±15kV ESD-Protected, RS-232 Transceivers for Multidrop Applications

±15kV ESD-Protected, RS-232 Transceivers for Multidrop Applications

Please check latest availability status for a specific part variant.


The MAX3322E/MAX3323E 3.0V to 5.5V powered EIA/TIA-232 and V.28/V.24 communications interfaces are designed for multidrop applications with low power requirements, high data-rate capabilities, and enhanced electrostatic discharge (ESD) protection. All RS-232 inputs and outputs are protected to ±15kV using the IEC 1000-4-2 Air-Gap Discharge method, ±8kV using the IEC 1000-4-2 Contact Discharge method, and ±15kV using the Human Body Model.

The MAX3322E/MAX3323E have pin-selectable 5kΩ /high-impedance RS-232 receivers. These devices are capable of receiving data in high-impedance mode. In multidrop applications, one receiver has a 5kΩ input resistance, while the other receivers are high impedance to ensure the RS-232 standard is observed. Logic control permits selection of the functional mode: high impedance or RS-232 standard load. The transmitters are enabled by logic control to allow the multiplexing of the inputs to a single UART.

A proprietary low-dropout transmitter output stage enables true RS-232 performance from a 3.0V to 5.5V supply with a dual charge pump. The charge pump requires only four small 0.1µF capacitors for operation from a 3.3V supply. The MAX3322E/MAX3323E are capable of running at data rates up to 250kbps while maintaining RS-232-compliant output levels. The MAX3322E/MAX3323E have a unique VL pin that allows operation in mixed-logic voltage systems. Both input and output logic levels are pin programmable through the VL pin.

The MAX3322E is a 2Tx/2Rx device for hardware handshaking in standard RS-232 mode, and the MAX3323E is a 1Tx/1Rx, required in most multidrop applications.

The MAX3322E is offered in a space-saving TSSOP package. The MAX3323E is offered in 16-pin DIP and space-saving TSSOP packages.
MAX3322E, MAX3323E: Typical Operating Circuit MAX3322E, MAX3323E: Typical Operating Circuit Enlarge+

Key Features

  • Pin-Selectable 5kΩ/High-Impedance Receivers
  • Transmitter Outputs Three-Stated by Logic Control
  • VL Pin for Compatibility with Mixed Voltage Systems
  • 1Tx/1Rx (MAX3323E) or 2Tx/2Rx (MAX3322E) Versions
  • 250kbps Data Rate
  • 1µA Low-Power Shutdown
  • High ESD Protection for RS-232 I/O Pins
    • ±15kV—Human Body Model
    • ±8kV—IEC 1000-4-2 Contact Discharge
    • ±15kV—IEC 1000-4-2 Air-Gap Discharge


  • Bar-Code Scanners
  • Data Splitters
  • Industrial Data Acquisition
  • Video Security
Part NumberVSUPPLY
TxRxData Rate
Internal Charge PumpExt. CapsCap. Value
ESD Protect.
Rx Active in ShutdnPackage/PinsBudgetary
mintypnomSee Notes
$4.20 @1k
MAX3323E 11
$4.49 @1k
See All RS-232 Line Driver/Receivers (136)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Technical Documents

App Note 3741 Analog ICs for Low Voltage Systems

Quality and Environmental Data

Product Reliability Reports: MAX3322E.pdf 
Lead-Free Package Tin (Sn) Whisker Reports

CAD Symbols and Footprints

  • MAX3322EEUP+
  • MAX3322EEUP+T
  • Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

    Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

    Quality Management System >
    Environmental Management System >


    Related Resources

    IO-Link Transceiver with Integrated Protection

    • High Configurability and Integration Reduces SKU
    • Integrated Protection Enables Robust Systems
    • Optimized for Small Designs

    100Mbps Full-Duplex 3V/5V RS-485/RS-422 Transceiver with High EFT Immunity

    • High-Speed Operation
    • Integrated Protection Increases Robustness
    • Flexibility for Many Different Applications

    Type ID PDF Title
    App Note 3741 Analog ICs for Low Voltage Systems

    Belle Isle 2020
    05/29/2020 - 05/31/2020, Detroit, MI
    2020 Detroit Grand Prix - Chevrolet Detroit Grand Prix presented by Lear Fast Facts The Chevrolet Detroit Grand Prix presented by Lear was hosted on Belle Isle, May 29 - 30 2020. The event featured the cars of the NTT IndyCar Series, the IMSA WeatherTech SportsCar Championship and the Trans Am Series presented by Pirelli. The weekend is collectively referred to as the Chevrolet Detroit Grand Prix presented by Lear and it once again featured the Chevrolet Dual in Detroit IndyCar doubleheader.