74LCX646TTR

Overview

The STMicroelectronics 74LCX646TTR is a low-voltage CMOS octal bus transceiver and register with 3-state outputs, fabricated using sub-micron silicon gate and double-layer metal wiring C2MOS technology. It operates within a supply voltage range of 2.0V to 3.6V, featuring 5V tolerant inputs and outputs for interfacing with 5V signal environments. The device provides high-speed performance with a maximum propagation delay of 7.0 ns at VCC = 3V. It includes power-down protection on inputs and outputs, symmetrical output impedance with minimum drive currents of 24 mA, and balanced propagation delays (tPLH ≈ tPHL). Latch-up performance exceeds 500 mA per JESD 17 standards.

Feature Summary

• Features 5V tolerant inputs and outputs for direct interfacing with 5V signal environments while operating at lower voltages.
• Includes internal D-type flip-flops allowing data storage from either the A or B bus upon clock transitions.
• Provides multiplexed transmission capabilities between real-time transparent mode and stored register data via select controls.
• Equipped with protection circuits against static discharge providing ESD immunity and transient excess voltage tolerance.

Applications

• Low-power and high-speed 3.3V applications requiring bus isolation and buffering
• Systems requiring interface between 3.3V logic and 5V signal environments
• Multiplexed data transmission systems utilizing internal registers for data storage

Procurement Notes

Verify that the ordering suffix 'TTR' corresponds specifically to the TSSOP-24 package in tape and reel configuration as listed in official documentation. Confirm the component status remains active before procurement. Ensure compatibility with required operating temperature ranges and verify pinout alignment with SO-24 alternatives if package substitution is considered.

Selection Notes

Select this component when an octal bus transceiver with integrated storage registers is required for 3.3V systems interfacing with 5V signals. Consider its high-speed characteristics and low power consumption relative to standard 5V AC/ACT families. Evaluate the need for 5V tolerance on both input and output lines and the necessity for internal data latching capabilities in the design architecture.

Part Context

This device belongs to the 74LCX series of low-voltage CMOS logic components manufactured by STMicroelectronics. It is functionally compatible with the 74 series 646 but optimized for lower voltage operation and reduced power consumption. The technology utilizes sub-micron silicon gate processes to achieve high speed performance comparable to 5V families while maintaining low power dissipation suitable for portable and battery-operated applications.

Replacement Considerations

The 74LCX646RM13TR serves as a pin and function compatible alternative packaged in SOP-24 format. Verify package dimensions and thermal characteristics when substituting between TSSOP and SOP variants. Ensure electrical specifications remain identical for functional interchangeability in existing designs.