74HCT646N,652

Overview

The NXP USA Inc. 74HCT646N,652 is an octal bus transceiver and register featuring three-state outputs. It operates within a supply voltage range of 4.5 V to 5.5 V and supports through-hole mounting in a 20-pin PDIP package. The device includes dedicated clock (CLK) and output enable (OE) inputs for controlling data transfer direction and output states. It functions as both a bidirectional bus driver and an eight-bit D-type flip-flop register, suitable for high-speed digital systems requiring robust signal integrity.

Feature Summary

• Octal bus transceiver with integrated register functionality
• Three-state outputs for efficient bus sharing
• Independent control of direction and output enable
• Compatible with standard CMOS logic families

Applications

• Bidirectional data bus interfacing in microprocessor systems
• Registering data on buses with controlled timing
• Memory interface circuits requiring tri-state buffering
• Digital communication gateways with direction switching

Procurement Notes

Verify the complete part number including the suffix '652' to ensure correct packaging and tape-and-reel specifications. Confirm that the procurement source provides official documentation from NXP or Nexperia, as the standard product business transition may affect labeling. Check RoHS compliance status and lead-free soldering requirements against current manufacturing standards before finalizing orders.

Selection Notes

Select this component when an octal buffer with latching capability is required for bidirectional data paths. The HCT series ensures TTL compatibility while maintaining CMOS low power consumption. Ensure the design accommodates the 20-pin DIP footprint and verify that the system voltage aligns with the specified 4.5 V to 5.5 V operating range for optimal performance.

Part Context

This device belongs to the 74HCT logic family, which bridges the gap between traditional TTL and modern CMOS technologies. It is manufactured by NXP USA Inc., now often referenced under Nexperia branding for standard products. The 74HCT646 serves as a versatile solution for systems needing simultaneous bus driving and data storage without external latch components.

Replacement Considerations

Check for direct pin-compatible substitutes such as the 74HC646 if TTL input levels are not strictly required. Verify electrical characteristics like propagation delay and drive strength against alternative vendors' datasheets to ensure functional equivalence in the specific application environment.