A Bluetooth 5 Transceiver With a Phase-Tracking RX and Its Corresponding Digital Baseband in 40-nm CMOS

Abstract

A 0.8-V Bluetooth 5 (BT5) digitally intensive trans- ceiver with a phase-tracking RX and a digital TX in 40-nm CMOS is presented. For the phase-tracking RX, a hybrid loop filter with a loop-delay compensation is proposed to suppress digi- tally controlled oscillator (DCO) sidelobe energy, enhancing inter- ference resilience. To facilitate the DCO-based phase-tracking RX for the reception of BT5 signals, a corresponding digital baseband is implemented with a carrier frequency offset (CFO) calibration to remove the initial static CFO error during the preamble, while an automatic frequency calibration tackles the frequency drift during the payload. An all-digital phase- locked loop (ADPLL)-based digital frequency-modulation (FM) interface shared between TX and RX provides a precise deviation frequency control, ensuring the quality of signal transmission and reception. In the RX mode, the chip consumes 2.3 mW from a 0.8-V supply, achieving a figure of merit (FoM) of 180 dB with −91-/−94-dBm sensitivity at 2/1 Mb/s. In the TX mode, it consumes 6.1 mW when delivering a maximum 1.8-dBm output power, resulting in 25% TX system efficiency.