A Type-II Phase-Tracking Receiver

We present a new analog-to-digital converter (ADC)-based architecture of a phase-tracking receiver (PT-RX) optimized for ultra-low-power (ULP) and ultra-low-voltage (ULV) operations for the Internet of Things (IoT). The RX employs a type-II loop configuration that offers improved stability compared with the previous type-I PT-RX solutions. In addition, the type-II loop is also very tolerant of long run-lengths of consecutive “1” or “0” symbol sequences. Fabricated in 28-nm CMOS, the prototype PT-RX targets Bluetooth low energy (BLE) standard consuming only 1.5 mW at a supply of ≤0.7 V. It maintains an adjacent-channel rejection (ACR) of ≥−11/3.5/17/27 dB at 0/±1/±2/±3 MHz offset and can tolerate out-of-band (OOB) blockers of minimum −21 dBm across 1.0–3.5 GHz while also offering a best-in-class figure of merit (FoM) of 181 dB, with a 1-Mb/s BLE sensitivity of −93 dBm.