Patent ID: 8575969

Claim:
A semiconductor device comprising: differential pair transistors; and a tail current source configured to supply switchable tail current so that an amount of current flowing in the differential pair transistors takes at least first current value and second current value smaller than the first current value, wherein the differential pair transistors have each a characteristic that, with a decrease of the current flowing in the differential pair transistor, a value of σ(ΔI/gm) decreases monotonously, where σ denotes a standard deviation, ΔI denotes a difference of the amounts of current of the differential pair transistors, and gm denotes transconductance of the differential pair transistors, and wherein the differential pair transistors are configured to operate in a strong inverse region with the tail current having the first current value, and are configured to operate in a moderate inversion region or a weak inversion region with the tail current having the second current value.