INTEGRATED CIRCUIT reverse ENGINEERING, 1970S style

We are utilized to stories about reverse engineering integrated circuits, in these pages. Some interesting exposés of traditional chips have been created by people such as the ever-hard-working [Ken Shirriff].

You may believe that this method would be something new, confined only to those thinking about the workings of now-obsolete silicon. however the tricks of these chips were carefully guarded industrial intelligence back in the day, as well as there was a little market of professionals whose living came from unlocking them.

Electron micrograph of a cable bond to the Z80 CTC die
Integrated Circuit engineering company were a Scottsdale, Arizona based business who specialised in semiconductor market data. They have long because been swallowed up in a series of business takeovers, however we have a interesting window into their activities since their archive is preserved by the Smithsonian Institution. They reverse engineered integrated circuits to create reports including comprehensive info about their mechanical properties in addition to their operation, as well as just such a report is our subject today. Their 1979 evaluation of the Zilog Z80 CTC (PDF) starts with an evaluation of the package, in this situation the much more costly ceramic variant, then looks in detail at the interior building of the die itself, as well as its bonding wires. We are then taken in its typewritten pages with an comprehensive analysis of the circuitry on the die, with gate-level circuits to discuss the operation of each part.

The detail contained in this report is extraordinary, it is remove that a significant amount of work went into its production as well as it would have been of significant value to specific of Zilog’s clients as well as competitors. At the time this would have been incredibly commercially sensitive information, even if it now seems like a historical curiosity.

The Z80 CTC is a 4-channel counter/timer peripheral chip for the wildly succesful Z80 8-bit microprocessor, in a 28-pin dual-in-line package. We were amazed to discover from a quick browse that you can still purchase this chip from a few of the typical providers rather than the surplus houses, so it may even still be in production.

If IC reverse engineering takes your fancy, take a look at our archive of [Ken Shirriff] posts.

Thanks [fortytwo] for the tip.