MAX221EAE+

Overview

The MAX221EAE+ is a single RS-232 transceiver operating from a +5V supply, housed in a 16-pin SSOP package. It supports full-duplex communication with a guaranteed data rate of 250kbps and features an internal dual charge pump for voltage generation. The device draws 1µA in shutdown mode via AutoShutdown technology, which activates when valid signal levels are absent. Electrical characteristics include a typical propagation delay of 0.15µs, input leakage current of ±1nA, and output short-circuit current of ±10mA. It operates within a temperature range of -40°C to +85°C.

Feature Summary

• AutoShutdown technology reduces power consumption by disabling the transmitter and charge pumps when no valid RS-232 signal is detected.
• Integrated dual charge pump generates required positive and negative voltages from a single +5V supply without external components.
• INVALID pin provides status indication of active RS-232 signal presence at the receiver input.

Applications

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

Procurement Notes

Verify the specific suffix 'E' indicates the extended temperature grade (-40°C to +85°C) compared to commercial variants. Confirm the 'AE' designation corresponds to the 16-pin SSOP package type. Ensure compatibility with existing BIOS or operating system configurations if relying on AutoShutdown behavior without software intervention.

Selection Notes

Select this component for applications requiring low standby power in single-supply +5V environments. The integrated charge pump eliminates the need for external voltage inversion circuits. Consider the 16-pin SSOP footprint constraints during PCB layout. Verify that the 250kbps maximum data rate meets the system's throughput requirements.

Part Context

This part belongs to the MAX221 family of single RS-232 transceivers. It is functionally similar to the MAX221CUE but offers an extended industrial temperature range. The device serves as a compact interface solution for serial communications where power efficiency and minimal external component count are critical design factors.

Replacement Considerations

MAX221CUE

FAQ

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

The device enters shutdown mode if the receiver input remains between +0.3V and -0.3V for at least 30µs, indicating no valid RS-232 signal is present.

What is the function of the INVALID output pin?

The INVALID pin is pulled low when no valid RS-232 level is detected on the receiver input and goes high when a valid signal is present, signaling port activity.

Can the MAX221 operate without external capacitors?

No, four external 0.1µF capacitors (C1-C4) are required to support the internal dual charge pump voltage conversion circuitry.