8 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification,

and TI does not warrant its accuracy or completeness. TI’s customers are responsible for

determining suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

8.1 Application Information

Toggle switches are typically large, mechanically complex and relatively expensive. It is desirable to use a

momentary switch instead because they are small, mechanically simple and low cost. Some systems require a

toggle switch's functionality but are space or cost constrained and must use a momentary switch instead.

If the data input (D) of the D-type flip-flop is tied to the inverted output (Q), then each clock pulse will cause

the value at the output (Q) to toggle. The momentary switch can be debounced and connected through a

Schmitt-trigger buffer to the clock input (CLK) to toggle the output.

This application also utilizes a power-on reset circuit so that the output always starts in the LOW state when

power is applied.

8.2 Typical Application

Q

Q

CLR

Output

R1

PRE

R2

C1

VCC

VCC

D

CLK

VCC

R3

C2

Figure 8-1. Typical Application Schematic

SN74ACT74-Q1

SCASE84 – APRIL 2025

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