A receiver IC provided with a SAW-based oscillator with an external SAW device. The receiver IC comprises an oscillating circuit. The oscillating circuit comprises an inverter stage, a first capacitor, a second capacitor, and a resistor. The inverter stage has input and output terminals respectively coupled to two ends of the external SAW device. The first and second capacitors are respectively coupled between the input/output terminal and a ground. The resistor is coupled between the input and output terminals of the inverter stage.