ADM242AR

Overview

The ADM242AR is a high-speed, single-supply RS-232 transceiver manufactured by Analog Devices Inc. Operating from a single +5 V power supply, it integrates two drivers and two receivers capable of transmission rates up to 200 kB/s. The device utilizes an internal charge pump with four external 0.1 µF capacitors to generate the required ±10 V bipolar levels. It features both shutdown (SHDN) and enable (EN) functions for power management and bus sharing. The component meets EIA-232-E specifications, operates within an industrial temperature range of -40°C to +85°C, and is housed in an 18-lead Standard Small Outline Package (RW-18).

Feature Summary

• Integrates on-board DC-DC converters to generate RS-232 voltage levels from a single 5 V supply.
• Includes active-low shutdown function to minimize power consumption while keeping receivers operational.
• Features an active-low enable input to disable receiver outputs for multi-drop bus applications.
• Incorporates Schmitt trigger inputs on receivers to ensure noise immunity and error-free reception.

Applications

• Computers and peripheral interfaces requiring serial communication.
• Modems and printers utilizing standard RS-232 signaling.
• Industrial instruments needing robust data transmission in noisy environments.

Procurement Notes

Verify that the specific part number corresponds to the RW-18 package variant. Confirm RoHS compliance status if required by project specifications. Ensure the ordering suffix matches the desired tape and reel or tube configuration. Cross-reference the manufacturer's current datasheet revision to validate pinout and electrical characteristics before finalizing procurement.

Selection Notes

Select this component when a single 5 V supply is available and RS-232 connectivity is required. The integrated shutdown and enable pins make it suitable for systems managing power states or sharing a common serial bus. Verify that the 200 kB/s data rate aligns with system timing requirements. Consider the 18-lead package dimensions against available PCB space constraints.

Part Context

This device belongs to the ADM222/ADM232A/ADM242 family of CMOS RS-232 drivers and receivers. While the ADM222 includes only a shutdown pin and the ADM232A lacks control pins, the ADM242 uniquely combines both shutdown and enable functionalities. This family serves as a modern replacement for older AD230-AD241 derivatives, offering improved performance and lower power consumption.

Replacement Considerations

The ADM232A is pin-compatible but lacks the SHDN and EN control pins. The ADM222 is also pin-compatible but disables all functions during shutdown rather than just the transmitter. Direct substitution requires verifying that the loss of the Enable pin does not impact bus arbitration logic.