ADM242ARZ

Overview

The ADM242ARZ is a high-speed RS-232 line driver and receiver manufactured by Analog Devices Inc. It operates from a single 5 V power supply and supports transmission rates up to 200 kB/s. The device integrates two drivers and two receivers with on-board DC-DC converters that generate ±10 V using four external 0.1 µF capacitors. It meets EIA-232-E and V.28 specifications, providing ±9 V output swing and ±30 V receiver input levels. The component features both shutdown (SHDN) and enable (EN) functions for power management and bus sharing. It is housed in an 18-lead Standard Small Outline Package (RW-18).

Feature Summary

• Integrates dual RS-232 drivers and receivers with internal charge pump voltage conversion.
• Includes active low shutdown function to minimize power consumption while keeping receivers operational.
• Features active low enable function to disable receiver outputs for common bus sharing.
• Provides TTL/CMOS compatible inputs with internal pull-up resistors and Schmitt trigger receivers.

Applications

• Computers
• Peripherals
• Modems
• Printers
• Instruments

Procurement Notes

Verify the specific package option RW-18 matches the design requirements. Confirm RoHS compliance status indicated by the Z suffix. Ensure the ordering suffix corresponds to the desired reel or tube packaging configuration. Cross-reference the manufacturer part number with authorized distributors to validate authenticity and current availability status.

Selection Notes

Select this component when a single 5 V supply is available and RS-232 communication is required. The integrated charge pump eliminates the need for external negative voltage supplies. The separate enable pin allows multiple devices to share a bus without signal contention. Verify that the 200 kB/s data rate meets the system timing requirements.

Part Context

The ADM242ARZ belongs to the ADM222/ADM232A/ADM242 family of CMOS RS-232 drivers/receivers. It shares pin compatibility with legacy MAX222/MAX232A/MAX242 devices. The ARZ suffix denotes the 18-lead SOIC wide body package with RoHS compliance. This series utilizes BiCMOS technology to combine low power CMOS with high-speed bipolar circuitry.

Replacement Considerations

Pin-compatible replacements include the ADM222 and ADM232A. The ADM222 lacks the enable pin but disables all functions during shutdown. The ADM232A lacks both shutdown and enable pins. Verify functional differences regarding bus sharing and power states before substitution.

FAQ

How does the shutdown function affect the receivers?

During shutdown mode, the transmitters are disabled, but the receivers continue to operate normally. This allows the device to monitor activity on the bus while minimizing power consumption.

What is the purpose of the EN pin?

The EN pin is an active low digital input that enables or disables the receiver outputs. It facilitates sharing a common bus by allowing the receiver outputs to be tri-stated independently of the shutdown state.

What external components are required for operation?

Four external 0.1 µF capacitors are required for the internal charge pump voltage converter. Capacitors C3 and C4 reduce output ripple, while C1 and C2 store charge for the voltage doubler and inverter.