19 Dec
2006
19 Dec
'06
6:57 p.m.
On 19 Dec 2006 at 15:41, Guy Sotomayor wrote:
LS usually has the speed of TTL with the power
dissipation of L.
Other variations:
74Hxx
74Lxx
74Sxx
74ASxx
74ALSxx
74Cxx
74F is another common one. Normally, one can assume that the
pinout's the same between all families, regardless of the letters
after the "74". The notable exception is 74L--some members of the
family have pinouts that differ from the corresponding 74/74S/74LS
ones. e.g., 74L85 vs. 7485.
Similarly, 74 and 74-followed-by-alphabet-soup ICs can differ in
implementation. Some notable examples are 7473--positive pulse-
triggered JK FF; 74LS73 negative-edge-triggered JK FF.
And again, one could get away with wire-OR-in 74L-series logic, which
would be a disaster in any other 74-series logic family.
Just a gentle reminder to check the databook before cross-
substituting...
Cheers,
Chuck