Maxim Integrated MAX232EESE Detailed Overview

The MAX232EESE is a widely used, industry-standard RS-232 line driver/receiver IC designed and produced by Maxim Integrated. It serves as a voltage level translator that converts signals between the TTL/CMOS logic levels commonly used in microcontrollers and the higher voltage RS-232 levels required for serial communication interfaces. The device integrates charge pump voltage converters and line drivers, enabling operation from a single 5 V supply without the need for a negative power supply.

Functional Description

The MAX232EESE functions as a dual transmitter and dual receiver line driver/receiver for RS-232 serial communications. It uses an internal charge pump to generate the required RS-232 voltage levels (+10 V and −10 V typical) from a single +5 V supply. The device contains two drivers and two receivers, supporting two independent serial channels, which are often used for UART communication.

Each driver converts TTL/CMOS input signals into RS-232 compliant output voltage levels, while each receiver translates RS-232 input signals back to TTL/CMOS logic levels. The receivers include built-in hysteresis for improved noise immunity and typically feature ±30 V input protection, ensuring durability in harsh environments.

Key Features

* Operates from a single +5 V power supply
* Generates RS-232 voltages from a single 5 V supply using an internal charge pump
* Two drivers and two receivers for dual-channel RS-232 communication
* Meets or exceeds TIA/EIA-232-F and ITU V.28 specifications
* Receiver inputs tolerant to ±30 V signals
* Output drivers provide ±7.5 V typical on ±5 V supply
* Low power consumption, with power-down mode reducing supply current to less than 1 µA
* ±15 kV ESD protection on all pins, exceeding human body model (HBM) standards
* Compatible with 3.3 V, 5 V, and 12 V UART systems (with adjusted VCC)
* Internal oscillator for charge pump operation, requiring only four external 0.1 µF capacitors
* Available in 16-pin SOIC, TSSOP, and other surface-mount packages
* Industrial temperature range: −40°C to +85°C
* Lead-free, RoHS-compliant packaging

Electrical Specifications

* Supply Voltage (VCC): 4.5 V to 5.5 V (nominal 5 V)
* Driver Output Voltage Swing: ±7.5 V typical at VCC = 5 V
* Receiver Input Voltage Range: ±30 V maximum
* Receiver Input Threshold Voltage: Typically ±1.3 V
* Driver Output Current: ±10 mA minimum
* Supply Current (No Load): 8 mA typical
* Shutdown Supply Current: Less than 1 µA
* Data Rate: Up to 120 kbps (typical)
* Capacitor Value for Charge Pump: Four 0.1 µF external capacitors required
* ESD Protection: ±15 kV human body model on all pins
* Operating Temperature Range: −40°C to +85°C

Package and Mechanical Details

* Package Type: 16-pin SOIC (Small Outline Integrated Circuit), TSSOP variants available
* Package Dimensions: Typical SOIC footprint approximately 9.8 mm × 4.9 mm
* Pin Pitch: 1.27 mm
* Mounting: Surface mount device (SMD) compatible with automated PCB assembly
* Marking: Manufacturer part number and date code for traceability
* Thermal Characteristics: Thermal resistance junction-to-ambient approximately 120°C/W depending on PCB layout

Typical Applications

* Serial communication interface between microcontrollers and RS-232 devices such as modems, printers, and terminals
* Data acquisition systems requiring reliable serial communication
* Industrial automation and control systems with legacy RS-232 interfaces
* Embedded systems integrating PC communication
* Networking equipment and point-of-sale terminals
* Consumer electronics with UART interface to external RS-232 peripherals
* Instrumentation and test equipment
* Automotive diagnostics and telematics systems

Performance Advantages

The MAX232EESE offers a complete, compact solution for RS-232 level conversion with minimal external components. Its integrated charge pump eliminates the need for multiple power supplies or external negative voltage sources, simplifying design and reducing board space. The device's dual driver and receiver configuration supports multi-channel communications in a single package, improving system integration.

High ESD protection levels ensure device robustness in environments prone to electrostatic discharge, making it suitable for industrial and consumer applications alike. The low power consumption and power-down mode enhance energy efficiency in battery-powered or energy-sensitive systems.

Its compliance with industry-standard RS-232 voltage and timing specifications guarantees interoperability with a wide range of RS-232 equipment. The wide receiver input voltage range and noise hysteresis improve signal integrity over long cable runs or electrically noisy environments.

Conclusion

Maxim Integrated’s MAX232EESE is a reliable, versatile RS-232 line driver/receiver designed to bridge TTL/CMOS logic levels and RS-232 communication standards with high efficiency and low external component count. Its integrated charge pump, dual channels, robust ESD protection, and wide operating temperature range make it an excellent choice for serial interface applications across industrial, automotive, consumer, and communication systems. The device’s simplicity, performance, and durability continue to make it a standard solution for RS-232 level translation.