Difference between 74Cxx, 74HCxx, 74AHCxx, 74ACxx, 74ACQxx


Joined Jan 22, 2004
Have you tried to read the datasheet of all those logic devices? I believe you can already surmise from the datasheet what's the difference between those prefixes.

the 74ACxxx and 74ACTxxx are considered as advance cmos. let's take the case of the 74AC00 has a Vcc of 2v to 6v, while the ACT has 4.5v to 5.5v.

the 74Hxxx is considered as high speed TTL while the 74HCxxx is a high speed cmos.

the 74AHC00 is positive NAND Gate

Pls. do some research;)



Joined Feb 24, 2006
Please help to know the difference between the logic families
74Cxx, 74HCxx, 74AHCxx, 74ACxx, 74ACQxx.
The difference is in the fabrication of the silicon die. The application differences center around the Vcc range (consult the datasehhet) and the definition of a logic high and logic low on the inputs as well as the drive capability of the outputs. Like moz said - RTFDS


Joined Dec 20, 2007
The 74Cxx is ordinary 4000-series Cmos with a low output current and fairly low speed.
The others have 15 times more output current and are high speed.


Joined Apr 26, 2005

Pick one number then read each of the datasheets. Build yourself a comparison table. Repeat with a random selection of numbers in the 74xx family. Your answer will become obvious.