Designed for RS485 communication isolation applications, the SP301H/L series offers significant improvements in data transmission speed, power consumption, electromagnetic immunity, and package size.
Compared to the previous generation SP301A and NIRS31 series products, the SP301H/L series supports communication speeds up to 8 Mbps, features a low quiescent current design, and offers improved electromagnetic immunity performance. Housed in a compact, wide-body SSOW10 package with fine-pitch terminals, the device achieves greater integration while significantly reducing the printed circuit board size, providing customers with a high-performance, highly reliable, and cost-effective isolation solution.
RS485 communication is widely used in power metering terminals, industrial automation systems, and renewable energy storage applications due to its long transmission distance, high noise immunity, and flexible ability to create multi-node networks. In these applications, isolation devices play a critical role in ensuring communication reliability and system safety. Conventional RS485 isolation solutions based on three optocouplers suffer from limitations such as a high component count, restricted bandwidth, performance drift related to aging, and a large PCB footprint, making them increasingly less capable of meeting the demands of high-speed communication, long lifespan, and compact system design. As system performance requirements continue to rise, digital isolation is becoming the preferred approach for next-generation RS485 isolation solutions.
Traditional isolated RS485 communication solutions typically require three optocouplers, along with multiple external resistors and capacitors, resulting in a complex bill of materials (BOM), higher acquisition and inventory management costs, and increased PCB space requirements. By integrating three isolation channels into a single device, the SP301H/L directly replaces the discrete optocouplers and their supporting circuitry, significantly simplifying the BOM, reducing component count and routing complexity, and improving overall system integration.
The SP301H/L adopts a compact, wide-body SSOW10 package, reducing the printed circuit board size by more than 60% compared to conventional optocoupler-based solutions and freeing up valuable board space for system designers.
In terms of performance, the SP301H/L supports transmission speeds of up to 8 Mbps on the data channel and up to 1 Mbps on the enable control channel, effectively overcoming the bandwidth limitations of traditional optocouplers. This enables the high-speed, low-latency communication required by applications such as smart electric meters and industrial fieldbus networks. To accommodate different system architectures, the SP301H features a high-by-default enable pin, while the SP301L features a low-by-default enable pin, providing greater flexibility for implementing MCU enable logic.
The device also features a low quiescent current design, making it suitable for battery-powered equipment and field instruments with stringent power consumption requirements. With an operating ambient temperature range of –40 °C to +125 °C, the SP301H/L models fully meet the requirements of industrial-grade applications. Combining high integration, a compact package, high performance, and simplified external circuitry, the SP301H/L models enable a smooth migration from optocoupler-based solutions while meeting the growing demand for miniaturization, lightweight design, and high reliability in smart metering and industrial systems.
Smart electricity meters are often installed in complex electromagnetic environments, where communication links must withstand power grid voltage spikes, switching noise, and interference from long-distance cabling. Thanks to an optimized isolation architecture and improved immunity design, the SP301H/L significantly enhances the electromagnetic susceptibility (EMS) performance of RS485 communication links, reducing bit error rates and communication interruptions while ensuring stable and reliable data transmission.
Compared to the previous generation SP301A and NIRS31 series, the SP301H/L offers substantial improvements in electromagnetic robustness:
Electrical Overload Tolerance (EOS) has been improved by approximately 10%, with latch-up immunity exceeding 10 V. This significantly enhances the power supply's resistance to overload conditions, reducing the risk of damage from abnormal voltage fluctuations and extending the overall system lifespan.
Excellent power supply noise immunity allows the device to maintain normal operation and error-free communication even under high-frequency, high-amplitude system noise interference in the MHz range, improving reliability in harsh electromagnetic environments.
Common-mode transient immunity (CMTI) achieves a typical value of 200 kV/µs, effectively suppressing common-mode transient disturbances and ensuring accurate and stable signal transmission.
Furthermore, the SP301H/L is based on NOVOSENSE's industry-leading third-generation capacitive isolation technology, delivering exceptional insulation performance. The device supports an insulation voltage of up to 5 kVrms (1 minute) and a surge voltage capacity exceeding 10 kV, thus meeting reinforced insulation requirements.
