MAX3238CAI+

Overview

The MAX3238CAI+ 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. The device achieves a typical supply current of 1µA through AutoShutdown Plus technology, which activates after 30 seconds of input inactivity. It supports data rates up to 250kbps with a guaranteed 6V/µs slew rate. The operating temperature range for this specific variant is 0°C to +70°C.

Feature Summary

• AutoShutdown Plus feature reduces supply current to 1µA upon detecting 30 seconds of inactivity
• Integrated dual charge-pump power supply generates required voltages from a single low-voltage source
• Receiver R1 includes an always-active complementary output (R1OUTB) for monitoring without forward biasing protection diodes
• Flow-through pinout design simplifies PCB layout for notebook and subnotebook applications

Applications

• Notebook, Subnotebook, and Palmtop Computers
• High-Speed Modems
• Battery-Powered Equipment
• Hand-Held Equipment
• Peripherals and Printers

Procurement Notes

Verify the suffix CAI corresponds to the commercial temperature range of 0°C to +70°C. Confirm the manufacturer designation as Analog Devices Inc./Maxim Integrated. Ensure the package type matches the 28-lead shrink small-outline package (SSOP). Cross-reference the datasheet revision to confirm component specifications remain unchanged.

Selection Notes

Select this component for systems requiring true RS-232 performance from a single low-voltage supply. The AutoShutdown Plus functionality is critical for battery-powered devices needing extended standby life. Verify that the 0°C to +70°C temperature range meets the environmental requirements of the target application. Consider the 28-pin SSOP footprint during mechanical design.

Part Context

This part belongs to the MAX3238 family of low-power RS-232 transceivers. The 'E' suffix denotes an industrial temperature range (-40°C to +85°C), while the 'C' suffix indicates the commercial range (0°C to +70°C). Both variants share identical electrical characteristics and pinouts but differ in thermal endurance limits.

Replacement Considerations

The MAX3238EAI+ serves as a direct functional substitute with an expanded industrial temperature range. Verify that the ambient operating conditions do not exceed the commercial limit of +70°C before selecting the CAI variant over the EAI variant.

FAQ

How does the AutoShutdown Plus feature function?

When FORCEOFF is high and FORCEON is low, the device monitors inputs. If no valid signal transitions occur on any receiver or transmitter input for 30 seconds, the internal power supply and drivers shut down, reducing current to 1µA.

What is the purpose of the R1OUTB pin?

R1OUTB is an extra, always-active noninverting output for Receiver 1. 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.