INMP441
Omnidirectional Microphone with Bottom Port and I2S Digital Output
GENERAL DESCRIPTION
The INMP441 is a high-performance, low power, digital-output,
omnidirectional MEMS microphone with a bottom port. The
complete INMP441 solution consists of a MEMS sensor, signal
conditioning, an analog-to-digital converter, anti-aliasing filters,
power management, and an industry-standard 24-bit I²S interface.
The I²S interface allows the INMP441 to connect directly to digital
processors, such as DSPs and microcontrollers, without the need
for an audio codec in the system.
The INMP441 has a high SNR, making it an excellent choice for
near field applications. The INMP441 has a flat wideband
frequency response, resulting in natural sound with high
intelligibility.
The INMP441 is available in a thin 4.72 × 3.76 × 1 mm surface-
mount package. It is reflow- solder compatible with no sensitivity
degradation. The INMP441 is halide free.
*Protected by U.S. Patents 7,449,356; 7,825,484; 7,885,423; and 7,961,897.
Other patents are pending.
APPLICATIONS
• Teleconferencing Systems
• Remote Controls
• Gaming Consoles
• Mobile Devices
• Laptops
• Tablets
• Security Systems
FEATURES
• Digital I²S Interface with High-Precision 24-Bit Data
• High SNR of 61 dBA
• High Sensitivity of -26 dBFS
• Flat Frequency Response from 60 Hz to 15 kHz
• Low Current Consumption of 1.4 mA
• High PSR of -75 dBFS
• Small 4.72 × 3.76 × 1 mm Surface-Mount Package
• Compatible with Sn/Pb and Pb-Free Solder Processes
• RoHS/WEEE Compliant
FUNCTIONAL BLOCK DIAGRAM
ORDERING INFORMATION
PART
TEMP RANGE
INMP441ACEZ-R0*
−40°C to +85°C
INMP441ACEZ-R7†
−40°C to +85°C
EV_INMP441
—
EV_INMP441-FX
—
* – 13” Tape and Reel
† – 7” Tape and reel to be discontinued. Contact sales@invensense.com for
availability.
INMP441
ADC
POWER
MANAGEMENT
SCK
SD
WS
GND
GND
GND
VDD
FILTER I2S
SERIAL
PORT
HARDWARE
CONTROL
L/R
CHIPEN
BOTTOM
TOP
InvenSense reserves the right to change the detail
specifications as may be required to permit improvements
in the design of its products.
InvenSense Inc.
1745 Technology Drive, San Jose, CA 95110 U.S.A
+1(408) 988–7339
www.invensense.com
Document Number: DS-INMP441-00
Revision: 1.0.
Rev Date: 02/06/2014
INMP441
TABLE OF CONTENTS
General Description ................................................................................................................................................... 1
Applications ............................................................................................................................................................... 1
Features ..................................................................................................................................................................... 1
Functional Block Diagram .......................................................................................................................................... 1
Ordering Information ................................................................................................................................................. 1
Specifications .................................................................................................................................................................... 4
Table 1. Electrical Characteristics .............................................................................................................................. 4
Table 2. I2S Digital Input/Output Characteristics ....................................................................................................... 5
Table 3. Serial Data Port Timing Specifications.......................................................................................................... 5
Timing Diagram .......................................................................................................................................................... 5
Absolute Maximum Ratings .............................................................................................................................................. 6
Table 4. Absolute Maximum Ratings ......................................................................................................................... 6
ESD Caution ............................................................................................................................................................... 6
Soldering Profile......................................................................................................................................................... 7
Table 5. Recommended Soldering Profile .................................................................................................................. 7
Pin Configurations And Function Descriptions ................................................................................................................. 8
Table 6. Pin Function Descriptions ............................................................................................................................. 8
Typical Performance Characteristics ................................................................................................................................. 9
Theory of Operation ....................................................................................................................................................... 10
Understanding Sensitivity ........................................................................................................................................ 10
Power Management ................................................................................................................................................ 10
Normal Operation ................................................................................................................................................... 10
Standby Mode ......................................................................................................................................................... 10
Power-Down Mode ................................................................................................................................................. 10
Startup .................................................................................................................................................................... 10
I²S Data Interface ..................................................................................................................................................... 11
Data Output Mode .................................................................................................................................................. 11
Data Word Length ................................................................................................................................................... 11
Data-Word Format .................................................................................................................................................. 11
Digital Microphone Sensitivity ................................................................................................................................. 12
Synchronizing Microphones .................................................................................................................................... 13
Digital Filter Characteristics ..................................................................................................................................... 13
High-Pass Filter ........................................................................................................................................................ 13
Table 7. High Pass Filter Characteristics .................................................................................................................. 13
Low-Pass Filter ......................................................................................................................................................... 13
Applications Information ................................................................................................................................................ 14
Power-Supply Decoupling ........................................................................................................................................ 15
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Document Number: DS-INMP441-00
Revision: 1.0.
