MAX3224EAAP+

Overview

The MAX3224EAAP+ is a dual RS-232 transceiver from Analog Devices/Maxim Integrated, housed in a 20-pin SSOP package. It operates on a single +3.0V to +5.5V supply and guarantees a data rate of 250kbps. The device features AutoShutdown Plus technology, achieving a typical supply current of 1μA when inactive. It includes two drivers and two receivers with full-duplex communication capability. Enhanced ESD protection is provided, rated at ±15kV for air-gap discharge and ±8kV for contact discharge. The component supports an extended industrial temperature range from -40°C to +125°C.

Feature Summary

• AutoShutdown Plus functionality automatically reduces power consumption by shutting down internal charge pumps during periods of inactivity.
• Integrated dual charge pump generates required positive and negative voltage rails using only four small external capacitors.
• Logic-level READY output pin indicates when the internal charge pumps are regulating and the device is ready for transmission.
• Robust electrostatic discharge protection safeguards transmitter outputs and receiver inputs against high-voltage events.

Applications

• Notebook, subnotebook, and palmtop computers
• Cellular phones and battery-powered equipment
• Hand-held devices and peripherals such as printers
• Automotive systems requiring extended temperature tolerance

Procurement Notes

Verify that the ordering suffix AA confirms the -40°C to +125°C temperature range and SSOP package type. Confirm RoHS compliance status associated with the plus sign. Ensure the specific revision level matches system requirements. Cross-reference the manufacturer part number with authorized distributors to confirm availability and authenticity before procurement.

Selection Notes

Select this component for applications requiring low-power standby modes without BIOS modifications. The 250kbps data rate suits standard serial communications where higher speeds are unnecessary. Verify that the 20-pin SSOP footprint fits the PCB layout constraints. Consider the READY pin utility for system power management sequencing. Ensure the operating voltage range aligns with the system's VCC supply.

Part Context

This part belongs to the MAX3224E/MAX3225E/MAX3226E/MAX3227E/MAX3244E/MAX3245E family of RS-232 transceivers. The family shares common features like AutoShutdown Plus and ESD protection but varies in driver/receiver counts and maximum data rates. The MAX3224E specifically provides two drivers and two receivers with a 250kbps guarantee, distinguishing it from the 1Mbps MAX3225E.

Replacement Considerations

MAX3224ECAP+ offers identical electrical specifications but operates within a commercial temperature range of 0°C to +70°C instead of the extended range.

FAQ

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

The device enters shutdown mode if no valid signal transition is detected on any receiver or transmitter input for more than 30 seconds. It wakes up upon sensing a valid transition.

What is the function of the INVALID output pin?

The INVALID output goes low when no valid RS-232 voltage levels are detected on all receiver inputs, indicating the absence of active communication signals.

Can unused transmitter inputs be left floating?

No, unused transmitter inputs should be connected to GND or VCC. They do not have internal pull-up resistors.