Pre-Production

WM7211

w

PP, Rev 3.1, January 2014

9

APPLICATIONS INFORMATION

RECOMMENDED EXTERNAL COMPONENTS

It is recommended to connect a 0.1µF decoupling capacitor between the VDD and GND pins of the

WM7211. A ceramic 0.1µF capacitor with X7R dielectric or better is suitable. The capacitor should be

placed as close to the WM7211 as possible.

OPTIMISED SYSTEM RF DESIGN

For optimised RF design please refer to document WAN0278 (Recommended PCB Layout for

Microphone RF Immunity in Mobile Cell Phone Applications) for further information.

.

CONNECTION TO A WOLFSON AUDIO CODEC

Wolfson provides a range of audio CODECs incorporating a digital microphone input interface; these

support direct connection to digital microphones such as the WM7211.

Stereo connection of two WM7211 digital microphones to the WM8280 CODEC is illustrated in Figure

2.

A 0.1µF decoupling capacitor is recommended; this should be positioned close to the VDD pin of the

WM7211. A ceramic 0.1µF capacitor with X7R dielectric or better is suitable.

Further information on the WM8280 is provided in the product datasheet, which is available from the

Wolfson website. The equivalent connections can be made to other Wolfson devices supporting a

digital microphone interface.

VDD

VDD

CLK

DAT

LRSEL

CLK

DAT

LRSEL

0.1 F

0.1 F

VDD

VDD

GND

GND

WM7211

WM7211

WM8280

DMICCLKn

DMICDATn

Figure 2 Stereo WM7211 Digital Microphone Connection to WM8280