Swiss firm ST Microelectronics’ ST8500 and S2-LP chipset has become the first to be certified according to the G3-PLC Hybrid communication standard that defines seamless connectivity over powerline and wireless media.

The G3-PLC Hybrid specification allows smart-grid and other IoT applications to select the best available wireless or powerline channel at any time, automatically and dynamically, according to network conditions. This enables better coverage, reliability and scalability, while allowing cost-efficient system operation and enabling new use cases.

STM demonstrated the chipset at a G3-PLC Alliance interoperability plugfest in 2020. The chipset has now completed the latest G3-PLC certification scheme, published in March 2021, which incorporates the Hybrid profile tests.

The certified chipset combines the ST8500 programmable multi-protocol powerline communication system-on-chip (SoC) and STLD1 line driver with the company’s S2-LP low-power sub-GHz radio transceiver. The SoC’s programmability enables a software-defined implementation capable of supporting a broad portfolio of powerline protocol stacks, in worldwide frequency bands such as from Cenelec and FCC.

The ST8500 powerline communication SoC is widely used in smart metering, smart industrial and infrastructure applications. The Hybrid turn-key offering has already been chosen by stakeholders in the smart-grid market. Moreover, STM’s hardware and firmware have been selected to power the official G3-PLC Alliance RF certification-testing equipment.

The SoC is packaged as a 7 by 7 by 1mm QFN56. The STLD1 and S2-LP are each packaged as 4 by 4 by 1mm QFN24. All devices are in full production.

Based on 6LowPan and IPv6 and combining RF connectivity with the native G3-PLC protocol stack, the ST8500 SoC consumes less than 100mW in receive mode, ensuring low-power performance in line with the latest specifications to reduce the grid load imposed by new smart meters.

It contains a DSP for real-time protocol processing and an Arm Cortex-M4F core for upper-layer processing and system management. Both the DSP and Arm core have their own code and data SRAM on-chip, while peripherals including a 128 and 256bit AES cryptographic engine are integrated to meet the needs of smart-energy applications.

The analogue front end (AFE) for connecting to the STLD1 line driver is also integrated. The STLD1 is said to communicate reliably, even across noisy power cables and with low impedance, with high drive capability and high linearity.

The S2-LP is a low-power RF transceiver for RF wireless applications in the sub-1GHz band. It is designed to operate in both the licence-free ISM and SRD frequency bands at 433, 512, 868 and 920MHz, and can be programmed to operate at additional frequencies in the 413-479, 452-527, 826-958 and 904-1055MHz bands. The transceiver allows an RF-link budget greater than 140dB for long communication ranges and meets radio-equipment regulations in territories worldwide including Europe, North America, China and Japan.

STM provides companion integrated balun and filter chips for the S2-LP that simplify antenna-connection circuitry and save PCB area in space-constrained applications.