These Schmitt-trigger devices contain six independent inverters. They perform the Boolean function Y = A. Because of the Schmitt action, they have different input threshold levels for positive-going (VT+) and for negative-going (VT–) signals.
The SN54AC00 device contains four independent 2-input NAND gates. Each gate performs the Boolean function of Y = A • B or Y = A + B in positive logic.
这个 16 位（双八进制）非反相总线收发器使用两个独立的可配置电源轨。