74HCT646D,652

Overview

The 74HCT646D,652 is an octal bus transceiver and register featuring three-state outputs, manufactured by NXP USA Inc. under the 74HCT logic series. It integrates eight D-type flip-flops with bidirectional data paths controlled by direction and output enable signals. The device operates within a supply voltage range of 4.5 V to 5.5 V and supports surface-mount installation in a 20-SOIC package. It provides synchronous data storage and high-speed bus interfacing capabilities for digital systems.

Feature Summary

• Integrates eight D-type flip-flops for simultaneous data latching
• Provides bidirectional data transfer between two ports
• Features three-state outputs for effective bus line sharing
• Supports synchronous operation with dedicated clock input

Applications

• Bidirectional bus transceivers in computer architectures
• Memory buffer stages for data storage systems
• I/O port expansion modules in embedded controllers
• Digital signal routing in communication interfaces

Procurement Notes

Verify current manufacturing status as this component may be subject to end-of-life notices or discontinuation. Confirm package availability and RoHS compliance through official Nexperia documentation before integration. Check for obsolescence alerts and ensure long-term supply stability for production requirements.

Selection Notes

Select this component when designing systems requiring octal-wide data transfer with storage capability. Ensure the application voltage aligns with the 4.5 V to 5.5 V operating range. Consider the SOIC-20 footprint constraints and thermal management needs for dense PCB layouts involving multiple bus lines.

Part Context

This part belongs to the 74HCT family, which offers CMOS technology with TTL-compatible input levels. The 74HCT646 variant specifically combines bus switching functionality with register storage, distinguishing it from simple transceivers like the 74HCT245. It serves as a critical interface element in legacy and modern digital designs requiring synchronized data handling.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided source material.