74HC7540PWJ

Overview

The Nexperia 74HC7540PWJ is an octal Schmitt trigger buffer and line driver featuring inverting outputs with three-state capability. It operates within a supply voltage range of 2.0 V to 6.0 V and includes two active LOW output enable inputs (OE1 and OE2). The device utilizes TSSOP20 (SOT360-1) packaging and supports ambient temperatures from -40 °C to +125 °C. Inputs incorporate clamp diodes for interfacing with voltages exceeding VCC, while Schmitt-trigger action ensures jitter-free signal transformation.

Feature Summary

• Features Schmitt-trigger inputs that transform slowly changing signals into sharply defined output waveforms.
• Provides dual active LOW output enables (OE1 and OE2) to control high-impedance OFF-states.
• Includes input clamp diodes allowing interface to voltages higher than the supply voltage using current limiting resistors.

Applications

• Buffering digital data lines requiring noise immunity
• Line driving applications with inverting logic requirements
• Systems utilizing mixed voltage levels with input clamping needs

Procurement Notes

Verify the specific suffix 'J' against the manufacturer's latest ordering information to confirm package type and tape-and-reel specifications. Ensure the design accounts for the TSSOP20 thermal derating characteristics above 100 °C. Confirm compliance with RoHS directives and halogen-free status as per the product data sheet.

Selection Notes

Select this component when an octal inverting buffer with Schmitt-trigger noise immunity is required. The dual output enable pins allow flexible bus management. Verify that the 2.0 V to 6.0 V operating range matches the system power supply. Consider the TSSOP20 package dimensions if board space is constrained compared to standard SOIC packages.

Part Context

This part belongs to the 74HC series of CMOS logic devices manufactured by Nexperia. It is functionally compatible with other octal buffers but specifically distinguished by its Schmitt-trigger inputs and inverting polarity. The PWJ designation indicates the TSSOP20 plastic thin shrink small outline package variant.

Replacement Considerations

The 74HC7540D is a direct functional equivalent housed in an SOIC-20 package. Designers must verify pinout compatibility and adjust footprint layouts accordingly when substituting between TSSOP20 and SOIC20 variants.

FAQ

How does the device handle input signals with slow rise and fall times?

The Schmitt-trigger inputs provide hysteresis, which transforms slowly changing input signals into sharply defined and jitter-free output signals.

What is the function of the OE1 and OE2 pins?

OE1 and OE2 are active LOW output enable inputs. When either pin is HIGH, the corresponding outputs assume a high-impedance OFF-state.