MAX3221EEAE+T

Overview

The MAX3221EEAE+T is a single-driver, single-receiver RS-232 transceiver designed for EIA/TIA-232 and V.28/V.24 communications interfaces. It operates from a +3.0V to +5.5V supply and achieves a 1µA supply current through the AutoShutdown feature, which activates when valid signal levels are absent. The device supports data rates up to 250kbps while maintaining true RS-232 output levels using a dual charge pump that requires only four 0.1µF capacitors. It provides enhanced electrostatic discharge protection rated at ±15kV via the Human Body Model, ±8kV via IEC 1000-4-2 Contact Discharge, and ±15kV via IEC 1000-4-2 Air-Gap Discharge. The component is housed in a 16-pin SSOP package and functions within an operating temperature range of -40°C to +85°C.

Feature Summary

• AutoShutdown technology reduces supply current to 1µA by disabling the charge pump and drivers when no valid RS-232 signals are detected on receiver inputs.
• Integrated dual charge pump generates internal +5.5V and -5.5V supplies from a single low-voltage source without requiring external inductors.
• Transmitter outputs deliver true RS-232 voltage swings compliant with EIA/TIA-232 standards across the full specified supply voltage range.
• Robust input and output protection structures withstand high-energy electrostatic discharge events without latch-up or functional degradation.

Applications

• Notebook, subnotebook, and palmtop computers
• Battery-powered handheld equipment and peripherals
• Cellular phones and mobile communication devices

Procurement Notes

Verify the specific suffix EEAE+T against the manufacturer's official ordering guide to confirm the extended temperature range (-40°C to +85°C) and SSOP-16 packaging. Ensure compatibility with RoHS directives and lead-free requirements as indicated in the datasheet documentation before finalizing procurement specifications.

Selection Notes

Select this component for applications requiring minimal power consumption during idle states where cable disconnection detection is necessary. The single driver/receiver configuration makes it suitable for space-constrained designs compared to multi-channel alternatives. Verify that the required data rate does not exceed 250kbps and that the system operates within the specified 3.0V to 5.5V voltage window.

Part Context

This part belongs to the MAX3221E/MAX3223E/MAX3243E family of 3V-powered RS-232 transceivers. While the MAX3223E offers two drivers and receivers, and the MAX3243E provides three drivers and five receivers, the MAX3221E serves as the smallest single-supply option in this series, sharing identical electrical characteristics and AutoShutdown functionality.

Replacement Considerations

Direct pin-compatible replacements within the same family include the MAX3223EEAE+T (2Tx/2Rx) and MAX3243EEAE+T (3Tx/5Rx), provided additional channels are acceptable. Other Maxim RS-232 transceivers may require schematic modifications due to differing pinouts or capacitor requirements.

FAQ

How does the AutoShutdown feature determine when to enter low-power mode?

The device enters AutoShutdown mode when all receiver inputs remain between +0.3V and -0.3V for at least 30µs, indicating that the RS-232 cable is disconnected or peripheral transmitters are off.

What is the function of the INVALID output pin?

The INVALID output goes low when no valid RS-232 signal levels are detected on any receiver input, serving as an indicator that the device has entered the shutdown state or that no active communication is present.

Can the MAX3221EEAE+T drive serial mice directly?

No, the MAX3221E lacks the specific driveability features required for serial mice; the MAX3243E variant is specifically designed and tested to drive serial mice while operating from low-voltage supplies.