Features

• Integrated, Logic-Selectable 120Ω Termination Resistor
• 20Mbps Max Data Rate
• No Damage or Latchup to ESD: ±15kV HBM
• High Input Impedance Supports 256 Nodes
• 250kbps Low-EMI Mode
• Guaranteed Failsafe Receiver Operation Over the Entire Common Mode Range
• Current Limited Drivers and Thermal Shutdown
• Delayed Micropower Shutdown (5μA Max)
• Power Up/Down Glitch-Free Driver Outputs
• Low Operating Current (900μA Max in Receive Mode)
• Meets All TIA/EIA-485-A Specifi cations
• Available in 10-Pin 3mm × 3mm DFN, 12-Pin 4mm × 3mm DFN and 16-Pin SSOP Packages

Typical Application

Description

The LTC2859 and LTC2861 are low power, 20Mbps RS485/422 transceivers operating on 5V supplies. The receiver includes a logic-selectable 120Ω termination, one-eighth unit load supporting up to 256 nodes per bus, and a failsafe feature that guarantees a high output state under conditions of floating or shorted inputs.

The driver features a logic-selectable low-EMI 250kbps operating mode, and maintains a high output impedance over the entire common mode range when disabled or when the supply is removed. Excessive power dissipation caused by bus contention or a fault is prevented by current limiting all outputs and by a thermal shutdown.

Enhanced ESD protection allows the LTC2859 and LTC2861 to withstand ±15kV (human body model) on the transceiver interface pins without latchup or damage.