Inside the vintage 74181 ALU chip

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https://www.electronics-lab.com/inside-vintage-74181-alu-chip/

Ken Shirriff writes: The 74181 ALU (arithmetic/logic unit) chip powered many of the minicomputers of the 1970s: it provided fast 4-bit arithmetic and logic functions, and could be combined to handle larger words, making it a key part of many CPUs. Inside the vintage 74181 ALU chip – [Link]

Inside the 74181 ALU chip: die photos and reverse engineering

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https://www.electronics-lab.com/inside-74181-alu-chip-die-photos-reverse-engineering/

A detailed die photos and reverse engineering of the 74181 ALU chip by Ken Shirriff: What’s inside a TTL chip? To find out, I opened up a 74181 ALU chip, took high-resolution die photos, and reverse-engineered the chip.1 Inside I found several types of gates, implemented with interesting circuitry and unusual transistors. The 74181 was a […]