MAX3238EAI

Overview

The MAX3238EAI is a true RS-232 transceiver manufactured by Analog Devices Inc./Maxim Integrated, housed in a 28-pin SSOP package. It operates on a single +3.0V to +5.5V supply and features five drivers and three receivers for full-duplex communication. The device supports data rates up to 250kbps with a guaranteed 6V/µs slew rate. Supply current is reduced to 1µA via AutoShutdown Plus when no signal transitions occur for 30 seconds. Propagation delay is typically 0.15µs, and the operating temperature range extends from -40°C to +85°C.

Feature Summary

• AutoShutdown Plus functionality reduces supply current to 1µA during periods of inactivity
• Integrated dual charge-pump power supply generates required RS-232 voltages from a single low-voltage source
• Always-active R1OUTB output enables external device monitoring without forward biasing protection diodes

Applications

• Notebook, subnotebook, and palmtop computers
• High-speed modems
• Battery-powered equipment and handheld devices

Procurement Notes

Verify the specific suffix 'EAI' corresponds to the extended temperature range (-40°C to +85°C) and SSOP package configuration. Confirm that the component meets RoHS standards as indicated by the '+' designation. Cross-reference the manufacturer's datasheet revision history to ensure compatibility with existing design specifications before finalizing procurement orders.

Selection Notes

Select this component for applications requiring low-power RS-232 interfaces in battery-operated systems. Ensure the system voltage falls within the 3.0V to 5.5V range. Verify that the 250kbps maximum data rate satisfies the application requirements. Consider the 28-pin SSOP footprint constraints during PCB layout planning.

Part Context

This part belongs to the MAX3238E series of true RS-232 transceivers designed for portable computing environments. It provides a complete serial port solution with integrated power management. The EAI variant specifically denotes the industrial temperature grade and surface-mount packaging suitable for space-constrained mobile electronics.

Replacement Considerations

MAX3238CAI: Identical electrical performance but limited to commercial temperature range (0°C to +70°C).

FAQ

How does the AutoShutdown Plus feature function?

When no valid signal transitions are detected on receiver or transmitter inputs for 30 seconds, the internal power supply and drivers shut down, reducing supply current to 1µA. The system reactivates upon detecting a new valid transition.

What is the purpose of the R1OUTB pin?

R1OUTB is an always-active noninverting complementary receiver output. It allows external devices like modems to be monitored even when other receivers are disabled or in shutdown mode, preventing current flow through protection diodes.

What capacitor values are required for 3.3V operation?

For VCC = 3.3V, the datasheet specifies minimum capacitance values of 0.1µF for C1 and 0.22µF for C2, C3, and C4.