To solve a problem of a conventional differential latch that an unstable operation begins when an input amplitude gets smaller due to the effect of a high speed operation or the like.

A plurality of threshold values of longitudinally stacked transistors (M1. M3) in the differential latch are used to decrease more a gate-source voltage of the stage (M1) closer to a positive power supply VDD in the longitudinally stacked transistor group and to bring the operation of the transistor (M3) remoter from the positive power supply closer to a saturation region from a linear region thereby extending a range of the input amplitude whereat the transistors can execute switching operations toward a lower amplitude and preventing increase in a consumed current.