Seeking ease of use, designers are increasingly turning to modules rather than SoCs to build out the Internet of Things, said a Silicon Labs executive overseeing the sector as he launched a new generation of IoT chips.

“We sell both chips and multiple flavors of modules including ones with antennas, and we see more customers adopting modules. It removes [wireless] certification complexity — people can save six months in time-to-market,” said Matt Johnson, who joined Silicon Labs last year as general manager of IoT products.

Modules still represent a minority of the company’s IoT sales, but they are growing faster than the 20% rate of its overall IoT products. “All of our ZWave and a lot of our Zigbee and Bluetooth sales are modules,” Johnson said.

Overall, the IoT market continues to fragment and is not growing as fast as once expected, but it will continue to expand for many years. “We see a multi-decade opportunity. IoT already is 50-60% of our revenue and more than two-thirds of our spending — so it’s a big commitment,” he said.

SiLabs BGM

Pre-certified modules with antennas are becoming increasingly popular (Image: Silicon Labs)

SiLabs supports Bluetooth, Wi-Fi, ZWave and Zigbee as part of a protocol-agnostic philosophy. But it has not yet fielded products for emerging low-power wide-area (LPWA) protocols such as LoRa and NB-IoT or chips optimized for deep learning.

“Machine learning will come to end nodes and we can support inference jobs today, but there are opportunities to be more optimized,” he said, declining to give a timeframe for AI products. As for LPWA, “we can support it today with sub-gigahertz products, but the market is earlier in adoption and growth. If and when it’s appropriate, we will jump in through acquisitions or organic designs,” he added.

SiLabs is now shipping its first Wireless Gecko Series 2 SoCs, the EFR32MG21 for Zigbee, Thread and Bluetooth mesh, and the BG21 for Bluetooth low energy and mesh. Modules made internally at SiLabs will be ready in the fall.

The products target a range of wired systems including gateways, lighting, voice assistants and smart electric meters. They are the first of about six chips on the road map SiLabs shares under NDA with customers with more SoCs in the pipeline.

The Series 2 represents a significant though stepwise redesign for TSMC’s 40-nm process of the original Gecko products made in its 90-nm node. The shrink enabled chips to fit in a 4x4mm QFN package while microcontrollers were upgraded from 39-MHz Arm Cortex-M4 cores to 80MHz M33s.

The new chips double embedded flash to 1,024 kilobytes. They raise output power and receive sensitivity to support about 20% greater range or throughput, and they drive max power down to 50.9 microamps/MHz from 69 microamps/MHz in the Series 1.

The Series 2 chips dedicate a core to security jobs to speed encryption, and they embed a random number generator to better secure keys. They also support a secure boot loader and a secure access-control process for debug.