Five-Level Switched-Capacitance DAC Using Bootstrapped Switches

An apparatus, comprising:

• a charge transfer digital-to-analog converter (DAC), the DAC comprising:
• a differential reference voltage;
• a pair of capacitors;
• a plurality of switches including a shorting switch;
• and
• wherein:
• the plurality of switches are configured to be switched in successive phases to generate a charge transfer through the capacitors to generate an output corresponding to a digital input, wherein the specific switches activated and deactivated in each phase are selected according to the digital input;
• each capacitor of the pair of capacitors is connected to a respective pin for the output;
• the shorting switch is configured to short the pair of capacitors to create a zero-differential charge on a first side of the capacitors;
• and
• the shorting switch is implemented with a bootstrap circuit to maintain a constant common mode voltage of the first side of the capacitors while the shorting switch is activated.