# US 2017/0288630 A1 · Low-pass filter

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- Number: US 2017/0288630 A1
- Document ID: US20170288630A1
- Status: Published application
- Kind: A1
- Application number: 15/472,588
- Filed: 2017-03-29
- Published: 2017-10-05
- Earliest claimed: 2016-03-30
- Assignees: Taiyo Yuden Co., Ltd.
- Applicants: Taiyo Yuden Co., Ltd.
- Inventors: Hirotaka TAKEUCHI
- Web page: https://patentgrep.com/patent/US20170288630A1

## CPC

- H03H 7/0115: {comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence)}
- H03H 7/1758: {Series LC in shunt or branch path (H03H7/1791 takes precedence)}
- H03H 7/1766: {Parallel LC in series path (H03H7/1783 takes precedence)}
- H03H 2001/0085: {Multilayer, e.g. LTCC, HTCC, green sheets}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

In one aspect, the present disclosure provides a surface-mounted low-pass filter, including: a mounting surface having an input terminal electrode, an output terminal electrode, and a ground terminal electrode; a parallel resonant circuit between the input terminal electrode and the output terminal electrode; and a series resonant circuit between one end of the parallel resonant circuit and the ground terminal electrode, wherein the series resonant circuit has a first capacitor and a first inductor, and wherein, when the low-pass filter is viewed from above in a direction perpendicular to the mounting surface with the mounting surface on the bottom, the first inductor of the series resonant circuit is above the first capacitor.

## Claims

### Claim 1

A surface-mounted low-pass filter, comprising:
a mounting surface having an input terminal electrode, an output terminal electrode, and a ground terminal electrode;
a parallel resonant circuit between the input terminal electrode and the output terminal electrode; and
a series resonant circuit between one end of the parallel resonant circuit and the ground terminal electrode,
wherein the series resonant circuit has a first capacitor and a first inductor, and
wherein, when the low-pass filter is viewed from above in a direction perpendicular to the mounting surface with the mounting surface on the bottom, the first inductor of the series resonant circuit is above the first capacitor.

### Claim 2 (depends on 1)

The low-pass filter according to claim 1,
wherein the parallel resonant circuit has a second capacitor and a second inductor, and
wherein, when the low-pass filter is viewed from above in the direction perpendicular to the mounting surface, the first inductor of the series resonant circuit does not overlap the second inductor of the parallel resonant circuit.

### Claim 3 (depends on 1)

The low-pass filter according to claim 1, wherein two or more of the parallel resonant circuit are provided and connected in series between the input terminal electrode and the output terminal electrode, and the series resonant circuit is provided between the ground terminal electrode and a connection node at which two of said two or more parallel resonant circuits connect in series.

### Claim 4 (depends on 3)

The low-pass filter according to claim 3,
wherein the two or more parallel resonant circuits each have a capacitor and an inductor, and
wherein, when the low-pass filter is viewed from above in the direction perpendicular to the mounting surface, the first inductor of the series resonant circuit does not overlap any of the inductors of the parallel resonant circuits.

### Claim 5 (depends on 1)

The low-pass filter according to claim 1, wherein, when the low-pass filter is viewed from above in the direction perpendicular to the mounting surface, the first inductor does not overlap the input terminal electrode or the output terminal electrode.

### Claim 6 (depends on 1)

The low-pass filter according to claim 1, wherein N number of said parallel resonant circuit is provided and connected in series between the input terminal electrode and the output terminal electrode, and 1 to (N+1) number of said series resonant circuit is provided and each connected between said ground terminal or a separate ground terminal and one end of one of the (N+1) series resonance circuits, where N is an integer greater than or equal to 1.