Did you know that?
Bitmain's first generation of Bitcoin miners(Antminers S1 ,S2 etc) were using BM1380. BM1380 is a 55nm mining chip. Now we have S19s, who have chips which are smaller than 7nm.
ALT Bitmain AntMiner S2 1 THS Miner , with embedded chips ‘BM1380’