CPC H03M 1/661 (2013.01) | 22 Claims |
1. A digital-to-analog converter (DAC) for converting a digital input word to an analog output signal, the DAC comprising:
a string DAC comprising:
a plurality of series-connected resistors; and
a most significant bit (MSB) switching circuit including pairs of switches, each pair of switches having an upper switch and a lower switch, each upper switch is connected to an upper terminal of one of the plurality of series-connected resistors and each lower switch is connected to a lower terminal of one of the plurality of series-connected resistors, the MSB switching circuit operable to provide a first voltage and a second voltage in response to an MSB control signal;
a first least significant bit (LSB) interpolator coupled to the string DAC and having an output, a plurality of non-inverting inputs and a plurality of inverting inputs coupled to the output, one of the non-inverting inputs coupled to receive the first voltage and the other non-inverting inputs coupled to receive the first or the second voltage, the first LSB interpolator operable to provide a first interpolated voltage at the output in response to a first LSB control signal; and
a second LSB interpolator coupled to the string DAC and the first LSB interpolator, the second LSB interpolator having an output, a plurality of non-inverting inputs and a plurality of inverting inputs coupled to the output, one of the non-inverting inputs coupled to receive the first interpolated voltage and the other non-inverting inputs coupled to receive the first voltage or the second voltage, the second LSB interpolator operable to provide an output voltage at the output in response to a second LSB control signal.
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