High speed and high accuracy A/D converter

摘要

An analog-to-digital converter comprises the following elements. A reference voltage generation circuit (1) is provided for dividing a reference voltage into a plurality of divided reference voltages having voltage levels different from each other. A plurality of comparators (C0, C1, C2) are provided, each of which has a first input terminal connected to an analog input line for fetching analog signals and a second input terminal connected to the reference voltage generation circuit (1) for fetching a corresponding one of the divided reference voltages so as to compare the analog signals with the divided reference voltage. Each of the comparators (C0, C1, C2) has an output terminal through which an output digital signal is outputted. The comparators (C0, C1, C2) are connected to any one of a plurality of pairs of different power supply lines and different ground lines, characterized in that the different power supply lines are separated from each other as well as the different ground lines are separated from each other so that no interference between the different power supply lines and between the different ground lines appears through any noise generated on any of the comparators (C0, C1, C2). A decoder circuit (2) is connected to the output terminals of the comparators (C0, C1, C2) for fetching the compared digital signals and decoding the compared digital signals.