MAX3238CAI+T

Overview

The MAX3238CAI+T is a true RS-232 transceiver manufactured by Analog Devices Inc./Maxim Integrated, designed for notebook and subnotebook applications. It operates on a single +3.0V to +5.5V supply and features five drivers and three receivers with full-duplex communication capability. The device achieves a typical supply current of 1µA in shutdown mode via AutoShutdown Plus technology, which activates after 30 seconds of input inactivity. It supports data rates up to 250kbps and includes 15kV ESD protection on I/O pins. The component is housed in a 28-pin SSOP package and functions within an operating temperature range of 0°C to +70°C.

Feature Summary

• AutoShutdown Plus technology reduces power consumption by shutting down internal charge pumps and drivers when no signal transitions are detected for 30 seconds.
• Integrated dual charge-pump power supply generates required RS-232 voltage levels from a single low-voltage supply without external transformers.
• Receiver R1 provides an always-active complementary output (R1OUTB) to monitor external devices like modems without forward-biasing protection diodes during system shutdown.
• Flow-through pinout architecture simplifies PCB layout and maintains compatibility with standard RS-232 interface designs.

Applications

• Notebook, Subnotebook, and Palmtop Computers
• High-Speed Modems
• Battery-Powered Equipment

Procurement Notes

Verify the specific suffix CAI corresponds to the commercial temperature range (0°C to +70°C) rather than the extended industrial range (-40°C to +85°C). Confirm RoHS compliance status through official manufacturer documentation or authorized distributors before finalizing procurement orders.

Selection Notes

Select this component for systems requiring ultra-low standby power in battery-operated portable devices. Ensure the application environment remains within the 0°C to +70°C commercial temperature limits. Verify that the required capacitor values for the charge pump circuitry align with the specified 3.3V or 5.0V operation modes.

Part Context

This part belongs to the MAX3238E family of true RS-232 transceivers. It shares functional similarities with the MAX3237 but offers enhanced power management features. The CAI suffix denotes the commercial temperature grade, distinguishing it from the EAI variant which supports wider industrial temperatures.

Replacement Considerations

The MAX3238EAI+T serves as a direct functional substitute with identical electrical characteristics but supports an extended temperature range of -40°C to +85°C. Verify thermal requirements before swapping between commercial and industrial grades.

FAQ

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

The device monitors receiver and transmitter inputs for valid signal transitions. If no transitions occur for 30 seconds, the internal power supply and drivers shut down to reduce current consumption to approximately 1µA.

What is the purpose of the R1OUTB pin?

R1OUTB is an extra, always-active noninverting output for Receiver 1. It allows external devices, such as modems, to be monitored even when the main receivers are disabled during shutdown, preventing current flow through protection diodes.

Can the MAX3238CAI+T operate directly with 5V logic families?

Yes, the device can interface directly with various 5V logic families, including ACT and HCT CMOS, when powered by a 5.0V supply.