Not true...Philips did at least a 74F and 74HCT version, and TI did a 74AS181. Weirdly, Hitachi did a 74AC182 (lookahead carry generator for '181), but AFAIK o

Not true...Philips did at least a 74F and 74HCT version, and TI did a 74AS181. Weirdly, Hitachi did a 74AC182 (lookahead carry generator for '181), but AFAIK only the 74HC181. Never figured that one out. There's also an ECL version (MC10181). If you jumped to the 74381 you could get nifty things like the IDT7381 or L4C381, which are the equivalent of 4 '381s in a PLCC package that ran at a 25ns cycle (faster, I think, as well).