HIGH-SPEED, HIGH-RESOLUTION VOLTAGE OUTPUT DIGITAL-TO ANALOG CONVERTER AND METHOD

摘要

A string DAC (4) having 2M string resistors includes a plurality of switches for selectively coupling, according to the decoding of an M-bit MSB subword, the voltage across a string resistor to an interpolation sub-DAC (8) which interpolates it according to the decoding of an N-bit mid-subword. The voltage across the string resistor is multiplexed, according to the decoding of an N-bit mid-subword, to various inputs of 2N differential transistor pairs of an interpolation amplifier. A P-bit delta sigma modulator (10) produces a delta sigma modulated signal, according to a P-bit LSB subword, to control multiplexing of voltages on the terminals of the string resistor to an input of one of the differential transistor pairs selected by decoding of the N-bit mid-subword to monotonically average a contribution of the selected differential transistor pair to generation of an output voltage (Vout) representing a word including the M-bit, N-bit, and P-bit subwords.