INMP441
Supporting Documents ................................................................................................................................................... 16
Evaluation Board User Guide ................................................................................................................................... 16
Application Notes (Product Specific) ....................................................................................................................... 16
Application Notes (General) .................................................................................................................................... 16
PCB Design And Land Pattern Layout ............................................................................................................................. 17
PCB Material And Thickness .................................................................................................................................... 18
Handling Instructions ...................................................................................................................................................... 18
Pick And Place Equipment ....................................................................................................................................... 18
Reflow Solder ........................................................................................................................................................... 18
Board Wash.............................................................................................................................................................. 18
Outline Dimensions ......................................................................................................................................................... 19
Ordering Guide ........................................................................................................................................................ 20
Revision History ....................................................................................................................................................... 20
Compliance Declaration Disclaimer: ............................................................................................................................... 21
Environmental Declaration Disclaimer: .......................................................................................................................... 21
Page 3 of 21
Document Number: DS-INMP441-00
Revision: 1.0
INMP441
SPECIFICATIONS
TABLE 1. ELECTRICAL CHARACTERISTICS
(TA = −40 to 85°C, VDD = 1.8 to 3.3 V, CLK = 2.4 MHz, CLOAD = 30 pF, unless otherwise noted. All minimum and maximum specifications
are guaranteed across temperature, voltage, and clock frequency specified in Table 1, Table 2, Table 3, unless otherwise noted.
Typical specifications are not guaranteed.)
PARAMETER
MIN
TYP
MAX
UNITS
NOTES
PERFORMANCE
Directionality
Omni
Sensitivity
−29
−26
−23
dBFS
1
Signal-to-Noise Ratio (SNR)
61
dBA
Equivalent Input Noise (EIN)
33
dBA SPL
Dynamic Range
87 dB
Frequency Response
60
Hz
2
15
kHz
Total Harmonic Distortion (THD)
3
%
Power-Supply Rejection (PSR)
wave superimposed on VDD =
−75 dBFS
Maximum Acoustic Input
120
dB SPL
Noise Floor
−87 dBFS
POWER SUPPLY
Supply Voltage (VDD)
1.62
3.63
V
Supply Current (IS)
VDD = 1.8 V
Normal Mode
1.4 1.6 mA
Standby 0.8 mA
Power Down 2 µA
VDD = 3.3 V
Normal Mode
2.2
2.5
mA
Standby
0.8
mA
Power Down
4.5
µA
DIGITAL FILTER
Group Delay
17.2/fS sec
fS = 48 kHz 359
µs
fS = 16 kHz 1078
µs
Pass-Band Ripple
±0.04
dB
Stop-Band Attenuation 60 dB
Pass Band 0.423 × f
S
20.3 kHz
Note 1: The peak-to-peak amplitude relative to peak-to-peak amplitude of (224 − 1.) The stimulus is a 104 dB SPL sinusoid having RMS amplitude of 3.1623 Pa.
Sensitivity is relative to 1 Pa.
Note 2: See Figure 4 and Figure 5.
