MAX3318CUP+T

Overview

The MAX3318CUP+T is a full-duplex RS-232 transceiver manufactured by Analog Devices Inc./Maxim Integrated. It operates on a single +2.25V to +3.0V supply and includes an internal dual charge pump generating +4.4V and -4.3V rails. The device features two drivers and two receivers, supporting data rates up to 460kbps with a guaranteed 4V/µs slew rate. Operating supply current is 300µA, while AutoShutdown Plus reduces standby current to 1µA when inputs are inactive for over 30 seconds. It utilizes a 20-pin TSSOP package and functions within a commercial temperature range of 0°C to +70°C.

Feature Summary

• AutoShutdown Plus automatically enters low-power shutdown mode after 30 seconds of inactivity
• Internal dual charge pump enables RS-232 compatibility at voltages as low as 2.25V
• READY output indicates when the charge pump is regulating and the device is ready to transmit
• INVALID output asserts low when no valid RS-232 voltage levels are detected on receiver inputs

Applications

• Palmtop Computers
• Hand-Held Instruments
• Cellular Phones
• GPS Systems
• Handy Terminals

Procurement Notes

Verify that the ordering suffix matches the required temperature grade and packaging format. Confirm the manufacturer designation aligns with current corporate ownership structures. Ensure the component meets RoHS compliance standards for the target market. Cross-reference the specific part number against official distributor catalogs to confirm availability status.

Selection Notes

Select this component for applications requiring low-voltage operation between 2.25V and 3.0V. The MAX3318 provides two independent transmitter and receiver channels suitable for full-duplex communication. Consider the AutoShutdown Plus feature for battery-powered designs requiring minimal standby current consumption during periods of inactivity.

Part Context

This component belongs to the MAX3316–MAX3319 family of 2.5V RS-232-compatible transceivers. The MAX3318 specifically offers two drivers and two receivers, distinguishing it from the single-channel MAX3319. All devices in this series share the same proprietary low-dropout transmitter output stage and dual charge pump architecture.

Replacement Considerations

Public confirmed substitute part numbers include MAX3318EAP+ and MAX3318EUP+. Verify pin compatibility and electrical specifications before substitution.

FAQ

How does the AutoShutdown Plus feature function?

The device automatically enters a low-power shutdown mode if all receiver and transmitter inputs remain inactive for more than 30 seconds. It resumes normal operation upon sensing a valid transition at any input.

What is the purpose of the INVALID output?

The INVALID output asserts low when no valid RS-232 voltage levels have been detected on all receiver inputs. This signal indicates the receiver's input condition and is independent of FORCEON and FORCEOFF states.

Can unused transmitter inputs be left floating?

No, the transmitter inputs do not have internal pullup resistors. Unused inputs must be connected to GND or VCC to ensure proper operation.