MAX3238CAI

Overview

The MAX3238CAI 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 an INVALID output signal. 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 supply current to 1µA when no valid signal transitions are detected for 30 seconds.
• Integrated dual charge-pump power supply generates internal voltage rails from a single low-voltage source.
• Receiver R1 provides an always-active complementary output (R1OUTB) for monitoring without forward biasing protection diodes.
• INVALID output pin indicates the presence of valid RS-232 signaling at receiver inputs.

Applications

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

Procurement Notes

Verify the specific suffix CAI to confirm the commercial temperature range of 0°C to +70°C, as other variants like EAI cover -40°C to +85°C. Confirm the package type is SSOP-28. Ensure the sourcing channel provides genuine Maxim Integrated products to avoid counterfeit components that may lack specified electrical characteristics.

Selection Notes

Select this component for systems requiring low-power standby modes where automatic shutdown is beneficial. It is suitable for mixed 3.3V and 5.0V logic environments. Verify that the application load capacitance does not exceed limits that would degrade the guaranteed 250kbps data rate or slew performance.

Part Context

The MAX3238 belongs to the MAX3238E family of multichannel RS-232 line drivers and receivers. This series is engineered for portable computing devices to extend battery life through advanced power management features while maintaining standard serial communication protocols.

Replacement Considerations

MAX3238EAI+ covers the same functional specifications but extends the operating temperature range to -40°C to +85°C.

FAQ

How does the AutoShutdown Plus feature function?

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

What is the purpose of the R1OUTB pin?

R1OUTB is a noninverting complementary output for Receiver 1 that remains active even during shutdown. It allows external devices like modems to be monitored without creating current paths through UART protection diodes.

Can the MAX3238CAI interface directly with 5V logic families?

Yes, when VCC is 5V, it is compatible with all TTL and CMOS families. When VCC is 3.3V, it is compatible with ACT and HCT CMOS families.