Patent ID: 8436697
Filing Date: 2013-05-07
Classification: H03H

Abstract:
1. A surface acoustic wave filter device comprising: a wiring board including a die-attach surface; and a surface acoustic wave filter chip flip-chip mounted on the die-attach surface of the wiring board; wherein the surface acoustic wave filter chip includes a piezoelectric substrate and a ladder surface acoustic wave filter unit located on the piezoelectric substrate; the ladder surface acoustic wave filter unit includes an input pad, an output pad, a series arm connecting the input pad and the output pad, and a plurality of resonators including at least one first resonator connected to the input pad or the output pad; the die-attach surface of the wiring board is provided with an inductor connected to the first resonator; the inductor is arranged such that at least a portion thereof faces the first resonator but does not face any of the plurality of resonators other than the first resonator; the wiring board includes an input terminal connected to the input pad and an output terminal connected to the output pad; the plurality of resonators include a plurality of series arm resonators connected in series in the series arm and at least one parallel arm resonator connected between the series arm and a ground potential; the first resonator is one of the plurality of series arm resonators; and the inductor is connected between the first resonator and the input terminal or between the first resonator and the output terminal.