74LCX240MTR

Overview

The STMicroelectronics 74LCX240MTR is a low voltage CMOS octal bus buffer featuring three-state inverted outputs. It utilizes sub-micron silicon gate and double-layer metal wiring C2MOS technology for high-speed, low-power operation at 3.3V. The device supports an operating voltage range of 2.0V to 3.6V with data retention down to 1.5V. It provides symmetrical output impedance with minimum drive currents of ±24mA at VCC = 3V. Propagation delay is guaranteed at a maximum of 6.5ns at VCC = 3V. The component includes power-down protection on inputs and outputs and ensures PCI bus levels are maintained at 24mA.

Feature Summary

• Features five-volt tolerant inputs and outputs suitable for interfacing between 3.3V and 5V signal environments.
• Provides balanced propagation delays where the high-to-low transition time approximates the low-to-high transition time.
• Includes power-down protection circuits on all inputs and outputs to manage leakage during off-states.
• Offers robust electrostatic discharge immunity exceeding 2000V under human body model testing conditions.

Applications

• Used as three-state memory address drivers in digital systems.
• Functions as an octal bus buffer for high-speed data transmission paths.
• Interfaces logic circuits within 5V tolerant signal environments requiring level shifting.

Procurement Notes

Verify the specific package type required, as the MTR suffix indicates tape and reel packaging for the SO-20 variant. Confirm that the design accommodates the absolute maximum ratings, particularly regarding supply voltage limits and output current constraints. Ensure ESD handling procedures are followed given the sensitivity of CMOS components. Check for pin compatibility if replacing existing designs based on the standard 74 series 240 architecture.

Selection Notes

Select this component when designing systems requiring octal buffering with simultaneous 3.3V and 5V interface capabilities. It is appropriate for applications demanding low power consumption alongside high-speed performance comparable to older AC/ACT families. Consider the symmetrical output impedance and balanced delays for timing-critical bus structures. Evaluate the operating temperature range and latch-up performance against environmental stress requirements.

Part Context

This device belongs to the 74LCX family of low voltage CMOS logic integrated circuits manufactured by STMicroelectronics. The LCX series is characterized by its ability to operate at lower voltages while maintaining speed performance similar to higher voltage counterparts. The 74LCX240 specifically implements the octal bus buffer function with inversion, serving as a foundational building block for complex digital interconnects and memory subsystems.

Replacement Considerations

Direct substitutes include parts from other manufacturers that maintain pin and function compatibility with the 74 series 240 architecture. Verify electrical specifications such as propagation delay and output drive current to ensure equivalent performance in the target application without modifying the board layout.

FAQ

What is the maximum propagation delay specified for this device?

The maximum propagation delay is 6.5 nanoseconds when the supply voltage is 3V.

Does the device support input signals from a 5V environment?

Yes, the inputs are five-volt tolerant, allowing direct interfacing with 5V signal environments.

How does the device handle power-down states?

It features power-down protection on both inputs and outputs to minimize leakage current when the device is not powered.