Description

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The MAX14853/MAX14855 isolated RS-485/RS-422 transceivers provide 2750V_RMS (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. These devices allow for robust communication up to 500kbps (MAX14853) or 25Mbps (MAX14855).

The MAX14853/MAX14855 include 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 MAX14853/MAX14855 include one drive channel and one receive channel. The receiver is ¼-unit load, allowing up to 128 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 and receiver inputs are protected from ±35kV electrostatic discharge (ESD) to GNDB on the cable-side, as specified by the Human Body Model (HBM).

The MAX14853/MAX14855 are available in a wide body 16-pin SOIC package and operate over the -40°C to +105°C temperature range.

Key Features

• Higher Integration Simplifies Designs
  • Integrated LDO for Powering Cable-Side
  • Integrated Transformer Driver for Power Transfer to Cable-Side
• High-Performance Transceiver Enables Flexible Designs
  • Compliant with RS-485 EIA/TIA-485 Standard
  • 500kbps (MAX14853)/25Mbps (MAX14855) Maximum Data Rate
  • Up to 128 Devices on the Bus
  • Slew-Rate Limited Outputs (MAX14853)
  • Integrated Receiver Deglitch Filter Increases Noise Immunity (MAX14853)
• Integrated Protection Ensures for Robust Communication
  • ±35kV ESD (HBM) on Driver Outputs/Receiver Inputs
  • 2.75kV_RMS Withstand Isolation Voltage for 60s (V_ISO)
  • 630V_PEAK Maximum Repetitive Peak Isolation Voltage (V_IORM)
  • 445V_RMS Maximum Working Isolation Voltage (V_IOWM)
  • > 30 Years Lifetime at Rated Working Voltage
  • Withstands ±10kV Surge per IEC 61000-4-5
  • Thermal Shutdown

Applications/Uses

• HVAC
• Industrial Automation Equipment
• Power Meters
• Programmable Logic Controllers