We propose an ultra-low-power (ULP) and low-voltage phase-tracking RX for IoT applications. Several popular standards are defined for IoT, e.g., IEEE802.15.4 and Bluetooth Low Energy (BLE), where they envision massive numbers of interconnected sensors; however, the cost of replacing/recharging batteries can become an impediment to their massive deployment. In this work, aggressively improving the transceiver energy efficiency, lowering the supply, and simultaneously reducing the cost (die area) of the design are our primary goals. Hence, we propose a digitally-controlled oscillator (DCO)-based phase-tracking RX, which efficiently combines frequency downconversion, channel selection, carrier generation and signal demodulation, all of which lead to an ultra-low-power, low-voltage and low-cost RX.