At this year’s International Solid State Circuits Conference (San Francisco, USA), imec and Renesas Electronics will present a 0.8V lowpower Bluetooth 5 transceiver. The low battery life offers up to 50 per cent improvement, for IoT applications where numerous tiny sensor nodes are embedded in the environment.

Reducing the power consumption and enabling operation at low supply voltage of IoT radio transceivers is key to enable reliable multi-year battery life of the billions of IoT devices, explains imec. The research centre points out that new applications are empowered by reducing power consumption and supply voltage, such as leave-behind sensors or wearables.

Imec, together with Renesas, developed an integrated, energy efficient Bluetooth 5 transceiver which showcases the best RX figure-of-merit (FoM) and the low supply voltage. A low supply voltage of 0.8V is beneficial because it extends battery life by up to 50 per cent, reduces the complexity of the power management unit, and allows the use of a wider range of energy sources such as energy harvesters.

The transceiver consists of a novel phase-tracking RX, a digital TX based on an all-digital PLL (ADPLL) and a PHY-layer digital baseband. A hybrid loop filter enhances interference tolerance, in conjunction with precise frequency control enabled by the ADPLL. The receiver fronted achieves a sensitivity of -95dBm, while consuming only 2.3mW (non-duty-cycled) at 0.8V.  The transceiver chip is implemented in 40nm CMOS, with a core area of only 0.8mm2, including on-chip matching.

Shin Saito, senior director, Industrial Analog & Power Business Division, at Renesas, says: “Renesas believes that by jointly developing with Imec, we can achieve a more innovative system architecture, enabling a further leap for ultra-low power wireless technology and the wireless IoT market.”

These results will be presented at ISSCC2018 on Feb 14, 2018 in session 28: Wireless connectivity at 2.30pm: 28.3 – A 0.8V 0.8mm2 Bluetooth 5/BLE Digital-Intensive Transceiver with a 2.3mW Phase-Tracking RX Utilizing a Hybrid Loop Filter for Interference Resilience in 40nm CMOS, Ding et al. (imec, Holst Centre and Renesas).

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