74LCX646MTC

Overview

The Fairchild Semiconductor 74LCX646MTC is a registered bus transceiver belonging to the 74LCX logic family. It features an 8-bit configuration with true output polarity and utilizes CMOS technology for fabrication. The device operates within a supply voltage range of 2V to 3.6V, ensuring compatibility with low-voltage systems while maintaining interface capabilities with 5V signal environments. It incorporates D-type flip-flops and control circuitry to facilitate multiplexed data transmission directly from input buses or internal registers. The component is housed in a 24-pin TSSOP surface-mount package, designed for industrial temperature ranges and high-speed digital applications requiring reliable data latching and direction control.

Feature Summary

• Integrates eight-bit registered bus transceiver functionality with D-type flip-flops for data storage and direction control
• Features true output polarity and three-state outputs to manage bidirectional data flow effectively
• Supports low-voltage operation compatible with 5V tolerant signal environments for mixed-voltage system interfacing

Applications

• Bidirectional data bus buffering and latching in low-voltage digital systems
• Interfacing between 3.3V or 2.5V logic domains and 5V tolerant peripherals
• Multiplexed data transmission circuits requiring registered output control

Procurement Notes

Verify the manufacturer origin, as Fairchild Semiconductor's logic division was acquired by onsemi. Confirm that the specific part number corresponds to the original Fairchild production run if legacy sourcing is required. Ensure the datasheet matches the registered bus transceiver specifications rather than unregistered variants. Check for RoHS compliance markings consistent with the manufacturing era. Validate the package type is the standard 24-TSSOP form factor.

Selection Notes

Select this component when registered bidirectional data transfer is required alongside level shifting capabilities. It is suitable for designs needing to latch data on a bus before driving it in a specific direction. Consider the propagation delay characteristics relative to your system clock speed. Ensure the power supply voltage remains within the specified 2V to 3.6V range for optimal performance. Verify that the 24-pin TSSOP package fits the available PCB footprint constraints.

Part Context

This device is part of the 74LCX series, which provides low-voltage CMOS performance with 5V tolerance. It serves as a registered alternative to unregistered transceivers like the 74LCX245, adding data storage capability via internal flip-flops. The 74LCX646 is functionally similar to other registered transceivers but optimized for the LCX voltage profile. It complements the broader 74LCX family used in portable and battery-powered electronics requiring efficient power management and robust signal integrity.

Replacement Considerations

Public confirmed substitute part numbers include 74LCX646MTDX and 74LCX646MTCX. These variants share identical logical functions and pinouts but may differ in packaging format such as tape-and-reel versus tube.