A low-power compact IEEE 802.15.6 compatible human body communication transceiver with digital sigma-delta IIR mask shaping

Abstract

To enhance the mask rejection below 2 MHz for effective human body communication (HBC), a new mask shaping technique is proposed for the HBC transmitter, where a digital sigma-delta modulated infinite impulse response (IIR) filter provides sufficient rejection with a digital-to-analog converter (DAC) of only 8 bits. A receiver with high input impedance is designed to improve the sensitivity, and a digital calibration technique is employed to eliminate the DC-to-DC offset. The proposed techniques are implemented in 65nm CMOS process, and a sub-mm sized IEEE 802.15.6 compatible HBC transceiver is demonstrated. Measurements show that the transmitter achieves a rejection of −86.5 dBr at 2 MHz with a power consumption of 3.52 mW. Consuming 620 μW, the receiver achieves a sensitivity of −72 dBm at a chip rate of 5.25 Mcps and a bit error rate (BER) less than 10−7.