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Intersil Corporation
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Intersil Rolls Out Small, Isolated RS-485 Transceiver for Industrial IoT Networks

MILPITAS, Calif.–Power management and precision analog technology specialist Intersil Corporation (now Renesas Electronics) has introduced what it calls the industry's smallest isolated RS-485 differential bus transceiver. The high-speed ISL32704E is designed to provide 4Mbps bidirectional data transmission for Industrial Internet of Things (IIoT) networks.

The ISL32704E RS-485 transceiver is reported to deliver excellent electromagnetic interference (EMI) and common-mode transient immunity (CMTI) in a small, 4mm x 5mm QSOP package that is 70 percent smaller than competitive devices. It also provides 600VRMS of working voltage, according to the manufacturer.

The ISL32704E RS-485 transceiver exploits giant magnetoresistance (GMR) technology to provide galvanic isolation that keeps the communication bus free from common-mode noise generated in electrically noisy factory and building automation environments. It is well suited for the equipment-to-bus interface in IIoT networks that connect programmable logic controllers (PLCs) to instruments, robots, motor drives, data acquisition, and digital I/O modules.

The advantage of Intersil's ISL32704E GMR isolation over other isolation technologies is its low radiated emission and low EMI susceptibility, Intersil says. In addition, its GMR isolation does not require the elaborate encoding schemes found in capacitive and transformer-based isolators that use RF carriers or pulse-width modulation (PWM) to transfer DC and low frequency signals across the barrier.

According to Renesas Electronics, the ISL32704E offers 80 percent less power consumption than competing devices because it doesn't use current hungry power transfer coils or transformers. Its 20mA supply current allows the ISL32704E to operate in a tiny QSOP package at maximum speed without overheating, the company says.

On the non-isolated control-side, the ISL32704E supports direct connection to a 3V microcontroller, while the isolated bus-side connects to a higher voltage 5V supply for communication of strong bus signals across 100 meters and longer distances. The ISL32704E is fully compliant with the EN 50081 and EN 50082-2 electromagnetic compatibility (EMC) standards and the umbrella line-voltage standard for information technology equipment (ITE) EN 61000.

"Our new ISL32704E isolated RS-485 transceiver generates virtually no radiated EMI, solving one of the biggest problems customers experience with their industrial designs," said Philip Chesley, senior vice president of Precision Products at Intersil, in a company release. "In addition to not requiring any shielding, this transceiver simplifies PCB layout, uses less board space, and enhances data transmission reliability and integrity."