February 8, 2021

Central 2N3808 - dual PNP BJT : weekend die-shot

Central Semiconductor 2N3808 has 2 separate PNP BJT dies in 1 metal package. This seems to be the most common layout of low-power BJTs.
Die size 343x340 µm.

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January 31, 2021

1US222 / K122UN2 - dual stage audio amplifier : weekend die-shot

1US222 is a dual stage audio amplifier (later renamed to K122UN2) - not an opamp. Date code is VI 1971 - so this year we can celebrate half a century since it's manufacturing. Scratches and dirt are not mine - apparently simple microchips were quite forgiving. Schematics below.

Die size 1392x1412 µm.

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January 4, 2021
November 1, 2020

Fairchild UA714HC - precision opamp : weekend die-shot

You can see some trimming action on the left side of the die: resistors adjusted via masks, fuses for trimming part-to-part variability.
Die size 2528x1541 µm.

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September 12, 2020
September 12, 2020

Behind the scene of Zeptobars - 2020Q3

You might have noticed, that there were extremely few posts in the blog over the last months. Well, it was COVID-related, but in slightly unexpected way.

As you know, I was in Moscow, Russia all these years. It was planned that in 2020 I will gradually relocate to Switzerland, move my whole lab, spend more and more time at new place closer to the end of the year.

Well, it did not happened this way. Daily coronavirus cases started to spike across Europe, and by May - all borders were closed. I ended up on 1-way evacuation flight from Russia with very short notice, organized by Switzerland embassy. Even 8 hours before departure - it was not certain if flight will happen at all. As we later learned - it was the last flight in the following 2.5 months.

I gathered 2 suitcases, and there was so much one can fit. I took shirts, 2 best microscope lenses, few decapsulated & previously imaged sample chips for first tests at new place, NVMe drive from my desktop - and that's mostly it.
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