MAX3243EEAI-T

Overview

The MAX3243EEAI-T is a true RS-232 transceiver manufactured by Analog Devices Inc./Maxim Integrated, housed in a 28-pin SSOP package. It integrates three drivers and five receivers to support full-duplex communication at data rates up to 250kbps. The device operates on a single +3.0V to +5.5V supply and utilizes a dual charge pump requiring only four 0.1µF capacitors. It features an AutoShutdown function that reduces supply current to 1µA when no valid signal is detected. ESD protection meets ±15kV Human Body Model standards. The operating temperature range extends from -40°C to +85°C.

Feature Summary

• AutoShutdown technology automatically disables the charge pump and drivers to achieve ultra-low 1µA standby current when the cable is disconnected or peripherals are off.
• Integrated dual charge pump generates internal ±5.5V rails from a single low-voltage supply using minimal external capacitance.
• Includes always-active complementary receiver outputs (R2OUTB) to monitor external signals without forward-biasing protection diodes during shutdown.
• Provides robust ±15kV ESD protection on all I/O pins compliant with IEC 1000-4-2 standards.

Applications

• Notebook, subnotebook, and palmtop computers
• Battery-powered handheld equipment and PDAs
• Serial mouse driveability applications
• Cellular phones and portable peripherals

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official datasheet to confirm the exact package type, temperature rating, and lead-free status. Ensure the component matches the required pin configuration for the target PCB layout. Cross-reference the part number with authorized distributors to confirm availability and authenticity before procurement.

Selection Notes

Select this component for designs requiring a complete serial port interface within space-constrained mobile devices. It is suitable for systems needing automatic power management without BIOS modifications. Consider the MAX3244E or MAX3245E if mouse driveability must be maintained while retaining the 1µA shutdown current feature.

Part Context

This device belongs to the MAX3221E/MAX3223E/MAX3243E family of low-power RS-232 transceivers. While sharing core architecture and AutoShutdown capabilities, it differs from the MAX3221E (1 driver/1 receiver) and MAX3223E (2 drivers/2 receivers) by providing a full 3-driver/5-receiver configuration ideal for standard PC serial ports.

Replacement Considerations

Public confirmed substitutes include MAX3243ECAI+ and MAX3243EEAP+. Verify compatibility regarding package dimensions and electrical characteristics before substitution.

FAQ

How does the AutoShutdown feature reduce power consumption?

When FORCEON is low and FORCEOFF is high, the device monitors receiver inputs. If no valid RS-232 levels are detected for 30µs, the charge pump and drivers shut down, reducing supply current to 1µA until a valid signal reactivates the circuit.

What is the purpose of the R2OUTB output on the MAX3243E?

R2OUTB is an always-active noninverting complementary receiver output. It allows monitoring of external devices, such as Ring Indicator signals, even when the main receivers are in a high-impedance state during shutdown, preventing current flow through UART protection diodes.

Can the MAX3243EEAI-T drive a serial mouse directly?

Yes, the device is specifically designed to drive serial mice. However, because the AutoShutdown feature may disable transmission, FORCEOFF and FORCEON should typically be tied to VCC to keep the transmitters active for mouse operation.