MAX3243EEWI+

Overview

The MAX3243EEWI+ is a full-duplex RS-232 transceiver manufactured by Analog Devices Inc./Maxim Integrated. It features three drivers and five receivers in a 28-pin Wide SO package, operating from a single +3.0V to +5.5V supply. The device supports data rates up to 235kbps with typical propagation delays of 0.3µs. It incorporates AutoShutdown technology, reducing supply current to 1µA when no valid signal is detected for 30µs. The component includes an always-active complementary receiver output (R2OUTB) for external monitoring during shutdown.

Feature Summary

• AutoShutdown functionality reduces power consumption by disabling the onboard power supply and drivers when no valid RS-232 signal is present on receiver inputs.
• Integrated dual charge pump circuitry generates required voltage levels using only four small 0.1µF external capacitors, eliminating the need for ±12V supplies.
• Complementary R2OUTB pin provides continuous monitoring of receiver activity even when the main transceiver logic is in a low-power shutdown state.

Applications

• Battery-powered equipment requiring extended standby life
• Hand-held devices and portable diagnostics equipment
• Serial mouse interfacing applications

Procurement Notes

Verify the specific ordering suffix 'EWI+' against the manufacturer's official documentation to confirm the Wide SO package type and RoHS compliance status. Ensure that the temperature range corresponds to the 'E' grade (-40°C to +85°C). Cross-reference the datasheet revision date to confirm the validity of the electrical characteristics provided.

Selection Notes

Select this component when a full-duplex RS-232 interface is needed with minimal external capacitance requirements. The inclusion of the always-active R2OUTB makes it suitable for systems where peripheral monitoring must persist during low-power states. Verify that the load capacitance does not exceed limits that would degrade the slew rate or data integrity at the target baud rate.

Part Context

This part belongs to the MAX3221/MAX3223/MAX3243 family of low-voltage RS-232 transceivers. While sharing the same core architecture and AutoShutdown feature, the MAX3243 variant specifically offers three drivers and five receivers, providing higher channel density compared to the 1-driver/1-receiver MAX3221 or the 2-driver/2-receiver MAX3223.

Replacement Considerations

Public confirmed substitute part numbers include V62-06624-01XE and V62-06624-01YE, which are enhanced product versions available from Texas Instruments.

FAQ

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

The device enters AutoShutdown mode if no valid RS-232 signal levels are detected on all receiver inputs for a duration of 30µs. It wakes up automatically when a valid level is applied to any receiver input.

What is the function of the R2OUTB pin on the MAX3243?

R2OUTB is a complementary, always-active receiver output. It allows the system to monitor RS-232 activity, such as Ring Indicator signals, even when the main transceiver outputs are in a high-impedance shutdown state.

Can the MAX3243 drive serial mice directly?

Yes, the MAX3243 is designed to drive serial mice. However, because the AutoShutdown feature may interfere with mouse operation, FORCEOFF and FORCEON should be connected to VCC to keep the transmitters active.