CS7331P
Miniature Bottom Port Analog MEMS Microphone
Features
Description
• High acoustic overload point (AOP, 124-dB SPL)
The CS7331P is a low-profile analog MEMS microphone. It
offers miniature dimensions and low-current consumption,
making it ideal for always-on, always-listening use in
space-constrained applications.
• High signal-to-noise ratio (63-dB SNR)
• Low variation in sensitivity (±1 dB)
• Low current consumption (55 A)
The CS7331P incorporates Cirrus Logic® proprietary
CMOS/MEMS membrane technology, offering high
reliability and high performance. The CS7331P is designed
to withstand the high temperatures associated with
automated flow solder assembly processes.
• Analog output
• Bottom-port LGA package
• 1.6- to 3.6-V supply
The CS7331P is ideally suited to the Cirrus Logic
SoundClear™ suite of audio processing algorithms,
including speech recognition, voice trigger, and noise
cancelation.
The CS7331P is available in a 2.5 × 1.6 × 0.9-mm,
bottom-port LGA package, with a 0.25-mm port diameter. It
is ideal for portable applications such as noise-canceling
earbuds, smartphones, wearables, and cameras.
VDD
MEMS
Transducer
GND
CMOS ASIC
Biasing
High
Performance
Amp
Preliminary Product Information
This document contains information for a new product.
Cirrus Logic reserves the right to modify this product without notice.
Cirrus Logic Confidential
http://www.cirrus.com
OUTPUT
Copyright Cirrus Logic, Inc. 2016–2017
(All Rights Reserved)
DS1165PP1
FEB '17
CS7331P
Table of Contents
1 Pin Descriptions ........................................................................................................................................................... 3
1.1 LGA Pinout ............................................................................................................................................................ 3
1.2 Pin Descriptions ..................................................................................................................................................... 3
2 Typical Connection Diagram ....................................................................................................................................... 4
3 Characteristics and Specifications ............................................................................................................................. 4
Table 3-1. Parameter Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Table 3-2. Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Table 3-3. Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Table 3-4. Acoustic and Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Typical Performance .................................................................................................................................................... 6
4.1 Audio Frequency Response .................................................................................................................................. 6
4.2 Ultrasonic Frequency Response ........................................................................................................................... 6
4.3 Phase Response ................................................................................................................................................... 7
4.4 THD Performance .................................................................................................................................................. 7
4.5 PSRR Performance ............................................................................................................................................... 8
5 Applications Information ............................................................................................................................................. 8
5.1 Important Assembly Guidelines ............................................................................................................................. 8
5.2 PCB Land Pattern and Paste Stencil ..................................................................................................................... 9
6 Package Dimensions .................................................................................................................................................. 10
7 Ordering Information .................................................................................................................................................. 10
8 References .................................................................................................................................................................. 10
9 Revision History ......................................................................................................................................................... 10
2
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CS7331P
1 Pin Descriptions
1 Pin Descriptions
1.1 LGA Pinout
3
4
1
2
Figure 1-1. Top-Down (Through-Package) View
1.2 Pin Descriptions
A description of each pin on the CS7331P is provided in Table 1-1.
Table 1-1. Pin Descriptions
Name
3
Pin #
I/O
Description
VDD
1
—
OUTPUT
2
O
Microphone analog output signal
GND
3
—
Ground
GND
4
—
Can be left floating (recommended), or connected to GND
Power supply
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CS7331P
2 Typical Connection Diagram
2 Typical Connection Diagram
CS7331P
OUTPUT
Audio Codec
C
INPUT
1 F
VDD
GND
0.1 F
1.8 V
Figure 2-1. Typical Connection Diagram
The recommended connection of a CS7331P silicon microphone is shown in Fig. 2-1.
A DC-blocking capacitor is required on the OUTPUT pin. The capacitor must be correctly selected as it affects the cut-off
frequency of the output path. A low cut-off frequency is desirable to ensure there is no significant filtering of the audio
bandwidth.
The 3-dB cut-off frequency of the output path can be calculated using Eq. 2-1, where C is the output capacitance and R
is the input resistance of the audio codec.
3-dB filter cut-off frequency
=
1
---------------2RC
Equation 2-1. Low-Pass Filter Calculation
A typical recommended configuration uses a 1-F DC-blocking capacitor and a 20-k codec input impedance, which
results in a 3-dB cut-off frequency of 10 Hz or less. Tantalum electrolytic capacitors are particularly suitable for the
DC-blocking components as they offer high stability in a small package size.
It is also recommended to place a 0.1-F decoupling capacitor close to the VDD pin of the CS7331P.
