MAX3224EUP+

Overview

The MAX3224EUP+ is a dual RS-232 transceiver manufactured by Analog Devices (Maxim Integrated). It operates from a single +3.0V to +5.5V supply and achieves a typical supply current of 1µA using AutoShutdown Plus technology, which automatically disables the charge pump when no valid signal transitions are detected for over 30 seconds. The device guarantees a maximum data rate of 250kbps and includes an internal dual charge pump requiring only four small capacitors. It features a logic-level READY output that asserts when the charge pump is regulating. The component is housed in a 20-pin TSSOP package and supports an industrial temperature range of -40°C to +85°C.

Feature Summary

• AutoShutdown Plus functionality enables ultra-low power consumption by automatically entering shutdown mode during periods of inactivity or cable disconnection.
• Integrated dual charge pump generates required RS-232 voltage levels from a low-voltage single supply without external inductors.
• READY output pin provides status indication regarding charge pump regulation and transmitter readiness.
• INVALID output detects valid RS-232 receiver input levels independent of shutdown control states.

Applications

• Notebook, subnotebook, and palmtop computers
• Cellular phones and handheld equipment
• Battery-powered peripherals and printers

Procurement Notes

Verify the specific suffix 'EUP+' corresponds to the 20-pin TSSOP package with an extended temperature range of -40°C to +85°C. Confirm RoHS compliance and lead-free status associated with the '+' designation. Ensure the source documentation matches the manufacturer's official datasheet for the MAX3224 series to validate electrical characteristics and pinout configurations before integration.

Selection Notes

Select this component for applications requiring automatic power management via AutoShutdown Plus to extend battery life. Choose the MAX3224 variant specifically when a guaranteed data rate of 250kbps is sufficient, as opposed to the 1Mbps capability found in the MAX3225/MAX3227 family members. Verify that the 20-pin TSSOP footprint aligns with the target PCB layout constraints.

Part Context

This device belongs to the MAX3224–MAX3227/MAX3244/MAX3245 family of 3V-powered RS-232 transceivers. While sharing the core AutoShutdown Plus architecture and charge pump design, variants within the family differ in guaranteed data rates and specific output configurations. The MAX3224 specifically targets standard baud rate applications compared to the MegaBaud-capable counterparts.

Replacement Considerations

Direct functional substitutes within the same family include MAX3224CAP+, MAX3224CPP+, and MAX3224CTP+. These alternatives share identical electrical specifications but utilize different packaging options such as SSOP, PDIP, or TQFN. Cross-referencing the pinout and thermal requirements is necessary when substituting packages.

FAQ

How does the AutoShutdown Plus feature reduce power consumption?

The circuitry monitors receiver and transmitter inputs. If no valid signal transition is detected for more than 30 seconds, the internal charge pumps shut down, reducing the supply current to approximately 1µA. The device 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 any receiver input. It indicates the physical layer signal condition and remains active regardless of the FORCEON or FORCEOFF shutdown states.

What capacitor values are required for operation at 3.3V?

For a 3.3V supply, the datasheet specifies using 0.1µF capacitors for C1 through C4. Increasing these values can reduce ripple on the transmitter outputs.