A 0.7-V Sub-mW Type-II Phase-Tracking Bluetooth Low Energy Receiver in 28-nm CMOS

We present an architecture of a Bluetooth low energy (BLE)-compliant receiver which, for the first time ever, breaks the 1mW barrier of power consumption. It is based on a type-II phase-tracking loop and addresses the mutual magnetic coupling between on-chip inductors of a digitally controller oscillator (DCO) and low-noise transconductance amplifier (LNTA), which causes RX performance degradation in the prior-art implementations. An inverter-based inductor-free LNTA is employed instead. The resulting adjacent channel rejection (ACR) improves by 1.5/2.5dB at 2/3MHz offset. By further leveraging current-reuse and switched-capacitor circuitry, this RX achieves the best-in-class FoM of 183.2dB with sensitivity of −93.2dBm. Thanks to the single-channel topology, the proposed RX occupies tiny area of 0.48mm2 in 28-nm CMOS.