| 摘要 |
An analog-to-digital converter of the successive-approximation type including a digital-to-analog converter (DAC) comprising a plurality of independently-switchable current sources producing identical currents and connected to respective junction points of an R-2R ladder network. The common ladder terminal is driven by an operational amplifier so that the potential of the common terminal tracks that of the ladder output terminal. The ladder common terminal is connected to a comparator together with a sense ground lead. The output of the comparator is directed to bit sequencer circuitry which controls the switching of the DAC current sources to effect a match between the analog input current and the ladder output current.
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