ICS-40720
Ultra-Low Noise Microphone with Differential Output
APPLICATIONS
GENERAL DESCRIPTION
The ICS-40720 is an ultra-low noise, differential analog
output, bottom-ported MEMS microphone. The ICS-40720
includes a MEMS microphone element, an impedance
converter, a differential output amplifier and an enhanced RF
package. The ICS-40720’s 70 dB SNR and ±2 dB sensitivity
tolerance make it an excellent choice for microphone arrays
and far field voice control applications.
The ICS-40720 has a linear response up to 124 dB SPL with a
differential output sensitivity specification of −32 dBV. It can
be used in a single-ended mode with −38 dBV sensitivity and
the same high SNR.
The ICS-40720 is available in a small 4.00 mm × 3.00 mm ×
1.20 mm surface-mount package.
FUNCTIONAL BLOCK DIAGRAM
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Smartphones
Tablet Computers
Teleconferencing Systems
Digital Still and Video Cameras
Bluetooth Headsets
Security and Surveillance
Microphone Arrays
Voice Control and Activation
FEATURES
•
•
•
•
•
•
•
•
•
•
•
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Ultra-High 70 dBA SNR
−32 dBV Differential Sensitivity, −38 dBV SingleEnded Sensitivity
±2 dB Sensitivity Tolerance
Small 4 × 3 × 1.2 mm Surface-Mount Package
Non-Inverted Signal Output
Extended Frequency Response from 75 Hz to 20 kHz
Enhanced RF Performance
285 µA Current Consumption
124 dB SPL Acoustic Overload Point
−77 dBV PSR
Compatible with Sn/Pb and Pb-Free Solder Processes
RoHS/WEEE Compliant
ORDERING INFORMATION
PART
OUTPUT
AMPLIFIER
ICS-40720
OUTPUT+
ICS-40720
EV_ICS-40720-FX
TEMP RANGE
PACKAGING
−40°C to +85°C
—
13” Tape and Reel
—
OUTPUT−
POWER
VDD GND
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-000045
Revision: 1.4
Rev Date: 07/03/2019
ICS-40720
TABLE OF CONTENTS
General Description ..................................................................................................................................................................... 1
Applications ................................................................................................................................................................................. 1
Features ....................................................................................................................................................................................... 1
Functional Block Diagram ............................................................................................................................................................ 1
Ordering Information ................................................................................................................................................................... 1
Table of Contents .................................................................................................................................................................................... 2
Specifications .......................................................................................................................................................................................... 3
Table 1. Electrical Characteristics ................................................................................................................................................ 3
Absolute Maximum Ratings .................................................................................................................................................................... 4
Table 2. Absolute Maximum Ratings ........................................................................................................................................... 4
ESD Caution ................................................................................................................................................................................. 4
Soldering Profile........................................................................................................................................................................... 5
Table 3. Recommended Soldering Profile*.................................................................................................................................. 5
Pin Configurations And Function Descriptions ....................................................................................................................................... 6
Table 4. Pin Function Descriptions............................................................................................................................................... 6
Typical Performance Characteristics ....................................................................................................................................................... 7
Theory Of Operation ............................................................................................................................................................................... 8
Balanced Output .......................................................................................................................................................................... 8
Single-Ended Operation ............................................................................................................................................................... 8
Applications Information ........................................................................................................................................................................ 9
Codec Connection ........................................................................................................................................................................ 9
Supporting Documents ......................................................................................................................................................................... 10
Evaluation Board User Guide ..................................................................................................................................................... 10
Application Notes ...................................................................................................................................................................... 10
PCB Design And Land Pattern Layout ................................................................................................................................................... 11
PCB Material And Thickness ...................................................................................................................................................... 11
Handling Instructions ............................................................................................................................................................................ 12
Pick And Place Equipment ......................................................................................................................................................... 12
Reflow Solder ............................................................................................................................................................................. 12
Board Wash................................................................................................................................................................................ 12
Outline Dimensions ............................................................................................................................................................................... 13
Ordering Guide .......................................................................................................................................................................... 13
Revision History ......................................................................................................................................................................... 14
Compliance Declaration Disclaimer ...................................................................................................................................................... 15
Document Number: DS-000045
Revision: 1.4
Page 2 of 15
ICS-40720
SPECIFICATIONS
TABLE 1. ELECTRICAL CHARACTERISTICS
TA = 25°C, VDD = 1.5 to 3.63 V, unless otherwise noted. Typical specifications are not guaranteed.
