30.7 A 60Mb/s wideband BCC transceiver with 150pJ/b RX and 31pJ/b TX for emerging wearable applications

Wearable technology is opening the door to future wellness and mobile experience. Following the first generation wearable devices in the form of headsets, shoes and fitness monitors, second generation devices such as smart glasses and watches are making an entrance to the market with a great potential to eventually replace the current mobile device platform eventually (Fig. 30.7.1). Wearable devices can be carried by users in a most natural way and provide all-round connectivity 24-7 without the hassle of stopping all other activities, which enables a totally different mobile experience. For wearable devices, body channel communication (BCC) is an excellent alternative of conventional wireless communication through the air, to obviate the need of high-power transceivers and bulky antennas. However, present BCC transceivers [1]-[5] that mainly target biomedical and sensing applications offer rather limited data rates up to 10Mb/s, which is insufficient in transferring multimedia data for emerging wearable smart devices and content-rich information for high-end medical devices (e.g. multi-channel neural recording microsystems). In this paper, a highly energy-efficient and robust wideband BCC transceiver is presented, which achieves a maximum data rate of 60Mb/s by employing 1) a high input impedance and an equalizer at the RX front-end, 2) transient-detection RX architecture using differentiator-integrator combination coupled with injection-locking-based clock recovery, and 3) 3-level direct digital Walsh-coded signaling at the TX.