ADM4850:  Half Duplex RS-485/RS-22 Transceiver w/115kbps Data Rate

The ADM4850-ADM4857 are differential line transceivers suitable for high speed full and half duplex data communication on multipoint bus transmission lines. They are designed for balanced data ...More

ADM4850:  Half Duplex RS-485/RS-22 Transceiver w/115kbps Data Rate

Product Description

The ADM4850-ADM4857 are differential line transceivers suitable for high speed full and half duplex data communication on multipoint bus transmission lines. They are designed for balanced data transmission and comply with EIA Standards RS-485 and RS-422. The ADM4850-ADM4853 are half duplex transceivers which share differential lines and have separate enable inputs for the driver and receiver. The full duplex ADM4854-ADM4857 transceivers have dedicated differential line driver outputs and receiver inputs.

The devices have a 1/8-unit-load receiver input impedance which allows up to 256 transceivers on a bus. Since only one driver should be enabled at any time, the output of a disabled or powered down driver is three-stated to avoid overloading the bus.

The receiver inputs have a true failsafe feature which ensures a logic high output level when the inputs are open or shorted. This guarantees that the receiver outputs are in a known state before communication begins and when communication ceases.

The driver outputs are slew rate limited in order to reduce EMI and data errors caused by reflections from improperly terminated buses. Excessive power dissipation caused by bus contention or by output shorting is prevented with a thermal shutdown circuit.

The parts are fully specified over the commercial and industrial temperature ranges and are available in 8-lead SOIC and LFCSP packages.

Features

  • EIA RS-485/RS-422 Compliant
  • Reduced Slew Rates for Low EMI
  • True Failsafe Receiver Inputs
  • 2µA (Max) Supply Current in Shutdown Mode
  • Up to 256 Transceivers on a bus
  • Outputs High-Z when Disabled or Powered-Off
  • -7V to +12V Bus Common Mode Range
  • Thermal Shutdown and Short Circuit Protection
  • Pin Compatible with MAX308x
  • Specified over –40°C to +85°C Temperature Range
  • Available in 8-Lead SOIC and LFCSP Packages

Diagrams

ADM4850 Diagram
Functional Block Diagram for ADM4850

Характеристики

Protocols RS-422,RS-485
Pwr Supply (Vnom) +5
#Tx 1
# Rx 1
Data Rate 115kbps
Low Power Shutdown Yes
Operating Temp Range -40 to +85

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