Switch circuit and a semiconductor integrated circuit device

PROBLEM TO BE SOLVED: To provide a switch circuit capable of transferring large amplitude, large current signal, while suppressing degradation at small amplitude signal transfer.SOLUTION: A switch circuit 100 includes a first terminal a, a second terminal b, a first switch 1, a second switch 2, a first separation switch 3a, and a second separation switch 3b. The first switch 1 connects the first terminal a and the second terminal b according to a control signal. The second switch 2, having a first node n1 and a second node n2, connects between the nodes in synchronizing with the first switch 1. The first separation switch 3a transfers a signal at the first node n1 to the second node n2 if a voltage at the first node n1 is higher than a predetermined voltage relative to the second node n2. The second separation switch 3b transfers a signal at the first node n1 to the second terminal b if a voltage at the first node n1 is higher than a predetermined voltage relative to the second node n2.SELECTED DRAWING: Figure 1