**ADM232AARN: A Comprehensive Technical Overview of the 5V-Powered Dual RS-232 Driver/Receiver**

In the realm of industrial control, telecommunications, and legacy computing, the RS-232 communication standard remains a persistent and vital interface. Bridging the gap between modern logic-level systems and this classic serial protocol requires a robust and efficient interface solution. The **ADM232AARN** from Analog Devices stands as a quintessential component in this space, offering a complete, **5V-powered dual RS-232 driver/receiver** in a compact package. This article provides a detailed technical examination of this influential integrated circuit.

The ADM232AARN is a monolithic device that integrates two RS-232 transmitters (drivers) and two receivers on a single chip. Its primary function is to translate signals between a **TTL/CMOS logic** environment (typically 0V to 5V) and the bipolar voltage levels mandated by the RS-232 standard (±5V to ±15V). A key feature of this device is its ability to generate the required RS-232 voltage levels from a single **+5V power supply**, eliminating the need for costly and bulky dual ±12V power supplies. This is achieved through an internal, high-efficiency **charge-pump voltage converter**, which consists of a switching capacitor voltage doubler and a voltage inverter.

The drivers convert TTL/CMOS inputs into RS-232 output levels. With a +5V supply, the charge pump generates approximately +10V and -10V internally, ensuring the driver outputs easily meet the ±5V minimum voltage swing required by the RS-232 specification, typically achieving **±8V outputs**. This provides a strong margin for noise immunity and signal integrity over longer cable runs. The receivers perform the inverse operation, translating RS-232 input signals (which can be as high as ±25V) back into TTL/CMOS-compatible 5V logic levels. They feature a **standard input hysteresis** of 0.5V, which enhances noise rejection and prevents output oscillation with slow-moving or noisy input signals.

Housed in a narrow 16-lead SOIC (N) package, the ADM232AARN is designed for space-constrained applications. It supports **data rates up to 120 kbps**, making it suitable for a wide range of standard baud rates from 9.6k to 115.2k baud. The device is engineered for low power consumption, with a typical supply current of 10 mA. Furthermore, it includes a critical protection feature: all RS-232 inputs and outputs are **protected against electrostatic discharge (ESD)** up to ±15kV (using the Human Body Model), safeguarding the IC and the system it resides in from damage during handling or in harsh electrical environments.

Typical applications are extensive, spanning from **PC serial ports** and industrial PLCs to medical instrumentation, point-of-sale terminals, and any embedded system requiring a legacy serial communication link. Its reliability and simplicity have made it a go-to solution for engineers for decades.

**ICGOO**DFIND: The ADM232AARN is a cornerstone of serial communication design, offering a highly integrated, reliable, and **single-supply solution** for RS-232 interfacing. Its internal charge pump, robust ESD protection, and compliance with the RS-232 standard ensure seamless and durable connectivity in modern electronic systems.

**Keywords:** RS-232, Charge Pump, Single 5V Supply, ESD Protection, Driver/Receiver