F FastEddie New Member Oct 19, 2006 #1 Can I substitute a 74ls20 for an obsolete 7440 if I can keep the IOl to 24 mA? The logic functions are the same except the 7440 has a buffered output. Both have totem pole outputs.
Can I substitute a 74ls20 for an obsolete 7440 if I can keep the IOl to 24 mA? The logic functions are the same except the 7440 has a buffered output. Both have totem pole outputs.
k7elp60 Active Member Oct 20, 2006 #2 My data book lists the IOL as 8mA max for the 74LS20. Hope this helps