5kVRMS Isolated 500kbps Half-Duplex RS-485/RS-422 Transceiver with ±30kV ESD Protection and Integrated Transformer Driver

Industry's Most Robust Isolated RS-485


The MAX14949 isolated RS-485/RS-422 transceiver provides 5000VRMS (60s) of galvanic isolation between the cable side (RS-485/RS-422 driver/receiver side) and the UART side of the device. Isolation improves communication by breaking ground loops and reduces noise when there are large differences in ground potential between ports. This device allows for robust communication up to 500kbps.

The device includes an integrated 450kHz transformer driver for power transfer to the cable side of the transceiver using an external transformer. An integrated LDO provides a simple and space-efficient architecture for providing power to the cable side of the IC.

The device includes one half-duplex driver/receiver channel. The receiver is 1/8-unit load, allowing up to 256 transceivers on a common bus.

Integrated true fail-safe circuitry ensures a logic-high on the receiver output when inputs are shorted or open. Undervoltage lockout disables the driver when cable-side or UART-side power supplies are below functional levels.

The driver outputs/receiver inputs are protected from ±30kV electrostatic discharge (ESD) to GNDB on the cable side, as specified by the Human Body Model (HBM).

The MAX14949 is available in a wide body 16-pin SOIC package and operates over the -40°C to +85°C temperature range.

MAX14949: Functional Diagram MAX14949: Functional Diagram Enlarge+

Key Features

  • High Integration Simplifies Designs
    • Integrated LDO for Cable-Side Power
    • Integrated Transformer Driver for Power Transfer to Cable Side Has Up to 80% Efficiency at 150mA Load
  • High-Performance Transceiver Enables Flexible Designs
    • Compliant with RS-485 EIA/TIA-485 Standard
    • 500kbps (max) Data Rate
    • Up to 256 Devices on the Bus
  • Integrated Protection for Robust Communication
    • ±30kV ESD (HBM) on Driver Outputs/Receiver Inputs
    • 5kVRMS Withstand-Isolation Voltage for 60 Seconds (VISO)
    • 1200VPEAK Maximum Repetitive Peak-Isolation Voltage (VIORM)
    • 848VRMS Maximum Working-Isolation Voltage (VIOWM)
    • >30 Years Lifetime at Rated Working Voltage
    • Withstands ±10kV Surge per IEC 61000-4-5
    • Thermal Shutdown


  • HVAC
  • Industrial Automation Equipment
  • Power Meters
  • Programmable Logic Controllers
Part Number Tx/Rx Duplex VSUPPLY
Galvanic Isolation
Data Rate
ESD Protect.
Tx EN Rx EN Rx/Tx on Bus Rx Failsafe w/ Inputs Oper. Temp.
Package/Pins Budgetary
typ min See Notes
MAX14949  1Tx + 1Rx Half 5 5000 4.7 500 30 No No 256 None -40 to +85
$4.00 @1k
See All RS-485/RS-422 Line Driver/Receivers (182)
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.

MAX149X2EVKIT: Evaluation Kit for the MAX14940/MAX14943/MAX14946/MAX14949

Quality and Environmental Data

Request Reliability Report for: MAX14949 
Lead-Free Package Tin (Sn) Whisker Reports

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