Hi Ben,

its impossible to build counters or shift registers with 373 / 573 latches !

Shift registers can only be build with 374 / 574 (D-Flip-Flop), but the 574 give also the easier pcb.

Counters with D-Flip-Flops can only be build, if the clock input was separate, e.g. with the 7474.


The reason for the strange 373 pin out was, that former ICs are build with easier wiring inside the circuit, not on the pcb.
But with cheaper ICs the relatice pcb cost rise and so an easier pcb was more important.
So nothing clever on the 373 pin out.


Peter