PARAMETER
PERFORMANCE
Directionality
Sensitivity
Signal-to-Noise Ratio (SNR)
Equivalent Input Noise (EIN)
Dynamic Range
Frequency Response
Total Harmonic Distortion (THD)
Power-Supply Rejection (PSR)
Power Supply Rejection Ratio (PSRR)
Acoustic Overload Point
POWER SUPPLY
Supply Voltage (VDD)
Supply Current (IS)
OUTPUT CHARACTERISTICS
Output Impedance
Output DC Offset
Maximum Output Voltage
Noise Floor
CONDITIONS
MIN
TYP
MAX
1 kHz, 94 dB SPL, differential
1 kHz, 94 dB SPL, single-ended
20 Hz to 20 kHz, A-weighted,
differential
20 Hz to 20 kHz, A-weighted,
single-ended
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
217 Hz, 100 mVp-p square wave
superimposed on VDD = 1.8 V,
A-weighted
1 kHz, 100 mV p-p sine wave
superimposed on VDD = 1.8 V
10% THD
−34
−40
Omni
−32
−38
−30
−36
dBA
70
dBA
24
dBA SPL
100
dB
75
>20
Hz
kHz
%
0.6
−77
dBV
−45
dB
124
dB SPL
3.63
V
350
375
µA
µA
VDD = 1.8 V
VDD = 3.3 V
285
Differential
750
Ω
Single-Ended, OUTPUT+
340
Ω
Single-Ended, OUTPUT−
410
Ω
OUTPUT+
0.66
V
OUTPUT−
0.70
V
Differential, 124 dB SPL input
0.79
V rms
Single-Ended, 124 dB SPL input
0.40
V rms
20 Hz to 20 kHz, A-weighted, rms
−102
dBV
Page 3 of 15
NOTES
dBV
dBV
70
1.5
Note 1: See Figure 3 and Figure 4.
Document Number: DS-000045
Revision: 1.4
UNITS
1
ICS-40720
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 2. ABSOLUTE MAXIMUM RATINGS
PARAMETER
Supply Voltage (VDD)
RATING
−0.3 V to +3.63 V
Sound Pressure Level
160 dB
Mechanical Shock
10,000 g
Vibration
Per MIL-STD-883 Method 2007, Test Condition B
Temperature Range
Biased
Storage
−40°C to +85°C
−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.
