Small circuits in TTL and RTL we could do intuitively, without any methodology. But what about a complex circuit like 555 timer?
If it was designed using logic gates, it could be easily deduced by using boolean algebra, truth table, k-map, etc. These could be the methodology.
The 555 timer was designed with a complex transistor network and some passive components.
I know that transistor building blocks are just what was used to make logic gates, but what methodology used to design the 555 timer, or it was completely intuitive (no methodology?)