May 1, 2023

RCA CD4035A - CMOS Shift Register : weekend die-shot

RCA CD4035A is a CMOS 4-Stage Parallel in / out Shift Register.
Die size 1733x1804 µm.

March 6, 2023

Zeptolab upgrade - March 2023

Thanks to the support of Zeptobars patrons - several vital hardware upgrades finally happened which will increase image quality and will make work more streamlined : custom wavelength RGB illuminator and 2-axis goniometer. Finally, we've also got Mastodon - - let's keep in touch there (just in case).

More details below:
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March 1, 2023

National LM3915N-1 - "Thermometer" LED driver : weekend die-shot

National LM3915N displays analog signal on LED bar with logarithmic 3 dB/steps. Multiple LM3915N's can be cascaded to expand display dynamic range.
Die size 2394x2545 µm.

February 1, 2023

Shenzhen Fuman LM358S - general purpose opamp : weekend die-shot

0.02$ each if buying full reel. Die size 560x440 µm. Quite a bit smaller than one from Ti.

Not sure manufacturer has a website. "Founded in 2001, Shenzhen Fuman Electronics Group Co., Ltd. is a state-level high-tech enterprise engaged in the research and development, packaging, testing and sales of high-performance analog and digital-analog integrated circuits. Currently has more than 400 kinds of IC products in the field of consumption including power management, LED driver, MOSFET and so on."

January 16, 2023

Toshiba 2SK369 - low noise JFET : weekend die-shot

Toshiba 2SK369 - is a classical low noise JFET with high gm0. Similar to BF862 we see lots and lots individual transistors in parallel.
Die size 765x765 µm.

January 1, 2023

Casio-F-91W - iconic quartz watch : weekend die-shot

Casio F-91W is an iconic watch worn (among others) by Barack Obama and Osama bin Laden. While working on precision watch firmware (with quartz temperature compensation, aiming for error of under 10 seconds per year) for SensorWatch which is built around F-91W - I was curious to see how original chip looked like.

Surprisingly, chip is more complicated than I anticipated and digital part is less than ~50% of the die area. F-91W has trim jumpers on the PCB to adjust part-to-part variability of the quartz crystal. Looking at die complexity - it might be that they use capacitive tuning of frequency rather than skipping/adding ticks. Also, it might happen that they even have coarse/cost-efficient temperature compensation. Casio specify accuracy of 30 seconds per month, but some F-91W watches are within 6 seconds per month which requires good adjustment & luck for non-temperature compensated watch.

Latest versions of the watch work 7-10 years on a single battery, while early versions lasted "only" 2 years. While original F-91W was introduced in 1989, this die is designed in 2006. If someone has original version from 1989/early 1990's - it would be interesting to compare if it's a "die shrink" or re-design with improved performance.

You can compare die complexity to Luch quartz watch. It's not a digital watch, but see how much less analog circuitry was there.

Die size 2990x2541 µm.

Pinout suggested by Joey Castillo:
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January 1, 2023

RCA CA3031 - opamp : weekend die-shot

RCA CA3031 is a general-purpose amplifier used in narrow-band and bandpass amplifier, feedback amplifier, dc and video amplifier, multivibrator, oscillator, comparator, servo driver, and scaling adder applications. Designed for asymmetrical power supplies: +12V and -6V. Rated for storage temperature of 200°C. RCA CA3031 is analog of Fairchild µA702.

Die size 1142x1134 µm.

Schematic below:
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