MAX3225EAP+

Overview

The MAX3225EAP+ is a dual RS-232 transceiver from the MAX3224–MAX3227 family, manufactured by Analog Devices Inc./Maxim Integrated. It operates on a single +3.0V to +5.5V supply and achieves a typical supply current of 1µA through AutoShutdown Plus technology. The device guarantees a data rate of 1Mbps (MegaBaud) for high-speed applications. It features two drivers and two receivers with full-duplex communication capability. The component is housed in a 20-pin SSOP package and supports an operating temperature range of -40°C to +85°C.

Feature Summary

• AutoShutdown Plus functionality automatically reduces power consumption when the interface is idle or disconnected.
• Integrated dual charge pump generates required internal voltages using only four small external capacitors.
• Logic-level READY output indicates when the charge pumps are regulating and the device is ready for transmission.

Applications

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

Procurement Notes

Verify the specific suffix 'EAP+' against official documentation to confirm the SSOP-20 package and industrial temperature rating (-40°C to +85°C). Ensure compatibility with existing BIOS or operating systems as the AutoShutdown feature operates transparently without software modifications.

Selection Notes

Select this model over the MAX3224 or MAX3226 variants if a guaranteed 1Mbps data rate is required, as those counterparts are limited to 250kbps. Confirm that the application requires two drivers and two receivers; single-driver options like the MAX3221 are available if fewer channels are needed.

Part Context

This component belongs to the MAX3224–MAX3227/MAX3244/MAX3245 series of 3V-powered EIA/TIA-232 communications interfaces. The series shares common architectural features including AutoShutdown Plus and low-dropout transmitter stages, differentiated primarily by data rate capabilities and driver/receiver counts.

Replacement Considerations

Public confirmed substitute part numbers: MAX3225EAP-TG1Z, MAX3225EUP+, MAX3225ECUP+. Verify pinout and electrical specifications match before substitution.

FAQ

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

The device enters shutdown mode when valid signal transitions are not detected on any receiver or transmitter input for more than 30 seconds, such as when the cable is disconnected or peripherals are inactive.

What is the function of the INVALID output pin?

The INVALID output asserts low when no valid RS-232 voltage levels are detected on all receiver inputs, indicating the absence of a valid signal regardless of the FORCEON/FORCEOFF states.

Can unused transmitter inputs be left floating?

No, unused transmitter inputs do not have internal pull-up resistors and must be connected to GND or VCC to prevent undefined states.