CMOS and TTL Output Drive Current

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
74HC 4 mA
AC / ACT / ACQ/ ACTQ 24 mA
4000 Series 4 mA
TTL TTL (Standard) 16 mA
Schottky (S) 20 mA
LPS 8 mA
ALPS 8 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.