MAX221ECUE+

Overview

The MAX221ECUE+ is a single RS-232 transceiver operating from a +5V supply. It features AutoShutdown technology, reducing supply current to 1µA when no valid signal is detected. The device guarantees data rates up to 250kbps with worst-case loads of 3kΩ in parallel with 1000pF. ESD protection on the transmitter output and receiver input withstands ±15kV (Human Body Model), ±8kV (IEC Contact Discharge), and ±15kV (IEC Air-Gap). It operates within a commercial temperature range of 0°C to +70°C and is housed in a 16-pin TSSOP package.

Feature Summary

• AutoShutdown functionality reduces power consumption by disabling the charge pump and driver when no valid RS-232 signal is present.
• Integrated dual charge pumps generate positive and negative voltages from a single +5V supply without external inductors.
• High electrostatic discharge protection ensures robustness against handling and assembly stresses.

Applications

• Maintenance and diagnostic ports
• Industrial systems
• Telecommunications equipment
• Set-top boxes

Procurement Notes

Verify the specific suffix 'C' indicates the commercial temperature range (0°C to +70°C) rather than the extended range (-40°C to +85°C). Confirm the 'UE' designation corresponds to the 16-pin TSSOP package. Ensure the '+' suffix confirms lead-free and RoHS compliance status as per manufacturer specifications before finalizing procurement orders.

Selection Notes

Select this component for applications requiring low standby power without BIOS modifications. The AutoShutdown feature eliminates the need for software-controlled shutdown logic. Verify that the 250kbps maximum data rate meets system requirements. Ensure the 16-pin TSSOP footprint fits the PCB layout constraints compared to larger SO packages.

Part Context

This part belongs to the MAX221E family of single RS-232 transceivers. The 'C' suffix denotes the commercial temperature grade, distinguishing it from the 'E' variant which supports -40°C to +85°C. The 'UE' suffix specifies the thin small-outline package type. This series is designed for space-constrained designs needing high reliability.

Replacement Considerations

The MAX221EEUE+ serves as a direct pin-compatible alternative offering an extended industrial temperature range (-40°C to +85°C). Other single-channel RS-232 transceivers may require circuit redesign due to differences in charge pump architecture or shutdown control logic.

FAQ

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

The device enters AutoShutdown mode if no valid RS-232 signal level is detected at the receiver input for 30µs. It wakes up and drives the INVALID pin high when a valid signal is applied.

What is the function of the INVALID output pin?

The INVALID output indicates the presence of a valid RS-232 signal. It is pulled low when no valid signal is present and driven high when a valid signal is detected, allowing the host to monitor port activity.

Can the MAX221ECUE+ operate without external capacitors?

No, the internal dual charge pumps require four external 0.1µF capacitors (C1-C4) to generate the necessary positive and negative voltage rails for RS-232 operation.