A pipelined analog-to-digital converter includes at least one multiplying digital-to-analog converter and at least one sub-ADC. The multiplying digital-to-analog converter includes at least one first capacitor, at least one second capacitor, an amplifier, and a plurality of switches. The amplifier is coupled to the first and the second capacitors. The switches control a connection between the first and the second capacitors according to a first control signal, a second control signal and a digital signal. In a first period, the first capacitor is connected to the second capacitor in parallel. In a second period, the first capacitor is connected to the second capacitor in series. At least one switch among the switches is composed of a transistor. The sub-ADC provides a digital signal according to the first and second control signals.