ISL81485: 5V, Half Duplex, 30Mbps, RS-485/RS-422 Transceiver

The Intersil ISL81485 is a BiCMOS, 5V powered, single transceiver that meets both the RS-485 and RS-422 standards for balanced communication, and features a larger output voltage and higher data rate to benefit high speed applications.

Unlike competitive devices, this Intersil transceiver is specified for 10% tolerance supplies (4.5V to 5.5V), and it delivers a much larger worst case differential output voltage (2.0V compared to the typical 1.5V) over the full supply range. The increased output voltage translates into longer reach, or better data integrity, at the 30Mbps data rate. This device presents a "1 unit load" to the RS-485 bus, which allows up to 32 transceivers on the network.

Receiver (Rx) inputs feature a "fail-safe if open" design, which ensures a logic high Rx output if Rx inputs are floating.

Driver (Tx) outputs are short circuit protected, even for voltages exceeding the power supply voltage. Additionally, on-chip thermal shutdown circuitry disables the Tx outputs to prevent damage if power dissipation becomes excessive.

Key Features
  • Specified for 10% Tolerance Supplies
  • High Data Rates up to 30Mbps
  • Large Differential Output Voltage 2.0V(min.) into 54Ω
  • Drop-In Replacement for the ADM1485
  • One Unit Load Allows up to 32 Devices on the Bus
  • Low Quiescent Current 800µA
  • -7V to +12V Common Mode Input Voltage Range
  • Three State Rx and Tx Outputs
  • 15ns (Max) Propagation Delays, 5ns (Max) Skew
  • Operates from a Single +5V Supply (10% Tolerance)
  • Current Limiting and Thermal Shutdown for driver Overload Protection
  • Pb-free available
Applications
  • SCSI "Fast 20" Drivers and Receivers
  • Factory Automation
  • Field Bus Networks
  • Security Networks
  • Building Environmental Control Systems
  • Industrial/Process Control Networks
Typical Diagram
Application Notes
TitleTypeUpdatedSizeOther Languages
AN1979: Surge Protection simplified with Intersil’s Overvoltage Protected (OVP) TransceiversPDF24 Aug 2016250 KB
AN1978: Surge Protection for Intersil’s Standard RS-485 TransceiversPDF18 Aug 2016199 KB
AN1976: Important Transient Immunity Tests for RS-485 NetworksPDF10 Aug 2016156 KB
AN1977: Transient Voltage Suppressors: Operation and FeaturesPDF09 Aug 2016198 KB
AN1980: Ground Potential Differences: Origin and RemediesPDF29 Jul 2016198 KB
Datasheets
TitleTypeUpdatedSizeOther Languages
ISL81485 DatasheetPDF10 Feb 2016376 KB
Tech Briefs
TitleTypeUpdatedSizeOther Languages
TB505: Understanding the Difference between HBM and IEC 61000-4-2 ESD ImmunityPDF29 Jul 2016121 KB
Order Information
Part NumberPackage TypeWeight(g)PinsMSL RatingPeak Temp (°C)RoHS Status
ISL81485IB8 Ld SOIC0.07281240
ISL81485IB-T8 Ld SOIC T+R0.07281240
ISL81485IBZ8 Ld SOIC0.07281260RoHS
ISL81485IBZ-T8 Ld SOIC T+R0.0728260RoHS
ISL81485IU8 Ld MSOP0.0258240
ISL81485IU-T8 Ld MSOP T+R0.0258240
ISL81485IUZ8 Ld MSOP0.02582260RoHS
ISL81485IUZ-T8 Ld MSOP T+R0.02582260RoHS
ISL81485 Datasheet 10 Feb 2016
AN1979: Surge Protection simplified with Intersil’s Overvoltage Protected (OVP) Transceivers 24 Aug 2016
AN1978: Surge Protection for Intersil’s Standard RS-485 Transceivers 18 Aug 2016
AN1976: Important Transient Immunity Tests for RS-485 Networks 10 Aug 2016
AN1977: Transient Voltage Suppressors: Operation and Features 09 Aug 2016
AN1980: Ground Potential Differences: Origin and Remedies 29 Jul 2016
TB505: Understanding the Difference between HBM and IEC 61000-4-2 ESD Immunity 29 Jul 2016