The output drive current is an extremely important parameter in the field of digital electronics. It describes the amount of current that a single pin of an integrated circuit (IC) can sink or source. This table shows the drive current to expect from CMOS and TTL categories of IC. It further sub-divides each category into the different series families.
|Series||Typical Drive Current|
|CMOS||Raspberry Pi GPIO||16 mA, in steps of 2 mA|
|AC / ACT / ACQ/ ACTQ||24 mA|
|4000 Series||4 mA|
|TTL||TTL (Standard)||16 mA|
|Schottky (S)||20 mA|
|High Speed (HS)||20 mA|
|Low Power (LP)||3.6 mA|
As you can see, the AC / ACT / ACQ/ ACTQ logic family provides the greatest drive current. This is very useful if you were designing a circuit and needed the maximum drive current.
For information about the meaning of the letterings, please consult the article 74 Family Series Meaning of Lettering.