MAX3243CUI+TG1Z

Overview

The MAX3243CUI+TG1Z is a true RS-232 transceiver featuring three drivers and five receivers in a 28-pin TSSOP package. It operates from a single +3.0V to +5.5V supply, utilizing an internal dual charge pump to generate ±5.5V levels without external high-voltage sources. 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 with typical propagation delays of 0.3µs. The component includes an always-active complementary receiver output (R2OUTB) for monitoring during shutdown.

Feature Summary

• AutoShutdown functionality reduces power consumption by disabling the onboard power supply and drivers when receiver inputs remain inactive for 30µs.
• Integrated dual charge-pump circuitry generates required RS-232 voltage levels from a single low-voltage supply, eliminating the need for external ±12V rails.
• Complementary R2OUTB pin provides continuous monitoring of receiver activity even when primary outputs are in a high-impedance shutdown state.

Applications

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

Procurement Notes

Verify the specific suffix 'CUI' corresponds to the commercial temperature range and TSSOP package configuration. Confirm RoHS compliance status associated with the '+T' tape-and-reel designation. Ensure the ordering code matches the exact pinout and electrical specifications required for the target design before finalizing procurement.

Selection Notes

Select this component for designs requiring three independent transmit channels and five receive channels within a compact surface-mount footprint. The AutoShutdown feature is critical for systems needing minimal quiescent current during idle periods. Verify that the 235kbps maximum data rate meets the communication requirements of the connected peripherals.

Part Context

This part belongs to the MAX3221/MAX3223/MAX3243 family of 3V-powered RS-232 transceivers. While the MAX3221 offers one driver/receiver and the MAX3223 provides two, the MAX3243 variant specifically delivers three drivers and five receivers. All members share the same core AutoShutdown architecture and charge-pump technology.

Replacement Considerations

MAX3243EUI+T is a verified industrial-grade alternative offering the same functional pinout and electrical characteristics but operating across an extended -40°C to +85°C temperature range compared to the commercial grade of the C-series.

FAQ

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

The device enters AutoShutdown 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. It allows the system to monitor RS-232 signals even when the main receiver outputs are disabled in shutdown mode, preventing current flow through connected UART protection diodes.

Can the MAX3243 drive serial mice directly?

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