3 Characteristics and Specifications
Table 3-1. Parameter Definitions
Parameter
Definition
A measure of the microphone output response to the acoustic pressure of a 1-kHz, 94 dB SPL (1 Pa RMS)
sine wave.
Total harmonic distortion (THD) The ratio of the RMS sum of the harmonic distortion products in the specified bandwidth (see note) relative
to the RMS amplitude of the fundamental (i.e., test frequency) output.
Signal-to-noise ratio (SNR)
A measure of the difference in level between the output response of a 1-kHz, 94 dB SPL sine wave and the
idle noise output.
Dynamic Range (DR)
The ratio of the 10% THD microphone output level (in response to a sine wave input) and the idle noise
output.
Note: Unless otherwise specified, all performance measurements are specified with a 20-kHz, low-pass brick-wall filter and, where noted, an
A-weighted filter. The low-pass filter removes out-of-band noise.
Sensitivity
Table 3-2. Recommended Operating Conditions
Parameter
Analog supply range
Ground
Operating temperature range
4
Symbol
VDD
GND
TA
Cirrus Logic Confidential
Min
1.6
—
–40
Typ
1.8
0
—
Max
3.6
—
+85
Units
V
V
ºC
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CS7331P
3 Characteristics and Specifications
Table 3-3. Absolute Maximum Ratings
Absolute maximum ratings are stress ratings only. Permanent damage to the device may be caused by continuously operating at or beyond these limits.
Device functional operating limits and guaranteed performance specifications are given under electrical characteristics at the test conditions specified.
Parameter
Symbol
Min
Max
Units
VDD
–0.3
4.2
V
Supply voltage 1
Operating temperature range
TA
–40
+105
ºC
Storage temperature prior to soldering
TStgp
—
30
ºC
Storage relative humidity prior to soldering
RHStgp
—
60
%
Storage temperature after soldering
TStg
–40
+105
ºC
ESD-sensitive device. The CS7331P is manufactured on a CMOS process. It is therefore generically susceptible to damage from
excessive static voltages. Proper ESD precautions must be taken during handling and storage of this device. This device is
qualified to current JEDEC ESD standards
1.All voltages are measured with respect to GND.
Table 3-4. Acoustic and Electrical Characteristics
Test conditions (unless specified otherwise): GND = 0 V; voltages are with respect to ground; performance data taken with VDD = 1.8 V, RL = 10 k,
CL = 100 pF, TA = +25ºC, 55 ±15% RH; 1 kHz test signal.
Parameter 1
Directivity
Polarity
Sensitivity
Acoustic overload
THD
SNR
DR
Acoustic noise floor
Electrical noise floor
PSRR (with respect to VDD)
PSR (with respect to VDD)
Frequency response
Frequency response flatness
Part-to-part phase matching
Min
Positive sound pressure
THD < 10%
94 dB SPL
114 dB SPL
120 dB SPL
A-weighted
A-weighted
A-weighted
A-weighted
217 Hz sine wave, 100 mV (peak-peak)
217 Hz square wave, 100 mV (peak-peak)
–3 dB low frequency
+3 dB high frequency
200 Hz–7 kHz
80–100 Hz
200 Hz
Current consumption
Output DC impedance
Typ
Max
Omnidirectional
Positive output voltage
–39
–38
–37
—
124
—
—
0.04
—
—
0.3
—
—
1
—
—
63
—
—
93
—
—
31
—
—
–101
—
—
62
—
—
–88
—
—
85
—
—
15
—
–1
—
+1
—
—
±10
—
—
±5
—
55
60
—
200
400
Units
—
—
dBV
dB SPL
%
%
%
dB
dB
dB SPL
dBV
dB
dBV
Hz
kHz
dB
°
°
A
1.All performance measurements are specified with a 20-kHz, low-pass brick-wall filter and, where noted, an A-weighted filter. The low-pass filter
removes out-of-band noise.
5
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CS7331P
4 Typical Performance
4 Typical Performance
4.1 Audio Frequency Response
Test conditions: VDD = 1.8 V, GND = 0 V, no output load.
10.0
9.0
8.0
7.0
6.0
5.0
Sensitivity (dB) wrt. Sensitivity @ 1kHz
4.0
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
-4.0
-5.0
-6.0
-7.0
-8.0
-9.0
-10.0
-11.0
-12.0
-13.0
-14.0
-15.0
10
100
1000
10000
100000
Frequency (Hz)
Figure 4-1. Sensitivity vs. Audio Frequency (20 Hz–20 kHz)
4.2 Ultrasonic Frequency Response
Sensitivity (dB) wrt. Sensitivity @ 1kHz
Test conditions: VDD = 1.8 V, GND = 0 V, no output load.
