Is it possible to short-circuit the outputs of multiple general-purpose logic ICs?

Wired-OR logic in which multiple outputs are connected together is prohibited because they are short-circuited. Obviously, any output must not be connected to VCC or GND. (Fig. 1)

Fig. 1 Example of prohibited Wired OR
Fig. 1 Example of prohibited Wired OR

Multiple gates in the same package can be connected together as shown below to increase the drive capability.
However, it is recommended to use high-drive ICs instead, such as the 74AC, 74LCX and 74VCX series.

Fig. 2 Example of a parallel connection to increase drive capability (Only gates in the same package may be paralleled.)
Fig. 2 Example of a parallel connection to increase drive capability (Only gates in the same package may be paralleled.)

In order to improve the drive capability, the gates in the same package can be connected as shown in Fig. 2. However, it is recommended to use a IC with high drive capability such as 74AC, 74LCX, 74VCX Series.

Related Links

The following documents also contain related information.

Product Lists

Application Notes

開啟新視窗