Document Number: DS-000045
Revision: 1.4
Page 4 of 15
ICS-40720
SOLDERING PROFILE
TEMPERATURE
CRITICAL ZONE
TL TO TP
tP
TP
RAMP-UP
TL
tL
TSMAX
TSMIN
tS
RAMP-DOWN
PREHEAT
t25°C TO PEAK TEMPERATURE
TIME
Figure 1. Recommended Soldering Profile Limits
TABLE 3. RECOMMENDED SOLDERING PROFILE*
PROFILE FEATURE
Average Ramp Rate (TL to TP)
Sn63/Pb37
1.25°C/sec max
Pb-Free
1.25°C/sec max
100°C
100°C
150°C
200°C
60 sec to 75 sec
1.25°C/sec
45 sec to 75 sec
60 sec to 75 sec
1.25°C/sec
~50 sec
183°C
217°C
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 (t25°C) to Peak Temperature
5 min max
5 min max
Minimum Temperature
(TSMIN)
Maximum
Preheat
Temperature (TSMAX)
Time (TSMIN to TSMAX), tS
Ramp-Up Rate (TSMAX to TL)
Time Maintained Above Liquidous (tL)
Liquidous Temperature (TL)
Peak Temperature (TP)
*Note: The reflow profile in Table 3 is recommended for board manufacturing with InvenSense MEMS microphones. All
microphones are also compatible with the J-STD-020 profile
Document Number: DS-000045
Revision: 1.4
Page 5 of 15
ICS-40720
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
GND
4
3
OUTPUT+
2
OUTPUT−
1
ICS-40720
VDD
TOP VIEW
(TERMINAL SIDE DOWN)
Not to Scale
Figure 2. Pin Configuration
TABLE 4. PIN FUNCTION DESCRIPTIONS
PIN
NAME
FUNCTION
1
2
VDD
OUTPUT−
Power Supply
Analog Output Signal−
3
4
OUTPUT+
GND
Analog Output Signal+
Ground
Document Number: DS-000045
Revision: 1.4
Page 6 of 15
ICS-40720
20
20
15
15
10
10
NORMALIZED AMPLITUDE (dB)
NORMALIZED AMPLITUDE (dB)
TYPICAL PERFORMANCE CHARACTERISTICS
5
0
–5
–10
5
0
–5
–10
–15
–15
–20
10
100
1k
–20
10k
10
100
1k
10k
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 3. Frequency Response Mask
Figure 4. Typical Frequency Response (Measured)
‐40
‐41
10
‐42
THD+N (%)
PSRR (dB)
‐43
‐44
‐45
‐46
1
0.1
‐47
‐48
‐49
0.01
‐50
90
100
1k
FREQUENCY (Hz)
95
10k
-5
0.75
-10
0.50
-15
0.25
OUTPUT (V)
1.00
-20
-25
OUTPUT AMPLITUDE (dBV)
0
120 dB
SPL
-0.50
-40
90
-1.00
124 dB SPL
128 dB
SPL
132 dB
SPL
0
130
Figure 7. Linearity
Document Number: DS-000045
Revision: 1.4
125
-0.25
-0.75
110
120
INPUT AMPLITUDE (dB SPL)
120
0.00
-35
100
105
110
115
INPUT (dB SPL)
Figure 6. THD + N vs. Input Level
Figure 5. Power-Supply Rejection Ratio (PSRR) vs. Frequency
-30
100
0.5
TIME (ms)
Figure 8 Clipping Characteristics
Page 7 of 15
1
130
ICS-40720
THEORY OF OPERATION
BALANCED OUTPUT
The ICS-40720 has a balanced differential output with 700 Ω output impedance. This configuration is compatible with a fullydifferential codec input and provides the benefits of a balanced signal between the microphone and codec. A balanced analog audio
signal provides rejection of common-mode noise that is present on both the positive and negative signals.
SINGLE-ENDED OPERATION
The ICS-40720 can be used as a single-ended microphone by using the signal from only one of the two output pins. In this
configuration, the sensitivity will be 6 dB lower than the differential output, but with the same high SNR performance. Pin OUTPUT+
will output the non-inverted signal, relative to the acoustic input, while the OUTPUT− pin will output an inverted signal. The unused
output pin should be left disconnected when the mic is used in single-ended mode; do not connect the unused pin to ground.
Document Number: DS-000045
Revision: 1.4
Page 8 of 15
ICS-40720
APPLICATIONS INFORMATION
CODEC CONNECTION
The ICS-40720 output can be connected to a dedicated codec microphone input (see Figure 9) or to a high input impedance gain
stage. A 0.1 µF ceramic capacitor placed close to the ICS-40720 supply pin is used for testing and is recommended to adequately
decouple the microphone from noise on the power supply. DC blocking capacitors are required at the outputs of the microphone.
These capacitors create a high-pass filter with a corner frequency at
fC = 1/(2π × C × R)
where R is the input impedance of the codec.
