WM7132, WM7132E w Bottom Port Analogue Silicon Microphone DESCRIPTION FEATURES The WM7132 is a low-profile silicon analogue microphone. It offers high Signal to Noise Ratio (SNR) and low power consumption and is suited to a wide variety of consumer applications. The WM7132 incorporates Wolfson’s proprietary CMOS/MEMS membrane technology, offering high reliability and high performance in a miniature, low-profile package. The WM7132 is designed to withstand the high temperatures associated with automated flow solder assembly processes. (Note that conventional microphones can be damaged by this process.) The WM7132E variant offers a tighter tolerance on the microphone sensitivity, giving reduced variation between parts. This removes the need for in-line production calibration of part-to-part microphone variations. High SNR; selectable sensitivity tolerance options - WM7132 - SNR 65dB, Sensitivity +/-3dB - WM7132E - SNR 65dB, Sensitivity +/-1dB Matched performance to top port microphone WM7121 - Matched sensitivity performance - Matched frequency response - Matched phase response Low supply current 200µA Low profile packaging Support for automated flow solder assembly Analogue output Bottom Port Package 1.5V to 3.7V supply 3.76mm x 3.00mm x 1.10mm Package APPLICATIONS Mobile phone handsets Portable media players Digital still cameras Digital video cameras Bluetooth headsets Portable navigation devices Portable games consoles BLOCK DIAGRAM WOLFSON MICROELECTRONICS plc To receive regular email updates, sign up at http://www.wolfsonmicro.com/enews Preliminary Technical Data, October 2012, 2.0 Copyright 2012 Wolfson Microelectronics plc WM7132 Preliminary Technical Data TABLE OF CONTENTS DESCRIPTION ....................................................................................................... 1 FEATURES ............................................................................................................ 1 APPLICATIONS..................................................................................................... 1 BLOCK DIAGRAM ................................................................................................ 1 TABLE OF CONTENTS ......................................................................................... 2 PIN CONFIGURATION .......................................................................................... 3 PIN DESCRIPTION ................................................................................................ 3 ORDERING INFORMATION .................................................................................. 3 ABSOLUTE MAXIMUM RATINGS ........................................................................ 4 IMPORTANT ASSEMBLY GUIDELINES .............................................................. 4 RECOMMENDED OPERATING CONDITIONS ..................................................... 4 ACOUSTIC AND ELECTRICAL CHARACTERISTICS ......................................... 5 TERMINOLOGY ............................................................................................................... 5 TYPICAL PERFORMANCE ................................................................................... 6 FREQUENCY RESPONSE .............................................................................................. 6 THD RATIO ...................................................................................................................... 6 APPLICATIONS INFORMATION .......................................................................... 7 RECOMMENDED EXTERNAL COMPONENTS .............................................................. 7 OPTIMISED SYSTEM RF DESIGN ................................................................................. 7 CONNECTION TO A WOLFSON AUDIO CODEC .......................................................... 8 MATCHED MICROPHONE PAIRS .................................................................................. 9 RECOMMENDED PCB LAND PATTERNS ..................................................................... 9 PACKAGE DIMENSIONS .................................................................................... 10 IMPORTANT NOTICE ......................................................................................... 11 ADDRESS: ..................................................................................................................... 11 REVISION HISTORY ........................................................................................... 