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Bench Talk for Design Engineers

Bench Talk


Bench Talk for Design Engineers | The Official Blog of Mouser Electronics

New Tech Tuesdays: onsemi's RSL15 Provides Ultra-Low Power for Today's Wearables Tommy Cummings

New Tech Tuesdays

Join journalist Tommy Cummings for a weekly look at all things interesting, new, and noteworthy for design engineers.

Designed for connected smart devices in industrial and medical applications, the RSL15 from onsemi is an ultra-low power Arm® Cortex M33 processor-based BLUETOOTH® Low Energy 5.2 wireless MCU. The RSL15’s low power consumption has been verified by the Embedded Microprocessor Benchmark Consortium. Regarded as the industry’s leading ultra-low-power MCUs and lowest-power Flash-based Secure Bluetooth Low Energy (BLE) MCU, the devices have achieved a best-in-class score of 60.5 on its ULPMark-CoreMark benchmark in the performance category. The RSL15 supports multiple Sleep modes, including:

  • Sleep mode (GPIO wakeup) @ 3V VBAT: only 36nA
  • Sleep mode (Crystal oscillator, RTC Timer wakeup) @ 3V VBAT: only 81nA

This week’s New Tech Tuesday will spotlight the RSL15, its features, and many applications.

What's In the RSL15?

RSL15 has built-in power management, a wide supply voltage range, flexible General-Purpose Input/Output (GPIO) and clocking scheme, and an extensive set of peripherals. It also includes 80kB RAM and is available in 284kB or 512kB Flash versions with two QSPI-capable Serial Peripheral Interface (SPI) ports. An innovative smart sensing feature allows the Cortex®-M33 processor to remain in a deep sleep mode while continuing to monitor sensor interfaces.

The RSL15 features an angle of arrival/angle of departure localization and extended sensor interfacing. The device also offers a coded PHY for extra long-range capabilities and Firmware Over The Air (FOTA) to support in-field products with new features, bug fixes, and security updates.

The RSL15 also provides a comprehensive mix of security capabilities to protect smart connected devices from multiple types of cyberattacks. The device includes Arm TrustZone® technology, which provides trusted execution environments for at-risk peripherals and functions. The RSL15 also features Arm CryptoCell-312 technology to provide roots-of-trust and additional security mechanisms.

RSL15 Applications

The RSL15 is ideal for industrial automation and sensing, connected medical sensors, wearables, asset tracking, electronic tags, and access control.

Medical Wearables

In medical wearable designs where low power is required, the RSL15 has proven valuable. Consider the case of hearing aids. Historically hearing aids have been large and obtrusive devices, often unreliable, expensive, and required the user to replace the batteries often. However, advances in digital signal processing and BLE have enabled hearing aids to be miniaturized and designed to integrate seamlessly into modern IoT ecosystems. This offers their users a wide range of benefits and excellent audio quality.

The RSL15 has numerous other medical uses, including drug-injection pens, blood glucose meters, wearable bracelets, blood analyzers, virus detectors, smart toothbrushes, heart-rate monitors, sleep monitors, e-stethoscopes, and more.

Smart Buildings

The RSL15 can be used in smart building applications, including electronic access badges, vending machines, HVAC systems, and air-filter systems.

Industrial Automation

Smart industry applications include electronic tags, power tools, shopping cart trackers, electronic labels, data loggers, helmets, food tracking sensors, and more.

Smart Home

In smart home applications, the RSL15 devices can be found in smart circuit breakers, thermometers, light switches, meters, and refrigerators. They also can power coffee makers, air purifiers, garage door controls, and sprinkler control systems.

Smart City

With smart city applications, the devices power people and asset tracking, door access controls, fleet management systems, outdoor and educational robots, bioprocessing equipment, and more.

What About the Dev Board?

The RSL15's Evaluation and Development Board is designed to be used with the RSL15 Software Development Kit (SDK). The RSL15-EVB evaluates the performance and capabilities of RSL15 MCUs. The board is also intended for developing, demonstrating, and debugging software applications for the RSL15.

Tuesday's Takeaway

As semiconductor processes evolve, they deliver small-form integrated devices with lower power dissipation, which are important contributors to expanding the potential applications for wearable technology where size and weight matter. This gives engineers greater design freedom with access to more integrated devices.

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Tommy Cummings is a freelance writer/editor based in Texas. He's had a journalism career that has spanned more than 40 years. He contributes to Texas Monthly and Oklahoma Today magazines. He's also worked at The Dallas Morning News, Fort Worth Star-Telegram, San Francisco Chronicle, and others. Tommy covered the dot-com boom in Silicon Valley and has been a digital content and audience engagement editor at news outlets. Tommy worked at Mouser Electronics from 2018 to 2021 as a technical content and product content specialist.

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