Patent ID: 7009549
Filing Date: 2006-03-07
Classification: H03M

Abstract:
1. A multiplying digital-to-analog converter (DAC), comprising: an operational amplifier, having first and second inputs, and having an output driving a signal over an output range between first and second output level voltages responsive to signals received at the first and second inputs; a first sampling capacitor circuit, comprising a first sample capacitor, for receiving an input voltage and storing the input voltage at the first sample capacitor in a first clock phase, the first sampling capacitor circuit having an output coupled to a first input of the operational amplifier; a first feedback switch, connected between the output of the operational amplifier and the first sample capacitor, for connecting the first sample capacitor in a feedback loop in a second clock phase; and a first reference capacitor circuit, comprising: switch circuitry, for receiving a reference voltage that exceeds the first output level voltage by a factor, and for charging the first reference capacitor with the reference voltage in the second clock phase, the first reference capacitor having a capacitance less than a capacitance of the first sample capacitor by the factor.