MAX3387ECUG

Overview

The MAX3387ECUG+ is a 3V-powered TIA/EIA-232 and V.28/V.24 RS-232 transceiver featuring three receivers and three transmitters. It operates from a +3.0V to +5.5V supply with a maximum data rate of 250kbps. The device includes AutoShutdown Plus, reducing supply current to 1µA when inactive. ESD protection reaches ±15kV via Human Body Model and IEC Air-Gap methods. It utilizes a dual charge pump requiring four 0.1µF capacitors for operation at +3.3V. The component is housed in a 24-pin TSSOP package and supports an operating temperature range of 0°C to +70°C.

Feature Summary

• AutoShutdown Plus technology reduces power consumption by shutting down internal charge pumps during idle periods.
• Integrated VL pin enables direct compatibility with mixed-voltage logic systems ranging from 1.8V to VCC.
• Robust electrostatic discharge protection on all RS-232 inputs and outputs ensures reliability during handling.
• Dual charge pump architecture generates required voltage levels without external inductors or transformers.

Applications

• Subnotebook and Palmtop Computers
• Personal Digital Assistants (PDAs) and PDA Cradles
• Cell Phone Data Cables
• Battery-Powered Equipment

Procurement Notes

Verify the specific suffix 'CUG' corresponds to the commercial temperature range (0°C to +70°C) and lead-free/RoHS compliance status as defined in the manufacturer's ordering information. Confirm that the 24-TSSOP package dimensions match the target PCB land pattern requirements before finalizing procurement orders.

Selection Notes

Select this component when interfacing low-voltage microcontrollers with RS-232 ports in space-constrained portable devices. Ensure the system requires only three transmitter/receiver channels. Verify that the application environment remains within the specified 0°C to +70°C operational temperature limits for the ECUG variant.

Part Context

This part belongs to the MAX3387E family of 3V RS-232 transceivers designed for mobile applications. It shares functional similarities with the MAX3386 but provides an additional transmitter channel. The ECUG designation specifically identifies the commercial grade version packaged in a 24-pin Thin Shrink Small Outline Package.

Replacement Considerations

The MAX3387EEUG+ serves as the industrial temperature range alternative (-40°C to +85°C). Direct pin-compatible substitutes within the same family include the MAX3386 series, though channel counts differ. Verify thermal requirements before substituting between commercial and extended grades.

FAQ

How does the INVALID output function?

The INVALID output indicates the presence of valid RS-232 signals on the receiver inputs. It goes high when a valid signal is detected and low when no signal is present, independent of the FORCEON/FORCEOFF control states.

What is the purpose of the VL pin?

The VL pin sets the logic level for both receiver outputs and transmitter input thresholds. This allows the device to interface directly with host logic supplies as low as 1.8V, facilitating compatibility with mixed-voltage systems.

Can unused transmitter inputs be left floating?

No. Unused transmitter inputs should be connected to GND or VL to prevent undefined states. The datasheet explicitly notes that transmitter inputs do not have internal pull-up resistors.