Page 4 of 21
Document Number: DS-INMP441-00
Revision: 1.0
INMP441
TABLE 2. I2S DIGITAL INPUT/OUTPUT CHARACTERISTICS
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
NOTES
DIGITAL INPUT
Input Voltage High (VIH) L/R, WS, SCK 0.7 x VDD VDD V 1
Input Voltage Low (VIL) L/R, WS, SCK 0 0.25 x VDD V 1
SD DIGITAL INPUT
Voltage Output Low (VOL) VDD = 1.8 V, ISINK = 0.25 mA 0.1 × VDD
V
1
Voltage Output Low (VOL) VDD = 1.8 V, ISINK = 0.7 mA 0.3 × VDD
V
1
Voltage Output High (VOH) VDD = 1.8 V, I
SINK
= 0.7 mA 0.7 × VDD V 1
Voltage Output High (VOH)
VDD = 1.8 V, ISINK = 0.25 mA
0.9 × VDD
V
1
Voltage Output Low (VOL) VDD = 3.3 V, ISINK = 0.5 mA
0.1 × V
DD
V 1
Voltage Output Low (VOL) VDD = 3.3 V, ISINK = 1.7 mA
0.3 × V
DD
V 1
Voltage Output High (VOH) VDD = 3.3 V, ISINK = 1.7 mA
0.7 × V
DD
V 1
Voltage Output High (VOH) VDD = 3.3 V, ISINK = 0.5 mA
0.9 × V
DD
V 1
Note 1: Limits based on characterization results; not production tested.
TABLE 3. SERIAL DATA PORT TIMING SPECIFICATIONS
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
NOTES
tSCH SCK high 50 ns
tSCL
SCK low
50
ns
t
SCP
SCK period
312
ns
f
SCK
SCK frequency
0.5
3.2
MHz
tWSS
WS setup
0
ns
tWSH
WS hold
20
ns
fWS
WS frequency
7.8
50
kHz
TIMING DIAGRAM
Figure 1. Serial Data Port Timing
SCK
WS
SD
tSCP
tSCH
tSCL tWSH
tWSS
Page 5 of 21
Document Number: DS-INMP441-00
Revision: 1.0.
INMP441
ABSOLUTE MAXIMUM RATINGS
Stress above those listed as Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only
and functional operation of the device at these conditions is not implied. Exposure to the absolute maximum ratings conditions for
extended periods may affect device reliability.
TABLE 4. ABSOLUTE MAXIMUM RATINGS
PARAMETER
RATING
Supply Voltage (VDD )
−0.3 V to +3.63 V
Digital Pin Input Voltage
−0.3 V to VDD + 0.3 V or 3.63 V, whichever is less
Sound Pressure Level
160 dB
Mechanical Shock
10,000 g
Vibration
Per MIL-STD-883 Method 2007, Test Condition B
Temperature Range
Biased
−40°C to +85°C
Storage
−55°C to +150°C
ESD CAUTION
ESD (electrostatic discharge) sensitive device.
Charged devices and circuit boards can
discharge without detection. Although this
product features patented or proprietary
protection circuitry, damage may occur on
devices subjected to high energy ESD.
Therefore proper ESD precautions should be
taken to avoid performance degradation or
loss of functionality.
Page 6 of 21
Document Number: DS-INMP441-00
Revision: 1.0
INMP441
SOLDERING PROFILE
Figure 2. Recommended Soldering Profile Limits
TABLE 5. RECOMMENDED SOLDERING PROFILE*
PROFILE FEATURE
Sn63/Pb37
Pb-Free
Average Ramp Rate (T
L
to T
P
)
1.25°C/sec max
1.25°C/sec max
Preheat
Minimum Temperature
(TSMIN )
100°C 100°C
Minimum Temperature
(TSMIN )
150°C 200°C
Time (TSMIN to TSMAX ), tS
60 sec to 75 sec
60 sec to 75 sec
Ramp-Up Rate (TSMAX to TL)
1.25°C/sec
1.25°C/sec
Time Maintained Above Liquidous (tL)
45 sec to 75 sec
~50 sec
Liquidous Temperature (T
L
) 183°C 217°C
Peak Temperature (T
P
)
215°C +3°C/−3°C 260°C +0°C/−5°C
Time Within +5°C of Actual Peak
Temperature (tP)
20 sec to 30 sec 20 sec to 30 sec
Ramp-Down Rate 3°C/sec max
3°C/sec max
Time +25°C (t
25°C
) to Peak
Temperature
5 min max 5 min max
*The reflow profile in Table 5 is recommended for board manufacturing with InvenSense MEMS microphones. All microphones are
also compatible with the J-STD-020 profile.
