Replacement for a DEC 7474 Chip

Chuck Guzis cclist at
Sat May 14 23:53:26 CDT 2022

On 5/14/22 15:35, dwight via cctalk wrote:

>>> You are stuck with using an original 7474 family assuming this is driving other early TTL. 74LS74, and others simply don't have the drive capability to work.
>> I know LS has less fanout, but is it not able to drive plain 74xx at all?  That doesn't sound right.  If the circuit in question runs near the fanout spec of plain 74 the yes, 74LS won't work.
>> Spec sheets and the actual schematic will give a definitive answer.

I've got a whole parts drawer full of 74S74s, which I believe exceed the
output current capabilities of the original 7474.   There's also the
74ABT74, if you want a beefer BiMOS version.  Heck, I can probably come
up with a couple of crufty old 74H74s...


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