9 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.

9.1 Application Information

The SN74HCS14 can be used to add an additional stage to a counter with an external flip-flop. Because

counters use a negative edge trigger, the flip-flop's clock input must be inverted to provide this function. Having

Schmitt-trigger inputs is important in this application to eliminate any noise issues that could impact the counting

function which could lead to incorrect frequency division. This function only requires one of the six available

inverters in the SN74HCS14 device, so the remaining channels can be used for other applications needing an

can be left floating.

9.2 Typical Application

D-Type

Flip-Flop

Counter

2

0

2

1

2

2

2

3

2

4

Input

Clear

Q

CLR

Q

D

CLR

Figure 9-1. Typical application block diagram

9.2.1 Design Requirements

9.2.1.1 Power Considerations

Ensure the desired supply voltage is within the range specified in the Recommended Operating Conditions. The

supply voltage sets the device's electrical characteristics as described in the Electrical Characteristics.

The positive voltage supply must be capable of sourcing current equal to the total current to be sourced by all

any transient current required for switching. The logic device can only source as much current as is provided by

Maximum Ratings.

The ground must be capable of sinking current equal to the total current to be sunk by all outputs of the

required for switching. The logic device can only sink as much current as can be sunk into its ground connection.

Be sure not to exceed the maximum total current through GND listed in the Absolute Maximum Ratings.

The SN74HCS14 can drive a load with a total capacitance less than or equal to 50 pF while still meeting all of

the datasheet specifications. Larger capacitive loads can be applied, however it is not recommended to exceed

50 pF.

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SN74HCS14

SCLS799D – JANUARY 2020 – REVISED DECEMBER 2021

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