MC3487 Technical Summary

Overview

The MC3487 is a quad differential line driver designed to comply with EIA (Electronic Industries Alliance) standards for balanced voltage digital interface circuits. It is specifically engineered to provide robust and reliable signal transmission in digital communication systems. The device features four independent driver chains, each capable of driving balanced lines with minimal signal distortion. The outputs are three-state structures, allowing for high impedance states when disabled, which is particularly useful in bus-oriented systems.

The MC3487 is designed with PNP-buffered inputs to reduce loading effects, ensuring efficient operation regardless of the input logic state. Additionally, internal circuitry ensures a high impedance output state during power-up and power-down transitions, preventing unintended signal transmission during these critical periods.

Features

• Four Independent Driver Chains: Each driver is capable of handling balanced voltage digital interface circuits, complying with EIA standards.
• Three-State Outputs: Outputs can be placed in a high impedance state by setting the appropriate output control pin to a logic zero, enabling bus sharing and multiplexing.
• PNP-Buffered Inputs: Minimizes input loading for both logic one and logic zero inputs, improving signal integrity and reducing power consumption.
• High Impedance During Power Transitions: Internal circuitry ensures outputs remain in a high impedance state during power-up and power-down, preventing erroneous data transmission.
• Robust Design: Suitable for industrial and commercial applications requiring reliable digital signal transmission.

Applications

The MC3487 is widely used in applications requiring high-speed digital signal transmission over balanced lines. Some common applications include:

• RS-422 and RS-485 Communication Systems: The device is ideal for implementing these standards, which are commonly used in industrial control systems, telecommunications, and networking.
• Data Acquisition Systems: Used to transmit digital data from sensors and other peripherals to central processing units with minimal noise interference.
• Telecommunication Equipment: Provides reliable signal transmission in modems, routers, and other communication devices.
• Industrial Automation: Suitable for use in programmable logic controllers (PLCs) and other automation equipment requiring robust digital interfaces.
• Test and Measurement Equipment: Ensures accurate signal transmission in oscilloscopes, logic analyzers, and other diagnostic tools.

Electrical Characteristics

The following table summarizes the key electrical characteristics of the MC3487 under typical operating conditions (unless otherwise specified):

Absolute Maximum Ratings

• Supply Voltage (VCC): 7V
• Input Voltage (VIN): -0.3V to +7V
• Output Voltage (VOUT): -7V to +12V
• Operating Temperature Range: -40°C to +85°C
• Storage Temperature Range: -65°C to +150°C

DC Electrical Characteristics

• High-Level Output Voltage (VOH): 2.0V (min) @ IOH = -20mA
• Low-Level Output Voltage (VOL): 0.4V (max) @ IOL = 20mA
• Input High Voltage (VIH): 2.0V (min)
• Input Low Voltage (VIL): 0.8V (max)
• Input Current (IIN): ±1.0mA (max) @ VIN = 0V to VCC
• Output Short-Circuit Current (IOS): ±150mA (max)

AC Electrical Characteristics

• Propagation Delay (tPLH, tPHL): 20ns (max) @ CL = 15pF
• Output Enable/Disable Time (tPZH, tPHZ): 25ns (max) @ CL = 15pF
• Output Skew (tSKEW): 5ns (max)

Package Information

The MC3487 is available in multiple package options to suit various application requirements. The following packages are commonly offered:

• 16-Pin Dual In-Line Package (DIP): A through-hole package suitable for prototyping and applications requiring manual assembly.
• 16-Pin Small Outline Integrated Circuit (SOIC): A surface-mount package offering a compact footprint for space-constrained applications.
• 16-Pin Plastic Leaded Chip Carrier (PLCC): A surface-mount package with leads on all four sides, providing a balance between size and ease of assembly.

Package Dimensions

• DIP-16: 19.3mm x 6.35mm (body), 2.54mm pin spacing.
• SOIC-16: 9.9mm x 3.9mm (body), 1.27mm pin spacing.
• PLCC-16: 9.0mm x 9.0mm (body), 1.27mm lead pitch.

Thermal Characteristics

• Thermal Resistance (θJA): 80°C/W (DIP), 100°C/W (SOIC), 70°C/W (PLCC).
• Maximum Power Dissipation (PD): 1.0W (DIP), 0.8W (SOIC), 1.2W (PLCC).

Conclusion

The MC3487 is a versatile and reliable quad differential line driver designed for high-performance digital communication systems. Its compliance with EIA standards, three-state outputs, and robust design make it suitable for a wide range of industrial, commercial, and telecommunications applications. With multiple package options and excellent electrical characteristics, the MC3487 provides engineers with a flexible solution for their signal transmission needs.