Low Power Bottom Port Digital Silicon Microphone

http://www.cirrus.com

Copyright

 Cirrus Logic, Inc., 2014–2016

(All Rights Reserved)

Rev 4.0

MAY

‘16

WM7236E

DESCRIPTION

The WM7236 is a low-profile digital silicon microphone,

optimised for use with low-

power ‘Always-on’ voice control

applications,

such

as

Cirrus

SoundClear

™

software.

The WM7236 supports two operational modes, selected

according to the applied clock frequency. ‘Voice’ mode

provides low current consumption, and sufficient SNR

performance for speech recognition algorithms. ‘Hi-Fi

Record’ mode offers wide dynamic range, and class-

leading THD performance. Operation in the ultrasonic

band is also supported at high clock frequencies.

The

WM7236

incorporates

Cirrus

Logic

proprietary

CMOS/MEMS

membrane

technology,

offering

high

reliability and high performance in a miniature, low-profile

package. The WM7236 is designed to withstand the high

temperatures associated with automated flow solder

assembly processes. (Note that conventional microphones

can be damaged by this process.)

The WM7236 incorporates a high-performance ADC,

which outputs a single-bit data stream using Pulse Density

Modulation (PDM) encoding. The WM7236 supports

selectable left/right channel assignment for a two-channel

digital microphone interface, enabling efficient connection

of multiple microphones in stereo/array configurations.

The WM7236 offers tight tolerance on the microphone

sensitivity, giving reduced variation between parts. This

removes the need for in-line production calibration of part-

to-part microphone variations.

FEATURES



High SNR (63dB)



Low variation in sensitivity (±1dB tolerance)



Low current consumption

-

10

μA (Sleep)

-

290

μA (Voice mode)

-

980

μA (Hi-Fi Record mode)



PDM digital audio output



Stereo/array operation



Proprietary ADC technology

-

Reduced clock-jitter sensitivity

-

Low noise floor

-

Stable in overload condition



Bottom Port LGA Package



1.62V to 2.0V supply

APPLICATIONS



Mobile telephone handsets



Wearable devices



Portable media players



Digital cameras



Tablets and laptop computers

BLOCK DIAGRAM

AMP

CMOS MEMS

Transducer

VDD

DAT

CHARGE

PUMP

GND

ADC

CONTROL

CLK

LRSEL

WM7236

3D VIEW

4.00mm x 3.00mm x 1.00mm LGA package