Interesting double-poly latches inside AMD's vintage LANCE Ethernet chip

149 · Ken Shirriff · Dec. 31, 2023, 6:32 p.m.
I've studied a lot of chips from the 1970s and 1980s, so I usually know what to expect. But an Ethernet chip from 1982 had something new: a strange layer of yellow wiring on the die. After some study, I learned that the yellow wiring is a second layer of resistive polysilicon, used in the chip's static storage cells and latches. A closeup of the die of the LANCE chip. The metal has been removed to show the layers underneath. The die photo above shows a closeup of a latch circuit, with the diagon...