MAX3243EUI

Overview

The MAX3243EUI is a +3.0V to +5.5V RS-232 transceiver manufactured by Analog Devices Inc./Maxim Integrated, housed in a 28-pin TSSOP package with an operating temperature range of -40°C to +85°C. It integrates three drivers and five receivers, featuring AutoShutdown technology that reduces supply current to 1µA when no valid signal is detected on receiver inputs for 30µs. The device operates at data rates up to 235kbps, utilizes internal dual charge pumps requiring only 0.1µF capacitors, and includes an always-active complementary receiver output (R2OUTB) for external monitoring during shutdown.

Feature Summary

• AutoShutdown functionality automatically disables the onboard power supply and drivers upon detecting invalid signal levels, significantly reducing power consumption.
• Integrated dual charge pump circuitry generates required voltage levels from a single low-voltage supply, eliminating the need for external ±12V sources.
• Complementary R2OUTB receiver remains active during shutdown states to monitor serial port activity without forward-biasing connected peripheral devices.

Applications

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

Procurement Notes

Verify the specific ordering suffix against official manufacturer documentation to confirm package type and temperature rating. Ensure compatibility with system power management requirements regarding the AutoShutdown control pins. Confirm component authenticity through authorized distribution channels before integration into production designs.

Selection Notes

Select this component for applications requiring low-power standby modes and direct interfacing with 3.3V or 5V logic families. The inclusion of an always-active receiver output makes it suitable for systems needing ring indicator detection while the main interface is powered down. Verify capacitor values match the specific VCC operating voltage to ensure stable charge pump performance.

Part Context

This part belongs to the MAX3221/MAX3223/MAX3243 family of RS-232 transceivers designed for low-voltage operation. While sharing core features like AutoShutdown and integrated charge pumps, the MAX3243 variant specifically provides three drivers and five receivers. The EUI suffix denotes the extended temperature grade and TSSOP packaging format within this product line.

Replacement Considerations

MAX3243EAI

FAQ

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

The device enters AutoShutdown mode when FORCEON is low and FORCEOFF is high, and no valid RS-232 signal levels are present on all receiver inputs for at least 30µs.

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

R2OUTB is a complementary, always-active receiver output that allows monitoring of receiver activity even when the other receivers are in a high-impedance state during shutdown.

Can the MAX3243 drive serial mice directly?

Yes, the MAX3243 is tested to drive serial mice; however, AutoShutdown must be disabled by connecting FORCEOFF and FORCEON to VCC to prevent the transmitters from shutting off during mouse operation.