4 ms·
Reverse-engineering a vintage comparator chip
- PhantomGremlin 5y agoMuch of the die is unused, especially the large metal area in the middle. I don't think the word "unused" is appropriate. 1) Probably they wanted to physically separate the comparators, for better noise isolation between them. 2) the large metal area is connected to V+. By using such a large amount of metal they get slightly lower voltage drop in their power distribution. 3) But here's what I think is the main reason. The metal is being used as a power decoupling capacitor. I can't be sure of what's underneath, but most likely the area is connected to V-. Voila! You couldn't possibly get a decoupling cap any closer to where it's needed than that.
- varispeed 5y agoGiven how old this technology appears to be. Is it possible today to build such chip at home?
- DougMerritt 5y agoThe chip's density is very low, and a few people have made ICs at home, but it's not a "just follow this easy recipe" DIY kind of thing. The first person I met to have done so was the now-well-known Jeri Ellsworth; she's mentioned in a more recent article on the subject. [1] [1] https://hackaday.com/2018/04/24/first-lithographically-produced-home-made-ic-announced/ https://hackaday.com/2018/04/24/first-lithographically-produ...