MAX3131CAI

Overview

The MAX3131CAI is a hybrid microcircuit integrating an IrDA 1.2 compatible infrared transceiver with a full RS-232 interface in a single 28-pin SSOP package. It operates on a single +3.0V to +5.5V supply, consuming 370µA during active operation and reducing to 1µA in shutdown mode. The infrared channel supports data rates from 2.4kbps to 115kbps, featuring a high-gain PIN-diode amplifier with 100µA ambient photodiode current rejection and a 200mA LED driver. The onboard encoder/decoder allows communication with non-IrDA UARTs. The RS-232 section includes two drivers and two receivers supporting up to 120kbps (typically 235kbps) via a dual charge-pump power supply.

Feature Summary

• Integrates IrDA 1.2 infrared transceiver and RS-232 interface in one package
• Onboard IR encoder/decoder enables compatibility with standard UARTs
• High-efficiency dual charge pump provides true RS-232 levels from a single low-voltage supply
• Independent data paths for simultaneous infrared and serial communication

Applications

• Personal Digital Assistants (PDAs)
• Palmtop Computers
• Battery-Powered Systems
• Hand-Held Equipment
• IrDA Applications

Procurement Notes

Verify the specific suffix CAI confirms the commercial temperature range of 0°C to +70°C. Confirm RoHS compliance status as older Maxim Integrated parts may vary. Ensure the 28-SSOP footprint matches the target PCB design. Check for obsolescence notices or lifecycle changes directly from Analog Devices documentation before finalizing procurement plans.

Selection Notes

Select the MAX3131CAI when independent infrared and RS-232 channels are required, unlike the multiplexed MAX3130. Ensure the application requires IrDA 1.2 compliance and data rates up to 115kbps. Verify that the system can accommodate the necessary external optical components, including a PIN photodiode and an IR LED with a current-setting resistor. Confirm the operating temperature range meets the 0°C to +70°C requirement.

Part Context

The MAX3131 belongs to the MAX3130/MAX3131 family of 3V to 5.5V IrDA infrared transceivers with integrated RS-232 interfaces. It differs from the MAX3130 by providing separate, independent data inputs and outputs for the IrDA and RS-232 sections, allowing for simultaneous multiprotocol operation without the need for hardware multiplexing control signals.

Replacement Considerations

Public confirmed substitute part number: MAX3131EAI.