20.0
19.0
18.0
17.0
16.0
15.0
14.0
13.0
12.0
11.0
10.0
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
-4.0
-5.0
-6.0
-7.0
-8.0
-9.0
-10.0
-11.0
-12.0
-13.0
-14.0
-15.0
20000
30000
40000
50000
60000
70000
80000
90000
100000
Frequency (Hz)
Figure 4-2. Sensitivity vs. Ultrasonic Frequency (20 kHz–100 kHz)
6
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CS7331P
4.3 Phase Response
4.3 Phase Response
Test conditions: VDD = 1.8 V, GND = 0 V, no output load.
100.0
90.0
80.0
70.0
60.0
Phase (o)
50.0
40.0
30.0
20.0
10.0
0.0
-10.0
-20.0
10
100
1000
10000
Frequency (Hz)
Figure 4-3. Phase Response vs. Frequency (20 Hz–10 kHz)
4.4 THD Performance
Test conditions: VDD = 1.8 V, GND = 0 V, no output load.
10.0
9.0
8.0
7.0
THD (%)
6.0
5.0
4.0
3.0
2.0
1.0
0.0
90.0
95.0
100.0
105.0
110.0
115.0
120.0
125.0
130.0
Input Sound Pressure Level (dB SPL)
Figure 4-4. THD (%) vs. Input Sound Pressure Level (dB SPL)
7
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CS7331P
4.5 PSRR Performance
4.5 PSRR Performance
Test conditions: VDD = 1.8 V, GND = 0 V, no output load.
70.0
68.0
66.0
64.0
62.0
60.0
PSRR (dB)
58.0
56.0
54.0
52.0
50.0
48.0
46.0
44.0
42.0
40.0
100
1000
10000
Frequency (Hz)
Figure 4-5. PSRR (dB) vs. Frequency (100 Hz–10 kHz)
5 Applications Information
Cirrus Logic provides a range of audio codecs incorporating an analog microphone input interface. These codecs support
direct connections to silicon microphones such as the CS7331P.
Further information on Cirrus Logic audio codecs is provided in the respective product data sheet, which is available from
the Cirrus Logic website.
5.1 Important Assembly Guidelines
8
•
Do not put a vacuum over the port hole of the microphone. Placing a vacuum over the port hole can damage the
device.
•
Do not board wash the microphone after a reflow process. Board washing and the associated cleaning agents can
damage the device.
•
Do not expose to ultrasonic cleaning methods.
•
Do not use a vapor phase reflow process. The vapor can damage the device.
•
Please refer to application note WAN0273 MEMS Mic Assembly and Handling Guidelines for further assembly and
handling guidelines.
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CS7331P
5.2 PCB Land Pattern and Paste Stencil
5.2 PCB Land Pattern and Paste Stencil
The recommended PCB Land Pattern and Paste Stencil Pattern for the CS7331P microphone are shown in Fig. 5-1 and
Fig. 5-2 respectively.
Note that no connection to Pin 4 should be made on the PCB. To avoid accidental connection to Pin 4, it is recommended
to ensure there are no exposed tracks, vias, or copper areas beneath Pin 4.
See also application note WAN0284 General Design Considerations for MEMS Microphones for further details of PCB
footprint design. Full definition of the package dimensions is provided in Section 6.
The recommended PCB Land Pattern is shown in Fig. 5-1.
Figure 5-1. PCB Land Pattern, Top View
The recommended PCB Paste Stencil Pattern is shown in Fig. 5-2.
Figure 5-2. PCB Paste Stencil, Top View
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CS7331P
6 Package Dimensions
6 Package Dimensions
B
( 1.150)
C
0.800
0.250 0.050
( 0.650)
(R0.200)
0.150
A
C A B
0.830
Pick Area
2.500
0.756
(2.240) (1.500)
3
4
2X 1.340
(R0.150)
0.260
2
1
2X (0.440)
(0.600)
4X
(0.230)
2X (0.470)
1.340
0.100 C
1.600
Top View
0.900
(0.720)
Side View
Bottom View
Unless otherwise specified, dimensions/tolerances are in millimeters and tolerance is
0.440
0.100
7 Ordering Information
Table 7-1. Ordering Information
Product
Description
CS7331P Miniature Bottom Port
Analog MEMS Microphone
Package
Halogen
Free
Pb
Free
Grade
LGA
Yes
Yes
Commercial
Temperature
Range
Container
–40 to +85°C Tape and Reel 1
Order #
CS7331P-CAZR
1.Reel quantity = 6,000 units.