12 w PTD, Rev 2.0, October 2012 2 WM7132 Preliminary Technical Data PIN CONFIGURATION PIN DESCRIPTION PIN NAME TYPE 1 OUTPUT Analogue Output DESCRIPTION 2 GND Supply 3 GND Supply Analogue ground 4 VDD Supply Analogue supply 5 GND Supply Analogue ground 6 GND Supply Analogue ground Microphone analogue output signal Analogue ground ORDERING INFORMATION MOISTURE SENSITIVITY LEVEL PEAK SOLDERING TEMPERATURE o MSL2A +260 C o MSL2A +260 C o MSL2A +260 C o MSL2A +260 C DEVICE DESCRIPTION TEMPERATURE RANGE WM7132IMS/V Standard -40 to +100 C WM7132IMS/RV Standard (tape and reel) -40 to +100 C WM7132IMSE/V Enhanced -40 to +100 C WM7132IMSE/RV Enhanced (tape and reel) -40 to +100 C o o o o Note: Reel quantity = 5000 All devices are Pb-free and Halogen free. w PTD, Rev 2.0, October 2012 3 WM7132 Preliminary Technical Data 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. ESD Sensitive Device. This device is manufactured on a CMOS process. It is therefore generically susceptible to damage from excessive static voltages. Proper ESD precautions must be taken during handling and storage of this device. Wolfson tests its package types according to IPC/JEDEC J-STD-020 for Moisture Sensitivity to determine acceptable storage conditions prior to surface mount assembly. These levels are: MSL1 = unlimited floor life at <30C / 85% Relative Humidity. Not normally stored in moisture barrier bag. MSL2 = out of bag storage for 1 year at <30C / 60% Relative Humidity. Supplied in moisture barrier bag. MSL2A = out of bag storage for 4 weeks at <30°C / 60% Relative Humidity. Supplied in moisture barrier bag. MSL3 = out of bag storage for 168 hours at <30C / 60% Relative Humidity. Supplied in moisture barrier bag. The Moisture Sensitivity Level for each package type is specified in Ordering Information. CONDITION MIN MAX Supply Voltage (VDD) -0.3V +4.2V Operating temperature range, TA -40ºC +100ºC Storage temperature prior to soldering 30C max / 60% RH max Storage temperature after soldering -40ºC +100ºC IMPORTANT ASSEMBLY GUIDELINES 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 re-flow process. Board washing and the associated cleaning agents can damage the device. Do not expose to ultrasonic cleaning methods. Do not use a vapour phase re-flow process. The vapour can damage the device. Please refer to application note WAN0273 for further assembly and handling guidelines. RECOMMENDED OPERATING CONDITIONS PARAMETER SYMBOL MIN Analogue Supply Range VDD 1.5 Ground GND w TYP 0 MAX UNIT 3.7 V V PTD, Rev 2.0, October 2012 4 WM7132 Preliminary Technical Data ACOUSTIC AND ELECTRICAL CHARACTERISTICS Test Conditions: VDD=2.1V, 1kHz test signal, TA = 25°C PARAMETER SYMBOL TEST CONDITIONS MIN Sensitivity (WM7132) S 94dB SPL -41 -38 -35 dBV Sensitivity (WM7132E) S 94dB SPL -39 -38 -37 dBV Directivity TYP MAX UNIT Omni-directional Acoustic Overload No Load 126 dB SPL A-Weighted 65 dB THD < 10% Signal to Noise Ratio SNR Total Harmonic Distortion THD 104dB SPL 0.25 % DR A-Weighted, 91 dB Dynamic Range Noise floor to 1% THD Frequency Response -3dB Low Frequency 62 Hz +3dB High Frequency 15000 Hz Acoustic Noise Floor A-Weighted 29 dB SPL Electrical Noise Floor A-Weighted -103 dBV 100mV RMS, 217Hz 52 dB Power Supply Rejection Ratio PSRR Current Consumption IVDD 200 µA Output DC Impedance ZOUT 100 Ω TERMINOLOGY 1. Sensitivity (dBV) - Sensitivity is a measure of the microphone output response to the acoustic pressure of a 1kHz 94dB SPL (1Pa RMS) sine wave. 2. Signal-to-Noise Ratio (dB) – SNR is a measure of the difference in level between the output response of a 1kHz 94dB SPL sine wave and the idle noise output. 3. Total Harmonic Distortion (dB) – THD is the ratio of the RMS sum of the harmonic distortion products in the specified bandwidth (see note below) relative to the amplitude of the fundamental (ie. test frequency) output. 4. Dynamic Range (dB) – DR is the ratio of the 1% THD microphone output level (in response to a sine wave input) and the idle noise output level. 5. All performance measurements are carried out with 20 kHz low pass ‘brick wall’ filter and, where noted, an A-weighted filter. Failure to use these filters will result in higher THD and lower SNR values than are found in the Acoustic and Electrical Characteristics. The low pass filter removes out of band noise. w PTD, Rev 2.0, October 2012 5 WM7132 Preliminary Technical Data TYPICAL PERFORMANCE FREQUENCY RESPONSE Sensitivity vs frequency (Relative to Sensitivity @ 1kHz) 10.0 9.0 8.0 7.0 6.0 5.0 4.0 Sensitivity (dB) 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 10.0 100.0 1000.0 10000.0 100000.0 Frequency (Hz) THD RATIO w PTD, Rev 2.0, October 2012 6 WM7132 Preliminary Technical Data APPLICATIONS