A/D Converter

An analog to digital converter comprising:

• a reference circuit adapted to generate reference voltages;
• differential amplifiers;
• normal phase circuits each of which samples a normal phase analog input signal and transfers a comparison voltage, obtained by comparison with a reference voltage generated by the reference circuit, to a first input terminal of one of the differential amplifiers when the input is differential and single-ended;
• and
• reversed phase circuits each of which samples a reversed phase analog input signal and transfers a comparison voltage, obtained by comparison with a reference voltage generated by the reference circuit, to a second input terminal of one of the differential amplifiers when the input is differential and which samples a ground level as a reference voltage of the reference circuit and supplies the reference voltage and comparison voltage to the second input terminal of the differential amplifier when the input is single-ended, wherein
• the reference circuit includes normal and reversed phase resistor ladders, each made up of a plurality of resistors,
• when the input is differential, the normal and reversed phase resistor ladders are connected in series between high and low potential power sources, and
• when the input is single-ended, the normal phase resistor ladder is connected in series between the high and low potential power sources, and the reversed phase resistor ladder has its ends connected to ground.