tP
tL
t25°C
TO PEAK TEMPERATURE
tS
PREHEAT
CRITICAL ZONE
T
L
TO T
P
TEMPERATURE
TIME
RAMP-DOWN
RAMP-UP
T
SMIN
T
SMAX
T
P
T
L
Page 7 of 21
Document Number: DS-INMP441-00
Revision: 1.0
INMP441
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
Figure 3. Pin Configuration
TABLE 6. PIN FUNCTION DESCRIPTIONS
PIN NAME FUNCTION
1
SCK
Serial-Data Clock for I²S Interface
2 SD
Serial-Data Output for I²S Interface. This pin tri-states when not actively driving the
appropriate output channel. The SD trace should have a 100 kΩ pulldown resistor to
discharge the line during the time that all microphones on the bus have tri-stated their
outputs.
3 WS Serial Data-Word Select for I²S Interface
4 L/R Left/Right Channel Select. When set low, the microphone outputs its signal in the left channel
of the I²S frame. When set high, the microphone outputs its signal in the right channel.
5 GND Ground. Connect to ground on the PCB.
6 GND Ground. Connect to ground on the PCB.
7 VDD Power, 1.8 V to 3.3 V. This pin should be decoupled to Pin 6 with a 0.1 μF capacitor.
8 CHIPEN Microphone Enable. When set low (ground), the microphone is disabled and put in power-
down mode. When set high (VDD), the microphone is enabled.
9 GND Ground. Connect to ground on the PCB.
4L/R 6GND
5GND
3WS7VDD
2SD 8CHIPEN
1SCK 9GND
BOTTOM VIEW
(Not to Scale)
Page 8 of 21
Document Number: DS-INMP441-00
Revision: 1.0.
INMP441
TYPICAL PERFORMANCE CHARACTERISTICS
Figure 4. Frequency Response Mask
Figure 5. Typical Frequency Response (Measured)
Figure 6. Power-Supply Rejection (PSR) vs. Frequency
10
–10
–8
–6
–4
–2
0
2
4
6
8
50 100 10k
FREQUENCY (Hz)
SENSITIVITY (dB)
1k
10
–20
–10
0
10 100 10k
FREQUENCY (Hz)
AMPLITUDE ( dB)
1k
0
–80
100 10k
FREQUENCY (Hz)
PSR (dB)
1k
–10
–20
–30
–40
–50
–60
–70
Page 9 of 21
Document Number: DS-INMP441-00
Revision: 1.0.
INMP441
THEORY OF OPERATION
The INMP441 is a high-performance, low-power, digital-output, omni-directional MEMS microphone with a bottom port. The
complete INMP441 solution consists of a MEMS sensor, signal conditioning, an analog-to-digital converter, anti-aliasing filters,
power management, and an industry-standard 24-bit I²S interface.
The INMP441 complies with the TIA-920 Telecommunications Telephone Terminal Equipment Transmission Requirements for
Wideband Digital Wireline Telephones standard.
UNDERSTANDING SENSITIVITY
The casual user of digital microphones may have difficulty understanding the sensitivity specification. Unlike an analog microphone
(whose specification is easily confirmed with an oscilloscope), the digital microphone output has no obvious unit of measure.
The INMP441 has a nominal sensitivity of −26 dBFS at 1 kHz with an applied sound pressure level of 94 dB. The units are in decibels
referred to full scale. The INMP441 default full-scale peak output word is 223 − 1 (integer representation), and −26 dBFS of that scale
is (223 − 1) × 10(−26/20) = 420,426. A pure acoustic tone at 1 kHz having a 1Pa RMS amplitude results in an output digital signal whose
peak amplitude is 420,426.
Although the industry uses a standard specification of 94 dB SPL, the INMP441 test method applies a 104 dB SPL signal. The higher
sound pressure level reduces noise and improves repeatability. The INMP441 has excellent gain linearity, and the sensitivity test
result at 94 dB is derived with very high confidence from the test data.
POWER MANAGEMENT
The INMP441 has three different power states: normal operation, standby mode, and power-down mode.
Normal Operation
The microphone becomes operational 218 clock cycles (85 ms with SCK at 3.072 MHz) after initial power-up. The CHIPEN pin then
controls the power modes. The part is in normal operation mode when SCK is active and the CHIPEN pin is high.
