MAX3221ECTE+

Overview

The MAX3221ECTE+ is a single-driver, single-receiver RS-232 transceiver manufactured by Analog Devices Inc./Maxim Integrated. It operates on a +3.0V to +5.5V supply and supports data rates up to 250kbps. The device features an AutoShutdown function that reduces supply current to 1µA when no valid signal is detected. It includes ±15kV IEC Air-Gap ESD protection and utilizes a dual charge pump requiring four 0.1µF capacitors for operation. The component is housed in a 16-pin TQFN-EP package with an exposed paddle and functions within a commercial temperature range of 0°C to +70°C.

Feature Summary

• AutoShutdown technology enables ultra-low power consumption by automatically disabling the charge pump and drivers when the RS-232 cable is disconnected or peripheral transmitters are off.
• Integrated dual charge pump generates true RS-232 voltage levels from a single low-voltage supply without requiring external inductors.
• Enhanced electrostatic discharge protection safeguards transmitter outputs and receiver inputs against high-voltage static events.

Applications

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

Procurement Notes

Verify the specific suffix 'ECTE+' corresponds to the 16-pin TQFN-EP package and the 0°C to +70°C commercial temperature range. Confirm RoHS compliance status and lead-free material declarations directly with the manufacturer or authorized distributors before procurement.

Selection Notes

Select this component for space-constrained designs requiring a minimal footprint for a single-channel interface. Ensure the application environment remains within the specified commercial temperature limits. Verify that the system logic levels are compatible with the TTL/CMOS inputs and outputs provided by the transceiver.

Part Context

This part belongs to the MAX3221E/MAX3223E/MAX3243E family of 3V-powered RS-232 transceivers. While the MAX3223E offers two channels and the MAX3243E provides three drivers and five receivers, the MAX3221E is optimized as the smallest single-supply option for applications requiring only one driver and one receiver.

Replacement Considerations

Public confirmed substitutes include MAX3221EEAE+, MAX3221EEUE+, and MAX3221EETE+. These variants offer alternative packages such as SSOP, TSSOP, or extended temperature ranges (-40°C to +85°C). Verify pin compatibility and thermal performance when substituting.

FAQ

How does the AutoShutdown feature reduce power consumption?

The AutoShutdown circuit monitors receiver inputs; if no valid RS-232 signal levels are detected for 30µs, it disables the onboard charge pump and drivers, reducing the supply current to 1µA.

What capacitor values are required for the charge pump at 3.3V?

For a +3.3V supply, the datasheet specifies using four 0.1µF capacitors (C1 through C4) for proper charge pump operation.

What is the purpose of the INVALID output pin?

The INVALID output goes low when no valid RS-232 signal levels are present on any receiver input, indicating that the port is inactive or disconnected.