8 References
•
WAN0273 MEMS Mic Assembly and Handling Guidelines
•
WAN0284 General Design Considerations for MEMS Microphones
9 Revision History
Table 9-1. Revision History
Revision
PP1
FEB ‘17
10
Changes
• PSRR performance plot added (Fig. 4-5).
• PCB land pattern and paste stencil drawings added (Section 5.2).
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9 Revision History
Contacting Cirrus Logic Support
For all product questions and inquiries, contact a Cirrus Logic Sales Representative.
To find the one nearest you, go to www.cirrus.com.
IMPORTANT NOTICE
“Preliminary” product information describes products that are in production, but for which full characterization data is not yet available. For the purposes of our
terms and conditions of sale, “Preliminary” or “Advanced” data sheets are nonfinal data sheets that include, but are not limited to, data sheets marked as “Target”,
“Advance”, “Product Preview”, “Preliminary Technical Data”, and/or “Preproduction”. Products provided with any such data sheet are therefore subject to relevant
terms and conditions associated with “Preliminary” or “Advanced” designations. The products and services of Cirrus Logic International (UK) Limited; Cirrus Logic,
Inc.; and other companies in the Cirrus Logic group (collectively either “Cirrus Logic” or “Cirrus”) are sold subject to Cirrus Logic’s terms and conditions of sale
supplied at the time of order acknowledgment, including those pertaining to warranty, indemnification, and limitation of liability. Software is provided pursuant to
applicable license terms. Cirrus Logic reserves the right to make changes to its products and specifications or to discontinue any product or service without notice.
Customers should therefore obtain the latest version of relevant information from Cirrus Logic to verify that the information is current and complete. Testing and
other quality control techniques are utilized to the extent Cirrus Logic deems necessary. Specific testing of all parameters of each device is not necessarily
performed. In order to minimize risks associated with customer applications, the customer must use adequate design and operating safeguards to minimize
inherent or procedural hazards. Cirrus Logic is not liable for applications assistance or customer product design. The customer is solely responsible for its selection
and use of Cirrus Logic products. Use of Cirrus Logic products may entail a choice between many different modes of operation, some or all of which may require
action by the user, and some or all of which may be optional. Nothing in these materials should be interpreted as instructions or suggestions to choose one mode
over another. Likewise, description of a single mode should not be interpreted as a suggestion that other modes should not be used or that they would not be
suitable for operation. Features and operations described herein are for illustrative purposes only.
CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR
ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). CIRRUS LOGIC PRODUCTS ARE NOT DESIGNED, AUTHORIZED OR WARRANTED FOR USE IN
PRODUCTS SURGICALLY IMPLANTED INTO THE BODY, AUTOMOTIVE SAFETY OR SECURITY DEVICES, NUCLEAR SYSTEMS, LIFE SUPPORT PRODUCTS OR
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RISK AND CIRRUS LOGIC DISCLAIMS AND MAKES NO WARRANTY, EXPRESS, STATUTORY OR IMPLIED, INCLUDING THE IMPLIED WARRANTIES OF
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CUSTOMER OR CUSTOMER’S CUSTOMER USES OR PERMITS THE USE OF CIRRUS LOGIC PRODUCTS IN CRITICAL APPLICATIONS, CUSTOMER AGREES, BY
SUCH USE, TO FULLY INDEMNIFY CIRRUS LOGIC, ITS OFFICERS, DIRECTORS, EMPLOYEES, DISTRIBUTORS AND OTHER AGENTS FROM ANY AND ALL
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This document is the property of Cirrus Logic and by furnishing this information, Cirrus Logic grants no license, express or implied, under any patents, mask work
rights, copyrights, trademarks, trade secrets or other intellectual property rights. Any provision or publication of any third party’s products or services does not
constitute Cirrus Logic’s approval, license, warranty or endorsement thereof. Cirrus Logic gives consent for copies to be made of the information contained herein
only for use within your organization with respect to Cirrus Logic integrated circuits or other products of Cirrus Logic, and only if the reproduction is without
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other copying such as copying for general distribution, advertising or promotional purposes, or for creating any work for resale. This document and its information
is provided “AS IS” without warranty of any kind (express or implied). All statutory warranties and conditions are excluded to the fullest extent possible. No
responsibility is assumed by Cirrus Logic for the use of information herein, including use of this information as the basis for manufacture or sale of any items, or
for infringement of patents or other rights of third parties. Cirrus Logic, Cirrus, the Cirrus Logic logo design, and SoundClear are among the trademarks of Cirrus
Logic. Other brand and product names may be trademarks or service marks of their respective owners.
Copyright © 2016–2017 Cirrus Logic, Inc. All rights reserved.
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