Time (100 Ps/div)

D001

D001

13

SN74HCS74-Q1

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SCES894A – APRIL 2019 – REVISED JUNE 2019

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Copyright © 2019, Texas Instruments Incorporated

Typical Application (continued)

as defined in the Timing Characteristics.

9.2.2 Detailed Design Procedure

1. Recommended Input Conditions:

–

Input signals to Schmitt-trigger inputs, like those found on the HCS family of devices, can support

unlimited edge rates.

–

Input thresholds are listed in the Electrical Characteristics.

–

Inputs include positive clamp diodes. Input voltages can exceed the device's supply so long as the clamp

current ratings are observed from the Absolute Maximum Ratings. Do not exceed the absolute maximum

voltage rating of the device or it could be damaged.

2. Recommended Output Conditions:

–

Load currents should not exceed the value listed in the Absolute Maximum Ratings.

–

Series resistors on the output may be used if the user desires to slow the output edge signal or limit the

output current.

3. Recommended Circuit Design Procedure:

–

For proper startup, the debounce circuit should have a much smaller delay than the power on reset

–

9.2.3 Application Curve

Figure 13 illustrates an example of a single button press bouncing and causing the output to toggle multiple

times. This will cause issues in the desired application. Figure 14 illustrates 4 button presses with an added

debounce circuit, fixing the unwanted toggling and allowing for proper toggle switch operation.

Figure 13. Circuit response without RC debounce