5 Sep
2007
5 Sep
'07
11:58 p.m.
It seems to me that there was one oddball case of a
74L series chip
having a different pinout that the 74 "vanilla" flavor. Anyone
remember?
There are many .A quick flip through my old TTL book shows :
74H01 (pinout as 7400!) as against 7401 ('gates turned round')
7451/74H51/74S51 as against 74L51/74LS51 (the latter has one more input
on each of the NANDs in one of the AOIs)
7454 as agains 74H54 (the latter has one extra input on one of the ANDs)
74H55 as against 74L55/74LS55 (the former has an 'expander' input)
74H71 (AND-D-OR gated JK master/slave flipflop with preset) as against
74L71 (AND gated R-S master-slave flipflop with preset and clear). And
the pinouts are totally different too!
7493 as against 74L93 (even the power pins move!)
7495/74LS95 as against 74L95 (the former has corner power pins, the
latter middle power pins.)
-tony