INMP441ACEZ-R7 [ETC]

Omnidirectional Microphone with Bottom Port and I2S Digital Output;
INMP441ACEZ-R7
型号: INMP441ACEZ-R7
厂家: ETC    ETC
描述:

Omnidirectional Microphone with Bottom Port and I2S Digital Output

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INMP441  
Omnidirectional Microphone with Bottom Port and I2S Digital Output  
APPLICATIONS  
GENERAL DESCRIPTION  
Teleconferencing Systems  
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.  
Remote Controls  
Gaming Consoles  
Mobile Devices  
Laptops  
Tablets  
Security Systems  
FEATURES  
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.  
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  
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.  
FUNCTIONAL BLOCK DIAGRAM  
ORDERING INFORMATION  
PART  
TEMP RANGE  
−40°C to +85°C  
−40°C to +85°C  
INMP441  
INMP441ACEZ-R0*  
INMP441ACEZ-R7†  
EV_INMP441  
EV_INMP441-FX  
* – 13” Tape and Reel  
FILTER  
ADC  
SCK  
SD  
2
I S  
SERIAL  
PORT  
POWER  
MANAGEMENT  
HARDWARE  
CONTROL  
WS  
† – 7” Tape and reel to be discontinued. Contact sales@invensense.com for  
availability.  
BOTTOM  
TOP  
InvenSense Inc.  
1745 Technology Drive, San Jose, CA 95110 U.S.A  
+1(408) 988–7339  
InvenSense reserves the right to change the detail  
specifications as may be required to permit improvements  
in the design of its products.  
Document Number: DS-INMP441-00  
Revision: 1.1  
Rev Date: 05/21/2014  
www.invensense.com  
 
 
 
 
 
INMP441  
TABLE OF CONTENTS  
General Description ................................................................................................................................................... 1  
Applications ............................................................................................................................................................... 1  
Features ..................................................................................................................................................................... 1  
Functional Block Diagram .......................................................................................................................................... 1  
Ordering Information................................................................................................................................................. 1  
Table of Contents.............................................................................................................................................................. 2  
Specifications .................................................................................................................................................................... 4  
Table 1. Electrical Characteristics .............................................................................................................................. 4  
Table 2. I2S Digital Input/Output Characteristics ....................................................................................................... 5  
Table 3. Serial Data Port 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 ................................................................................................................................................ 15  
Page 2 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
 
INMP441  
Power-Supply Decoupling........................................................................................................................................ 15  
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  
Page 3 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
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  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
NOTES  
PERFORMANCE  
Directionality  
Sensitivity  
Signal-to-Noise Ratio (SNR)  
Equivalent Input Noise (EIN)  
Omni  
26  
61  
1 kHz, 94 dB SPL  
29  
23  
dBFS  
dBA  
1
20 Hz to 20 kHz, A-weighted  
20 Hz to 20 kHz, A-weighted  
Derived from EIN and  
maximum acoustic input  
Low frequency 3 dB point  
High frequency 3 dB point  
105 dB SPL  
33  
dBA SPL  
Dynamic Range  
87  
dB  
60  
15  
Hz  
kHz  
%
Frequency Response  
2
Total Harmonic Distortion (THD)  
3
217 Hz, 100 mVp-p square  
wave superimposed on VDD  
Power-Supply Rejection (PSR)  
=
75  
dBFS  
1.8 V  
Maximum Acoustic Input  
Noise Floor  
Peak  
120  
dB SPL  
dBFS  
20 Hz to 20 kHz, A-weighted,  
RMS  
87  
POWER SUPPLY  
Supply Voltage (VDD  
)
1.62  
3.63  
V
Supply Current (IS)  
Normal Mode  
Standby  
1.4  
2.2  
1.6  
0.8  
2
mA  
mA  
µA  
VDD = 1.8 V  
Power Down  
Normal Mode  
Standby  
Power Down  
2.5  
0.8  
4.5  
mA  
mA  
µA  
VDD = 3.3 V  
DIGITAL FILTER  
17.2/fS  
359  
sec  
µs  
Group Delay  
fS = 48 kHz  
fS = 16 kHz  
µs  
1078  
Pass-Band Ripple  
±0.04  
dB  
dB  
Stop-Band Attenuation  
Pass Band  
60  
0.423 × fS  
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: 1.1  
 
