An energy efficient fully integrated OOK transceiver SoC for wireless body area networks

Abstract

This work presents a low-power high-speed system-on-chip (SoC) for wireless body area networks (WBANs). The SoC is fully integrated with a 10 Mb/s on-off keying (OOK) RF transceiver, digital processing units, an 8051 micro-controlled unit (MCU), a successive approximation (SAR) ADC, and etc. The receiver adopts envelop detector (ED) based structure to improve the energy efficiency. Conventional ED based structure has a poor sensitivity when reaching a bit rate of Mb/s level. To resolve the problem, we design a receiving (Rx) front-end with 77 dB gain at 10 Mb/s data rate, and propose a novel supply isolation scheme to avoid the instability induced by such a high gain. The transmitter is based on a 2 GHz digitally controlled oscillator (DCO), which uses bond wires as inductors to further reduce the power at transmitting (Tx) mode. The digital baseband is designed by a near-threshold design (NTD) method for low power consumption. The chip is implemented with 0.13 μm CMOS technology, measured results show that the receiver consumes 0.214 nJ/bit at -65 dBm sensitivity, and the Tx energy efficiency is 0.285 nJ/bit at an output power of -5.4 dBm. In addition, the digital baseband consumes 34.8 pJ/bit with its supply voltage lowered to 0.55 V, indicating its energy per bit is reduced to nearly 1/4 of the super-threshold operation.