A minimum value of 2.2 μF is recommended in Figure 9 because the input impedance of some codecs can be as low as 2 kΩ at their
highest PGA gain setting, which results in a high-pass filter corner frequency at 37 Hz.
MICBIAS
0.1µF
CODEC
VDD
ICS-40720
OUTPUT+
2.2µF
MINIMUM
IN+
IN−
OUTPUT−
GND
Figure 9. ICS-40720 Connected to a Differential-Input Codec
Document Number: DS-000045
Revision: 1.4
Page 9 of 15
ICS-40720
SUPPORTING DOCUMENTS
For additional information, see the following documents.
EVALUATION BOARD USER GUIDE
AN-000012, Differential Analog Output MEMS Microphone Flex Evaluation Board
APPLICATION NOTES
AN-100, MEMS Microphone Handling and Assembly Guide
AN-1003, Recommendations for Mounting and Connecting the InvenSense Bottom-Ported MEMS Microphones
AN-1112, Microphone Specifications Explained
AN-1124, Recommendations for Sealing InvenSense Bottom-Port MEMS Microphones from Dust and Liquid Ingress
AN-1140, Microphone Array Beamforming
AN-1165, Op Amps for Microphone Preamp Circuits
AN-1181, Using a MEMS Microphone in a 2-Wire Microphone Circuit
Document Number: DS-000045
Revision: 1.4
Page 10 of 15
ICS-40720
PCB DESIGN AND LAND PATTERN LAYOUT
Lay out the PCB land pattern for the ICS-40720 at a 1:1 ratio to the solder pads on the microphone package (see Figure 10.) Take
care to avoid applying solder paste to the sound hole in the PCB. Figure 11 shows a suggested solder paste stencil pattern layout.
The response of the ICS-40720 is not affected by the PCB hole size, as long as the hole is not smaller than the sound port of the microphone (0.75 mm, or 0.0295 inch, in diameter). A 1 mm (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 10. Suggested PCB Land Pattern Layout
Figure 11. Suggested Solder Paste Stencil Pattern Layout
PCB MATERIAL AND THICKNESS
The performance of the ICS-40720 is not affected by PCB thickness. The ICS-40720 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.
Document Number: DS-000045
Revision: 1.4
Page 11 of 15
ICS-40720
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 1 and Table 3.
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.
Document Number: DS-000045
Revision: 1.4
Page 12 of 15
ICS-40720
OUTLINE DIMENSIONS
Figure 12. 4-Terminal Chip Array Small Outline No Lead Cavity
4 mm × 3 mm × 1.2 mm
Dimensions shown in millimeters
DATE COD E
LOT TR ACEABILIT Y
YYXXXX
720
PART NUMBE R
PIN 1 INDIC ATION
Figure 13. Package Marking Specification (Top View)
ORDERING GUIDE
PART
ICS-40720
EV_ICS-40720-FX
Document Number: DS-000045
Revision: 1.4
TEMP RANGE
−40°C to +85°C
PACKAGE
4-Terminal LGA_CAV
Flex Evaluation Board
Page 13 of 15
QUANTITY
5000
PACKAGING
13” Tape and Reel
ICS-40720
REVISION HISTORY
REVISION DATE
REVISION
DESCRIPTION
2/20/2015
1.0
Initial Version
05/07/2015
1.1
Removed Preliminary Technical Data from headers
5/26/2015
1.2
Corrected tape and reel quantities
1/20/2016
1.3
Corrected Package Marking Specification
07/03/2019
1.4
Table 3 and Formatting
Document Number: DS-000045
Revision: 1.4
Page 14 of 15
ICS-40720
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, Inc. (“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.
©2019 InvenSense. All rights reserved. InvenSense, MotionTracking, MotionProcessing, MotionProcessor, MotionFusion, MotionApps, DMP, AAR, and the InvenSense
logo are trademarks of InvenSense, Inc.
©2019 InvenSense. All rights reserved.
Document Number: DS-000045
Revision: 1.4
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