A Sub-100-μW 0.1-to-27-Mb/s Pulse-Based Digital Transmitter for the Human Intranet in 28-nm FD-SOI CMOS

Abstract

Human body communications require energy-efficient transceivers to connect diverse devices on the human body for wellness and medical applications. This article presents a fully digital pulse-based transmitter (TX) for capacitive body-coupled communications (c-BCCs) in 28-nm Fully Depleted Silicon on Insulator (FD-SOI) CMOS. The TX is operating at 450 MHz where surface-wave (SW) propagation is the dominant mechanism of c-BCC, offering a larger bandwidth with a more stable channel. The heavily duty-cycled TX uses a 90-MHz free-running oscillator and edge combiners to generate OOK Gaussian-shaped pulses through a switched-capacitor power amplifier (PA). Wide range forward body biasing (FBB), specific to FD-SOI technology, allows frequency tuning and adaptive efficiency optimization as a function of data rate. The proposed TX consumes 17–76 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> for flexible data rates from 0.1 to 27 Mb/s (170 down to 2.8 pJ/b) with up to 14% system efficiency under 0.5-V supply voltage.