Japanese semiconductor company Renesas Electronics has added Bluetooth 5.0 to its low-power RE family for battery-operated maintenance-free IoT devices.

This means the RE01B MCU can simplify software updates and data transfers for IoT devices powered by energy harvesting.

Developed using the firm’s SOTB silicon-on-thin-buried oxide process technology, the MCU is for energy harvesting systems and intelligent IoT devices that need to operate constantly at extremely low power levels without the need to replace or recharge batteries.

It makes it easier to implement regular data management and firmware updates over Bluetooth while maintaining low power consumption, and extending the battery life.

Applications include compact healthcare devices such as pulse oximeters and biomedical sensor patches, remote controls with voice recognition capabilities, and smart meter modules. In addition, the RE01B suits IoT devices that require constant operation, period data collection and updates, such as devices for monitoring the elderly, children or assets in transit.

“Managing battery maintenance and replacement is one crucial hurdle ahead of the widespread adoption of ultra-low-power IoT devices that are expected to run for long periods with limited or no maintenance,” said Shigeki Kato, vice president at Renesas. “I am excited that the addition of the new Bluetooth-capable RE MCU will remove the needs for battery maintenance in a broader range of systems, and meet the needs of IoT system manufacturers.”

Built around the ArmCortex-M0+ core, the RE01B operates at a maximum frequency of 64MHz and achieves current consumption down to 35µA/MHz during operation and 600nA during standby. In addition, it can be combined with Renesas’ ISL9123 ultra-low Iq DC-DC converter, configured as an external step-down regulator, to reduce current consumption during operation down to 15µA/MHz.

It supports Bluetooth 5.0 up to 400m and data throughput of 2Mbit/s. Peak current is 3.0mA at 1Mbit/s during Bluetooth reception and 4.3mA during transmission.

The 1.5Mbyte flash memory and 256kbyte SRAM with Bluetooth functionality is suitable for over-the-air (OTA) firmware updating.

Operating voltage is 1.62 to 3.6V with operation up to 64MHz. It comes in a 64-pin QFN package measuring 8 by 8mm.

The on-chip energy harvesting control circuit – rapid start-up capacitor charging and secondary battery charge protection functionality – allows users to achieve battery-less Bluetooth communication. Energy harvesting and power storage can be directly connected to the RE01B.

The on-chip 14bit A-D converter has power consumption of approximately 4µA. It can programme flash memory with a current of approximately 0.6mA. Security functions use trusted secure IP.

Available APIs conform to standard protocols, such as heart rate profile, environment sensing profile and automation IO profile, in addition to the Bluetooth 5.0 protocol stack.

Renesas provides development tools for the RE family, including a QE for BLE, which generates programmes for custom Bluetooth profiles that can then be integrated into the user’s application programmes, and a Bluetooth test tool suite, which provides an interface that allows users to perform initial wireless characteristics evaluations and Bluetooth functionality verification.

The RE01B will be combined with Renesas’ complementary analogue and power offerings for applications such as reference designs using the RE family including wearable devices with the RE01 32bit MCU and the low-power GNSS tracking of persons, animals or assets.