Patent ID: 7215159

Claim:
A differential amplifier comprising: a pair of comparators differentially connected to each other, wherein: each of the comparators comprises: a sampling capacitor; a first switching unit connected to an input end of said sampling capacitor, said first switching unit applying an input signal to the input end of said sampling capacitor; a second switching unit connected to the input end of said sampling capacitor, said second switching unit applying a reference signal to the input end of said sampling capacitor; an output transistor directly connected to an output end of said sampling capacitor in a source follower connection manner or an emitter follower connection manner; and a third switching unit connected to an output end of said sampling capacitor, said third switching unit maintaining a voltage at the output end of said sampling capacitor to be constant; and the input signal is compared with the reference signal; and the comparators include input-impedance lowering means provided between the output ends of the sampling capacitors of the comparators, wherein said first switching unit, said second switching unit, and said third switching unit comprise transistors, and said third switching unit is larger in cell size than each of said first switching unit and said second switching unit.