ADM202EARN

Overview

The ADM202EARN is a dual-channel RS-232/V.28 interface device manufactured by Analog Devices Inc., operating from a single 5 V power supply. It features a guaranteed data rate of 230 kbps and includes internal charge-pump circuitry requiring four external 0.1 µF capacitors to generate ±10 V levels. The device provides ESD protection up to ±15 kV (air-gap) and ±8 kV (contact), along with EFT immunity of ±2 kV. It operates within a voltage range of 4.5 V to 5.5 V, drawing a maximum supply current of 18 mA under load. The component is housed in a 16-lead SOIC package and supports an industrial temperature range of -40°C to +85°C.

Feature Summary

• Complies with the EU EMC directive (89/336/EEC) for electromagnetic compatibility.
• Provides robust protection against electrostatic discharge and electrical fast transients on all I/O lines.
• Features controlled slew rates to minimize electromagnetic interference emissions.
• Offers Schmitt-trigger receiver inputs with hysteresis for noise immunity.

Applications

• General-purpose RS-232 data links
• Portable instruments
• Personal Digital Assistants (PDAs)

Procurement Notes

Verify the specific ordering suffix to confirm the package type and tape/reel configuration. Ensure the procurement documentation matches the required RoHS compliance status and lead-free specifications. Cross-reference the manufacturer's latest datasheet revision to confirm active status and any potential pinout or functional updates before finalizing orders.

Selection Notes

Select this component when high-speed RS-232 communication at 230 kbps is required alongside strict EMC compliance. It serves as a direct upgrade for legacy MAX202E/MAX232E designs. Consider the internal pull-down resistors on receiver inputs which define default logic states for unconnected pins. Verify that the application environment requires the specified industrial temperature range and ESD protection levels.

Part Context

The ADM202E is part of the ADM202E/ADM1181A family of robust, high-speed RS-232 line drivers and receivers. This series is designed to replace older generation charge-pump transceivers while offering enhanced electromagnetic immunity. The device integrates CMOS technology to minimize power dissipation, making it suitable for battery-operated portable applications requiring reliable serial communication interfaces.

Replacement Considerations

The ADM202E is documented as a pin-compatible upgrade for MAX202E and MAX232E devices. Designers replacing these parts should verify that the existing board layout accommodates the ADM202E's specific capacitor requirements and that the system does not rely on differences in absolute maximum ratings between the legacy and new components.

FAQ

What is the function of the internal 5 kΩ pull-down resistors?

The internal 5 kΩ pull-down resistors on each RS-232 receiver input ensure that unconnected inputs are pulled to ground, resulting in a Logic 1 output level and preventing undefined states.

How does the device manage electromagnetic emissions?

The ADM202E utilizes internally controlled slew rates limited to less than 30 V/µs to minimize radiated emissions. Additionally, the charge-pump design incorporates break-before-make switching to reduce conducted emissions, ensuring compliance with EN55022 limits.

What external components are required for operation?

Four external 0.1 µF capacitors are required for the charge-pump voltage doubler and inverter stages. Larger capacitors up to 47 µF may be used if desired to facilitate substitution with older designs.