[time-nuts] 74AC logic differences between manufactures

Bob Camp lists at rtty.us
Tue Jul 13 18:05:56 EDT 2010


Without plugging them into a board, you'll never really know which one is


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Stanley Reynolds
Sent: Tuesday, July 13, 2010 3:31 PM
To: time-nuts at febo.com
Subject: [time-nuts] 74AC logic differences between manufactures

Learning about the differences between families now know why a 74F is not a 
substitute for 74AC.

But remembering something I read in Brooks Shera, W5OJM GPSDO notes "Take
about which 4046 chips you use for U1 and U3. The Phillips 74HCT4046 chips 
(formerly sold by Radio Shack) are fine. So are CD74HC4046 chips made by
or T.I. Do not use chips made by Fairchild and do not use CD4046 chips; both

have a different design and will not work in this circuit."

Does anyone know about any differences in Fairchild and National
74AC175PC ?


time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
and follow the instructions there.

More information about the time-nuts mailing list