MC145406 - Triple Driver/Receiver IC for EIA-232-D and CCITT V.28 Standards

Overview

The MC145406 is a silicon-gate CMOS integrated circuit designed to provide a complete interface solution for serial communication applications. This IC combines three drivers and three receivers in a single package, fully compliant with both EIA-232-D and CCITT V.28 standards. The device offers an efficient, low-power solution for data communication systems requiring robust signal transmission and reception capabilities.

Built using advanced CMOS technology, the MC145406 features excellent noise immunity and power efficiency. The integration of both drivers and receivers on a single chip makes it particularly suitable for space-constrained applications while maintaining high performance and reliability.

Features

Driver Features

• True TTL input compatibility for easy integration with digital systems
• Slew-rate limited output for reduced EMI and improved signal integrity
• 300Ω power-off source impedance for protection against short circuits
• Output current limiting for enhanced reliability
• Outputs typically switch to within 25% of supply rails
• Wide supply voltage range: +5V to +12V

Receiver Features

• Can handle input voltages up to +25V
• Input impedance of 3kΩ to 7kΩ
• Built-in hysteresis for improved noise immunity
• TTL-compatible outputs
• Designed to meet EIA-232-D and CCITT V.28 specifications

General Features

• Low power consumption typical of CMOS technology
• Combined driver/receiver configuration saves board space
• Robust ESD protection
• Wide operating temperature range

Applications

The MC145406 is ideally suited for a variety of serial communication applications, including:

• RS-232 interface circuits
• Modem interfaces
• Data terminal equipment (DTE)
• Data communication equipment (DCE)
• Computer peripheral interfaces
• Industrial control systems
• Telecommunication equipment
• Point-of-sale terminals
• Embedded systems requiring serial communication

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (VDD to VSS): -0.5V to +13V
• Input Voltage (any pin): -0.5V to VDD +0.5V
• Receiver Input Voltage: ±25V
• Driver Output Current: ±10mA continuous
• Operating Temperature Range: -40°C to +85°C
• Storage Temperature Range: -65°C to +150°C

Recommended Operating Conditions

• Supply Voltage Range: +5V to +12V
• Operating Temperature Range: -40°C to +85°C
• Input High Voltage (Drivers): 2.0V min (TTL compatible)
• Input Low Voltage (Drivers): 0.8V max (TTL compatible)
• Output High Voltage (Receivers): 2.4V min (TTL compatible)
• Output Low Voltage (Receivers): 0.4V max (TTL compatible)

Typical Performance Characteristics

• Driver Output Voltage Swing: Typically within 25% of supply rails
• Driver Slew Rate: 30V/μs maximum (controlled for EMI reduction)
• Receiver Input Threshold: 1.3V typical with 0.4V hysteresis
• Power Supply Current: 5mA typical with all drivers active
• Propagation Delay: 100ns typical (driver input to output)

Package Information

The MC145406 is available in two package options:

16-Pin Dual In-Line Package (DIP)

• Package Designator: D
• Package Dimensions: 19.3mm x 6.35mm
• Lead Pitch: 2.54mm
• Material: Plastic
• Operating Temperature: -40°C to +85°C

16-Pin Plastic Leaded Chip Carrier (PLCC)

• Package Designator: N
• Package Dimensions: 10.16mm x 10.16mm
• Lead Pitch: 1.27mm
• Material: Plastic
• Operating Temperature: -40°C to +85°C

Pin Configuration

The pinout for both package options is as follows:

• Pin 1: VDD
• Pin 2: RX1
• Pin 3: VCC
• Pin 4: DO1
• Pin 5: DI1
• Pin 6: DO2
• Pin 7: DI2
• Pin 8: DO3
• Pin 9: GND
• Pin 10: TX1
• Pin 11: VSS
• Pin 12: RX2
• Pin 13: TX2
• Pin 14: RX3
• Pin 15: TX3
• Pin 16: DI3

Design Considerations

Power Supply Decoupling

Proper decoupling is essential for optimal performance. A 0.1μF ceramic capacitor should be placed as close as possible between VDD and GND pins. For systems with particularly noisy power supplies, additional bulk capacitance (10μF electrolytic) may be required.

PCB Layout Guidelines

• Keep driver outputs and receiver inputs as short as possible
• Route high-speed signals away from sensitive analog circuits
• Use ground planes for improved noise immunity
• Maintain proper spacing between signal traces to minimize crosstalk

ESD Protection

While the MC145406 includes basic ESD protection, additional protection components may be required in harsh environments. Consider using transient voltage suppressors (TVS) on interface lines exposed to external connections.

Conclusion

The MC145406 provides a complete, cost-effective solution for RS-232 interface requirements in a wide range of applications. Its combination of three drivers and three receivers in a single package, along with robust electrical characteristics and standard compliance, makes it an excellent choice for designers needing reliable serial communication interfaces. The device's CMOS technology ensures low power consumption while maintaining the necessary drive capability for standard RS-232 applications.