MAX3386EEUP

Overview

The MAX3386EEUP is a 3.0V-powered EIA/TIA-232 and V.28/V.24 communications interface featuring two receivers and three transmitters. It operates from a +3.0V to +5.5V supply with a typical supply current of 1mA and a shutdown current of 1µA. The device supports data rates up to 250kbps and includes a dual charge pump requiring four 0.1µF capacitors for operation at +3.3V. All RS-232 inputs and outputs provide enhanced ESD protection rated at ±25kV (Air-Gap), ±8kV (Contact), and ±15kV (Human Body Model). It utilizes a separate VL pin for mixed-voltage logic compatibility and is housed in a 20-pin TSSOP package.

Feature Summary

• Features a dedicated VL pin allowing receiver output levels and transmitter input thresholds to be programmable for mixed-voltage system interoperability.
• Provides enhanced electrostatic discharge protection on all RS-32 inputs and outputs, ensuring robustness against high-voltage static events without latchup.
• Incorporates a proprietary low-dropout transmitter output stage that guarantees true RS-232 performance using only small external capacitors.

Applications

• Subnotebook and Palmtop Computers
• PDAs and PDA Cradles
• Cell Phone Data Cables
• Battery-Powered Equipment

Procurement Notes

Verify the specific suffix 'E' confirms the extended temperature range of -40°C to +85°C, as the standard 'C' variant covers 0°C to +70°C. Confirm the package type is TSSOP-20. Ensure the component is lead-free if RoHS compliance is required for the assembly process. Cross-reference the manufacturer part number with authorized distributors to ensure authenticity.

Selection Notes

Select this component when interfacing between low-voltage microcontrollers or baseband processors and RS-232 ports in battery-operated devices. The separate VL supply pin is critical for systems where the host logic voltage differs from the main power supply. Ensure the application requires full-duplex communication with an additional transmitter for ring indicator signals.

Part Context

The MAX3386E belongs to Maxim Integrated's family of low-power RS-232 transceivers designed specifically for portable electronics. It addresses the need for reliable serial communication in space-constrained mobile devices like PDAs and cell phones. The device simplifies design by integrating charge pumps and high ESD protection into a compact TSSOP package.

Replacement Considerations

The MAX3386ECUP serves as a lower-temperature-range alternative within the same series. Other similar transceivers may lack the specific VL pin feature or the ±25kV ESD rating. Verify pin compatibility and electrical specifications before substituting with other RS-232 interface ICs.

FAQ

How does the VL pin function in mixed-voltage systems?

The VL pin acts as a separate logic supply input. It sets the output voltage level for the receiver outputs and defines the input thresholds for the transmitters and shutdown pin, allowing direct interfacing with logic families ranging from 1.8V to VCC.

What are the ESD protection ratings for the MAX3386E?

The device offers ±25kV protection via the IEC 1000-4-2 Air-Gap Discharge method, ±8kV via the Contact Discharge method, and ±15kV via the Human Body Model on all RS-232 inputs and outputs.

Why is the third transmitter included in this device?

The third transmitter allows the generation of a Ring Indicator (RI) signal. This enables the UART on the host PC to generate an interrupt when a peripheral device, such as a PDA or phone, is cradled, eliminating the need for software-intensive polling.