The HI-4851 is a slew-rate controlled TIA-485/TIA-422-B and ISO 8482:1993 compliant transceiver. The device can operate over an extended power-supply range (3.0V to 5.5V) and wide common mode voltage range (-15V to +20V). The HI-4851 has a full-duplex configuration, with slew rate optimized for data rates below 5 Mbps. The driver slew-rate control and pre-emphesis reduces high-frequency components in the output signal transitions along with compensating for impedance mismatch. These features provide optimum EMI and jitter performance essential in EMI sensitive environments and high-integrity data link applications such as industrial automation.

The device delivers at least ± 1.54V and ± 2.45V output drive at worst-case supply voltages of 3.0V and 4.5V respectively, over an extended temperature range of -55°C to +125°C into a differential load of 54Ω and 100pF.

The receiver offers true Fail-Safe operation, providing a guaranteed logic high on RO when the bus is open-circuit, short-circuit or idle (terminated but not driven). The receiver minimum input resistance is 90KΩ, supporting up to 224 nodes per bus.

The device comes in a compact 8-pin SOIC package.



  • Slew Rate Control and Pre-Emphasis for superior EMI
  • Extended Power Supply Operating Range (3.0V - 5.5V)
  • Extended Receiver Common-Mode Range
    • -15V to +20V Half-Duplex
    • +/-24V Full-Duplex
  • ESD Protection:
    • 16KV HBM (Bus Pins)
    • 8KV HBM (Logic Pins)
  • 5 Mbps Data Rate up to 100ft (CAT-5 UTP)
  • 2 Mbps Data Rate up to 1000ft
  • Input Impedance ≥ 1/7 UL Supporting 224 Nodes
  • Guaranteed Fail-Safe Receiver Operation
  • Thermal Shutdown and Current
  • Extended Temperature Range (-55°C to +125°C)
  • Industry Standard 75176 Pinout



  • Extended Temperature Range RS-485/422 Networks
  • Process Control and Factory Automation
  • EMI Emission Sensitive Avionics
  • Industrial Field Bus Networks
  • Networks requiring extended common-mode range