 
INMP441  
TABLE 2. I2S DIGITAL INPUT/OUTPUT CHARACTERISTICS  
PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
NOTES  
DIGITAL INPUT  
Input Voltage High (VIH)  
Input Voltage Low (VIL)  
SD DIGITAL INPUT  
L/R, WS, SCK  
L/R, WS, SCK  
0.7 x VDD  
VDD  
V
V
1
1
0
0.25 x VDD  
V
V
1
1
Voltage Output Low (VOL)  
Voltage Output Low (VOL)  
VDD = 1.8 V, ISINK = 0.25 mA  
VDD = 1.8 V, ISINK = 0.7 mA  
0.1 × VDD  
0.3 × VDD  
Voltage Output High (VOH)  
Voltage Output High (VOH)  
VDD = 1.8 V, ISINK = 0.7 mA  
VDD = 1.8 V, ISINK = 0.25 mA  
0.7 × VDD  
0.9 × VDD  
V
V
1
1
0.1 × VDD  
0.3 × VDD  
Voltage Output Low (VOL)  
Voltage Output Low (VOL)  
Voltage Output High (VOH)  
Voltage Output High (VOH)  
VDD = 3.3 V, ISINK = 0.5 mA  
VDD = 3.3 V, ISINK = 1.7 mA  
VDD = 3.3 V, ISINK = 1.7 mA  
VDD = 3.3 V, ISINK = 0.5 mA  
V
V
V
V
1
1
1
1
0.7 × VDD  
0.9 × VDD  
Note 1: Limits based on characterization results; not production tested.  
TABLE 3. SERIAL DATA PORT TIMING SPECIFICATIONS  
PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
NOTES  
SCK high  
50  
ns  
tSCH  
SCK low  
50  
312  
0.5  
0
ns  
ns  
tSCL  
tSCP  
SCK period  
SCK frequency  
WS setup  
fSCK  
MHz  
ns  
3.2  
50  
tWSS  
tWSH  
fWS  
WS hold  
20  
ns  
WS frequency  
7.8  
kHz  
TIMING DIAGRAM  
tSCP  
tSCH  
SCK  
WS  
SD  
tWSS  
tSCL  
tWSH  
Figure 1. Serial Data Port Timing  
Page 5 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
 
 
 
 
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  
Sound Pressure Level  
Mechanical Shock  
Vibration  
−0.3 V to VDD + 0.3 V or 3.63 V, whichever is less  
160 dB  
10,000 g  
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: 1.1  
 
 
INMP441  
SOLDERING PROFILE  
CRITICAL ZONE  
TO T  
tP  
T
L
P
T
P
RAMP-UP  
T
L
tL  
T
SMAX  
T
SMIN  
tS  
RAMP-DOWN  
PREHEAT  
t25°C TO PEAK TEMPERATURE  
TIME  
Figure 2. Recommended Soldering Profile Limits  
TABLE 5. RECOMMENDED SOLDERING PROFILE*  
PROFILE FEATURE  
Sn63/Pb37  
Pb-Free  
Average Ramp Rate (TL to TP)  
1.25°C/sec max  
1.25°C/sec max  
Minimum Temperature  
(TSMIN  
Minimum Temperature  
(TSMIN  
100°C  
100°C  
)
Preheat  
150°C  
200°C  
)
Time (TSMIN to TSMAX), tS 60 sec to 75 sec  
60 sec to 75 sec  
1.25°C/sec  
~50 sec  
Ramp-Up Rate (TSMAX to TL)  
Time Maintained Above Liquidous (tL)  
Liquidous Temperature (TL)  
Peak Temperature (TP)  
1.25°C/sec  
45 sec to 75 sec  
183°C  
217°C  
215°C +3°C/−3°C  
20 sec to 30 sec  
3°C/sec max  
260°C +0°C/−5°C  
Time Within +5°C of Actual Peak  
20 sec to 30 sec  
Temperature (tP)  
3°C/sec max  
Ramp-Down Rate  
5 min max  
Time +25°C (t25°C) to Peak Temperature 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.  
Page 7 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
 
 
 
INMP441  
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS  
L/R  
WS  
SD  
4
3
2
1
6 GND  
7 VDD  
8 CHIPEN  
9 GND  
SCK  
BOTTOM VIEW  
(Not to Scale)  
Figure 3. Pin Configuration  
TABLE 6. PIN FUNCTION DESCRIPTIONS  
PIN NAME  
FUNCTION  
Serial-Data Clock for I²S Interface  
1
SCK  
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.  
2
SD  
3
4
WS  
L/R  
Serial Data-Word Select for I²S Interface  
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
6
7
8
9
GND  
Ground. Connect to ground on the PCB.  
GND  
Ground. Connect to ground on the PCB.  
VDD  
Power, 1.8 V to 3.3 V. This pin should be decoupled to Pin 6 with a 0.1 μF capacitor.  
Microphone Enable. When set low (ground), the microphone is disabled and put in power-  
down mode. When set high (VDD), the microphone is enabled.  
CHIPEN  
GND  
Ground. Connect to ground on the PCB.  
Page 8 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
 
 
INMP441  
TYPICAL PERFORMANCE CHARACTERISTICS  
10  
10  
8
6
4
0
2
0
–2  
–4  
–6  
–8  
–10  
–10  
–20  
50  
100  
1k  
10k  
10  
100  
1k  
10k  
FREQUENCY (Hz)  
FREQUENCY (Hz)  
Figure 4. Frequency Response Mask  
Figure 5. Typical Frequency Response (Measured)  
0
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
100  
1k  
10k  
FREQUENCY (Hz)  
Figure 6. Power-Supply Rejection (PSR) vs. Frequency  
Page 9 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
 
 
 
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: 1.1  
 
 
 
 
 
 
 
