Patent ID: 11476835

Abstract:
A filter (22A) includes: a series arm circuit (11) that is connected between an input/output terminal (22m) and an input/output terminal (22n); and a parallel arm circuit (12) that is connected between a node (x1), which is on a path that connects the input/output terminal (22m) and the input/output terminal (22n), and ground. The parallel arm circuit (12) includes a parallel arm resonator (22p) and an impedance circuit (13) that is serially connected to the parallel arm resonator (22p). The impedance circuit (13) includes a first impedance element, which is one of an inductor and a capacitor, a second impedance element, which is the other of an inductor and a capacitor, and a switch (22SW) that is serially connected to the second impedance element. A first series circuit (14) comprising of the second impedance element and the switch (22SW) is connected in parallel with the first impedance element.