Standby Mode
The microphone enters standby mode when the serial-data clock SCK stops and CHIPEN is high. Normal operation resumes 214 clock
cycles (5 ms with SCK at 3.072 MHz) after SCK restarts.
The INMP441 should not be transitioned from standby to power-down mode, or vice versa. Standby mode is only intended to be
entered from the normal operation state.
Power-Down Mode
The microphone enters power-down mode when CHIPEN is low, regardless of the SCK operation. Normal mode operation resumes
217 SCK clock cycles (43 ms with SCK at 3.072 MHz) after CHIPEN returns high while SCK is active.
It always takes 217 clock cycles to restart the INMP441 after VDD is applied.
It is not recommended to supply active clocks (WS and SCK) to the INMP441 while there is no power supplied to VDD. Doing this
continuously turns on ESD protection diodes, which may affect long-term reliability of the microphone.
Startup
The microphones have zero output for the first 218 SCK clock cycles (85ms with SCK at 3.072 MHz) following power-up.
Page 10 of 21
Document Number: DS-INMP441-00
Revision: 1.0.
INMP441
I²S DATA INTERFACE
The slave serial-data port’s format is I²S, 24-bit, twos complement. There must be 64 SCK cycles in each WS stereo frame, or 32 SCK
cycles per data-word. The L/R control pin determines whether the INMP441 outputs data in the left or right channel. For a stereo
application, the SD pins of the left and right INMP441 microphones should be tied together as shown in Figure 7. The format of a
stereo I²S data stream is shown in Figure 8. Figures 9 and 10 show the formats of a mono microphone data stream for left and right
microphones, respectively.
Data Output Mode
The output data pin (SD) is tri-stated when it is not actively driving I²S output data. SD immediately tri-states after the LSB is output
so that another microphone can drive the common data line.
The SD trace should have a pull-down resistor to discharge the line during the time that all microphones on the bus have tri-stated
their outputs. A 100 kΩ resistor is sufficient for this, as shown in Figure 7.
Data Word Length
The output data word length is 24 bits per channel. The INMP441 must always have 64 clock cycles for every stereo data-word (fSCK
= 64 × fWS ).
Data-Word Format
The default data format is I²S (two’s complement), MSB-first. In this format, the MSB of each word is delayed by one SCK cycle from
the start of each half-frame.
Figure 7. System Block Diagram
SCK
WS
SD
SYSTEM MASTER
(DSP, MICROCONTROLLER,
CODEC)
CHIPEN SCK
WS
L/R SD
VDD
LEFT
INMP441
GND GND GND
0.1µF
FROM VOLTAGE
REGULATOR
(1.8V TO 3.3V )
CHIPENSCK
WS
L/RSD
VDD
RIGHT
INMP441
GND GND GND
0.1µF
100kΩ
VDD VDD
Page 11 of 21
Document Number: DS-INMP441-00
Revision: 1.0.
INMP441
Figure 8. Stereo-Output I²S Format
Figure 9. Mono-Output I²S Format Left Channel (L/R = 0)
Figure 10. Mono-Output I²S Format Right Channel (L/R = 1)
DIGITAL MICROPHONE SENSITIVITY
The sensitivity of a PDM output microphone is specified in units of dBFS (decibels relative to a full-scale digital output). A 0 dBFS sine
wave is defined as a signal whose peak just touches the full-scale code of the digital word (see Figure 5). This measurement
convention means that signals with a different crest factor may have an RMS level higher than 0dBFS. For example, a full-scale
square wave has an RMS level of 3dBFS.
Figure 11. 1 kHz, 0 dBFS Sine Wave
The definition of a 0 dBFS signal must be understood when measuring the sensitivity of the INMP441. An acoustic input signal of a
1 kHz sine wave at 94 dB SPL applied to the INMP441 results in an output signal with a −26 dBFS level. This means that the output
digital word peaks at −26 dB below the digital full-scale level. A common misunderstanding is that the output has an RMS level of
−29 dBFS; however, this is not the case because of the definition of a 0 dBFS sine wave.
