperature monitoring to correct the crystal
> > frequency: is this something where they would have bothered putting a
> > separate sensor next to the crystal itself, or are the die and the
> > crystal are close enough and in the same package that they could use an
> > on-die sensor like a diode and call that "good enough"?
>
> My guess would be that it's a PN-junction or a bandgap temperature
> sensor somewhere on the chip. Adding another part increases the cost
> of production quite considerably.
Indeed. At first glance, I was surprised not to see tiny discrete
capacitors within the chip package itself, as I assumed (incorrectly)
that getting sufficient capacitance to steer a crystal a little would
require larger capacitors than could be easily put on a die, but then I
remembered that each LSB in the aging register only changes the
frequency by 0.1ppm at 25C, so that wouldn't need a large amount of
capacitance.
As you say, minimizing part count keeps the price down and makes the
design simpler.
Cheers!
-Pete
--
Pete Stephenson
