October 30, 2023

NXP PMBT2369 - supercomputer NPN BJT : weekend die-shot

This is how peak compute looked like in 1960's: PMBT2369 is a successor of 2N709, heart of CDC 6600 supercomputer from 1964. I was long fascinated by transistor computers, and deep dive by Tim was extremely interesting. Key to success here is not just multi-finger layout (which is quite common in high-frequency transistors) but also gold doping which dramatically reduce saturation recovery time without any additional circuitry. You can also see this Gold trick in Fast Recovery Diodes.

If you know other widely available yet inexpensive fast transistor for logic circuits - please let us know!

Die size 299x239 ┬Ám. That's probably the first transistor we've seen where there is small test BJT in every BJT.