MC74ACT648N

Overview

The MC74ACT648N is a registered bus transceiver from the 74ACT logic series, manufactured by onsemi. It features eight bits of data storage and bidirectional data transfer capabilities. The device operates within a supply voltage range of 4.5 V to 5.5 V. It utilizes a 20-pin SOIC package for surface mount installation. Key electrical specifications include a propagation delay of 14 ns at 5.0 V with a 50 pF load, a quiescent current of 80 µA, and output currents of 24 mA for both high and low states. The component supports an operating temperature range from -40 °C to +85 °C.

Feature Summary

• Integrates eight-bit D-type flip-flops with three-state outputs for temporary data storage during bus transfers.
• Provides bidirectional data transmission between two buses controlled by separate direction signals.
• Features TTL-compatible input levels while driving CMOS-compatible output loads.

Applications

• High-performance microprocessor-based systems requiring buffered memory interfaces
• Clocked data buffering in communication protocols
• Bidirectional bus architectures in industrial control systems

Procurement Notes

Verify the specific suffix 'N' indicates the standard plastic SOIC-20 package configuration. Confirm that the order quantity aligns with tube packaging standards typical for this through-hole or surface-mount variant. Ensure the procurement channel provides original manufacturer documentation to validate authenticity against counterfeits. Check for RoHS compliance status if environmental regulations apply to the final assembly.

Selection Notes

Select this component when a registered bus transceiver is required for synchronous data handling. The ACT series offers faster switching speeds compared to standard HC logic, making it suitable for higher frequency applications. Consider the 20-pin SOIC footprint for PCB layout compatibility. Evaluate the 4.5 V to 5.5 V supply requirement to ensure alignment with the system's power rail infrastructure.

Part Context

This part belongs to the 74ACT family of logic integrated circuits, which bridges the performance gap between older TTL and modern CMOS technologies. Registered bus transceivers like the MC74ACT648N are essential for managing data flow in complex digital systems where timing synchronization is critical. The ACT series is characterized by its high-speed operation and robust drive capability.

Replacement Considerations

Cross-reference with other manufacturers offering 74ACT648 equivalents. Verify pinout compatibility and electrical parameters such as propagation delay and output current before substitution. Ensure the alternative component supports the same 20-pin SOIC package dimensions.

FAQ

What is the function of the OE and DIR pins?

The Output Enable (OE) pin controls the three-state outputs, while the Direction (DIR) pin determines the data flow direction between Port A and Port B.

How does the registered feature benefit bus operations?

The internal D-type flip-flops latch the data on the rising edge of the clock, ensuring stable data output even if inputs change, which prevents glitches on the bus.