74LCX245TTR

Overview

The STMicroelectronics 74LCX245TTR is a low-voltage CMOS octal bus transceiver featuring three-state outputs and 5V tolerant inputs and outputs. Fabricated using sub-micron silicon gate and double-layer metal wiring C2MOS technology, it supports an operating voltage range of 2.0V to 3.6V with data retention at 1.5V. The device provides high-speed performance with a maximum propagation delay of 7.0 ns at VCC = 3V. It offers symmetrical output impedance with minimum drive currents of 24 mA at VCC = 3V and balanced propagation delays (tPLH ≈ tPHL).

Feature Summary

• Features 5V tolerant inputs and outputs for interfacing between low-voltage and 5V signal environments.
• Includes power-down protection on both inputs and outputs to prevent current backflow during suspend mode.
• Provides symmetrical output impedance ensuring equal high and low level output drive capabilities.

Applications

• Two-way asynchronous communication between data buses.
• Low-power and high-speed 3.3V applications requiring interface to 5V signal environments.
• PCI bus level applications guaranteed at specific drive currents.

Procurement Notes

Verify the package type matches the required footprint, as the TTR suffix indicates Tape and Reel packaging in TSSOP-20. Confirm that the design accommodates the specified operating temperature range of -55°C to +125°C. Ensure input signals do not exceed absolute maximum ratings to avoid damage. Check that floating bus terminals are held HIGH or LOW during High-Z states to maintain circuit stability.

Selection Notes

Select this component when bidirectional data transfer is required between buses operating at different voltage levels, specifically interfacing 3.3V logic with 5V systems. Consider its low power consumption compared to the 5V AC/ACT family while maintaining similar speed performance. Ensure the application benefits from the integrated power-down protection and ESD immunity features for robust operation in noisy environments.

Part Context

This device belongs to the 74LCX series of low-voltage CMOS logic components manufactured by STMicroelectronics. It is pin and function compatible with the standard 74 series 245, facilitating direct replacement in existing designs. The series utilizes advanced sub-micron technology to achieve high speed and low power dissipation suitable for modern portable and battery-operated electronic devices.

Replacement Considerations

The 74LCX245M is the tube-packaged equivalent of the 74LCX245TTR. Both share identical electrical characteristics and functionality; the primary difference lies in the packaging format (TSSOP-20 Tube vs. Tape and Reel). Designers should verify board space constraints and assembly equipment compatibility when substituting between these ordering codes.