MAX3243CAI+G1Z

Overview

The MAX3243CAI+G1Z is a true RS-232 transceiver featuring three drivers and five receivers in a 28-pin SSOP package. It operates from a single +3.0V to +5.5V supply, utilizing an internal dual charge pump to generate ±5.5V rails with only four 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 circuitry eliminates the need for external ±12V supplies, enabling operation from a single low-voltage source.
• Complementary R2OUTB receiver remains active during shutdown to monitor external devices without forward-biasing connected logic.

Applications

• Battery-powered equipment requiring extended standby life
• Hand-held portable devices with serial communication interfaces
• Portable diagnostic equipment

Procurement Notes

Verify the specific suffix G1Z against the manufacturer's current ordering guide to confirm RoHS compliance and lead-free status. Ensure the CAI designation matches the required commercial temperature range of 0°C to +70°C and the 28-pin SSOP package type for your design.

Selection Notes

Select this component when a single-supply RS-232 interface with minimal external capacitance is required. The MAX3243 variant is necessary if three drivers and five receivers are needed, or if the complementary R2OUTB pin is utilized for ring indicator monitoring while the main receivers are tri-stated.

Part Context

This part belongs to the MAX3221/MAX3223/MAX3243 family of 3V to 5.5V RS-232 transceivers. The 'C' indicates a commercial temperature range, 'AI' specifies the 28-pin SSOP package, and '+' denotes lead-free/RoHS compliance. It shares the AutoShutdown architecture with the MAX3221 and MAX3223 but offers higher I/O density.

Replacement Considerations

MAX3243CWI+ is a compatible alternative offering the same electrical specifications in a 28-pin Wide SOIC package instead of SSOP.

FAQ

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

The device enters AutoShutdown mode after detecting no valid signal levels (between +0.3V and -0.3V) on all receiver inputs for a duration of 30µs.

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

R2OUTB is a complementary, always-active receiver output that allows monitoring of RS-232 activity even when the main receivers are disabled in shutdown mode.

Can the MAX3243 drive serial mice directly?

Yes, the MAX3243 is designed to drive serial mice; however, AutoShutdown must be disabled by connecting FORCEOFF and FORCEON to VCC to ensure continuous operation.