MAX3243EEWI+T

Overview

The MAX3243EEWI+T is a full-duplex RS-232 transceiver featuring three drivers and five receivers in a 28-pin Wide SO package. It operates from a single +3.0V to +5.5V supply with an integrated dual charge pump requiring only 0.1µF capacitors. The device incorporates AutoShutdown technology, reducing supply current to 1µA when no valid signal is detected on receiver inputs for 30µs. It supports data rates up to 235kbps and 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 valid RS-232 signals are absent.
• Integrated dual charge pump generates required voltage levels using small 0.1µF external capacitors, eliminating the need for ±12V supplies.
• Complementary R2OUTB pin provides continuous monitoring of receiver activity even when primary receivers are disabled in shutdown mode.

Applications

• Battery-powered equipment
• Hand-held devices
• Portable diagnostics equipment

Procurement Notes

Verify the component matches the exact part number MAX3243EEWI+T. Confirm the manufacturer is Analog Devices Inc./Maxim Integrated. Ensure the package type corresponds to the 28-Wide SOIC variant. Check that the suffix indicates RoHS compliance as specified in the ordering information.

Selection Notes

Select this component for applications requiring low-power standby modes and single-supply operation. The EE suffix designates an extended temperature range of -40°C to +85°C. The WI suffix specifies the 28-pin Wide SO package. Verify compatibility with system logic families such as ACT or HCT CMOS at the chosen supply voltage.

Part Context

This device belongs to the MAX3221/MAX3223/MAX3243 family of 3V to 5.5V RS-232 transceivers. It shares the same core architecture and AutoShutdown features as the MAX3221 and MAX3223 but offers higher channel density with three drivers and five receivers. The family utilizes proprietary low-dropout transmitter stages for true RS-232 performance.

Replacement Considerations

MAX3243EAI+T

FAQ

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

The device enters AutoShutdown mode if no valid signal levels are sensed on all receiver inputs for a duration of 30µs. This typically occurs when the RS-232 cable is disconnected or peripheral transmitters are turned off.

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 while the other receivers are in a high-impedance state during shutdown, preventing current paths through connected UART protection diodes.

Can the MAX3243 drive serial mice directly?

Yes, the MAX3243 is specifically designed to drive serial mice from low-voltage supplies. However, because AutoShutdown may interfere with mouse wake-up sequences, FORCEOFF and FORCEON should be tied to VCC to keep the transmitters active.