74HCT540N,652

Overview

The NXP 74HCT540N,652 is an octal buffer and line driver featuring inverting outputs with three-state capability. It operates within a supply voltage range of 4.5 V to 5.5 V. The device includes two active-low output enable inputs (OE1 and OE2) that control the high-impedance OFF-state. Inputs are equipped with clamp diodes to facilitate interfacing with voltages exceeding VCC using current-limiting resistors. The component utilizes a 20-pin plastic dual in-line package (PDIP) compliant with SOT146-1 standards.

Feature Summary

• Octal configuration providing eight independent inverting buffer channels
• Three-state outputs controlled by two separate active-low enable inputs
• Input clamp diodes allow safe interfacing with voltages higher than the supply rail

Applications

• Bus-oriented memory and address drivers
• Clock drivers for high-capacitance loads
• Bidirectional data bus transceivers

Procurement Notes

Verify the specific ordering suffix matches the required package type and temperature range. Confirm the logic family designation corresponds to TTL input levels rather than CMOS levels. Ensure the manufacturer source aligns with NXP Semiconductors specifications for the 74HCT540N variant.

Selection Notes

Select this component when TTL-compatible input thresholds are required for driving CMOS or other logic families. The HCT series ensures compatibility with standard TTL logic levels while maintaining CMOS noise immunity. Verify that the application requires inverting functionality and three-state bus isolation capabilities.

Part Context

This part belongs to the 74HCT logic family, which bridges TTL and CMOS technologies. It shares functional similarities with the non-inverting 74HCT244 but provides inverted signal paths. The DIP20 packaging offers through-hole mounting options suitable for prototyping and legacy board designs requiring robust mechanical stability.

Replacement Considerations

Direct replacements include the 74HC540N for CMOS-level inputs or the 74HCT244N for non-inverting applications. Cross-vendor equivalents must maintain the HCT logic level and 3-state output characteristics.