MAX3243ECWI+

Overview

The MAX3243ECWI+ is a full-duplex RS-232 transceiver in a 28-pin Wide SO package, rated for the extended temperature range of -40°C to +85°C. It integrates three drivers and five receivers with an always-active complementary receiver output. Operating from a single +3.0V to +5.5V supply, it utilizes internal dual charge pumps to generate ±5.5V levels. The device supports data rates up to 235kbps and features AutoShutdown technology, reducing supply current to 1µA when no valid signal is detected on receiver inputs.

Feature Summary

• AutoShutdown functionality automatically disables onboard power supplies and drivers upon detecting invalid signal levels, significantly reducing power consumption during idle periods.
• Integrated dual charge pump circuitry eliminates the need for external ±12V supplies by generating required RS-232 voltage levels from a single low-voltage source.
• Complementary always-active receiver output allows continuous monitoring of RS-232 activity even when the main transceiver logic is powered down.

Applications

• Battery-powered equipment requiring low standby current
• Hand-held devices and portable diagnostics equipment
• Serial mouse driver applications

Procurement Notes

Verify that the ordering suffix 'E' corresponds to the -40°C to +85°C industrial temperature range and 'W' indicates the 28-pin Wide SOIC package. Confirm RoHS compliance status via the manufacturer's official documentation before finalizing procurement specifications.

Selection Notes

Select this component when designing systems requiring three independent transmit channels and five receive channels. Ensure the application benefits from the AutoShutdown feature for power management or requires the specific complementary receiver output for ring indicator monitoring.

Part Context

This part belongs to the MAX3221/MAX3223/MAX3243 family of +3V to +5.5V RS-232 transceivers. While sharing core architecture with the MAX3221 (1/1) and MAX3223 (2/2), the MAX3243 provides expanded I/O capacity suitable for complex peripheral interfaces.

Replacement Considerations

Public confirmed substitutes include MAX3243EWI, MAX3243EAI, and MAX3243EUI. Verify pinout compatibility and package dimensions before substitution.

FAQ

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

The device enters shutdown mode if all receiver inputs remain between +0.3V and -0.3V for at least 30µs. It wakes up when any receiver input exceeds +2.7V or drops below -2.7V.

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

R2OUTB is a complementary, always-active receiver output that monitors RS-232 activity. It remains functional during shutdown to prevent forward biasing connected UART protection diodes.

Can the MAX3243 drive serial mice directly?

Yes, the MAX3243 is specifically designed to drive serial mice. However, AutoShutdown must be disabled by tying FORCEOFF and FORCEON to VCC to ensure continuous operation.