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10

SN54HC02, SN74HC02

SCLS076F – DECEMBER 1982 – REVISED APRIL 2015

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Copyright © 1982–2015, Texas Instruments Incorporated

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

The SNX4HC02 is a low-drive CMOS device that can be used for a multitude of NOR type functions. The device

can produce 4 mA of drive current at 5 V, making it Ideal for driving multiple outputs and good for low-noise

applications. This application is for using a single SNX4HC02 as a falling edge detector circuit.

The edge detector operates by using the inherent propagation delay from input to output of each device stage. In

steady-state, the inputs to the output stage will always be different, and thus the output will always be low. Only

be high.

9.2 Typical Application

Figure 4. Falling Edge Detector Schematic

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. The high drive also creates fast edges into light loads, so

routing and load conditions must be considered to prevent ringing.

device, and temperature range.

9.2.2 Detailed Design Procedure

1. Recommended Input Conditions – For rise time and fall time specifications, see

Δt/ΔV in Recommended

Operating Conditions.

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2. Recommend Output Conditions

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Load currents must not exceed 20 mA per output and 50 mA total for the part.

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