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DESCRIPTION
The WM7120 is a compact high Signal to Noise Ratio
(SNR) silicon analogue microphone for use in consumer
applications requiring low supply current, typically 140μA,
and excellent signal quality. It offers low THD and good
linearity to offer excellent sound quality. Using Wolfson
Microelectronics’
unique
CMOS/MEMS
membrane
technology it delivers high reliability and performance in a
miniature low profile package.
The WM7120 can withstand the high temperatures needed
for automated reflow solder assembly, which can damage
conventional microphones.
Automated pick and place
equipment can be used for assembly on to circuit boards.
The WM7120E offers tighter sensitivity tolerance which
reduces the variation between microphones and removes
the need for production in-line calibration to compensate for
microphone variation.
WM7120 Series
Analogue Silicon Microphone
FEATURES
•
Excellent SNR and Sensitivity tolerance options
- WM7120IMS, SNR 59dB, Sensitivity +/-3dB
- WM7120IMSE, SNR 59dB, Sensitivity +/-1dB
Low supply current 140μA
Low profile packaging
Automated flow solder assembly
Analogue output
Top Port Package
1.5V to 3.7V supply
3.76mm x 2.95mm x 1.10mm Package
•
•
•
•
•
•
•
APPLICATIONS
•
•
•
•
•
•
•
Mobile phone handsets
Portable media players
Digital still cameras
Digital video cameras
Bluetooth headsets
Portable navigation devices
Portable games consoles
BLOCK DIAGRAM
WOLFSON MICROELECTRONICS plc
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http://www.wolfsonmicro.com/enews/
Pre-Production, May 2009, Rev 3.0
Copyright
©2009
Wolfson Microelectronics plc
WM7120
TABLE OF CONTENTS
Pre-Production
DESCRIPTION ....................................................................................................... 1
FEATURES............................................................................................................. 1
APPLICATIONS ..................................................................................................... 1
BLOCK DIAGRAM ................................................................................................. 1
TABLE OF CONTENTS ......................................................................................... 2
PIN CONFIGURATION ........................................................................................... 3
PIN DESCRIPTION ................................................................................................ 3
ORDERING INFORMATION .................................................................................. 3
ABSOLUTE MAXIMUM RATINGS ......................................................................... 4
RECOMMENDED OPERATING CONDITIONS ..................................................... 4
ACOUSTIC AND ELECTRICAL CHARACTERISTICS .......................................... 5
TERMINOLOGY ............................................................................................................ 5
APPLICATIONS INFORMATION ........................................................................... 7
RECOMMENDED EXTERNAL COMPONENTS ............................................................ 7
CONNECTION TO A WOLFSON AUDIO CODEC ........................................................ 7
PACKAGE DIMENSIONS ...................................................................................... 8
RECOMMENDED CUSTOMER LAND PATTERNS............................................... 9
IMPORTANT NOTICE .......................................................................................... 10
ADDRESS: ........................................................................................................... 10
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WM7120
PIN CONFIGURATION
PIN DESCRIPTION
PIN
1
2
3
4
NAME
OUTPUT
GND
GND
VDD
TYPE
Analogue Output
Supply
Supply
Supply
DESCRIPTION
Microphone analogue output signal
Analogue ground
Analogue ground
Analogue supply
ORDERING INFORMATION
DEVICE
WM7120IMS/V
WM7120IMS/RV
WM7120IMSE/V
WM7120IMSE/RV
Note:
Reel quantity = 5,700
All devices are Pb-free and Halogen free.
