A 1.9nJ/b 2.4GHz multistandard (Bluetooth Low Energy/Zigbee/IEEE802.15.6) transceiver for personal/body-area networks

TLDR

Short‑range radios for Zigbee and BT‑LE typically consume over 20 mW, which is too high for battery‑powered autonomous systems. The authors aim to deliver a multistandard ultra‑low‑power 2.36/2.4 GHz transceiver for PAN/BAN that incorporates an energy‑efficient architecture and advanced RF techniques. They implement a sliding‑IF receiver, polar transmitter, push‑pull mixer, and digitally‑assisted PA with a carefully chosen LO frequency plan to meet BT‑LE, Zigbee, and MBAN standards, including a proprietary 2 Mb/s mode for data‑streaming. The resulting device consumes only 3.8 mW (RX) and 4.6 mW (TX) from a 1.2 V supply while satisfying all PHY requirements of the three standards.

Abstract

This paper presents a multistandard ultra-low-power (ULP) 2.36/2.4GHz transceiver for personal and body-area networks (PAN/BAN). The presented radio complies with 3 short-range standards: Bluetooth Low Energy (BT-LE), IEEE802.15.4 (ZigBee) and IEEE802.15.6 (Medical Body-Area Networks, MBAN). A proprietary 2Mb/s mode is also implemented to support data-streaming applications like hearing aids. Current short-range radios for Zigbee and BT-LE typically consume more than 20mW DC power, which is rather high for autonomous systems with limited battery energy. The dual-mode MBAN/BT-LE transceiver achieves a power consumption of 6.5mW for the RX and 5.9mW for the TX by employing a sliding-IF RX and a polar TX architecture. However, it suffers from limited RX image rejection and needs a PA operating at a higher supply voltage. In this paper, an energy-efficient radio architecture with a suitable LO frequency plan is selected, and several efficiency-enhancement techniques for the critical RF circuits (e.g., a push-pull mixer and a digitally-assisted PA) are utilized. As a result, the presented transceiver dissipates only 3.8mW (RX) and 4.6mW (TX) DC power from a 1.2V supply, while exceeding all of the PHY requirements of above 3 standards.