MSB LSB
LEFT CHANNEL
MSB LSB
RIG HT CHANNELHIGH-Z HIGH-Z HIGH-Z
123 4 24 25 26 32 33 34 35 36 56 57 58 64
WS
SCK (64 ×
f
S
)
SD (24-BIT )
MSB LSB
LEFT CHANNELHIGH-Z HIGH-Z
123424 25 26 32 33 34 35 36 56 57 58 64
WS
SCK (64 ×
f
S
)
SD (24-BIT )
MSB LSB
RIG HT CHANNELHIGH-Z HIGH-Z
1 2 3424 25 26 32 33 34 35 36 56 57 58 64
WS
SCK (64 ×
f
S
)
SD (24-BIT )
1.0
–1.0
–0.8
–0.6
–0.4
–0.2
0
0.2
0.4
0.6
0.8
00.9 1.00.80.70.60.50.40.30.20.1
DIGITAL AMPLITUDE (D)
TIME (ms)
Page 12 of 21
Document Number: DS-INMP441-00
Revision: 1.0.
INMP441
There is no commonly accepted unit of measurement to express the instantaneous level of a digital signal output from the
microphone, as opposed to the RMS level of the signal. Some measurement systems express the instantaneous level of an individual
sample in units of D, where 1.0 D is digital full scale (see Figure 11). In this case, a −26 dBFS sine wave has peaks at 0.05 D.
For more information about digital microphone sensitivity, see the AN-1112 Application Note, Microphone Specifications Explained.
SYNCHRONIZING MICROPHONES
Stereo INMP441 microphones are synchronized by the WS signal, so audio captured from two microphones sharing the same clock
will be in sync. If the mics are enabled separately, this synchronization may take up to 0.35 ms after the enable signal is asserted
while internal data paths are flushed.
DIGITAL FILTER CHARACTERISTICS
The INMP441 has an internal digital band-pass filter. A high-pass filter eliminates unwanted low-frequency signals. A low-pass filter
allows the user to scale the pass band with the sampling frequency, as well as perform required noise reduction.
HIGH-PASS FILTER
The INMP441 incorporates a high-pass filter to remove unwanted DC and very low frequency components. This shows the high-pass
characteristics for a nominal sampling rate of 48 kHz. The cutoff frequency scales with changes in sampling rate.
TABLE 7. HIGH PASS FILTER CHARACTERISTICS
FREQUENCY ATTENTUATION
3.7 Hz −3 dB
10.4 Hz −0.5 dB
21.6 Hz
−0.1 dB
This digital filter response is in addition to the natural high-pass response of the INMP441 MEMS acoustic transducer that has a -3 dB
cutoff of 60 Hz.
LOW-PASS FILTER
The analog-to-digital converter in the INMP441 is a single-bit, high-order, sigma-delta (Σ-Δ) running at a high oversampling ratio. The
noise shaping of the converter pushes the majority of the noise well above the audio band and gives the microphone a wide
dynamic range. However, it does require a good quality low-pass filter to eliminate the high-frequency noise.
Figure 12 shows the response of this digital low-pass filter included in the microphone. The pass band of the filter extends to 0.423 ×
fS and, in that band, has an unnoticeable 0.04 dB of ripple. The high-frequency cutoff of −6 dB occurs at 0.5 × fS. A 48 kHz sampling
rate results in a pass band of 20.3 kHz and a half amplitude corner at 24 kHz. The stop-band attenuation of the filter is greater than
60 dB. Note that these filter specifications scale with sampling frequency.
Page 13 of 21
Document Number: DS-INMP441-00
Revision: 1.0
INMP441
Figure 12. Digital Low-Pass Filter Magnitude Response
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
MAG NI TUDE ( dB)
NORM ALIZED FREQUENC Y (
fS
)
Page 14 of 21
Document Number: DS-INMP441-00
Revision: 1.0
INMP441
APPLICATIONS INFORMATION
POWER-SUPPLY DECOUPLING
For best performance and to avoid potential parasitic artifacts, placing a 0.1 µF ceramic type X7R or better capacitor between Pin 7
(VDD) and ground is strongly recommended. The capacitor should be placed as close to Pin 7 as possible.
The connections to each side of the capacitor should be as short as possible, and the trace should stay on a single layer with no vias.
