μblog: engineering from the trenches

Hide the children and lock the doors, Phrack #64 is available. This news is a few days late since I didn’t pay too much attention to the security mailing lists this weekend, nevertheless, better late then never!

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CMOS: Circuit Design, Layout and Simulation by RJ Baker is probably one of the leading texts on subject. The book is pretty reasonably priced and access to the digital versions of the figures is publicly available. The figures may not be able to teach you everything, but they are worthwhile to take a look at if you happen to enjoy IC Friday.

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This was the other Realtek chip, a highly-integrated ethernet controller, that I subjected to the sulfuric acid two weeks ago. Unfortunately, just as the previous chip, I did a poor job gluing the die to a microscope slide resulting in some glue on top of the chip. Like the previous chip, this one shows little surprises and no artifacts. The designers of the chip did include labels for each processing steps, somewhere around ten different procedures.

( rtl8101lv15.pdf )

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Sorry it took so long, but here they are: scale bars. To accomplish this, I took pictures of 50, 125 and 250 micron wire from California Fine Wire at 4x, 10x, 20x, 40x, 60x, and 100x magnification. The wire has a thin coating of polyimide insulation (~3-5 microns thick) that can be seen in the higher resolution 50 micron wire images. These images were taken on the same scope, with the same camera and objectives, as all of the previous IC Friday images, so the image dimensions are exactly the same for each magnification. I didn’t bother with 60x and 100x for 125 and 250 microns since their diameter was larger than the field of view.

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I really enjoy using my gyration mouse and keyboard set, so much so that I have recharged the mouse battery pack enough times to reduce its operating capacity to about an hour. I decided that it was time to replace the NiMH battery pack. Having taken apart portable electronics before, I was sure that the battery pack was actually built up from standard battery sizes to conserve on costs instead of a custom battery pack that one would find in an iPod or PDA. After carefully opening the pack with a razor, this notion was confirmed. The battery pack was simply three AAA rechargeable batteries held together with plastic. I promptly went to the store and bought a pack of 1000mAh NiMH batteries and constructed a replacement battery pack using the original metal pieces and electrical tape. Being careful not to use too much or too little, the resulting pack fit snugly into the mold and onto the mouse. After letting the whole system charge fully, I was able to get several days of use out of the mouse without running out of energy. On a final note, in retrospective, it may have been easier to just buy the replacement battery pack, if it was available, as its cost is comparable to the cost of the four rechargeable batteries, but that would not be as much fun.

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This is the die of a Realtek ALC655 AC’97  audio CODEC. This came off a P4 mainboard that burned out. Sulfuric acid was used to liberate this die, however, the black coatings at the top left and bottom right sides of the die are simply super-glue and the result of a sloppy mounting job by myself. Still no artifacts and a lot of metal on the surface. Some interesting features can be seen in the three successive 100x images with varying depth.

( alc655_datasheet_13.pdf )

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AMD and Intel were ahead of their times with their shared-license agreements. These days, no one integrated circuit manufacturer can stand on their own too well, and only multi-partner collaborations can approach the 45nm and 32nm process nodes. I have been putting off looking at some uncapped digital chips because of the die size since we don’t have a low resolution objective that can image most of a 4mm x 4mm chip much less 12mm x 12mm like this. I am trying to avoid using sulfuric acid as much as I can since it takes a long time to neutralize, so the next few IC Fridays will contain larger digital chips. It is admirable that AMD still maintains a decent website for their AM486 line of products.

( ad486dx2.pdf )

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BrandonU from uC Hobby has come up with a clever write-up on how to read a flash chip that is already in a circuit. The idea comes from the realization that Smartmedia cards are effectively flash chips and have compatible pinout with some industry standard NAND flash chips. The device must use 8-bit blocks and share an 8-bit wide I/O for both the address and data. This is by no means an end-all solution to reading flash chips, but it may come in handy. The one part of the write up that may be problematic is inadvertently powering the board by providing power to the flash chip, but that can be looked at on a case-by-case basis.

[Via Hacked Gadgets]

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Since I am taking a CMOS linear integrated circuit design course, I thought it would be reasonable to try to find a few designs of practical operational amplifiers that have been commercially used. Everyone knows the LM741 BJT op amp, but I found it to be difficult to find some complete CMOS designs, even for obsolete parts. I emailed many linear device vendors (TI, Analog Devices, National Semiconductor, On Semiconductor), introduced myself as a student, and then inquired if they had some complete CMOS design that were available to the public. Unfortunately, most of the support people either responded that all of their designs were proprietary information and was not for public viewing, or they sent me a 741 BJT schematic and then said all of their CMOS designs were private. Undeterred from my mission to study complete CMOS op-amps, I went to Google Patent Search. And found designs and explanations straight from the various manufacturers. Since patent information is publicly available, why not provide this information from the start?

( cmos-op-amp-ti.pdf )

( cmos-op-amp-national.pdf )

( cmos-op-amp-mot.pdf )

( cmos-op-amp-analog.pdf )

( cmos-op-amp-ami.pdf )

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This is one of the popular instrumentation amplifiers from Analog Devices. The current datasheet is in revision D, and this chip is in a CERDIP case made in the 1980’s so there may be some discrepancies in performance. Unlike some other analog chips we have looked at, this one contains three sets of initials, if the one above can be considered as one.

( amp01.pdf )

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