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.  
FROM VOLTAGE  
SYSTEM MASTER  
REGULATOR  
(DSP, MICROCONTROLLER,  
(1.8V TO 3.3V)  
CODEC)  
0.1µF  
0.1µF  
V
V
DD  
DD  
VDD  
VDD  
CHIPEN  
L/R  
SCK  
WS  
SD  
SCK  
CHIPEN  
L/R  
WS  
SD  
LEFT  
RIGHT  
INMP441  
INMP441  
100kΩ  
GND GND GND  
GND GND GND  
Figure 7. System Block Diagram  
Page 11 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
 
 
 
 
 
INMP441  
1
2
3
4
24  
25  
26  
32  
33  
34  
35  
36  
56  
57  
58  
64  
WS  
SCK (64 × fS  
)
SD (24-BIT)  
MSB  
LSB  
MSB  
LSB  
HIGH-Z  
LEFT CHANNEL  
HIGH-Z  
RIGHT CHANNEL  
HIGH-Z  
Figure 8. Stereo-Output I²S Format  
1
2
3
4
24  
25  
26  
32  
33  
34  
35  
36  
56  
57  
58  
64  
WS  
SCK (64 × fS  
)
SD (24-BIT)  
MSB  
LSB  
HIGH-Z  
HIGH-Z  
LEFT CHANNEL  
Figure 9. Mono-Output I²S Format Left Channel (L/R = 0)  
1
2
3
4
24  
25  
26  
32  
33  
34  
35  
36  
56  
57  
58  
64  
WS  
SCK (64 × fS  
)
SD (24-BIT)  
MSB  
LSB  
HIGH-Z  
RIGHT CHANNEL  
HIGH-Z  
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.  
1.0  
0.8  
0.6  
0.4  
0.2  
0
–0.2  
–0.4  
–0.6  
–0.8  
–1.0  
0
0.1  
0.2  
0.3  
0.4  
0.5  
0.6  
0.7  
0.8  
0.9  
1.0  
TIME (ms)  
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.  
Page 12 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
 
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  
21.6 Hz  
0.5 dB  
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: 1.1  
 
 
 
 
 
INMP441  
0
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
0
0.1  
0.2  
0.3  
0.4  
0.5  
0.6  
0.7  
0.8  
0.9  
1.0  
NORMALIZED FREQUENCY (fS  
)
Figure 12. Digital Low-Pass Filter Magnitude Response  
Page 14 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
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.  
V
GND  
DD  
CAPACITOR  
TO V  
DD  
TO GND  
Figure 13. Recommended Power-Supply Bypass Capacitor Layout  
Page 15 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
 
 
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: 1.1  
 
 
 
 
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.  
1.05  
(6×)  
0.25 DIA.  
(THRU HOLE)  
2.66 (4×)  
0.96 1.33 (2×)  
1.56  
3.16  
0.40 × 0.60  
(8×)  
DIMENSIONS SHOWN IN MILLIMETERS  
Figure 14. Suggested PCB Land Pattern Layout  
1.05  
(6×)  
0.20  
1.05  
2.66 (4×)  
3.76  
1.33 (2×)  
1.6  
1.07  
0.350 × 0.550  
(8×)  
4.72  
DIMENSIONS SHOWN IN MILLIMETERS  
Figure 15. Suggested Solder Paste Stencil Pattern Layout  
Page 17 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
 
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.  
Page 18 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
 
 
 
 
 
INMP441  
OUTLINE DIMENSIONS  
4.82  
4.72  
4.62  
0.30  
E
REFERENC  
CORNER  
1.07  
4.10 REF  
1.05 BSC  
0.40 × 0.60  
(PINS 1-8)  
PIN 1  
1.56 DIA.  
0.96 DIA.  
1
4
0.275  
0.250 DIA.  
0.225  
1.33 BSC  
3.86  
3.76  
3.66  
2.66 BSC  
5
3.14  
REF  
9
6
TOP VIEW  
SIDE VIEW  
BOTTOM VIEW  
1.05  
0.98  
0.88  
0.73 REF  
0.24 REF  
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  
PART NUMBER  
PIN 1 INDICATION  
441  
YYXXXX  
DATECODE  
LOT TRACEABILITY CODE  
Figure 17. Package Marking Specification (Top View)  
Page 19 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
 
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  
EV_INMP441  
* – 13” Tape and Reel  
Flexible Evaluation Board  
Evaluation Board  
† – 7” Tape and reel to be discontinued. Contact sales@invensense.com for availability.  
REVISION HISTORY  
REVISION DATE  
REVISION DESCRIPTION  
02/06/2014  
05/21/2014  
1.0  
1.1  
Initial Release  
Updated Compliance Disclaimer  
Page 20 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
 
 
INMP441  
COMPLIANCE DECLARATION DISCLAIMER  
InvenSense believes the environmental and other compliance information given in this document to be correct but cannot  
guarantee accuracy or completeness. Conformity documents substantiating the specifications and component characteristics 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.  
Page 21 of 21  
Document Number: DS-INMP441-00  
Revision: 1.1  
 

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