For maximum effectiveness, locate the capacitor equidistant from the power and ground pins, or if equidistant placement is not
possible, slightly closer to the power pin. Thermal connections to the ground planes should be made on the far side of the capacitor,
as shown in Figure 13.
Figure 13. Recommended Power-Supply Bypass Capacitor Layout
VDD GND
TO GND
TO V
DD
CAPACITOR
Page 15 of 21
Document Number: DS-INMP441-00
Revision: 1.0
INMP441
SUPPORTING DOCUMENTS
For additional information, see the following documents.
EVALUATION BOARD USER GUIDE
UG-303, EV_INMP441Z-FX: Bottom Port I2S Output MEMS Microphone Evaluation Board
UG-362, EV_INMP441Z SDP Daughter Board for the INMP441 I2S MEMS Microphone
APPLICATION NOTES (PRODUCT SPECIFIC)
AN-0208, High Performance Digital MEMS Microphone’s Simple Interface to SigmaDSP Audio Processor
AN-0266, High Performance Digital MEMS Microphone Standard Digital Audio Interface to Blackfin DSP
APPLICATION NOTES (GENERAL)
AN-1003, Recommendations for Mounting and Connecting the Invensense, Inc., Bottom-Ported MEMS Microphones
AN-1068, Reflow Soldering of the MEMS Microphone
AN-1112, Microphone Specifications Explained
AN-1124, Recommendations for Sealing Invensense, Inc., Bottom-Port MEMS Microphones from Dust and Liquid Ingress
AN-1140, Microphone Array Beamforming
Page 16 of 21
Document Number: DS-INMP441-00
Revision: 1.0.
INMP441
PCB DESIGN AND LAND PATTERN LAYOUT
Lay out the PCB land pattern for the INMP441 at a 1:1 ratio to the solder pads on the microphone package (see Figure 14.) Take care
to avoid applying solder paste to the sound hole in the PCB. Figure 15 shows a suggested solder paste stencil pattern layout.
The response of the INMP441 is not affected by the PCB hole size, as long as the hole is not smaller than the sound port of the micro-
phone (0.25 mm, or 0.010 inch, in diameter). A 0.5 mm to 1 mm (0.020 inch to 0.040 inch) diameter for the hole is recommended.
Align the hole in the microphone package with the hole in the PCB. The exact degree of the alignment does not affect the
performance of the microphone as long as the holes are not partially or completely blocked.
Figure 14. Suggested PCB Land Pattern Layout
Figure 15. Suggested Solder Paste Stencil Pattern Layout
DIMENSIONS SHOWN IN MILLIMETERS
1.33 ( 2× )
2.66 ( 4× )
0.40 × 0.60
(8×)
0.96
1.56
3.16
1.05
(6×)
0.25 DIA.
(T HRU HOL E )
DIMENSIONS SHOWN IN MILLIMETERS
1.33 ( 2× )
3.76
0.20
2.66 ( 4× )
0.350 × 0.550
(8×)
1.6
4.72
1.07
1.05
(6×)
1.05
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Document Number: DS-INMP441-00
Revision: 1.0.
INMP441
PCB MATERIAL AND THICKNESS
The performance of the INMP441 is not affected by PCB thickness. The INMP441 can be mounted on either a rigid or flexible PCB. A
flexible PCB with the microphone can be attached directly to the device housing with an adhesive layer. This mounting method
offers a reliable seal around the sound port while providing the shortest acoustic path for good sound quality.
HANDLING INSTRUCTIONS
PICK AND PLACE EQUIPMENT
The MEMS microphone can be handled using standard pick-and-place and chip shooting equipment. Take care to avoid damage to the
MEMS microphone structure as follows:
• Use a standard pickup tool to handle the microphone. Because the microphone hole is on the bottom of the package, the
pickup tool can make contact with any part of the lid surface.
• Do not pick up the microphone with a vacuum tool that makes contact with the bottom side of the microphone.
Do not pull air out of or blow air into the microphone port.
• Do not use excessive force to place the microphone on the PCB.
REFLOW SOLDER
For best results, the soldering profile must be in accordance with the recommendations of the manufacturer of the solder paste used to
attach the MEMS microphone to the PCB. It is recommended that the solder reflow profile not exceed the limit conditions specified
in Figure 2 and Table 5.
