A 50 Mb/s Full HBC TRX with Adaptive DFE and Variable-Interval 3x Oversampling CDR in 28nm CMOS Technology for A 75 cm Body Channel Moving at 0.75 Cycle/sec

This paper reports a 50 Mb/s full human body communication (HBC) transceiver (TRX) that communicates through a 75 cm body channel moving at speed of 0.75 cycle/sec. For the first time, adaptive decision feedback equalization (DFE) and a clock and data recovery (CDR) were integrated in a HBC TRX to adapt to a moving body channel in real time. In the proposed design, the transmitter (TX) consists of inverter-based driver that transmits non-return-to-zero (NRZ) signal to human body. The receiver (RX) utilized a 10-tap adaptive DFE to compensate for time-varying inter symbol interferences (ISIs) of moving body channel. Also, for clock synchronization, variable-interval 3x oversampling CDR (VI-3x-CDR) was adopted to overcome wide and asymmetric data-dependent jitter (DDJ). A test chip was fabricated in 28 nm CMOS technology. Compared with the prior arts that were measured with moving body channel, the data rate and the area were improved by 10x and 3x, respectively.