5 V

5 V

5 V

SN74HC74

SN74LVC1G17

SN54HC74, SN74HC74

www.ti.com

SCLS094E – DECEMBER 1982 – REVISED DECEMBER 2015

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. Customers should

validate and test their design implementation to confirm system functionality.

9.1 Application Information

A low level at the preset (PRE) or clear (CLR) input sets or resets the outputs, regardless of the levels of the

other inputs. When PRE and CLR are inactive (high), data at the data (D) input meeting the setup time

requirements is transferred to the outputs on the positive-going edge of the clock pulse. Clock triggering occurs

at a voltage level and is not related directly to the rise time of the clock pulse. Following the hold-time interval,

data at the D input can be changed without affecting the levels at the outputs.

The resistor and capacitor at the CLR pin are optional. If they are not used, the CLR pin should be connected

9.2 Typical Application

Figure 4. Device Power Button Circuit

9.2.1 Design Requirements

This device uses CMOS technology and has balanced output drive. Take care to avoid bus contention because it

can drive currents that would exceed maximum limits. Outputs may be combined to produce higher drive, but the

high drive will also create faster edges into light loads. Because of this, routing and load conditions should be

considered to prevent ringing.

9.2.2 Detailed Design Procedure

1. Recommended Input Conditions:

–

For rise time and fall time specifications, see (

Δt/ΔV) in Recommended Operating Conditions table.

–

–

2. Recommended Output Conditions:

–

Load currents should not exceed 25 mA per output and 50 mA total for the part.

–

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

output current.

Copyright © 1982–2015, Texas Instruments Incorporated

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