BOARD WASH
When washing the PCB, ensure that water does not make contact with the microphone port. Do not use blow-off procedures or
ultrasonic cleaning.
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Document Number: DS-INMP441-00
Revision: 1.0
INMP441
OUTLINE DIMENSIONS
Figure 16. 9-Terminal Chip Array Small Outline No Lead Cavity [LGA_CAV]
4.72 mm × 3.76 mm × 1.00 mm Body
Dimensions shown in millimeters
Figure 17. Package Marking Specification (Top View)
3.86
3.76
3.66
4.82
4.72
4.62
BOTTOM VIEW
TOP VIEW
SIDE VIEW
0.275
0.250 DIA.
0.225
5
0.96 DIA.
1.56 DIA.
1.05 BSC 1.07
0.30
1.33 BSC
1.05
0.98
0.88
0.24 REF
0.73 REF
2.66 BSC
3.14
REF
4.10 REF
0.40 × 0.60
(PINS 1-8)
1
9 6
4
REFERENCE
CORNER
PIN 1
YY XXXX
441
LOT TRACEABILITY CODE
PIN 1 INDICATIONPART NUMBER
DATE CODE
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Document Number: DS-INMP441-00
Revision: 1.0
INMP441
ORDERING GUIDE
PART
TEMP RANGE
PACKAGE
QUANTITY
INMP441ACEZ-R0*
−40°C to +85°C
9-Terminal LGA_CAV
4,500
INMP441ACEZ-R7†
−40°C to +85°C
9-Terminal LGA_CAV
1,000
EV_INMP441-FX
—
Flexible Evaluation Board
—
EV_INMP441
—
Evaluation Board
—
* – 13” Tape and Reel
† – 7” Tape and reel to be discontinued. Contact sales@invensense.com for availability.
REVISION HISTORY
REVISION DATE REVISION DESCRIPTION
02/06/2014 1.0 Initial Release
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Document Number: DS-INMP441-00
Revision: 1.0
INMP441
Compliance Declaration Disclaimer:
InvenSense believes this compliance information to be correct but cannot guarantee accuracy or completeness. Conformity
documents for the above component constitutes are on file. InvenSense subcontracts manufacturing and the information contained
herein is based on data received from vendors and suppliers, which has not been validated by InvenSense
Environmental Declaration Disclaimer:
InvenSense believes this environmental information to be correct but cannot guarantee accuracy or completeness. Conformity
documents for the above component constitutes are on file. InvenSense subcontracts manufacturing and the information contained
herein is based on data received from vendors and suppliers, which has not been validated by InvenSense
This information furnished by InvenSense is believed to be accurate and reliable. However, no responsibility is assumed by
InvenSense for its use, or for any infringements of patents or other rights of third parties that may result from its use. Specifications
are subject to change without notice. InvenSense reserves the right to make changes to this product, including its circuits and
software, in order to improve its design and/or performance, without prior notice. InvenSense makes no warranties, neither
expressed nor implied, regarding the information and specifications contained in this document. InvenSense assumes no
responsibility for any claims or damages arising from information contained in this document, or from the use of products and
services detailed therein. This includes, but is not limited to, claims or damages based on the infringement of patents, copyrights,
mask work and/or other intellectual property rights.
Certain intellectual property owned by InvenSense and described in this document is patent protected. No license is granted by
implication or otherwise under any patent or patent rights of InvenSense. This publication supersedes and replaces all information
previously supplied. Trademarks that are registered trademarks are the property of their respective companies. InvenSense sensors
should not be used or sold in the development, storage, production or utilization of any conventional or mass-destructive weapons
or for any other weapons or life threatening applications, as well as in any other life critical applications such as medical equipment,
transportation, aerospace and nuclear instruments, undersea equipment, power plant equipment, disaster prevention and crime
prevention equipment.
©2014 InvenSense, Inc. All rights reserved. InvenSense, MotionTracking, MotionProcessing, MotionProcessor, MotionFusion,
MotionApps, DMP, AAR, and the InvenSense logo are trademarks of InvenSense, Inc. Other company and product names may be
trademarks of the respective companies with which they are associated.
©2014 InvenSense, Inc. All rights reserved.
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Document Number: DS-INMP441-00
Revision: 1.0.