DESCRIPTION
Standard
Standard (tape and reel)
Standard Enhanced
Standard Enhanced (tape
and reel)
TEMPERATURE
RANGE
-40 to +100
o
C
-40 to +100
o
C
-40 to +100
o
C
-40 to +100
o
C
MOISTURE SENSITIVITY
LEVEL
MSL2A
MSL2A
MSL2A
MSL2A
PEAK SOLDERING
TEMPERATURE
+260
o
C
+260
o
C
+260
o
C
+260 C
o
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WM7120
ABSOLUTE MAXIMUM RATINGS
Pre-Production
Absolute Maximum Ratings are stress ratings only. Permanent damage to the device may be caused by continuously operating at
or beyond these limits. Device functional operating limits and guaranteed performance specifications are given under Electrical
Characteristics at the test conditions specified.
ESD Sensitive Device. This device is manufactured on a CMOS process. It is therefore generically susceptible
to damage from excessive static voltages. Proper ESD precautions must be taken during handling and storage
of this device.
Wolfson tests its package types according to IPC/JEDEC J-STD-020 for Moisture Sensitivity to determine acceptable storage
conditions prior to surface mount assembly. These levels are:
MSL1 = unlimited floor life at <30°C / 85% Relative Humidity. Not normally stored in moisture barrier bag.
MSL2 = out of bag storage for 1 year at <30°C / 60% Relative Humidity. Supplied in moisture barrier bag.
MSL2A = out of bag storage for 4 weeks at <30°C / 60% Relative Humidity. Supplied in moisture barrier bag.
MSL3 = out of bag storage for 168 hours at <30°C / 60% Relative Humidity. Supplied in moisture barrier bag.
The Moisture Sensitivity Level for each package type is specified in Ordering Information.
CONDITION
Supply Voltage
Operating temperature range, T
A
Storage temperature prior to soldering
Storage temperature after soldering
MIN
-0.3V
-40ºC
30°C max / 60% RH max
-40ºC
+100ºC
MAX
+4.2V
+100ºC
Do not put a vacuum over the port hole of the microphone. Placing a vacuum over the port hole can damage the device.
For information on recommended pick and place vacuum point, please refer to the package dimension drawing.
Do not board wash the microphone after a reflow process. Board washing and the associated cleaning agents can damage
the device. Do not expose to ultrasonic cleaning methods.
RECOMMENDED OPERATING CONDITIONS
PARAMETER
Analogue Supply Range
Ground
SYMBOL
VDD
GND
MIN
1.5
0
TYP
MAX
3.7
UNIT
V
V
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WM7120
ACOUSTIC AND ELECTRICAL CHARACTERISTICS
Test Conditions:
VDD=2.1V, T
A
= 25°C
PARAMETER
Directivity
Sensitivity
Current Consumption
Total Harmonic Distortion
Signal to Noise Ratio
Input Referred Noise
Power Supply Rejection Ratio
Output DC Impedance
Minimum Load Impedance
Acoustic Overload
THD < 10%
S
I
VDD
THD
SNR
ENL
PSRR
Z
OUT
1kHz 104dB SPL
A- Weighted
20Hz – 20kHz
A- Weighted
20Hz – 20kHz
40
1kHz 94dB SPL
(0dB = 1V/Pa)
-45
-43
SYMBOL
TEST
CONDITIONS
MIN
TYP
Omni-directional
-42
-42
140
0.25
59
35
50
100
20
125
-39
-41
190
dB
dB
μA
%
dB
dB SPL
dB
Ω
kΩ
dB SPL
Standard
Enhanced
MAX
UNIT
NOTE
TERMINOLOGY
1.
2.
3.
Signal-to-Noise Ratio (dB) – SNR is a measure of the ratio between the sensitivity of the microphone to a 94dB SPL
sine wave and the A-Weighted analogue idle noise.
Total Harmonic Distortion (dB) – THD is the level of the rms value of the sum of harmonic distortion products relative
to the amplitude of the applied sound pressure level.
All performance measurements carried out with 20 kHz low pass filter, and where noted an A-weighted filter. Failure to
use such a filter will result in higher THD and lower SNR readings than are found in the Acoustic and Electrical
Characteristics. The low pass filter removes out of band noise; although it is not audible it may affect dynamic
specification values.
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Analogue and Mixed Signal
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