M74HCT540B1R

Overview

The M74HCT540B1R is an octal bus buffer with inverted 3-state outputs manufactured by STMicroelectronics. It operates on a supply voltage of 4.5V to 5.5V and features a typical propagation delay of 12ns at VCC = 4.5V. The device provides symmetrical output impedance with |IOH| = IOL = 6mA minimum drive capability. Quiescent supply current is 4μA maximum at TA=25°C. It utilizes silicon gate C2MOS technology for high-speed performance and low power dissipation.

Feature Summary

• Octal bus buffer with inverted 3-state outputs
• Compatible with TTL outputs (VIH = 2V min, VIL = 0.8V max)
• Balanced propagation delays (tPLH ≈ tPHL)
• Symmetrical output impedance

Applications

• Direct interface between HSC2MOS systems and TTL/NMOS components
• High-speed data buffering in digital circuits
• PC board layout optimization using opposite-side input/output pinout

Procurement Notes

Verify the component status as obsolete or end-of-life before procurement planning. Confirm availability of direct substitutes such as CD74HCT540E from Texas Instruments if sourcing new production units is required. Ensure compatibility with existing DIP-20 footprint designs during transition.

Selection Notes

Select this component when interfacing CMOS systems with TTL logic levels requiring inversion. The wide operating temperature range (-55°C to 125°C) supports industrial applications. Consider the 3-state control functionality for bus sharing applications where high-impedance states are necessary.

Part Context

Part of the 74HCT series of advanced high-speed CMOS logic devices. Designed for compatibility with standard 74-series logic functions while offering improved speed and lower power consumption compared to older technologies like LS or ALS families.

Replacement Considerations

CD74HCT540E (Texas Instruments) is listed as a direct replacement option.