Intersil announces isolated RS-485 transceiver

An isolated RS-485 differential bus transceiver has been designed by Intersil to provide 4Mbit/s bidirectional data transmission for industrial IoT (IIoT) networks. The ISL32704E delivers electromagnetic interference and common-mode transient immunity in a 4 x 5mm QSOP package that is said to be 70% smaller than competitive devices.

The transceiver employs giant magnetoresistance technology to provide galvanic isolation that keeps the communication bus free from common-mode noise generated in electrically noisy factory and building automation environments.

The ISL32704E is suited to equipment-to-bus interface in IIoT networks that connect programmable logic controllers to instruments, robots, motor drives, data acquisition and digital I/O modules.

The device’s GMR isolation is claimed to have low radiated emission and low EMI susceptibility, and does not require elaborate encoding schemes.

According to the company, the ISL32704E offers 80% less power consumption than competing devices because it doesn’t use power hungry transfer coils or transformers. It also provides 600V RMS of working voltage.

On the non-isolated control-side, the transceiver supports direct connection to a 3V MCU while the isolated bus-side connects to a higher voltage 5V supply for communication of strong bus signals across 100m and longer distances.

The ISL32704E is fully compliant with the EN 50081 and EN 50082-2 electromagnetic compatibility standards and the umbrella line-voltage standard for information technology equipment EN 61000.

Additional features

  • 2.5kV RMS isolation per UL 1577 standard, and 600V RMS working voltage per VDE 0884 standard
  • Single unit load allows up to 32 devices on the bus
  • 50kV/µs (typ), 30kV/µs (min) common-mode transient immunity provides reliable data transmission in noisy environments
  • 15kV ESD bus-pin protection
  • Thermal shutdown protection prevents damage during bus contention
  • Operates in temperatures ranging from -40 to 85°C
  • Meets or exceeds ANSI RS-485 standard
  • VDE V0884-11 certification pending
  • Author
    Peggy Lee