MAX233 Multichannel RS-232 Driver/Receiver IC

Overview

The MAX233 is a dual RS-232 driver/receiver IC from Maxim Integrated that provides reliable voltage level translation between TTL/CMOS logic and RS-232-compatible devices such as PCs, modems, and serial peripherals. Designed for embedded systems, the MAX233 integrates internal charge-pump capacitors so no external capacitors are required, saving board space and simplifying design.

Key Benefits

• Compact RS-232 level converter with all charge-pump capacitors built in
• Single +5V operation simplifies power management on microcontroller boards
• Low power, high-speed operation for error-free serial data transfer
• Standard 20-pin DIP package for easy prototyping and PCB integration
• Enhanced ESD protection and robust signal integrity for industrial use

Features

• Dual RS-232 line driver and receiver (2 transmitters and 2 receivers)
• No external capacitors required due to internal charge-pump design
• Converts TTL/CMOS logic levels to RS-232 and vice versa
• Operates from a single +5V supply
• Supports full-duplex serial communication
• Low power consumption and high-speed operation (up to 120 kbps)
• Compatible with RS-232, RS-422, and UART systems
• Excellent ESD protection and signal integrity
• TTL/CMOS compatible logic interface
• Standard 20-pin DIP package for easy integration

Functional Description

• The MAX233 functions as a bi-directional voltage level converter, translating RS-232 input signals (±10V) to TTL outputs (0-5V) and vice versa.
• Integrated charge-pump voltage generators create the required ±10V levels from a single +5V supply without external capacitors, reducing component count and PCB footprint.
• Driver and receiver channels operate independently to enable full-duplex communication for simultaneous transmit and receive data flows.

Typical Applications

• RS-232 serial communication interfaces
• Microcontroller-to-PC or modem communication
• GPS, GSM, and Bluetooth serial modules
• Embedded systems, data loggers, and portable electronics
• Industrial automation and instrumentation systems
• UART-based data exchange and serial peripherals

Specifications

• Type: RS-232 line driver/receiver
• Logic Family: TTL/CMOS
• Supply Voltage (VCC): 4.5V to 5.5V
• Input High Voltage (VIH): ≥ 2V
• Input Low Voltage (VIL): ≤ 0.8V
• Typical Supply Current: 10 mA
• Data Rate: Up to 120 kbps
• Output Voltage (RS-232 side): ±10V
• Output Voltage (TTL side): 0V to 5V
• Operating Temperature Range: 0°C to +70°C
• Package Type: 20-pin DIP

Advantages Over MAX232

• No external capacitors required, simplifying circuit design and assembly
• Smaller PCB footprint and cleaner layout compared to older devices
• Reduced component count and lower assembly cost
• Ideal for compact, portable, or space-constrained devices

Design Notes and Best Practices

• Ensure VCC stays within 4.5V to 5.5V for reliable charge-pump operation.
• Observe proper PCB routing for RS-232 lines to maintain signal integrity and minimize EMI.
• Use recommended grounding and decoupling practices for microcontroller and interface circuitry.
• For industrial applications, consider additional surge or isolation protection if long RS-232 cables are used.

Manufacturer

Maxim Integrated

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