ULN2003 - practical example of «reading» microchip schematic

We often receive comments that while our microchip photos are beautiful and interesting, it is completely unclear how integrated circuit implements basic elements and form larger circuit. Of course it is impossible to do a detailed review of an 1'000'000 transistor chip, so we've found simpler example: ULN2003 - array of Darlington transistors.

Despite it's simplicity this microchip is still widely used and mass manufactured. ULN2003 contains 21 resistors, 14 BJT transistors and 7 diodes. It is used to control relatively high load (up to 50V/0.5A) from microcontroller pin. Canonical use case - controlling segments of large 7-segment LED displays.
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Bitfury - specialized Bitcoin processor : weekend die-shot

Recently we've received sample chips from engineering run of Bitfury - specialized Bitcoin processor.

Compared to Avalon/BFL it is much more advanced thanks to 55nm manufacturing technology (TSMC) and full-custom design. Performance of single chip is ~2-3 Ghash/sec (final numbers are TBD) compared to ~282 Mhash/sec for Avalon.

Designer of Bitfury decided to remain anonymous, it is only known that he is from Ukraine. This was his first ASIC project, he was doing few FPGA projects in the past. What is even more unbelievable is that due to tight time requirements they had to skip MPW run and go straight to full mask run. Cost of mistake was extremely high, but it all worked from the first time. Final devices would be assembled by Metabank in Russia.

Photos

The package is QFN again (like in Avalon) - due to it's excellent thermal performance and short/low inductance connections to leads.

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Avalon - specialized Bitcoin processor : weekend die-shot

Yifu Guo (designer of Avalon) agreed to send us several chips for decapsulation, but while they were slowly traveling around the world - needbmw gave us damaged chip from his working Avalon mining unit.

Damaged chip itself (fortunately, die itself is not damaged):
This tiny thing does 282 Mhash/s (like AMD 6970 videocard), consuming ~2.5W of power.

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K553UD1A : weekend die-shot

K553UD1A is one of the first Soviet integrated operational amplifiers. This one was manufactured in June 1978.



It is a functional analog of µa709, though, it is not it's per-layer copy:


Image from diyaudio.com.

KT315 and KT361 transistors : weekend die-shot

KT315 (npn) and KT361 (pnp) - are the first planar epitaxial transistors manufactured in Soviet Union. Manufacturing started at the end of 60's. The oldest KT315A we were able to find was manufactured in march 1978.

You can see dicing defects, and alot of extra space around the transistor.

Crystal body is collector, at the center - base, and around it - emitter ring. Base goes under emitter, and continues on the other side of the ring.


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NXP BC847B : Weekend die-shot

BC847B is one of the most common general purpose bipolar junction transistors (npn).
Die size 275x275 µm is so small, that thickness of the die is almost the same as width/height - it's almost a "silicon cube".
Probably it's one of these cases when dicing & packaging is the most challenging part of manufacturing :-)

1986VE91T: What's inside Russian ARM?

1986VE91T (1986ВЕ91Т in Russian) - is an ARM Cortex-M3 based microcontroller, designed by Russian company Milandr. It has 128 KiB of flash memory, 32 KiB of SRAM, hardware USB and 80Mhz core clock. Manufactured using 180nm technology with aluminum metalization.

As this chip was in ceramic package, no plastic etching was necessary - so all bonding wires are intact. Die size - 6.54x5.9 mm.

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