Analog-to-digital converter including differential pair circuit

An analog-to-digital converter, comprising:

• a voltage generating unit configured to divide an externally applied reference voltage by a plurality of resistors to generate a plurality of comparative voltages;
• and
• a plurality of comparators each configured to compare any one of the plurality of comparative voltages with an analog input voltage and output a digital signal based on a result of a comparison between the comparative voltage and the analog input voltage,
• wherein each of the plurality of comparators includes a differential pair circuit configured to detect a potential difference between two inputs of the comparative voltage and the analog input voltage,
• the differential pair circuit includes a first circuit portion and a second circuit portion,
• the first circuit portion includes:
• a first input transistor having a gate to which one input is supplied;
• and
• a resistor which is connected in series with the first input transistor,
• the second circuit portion includes:
• a second input transistor that has a gate to which the other input is supplied and forms a differential pair with the first input transistor;
• and
• a variable resistor which is connected in series with the second input transistor, and
• the variable resistor includes a plurality of variable resistive elements which are connected in series, and each of the variable resistive elements has a resistance value variably set according to a control signal.