US 12,349,266 B2
Externally grounded printed circuit board
Joshua Watson, Aurora, IL (US); and Adam Ariffin, Itasca, IL (US)
Assigned to Knowles Electronics, LLC, Itasca, IL (US)
Filed by Knowles Electronics, LLC, Itasca, IL (US)
Filed on Dec. 18, 2020, as Appl. No. 17/126,733.
Claims priority of provisional application 62/955,385, filed on Dec. 30, 2019.
Prior Publication US 2021/0204394 A1, Jul. 1, 2021
Int. Cl. H05K 1/02 (2006.01); B81B 7/00 (2006.01); B81C 1/00 (2006.01); H05K 1/18 (2006.01); H05K 3/40 (2006.01)
CPC H05K 1/0215 (2013.01) [B81B 7/0006 (2013.01); B81C 1/00095 (2013.01); H05K 1/181 (2013.01); H05K 3/403 (2013.01); B81B 2201/0257 (2013.01); H05K 2201/10083 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A MEMS microphone assembly comprising:
a housing having a sound port and a surface-mountable external-device electrical interface;
a MEMS transducer disposed in the housing and configured to generate an electrical signal in response to detecting sound entering the sound port; and
an integrated circuit disposed in the housing, the integrated circuit coupled to the MEMS transducer and to contacts of the external-device electrical interface,
the housing comprising a printed circuit board (PCB) having a conductor electrically connecting a ground plane to an external ground, the conductor extending vertically from a top layer of the PCB to a bottom layer of the PCB and horizontally along a length of at least one edge of the PCB,
wherein an area of the PCB is underneath the MEMS transducer, and
wherein the conductor provides a low-impedance path that is away from the area of the PCB underneath the MEMS transducer, where the low-impedance path is for radio frequency currents to the ground plane,
wherein the PCB includes a single via electrically connected to a secondary ground for connection to the integrated circuit,
wherein the ground plane and the secondary ground are electrically isolated, and
wherein the MEMS transducer comprises:
a substrate comprising an aperture aligned at least partially with the sound port;
an electro-acoustic transduction element located at least partially over the aperture and coupled to the substrate; and
electrical contacts coupled to the transduction element,
wherein the transduction element comprises a back plate and a diaphragm comprising layers of piezoelectric material located at least partially over the aperture of the substrate.