Patent ID: 7746260

Claim:
A multiplying digital-to-analog converter (MDAC), comprising: an operational amplifier (OP-amp), operated under a first power supply voltage and a second power supply voltage, wherein the first power supply voltage is higher than the second power supply voltage; an OP-amp input switch block, coupled to a common mode voltage, for selectively coupling the common mode voltage to input nodes of the OP-amp, wherein all switches included in the OP-amp input switch block are implemented utilizing PMOS transistors only, and a first voltage difference between the first power supply voltage and the common mode voltage is smaller than a second voltage difference between the common mode voltage and the second power supply voltage; a capacitor block, coupled to the OP-amp input switch block, for sampling charges corresponding to an input signal or sampling charges corresponding to a reference signal; a sampling switch block, coupled to the input signal, for selectively coupling the input signal to the capacitor block; a reference voltage switch block, coupled to the capacitor block, for selectively coupling the reference signal to the capacitor block; and a feedback switch block, coupled between the capacitor block and output nodes of the OP-amp, for selectively coupling the output nodes of the OP-amp to the capacitor block.