INFORMATION RECOMMENDED EXTERNAL COMPONENTS Figure 1 WM7132 Recommended External Components A DC-blocking output capacitor is required on the OUTPUT pin, as illustrated in Figure 1. A single capacitor is required for a single-ended connection. The capacitor must be correctly selected as it affects the cut-off frequency of the output path. A low cut-off frequency is desirable as it means there is no significant filtering of the audio bandwidth. The 3dB cut-off frequency of the output path is given by the equation below, where C is the output capacitance and R is the input resistance of the other circuit. A typical recommended configuration, with 1uF DC-blocking capacitor and 20kΩ minimum input circuit impedance, gives a 3dB cut-off frequency of 10Hz or less. Tantalum electrolytic capacitors are particularly suitable for the DC-blocking components as they offer high stability in a small package size OPTIMISED SYSTEM RF DESIGN For optimised RF design please refer to document WAN0278 for further information. w PTD, Rev 2.0, October 2012 7 WM7132 Preliminary Technical Data CONNECTION TO A WOLFSON AUDIO CODEC Wolfson provides a range of audio CODECs incorporating an analogue microphone input interface; these support connection to silicon microphones such as the WM7132. The recommended connection of a WM7132 silicon microphone to the WM8994 is illustrated in Figure 2 (for single-ended mode) and Figure 3 (for pseudo-differential mode). A DC blocking capacitor is required, as described in the previous section. A 1µF decoupling capacitor is also recommended; this should be positioned close to the VDD pin of the WM7132. Further information on the WM8994 is provided in the product datasheet, which is available from the Wolfson website. The equivalent connections can be made to other Wolfson devices in a similar manner. Figure 2 WM7132 Silicon Microphone Single-ended Connection to WM8994 Figure 3 WM7132 Silicon Microphone Pseudo-differential Connection to WM8994 w PTD, Rev 2.0, October 2012 8 WM7132 Preliminary Technical Data MATCHED MICROPHONE PAIRS WM7121 and WM7132 are sensitivity matched microphone pairs. The enhanced versions, WM7121E and WM7132E have tight tolerance of ±1dB and compatible output performance. These microphones are ideal for accurate sound pickup from opposite directions in slim profile applications. WM7121E should be positioned close to WM7132E on the same side of the PCB to maximise acoustic matching for effective DSP application. The WM7121 and WM7132 also have matched frequency response at both high and low frequencies, allowing simplified system design. RECOMMENDED PCB LAND PATTERNS 1.93mm Figure 4 Recommended Customer PCB Land Pattern (Note that all other dimensions can be obtained from the package dimensions) w PTD, Rev 2.0, October 2012 9 WM7132 Preliminary Technical Data PACKAGE DIMENSIONS w PTD, Rev 2.0, October 2012 10 Preliminary Technical Data WM7132 IMPORTANT NOTICE Wolfson Microelectronics plc (“Wolfson”) products and services are sold subject to Wolfson’s terms and conditions of sale, delivery and payment supplied at the time of order acknowledgement. Wolfson warrants performance of its products to the specifications in effect at the date of shipment. Wolfson 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 Wolfson to verify that the information is current. Testing and other quality control techniques are utilised to the extent Wolfson deems necessary to support its warranty. Specific testing of all parameters of each device is not necessarily performed unless required by law or regulation. In order to minimise risks associated with customer applications, the customer must use adequate design and operating safeguards to minimise inherent or procedural hazards. Wolfson is not liable for applications assistance or customer product design. The customer is solely responsible for its selection and use of Wolfson products. Wolfson is not liable for such selection or use nor for use of any circuitry other than circuitry entirely embodied in a Wolfson product. Wolfson’s products are not intended for use in life support systems, appliances, nuclear systems or systems where malfunction can reasonably be expected to result in personal injury, death or severe property or environmental damage. Any use of products by the customer for such purposes is at the customer’s own risk. Wolfson does not grant any licence (express or implied) under any patent right, copyright, mask work right or other intellectual property right of Wolfson covering or relating to any combination, machine, or process in which its products or services might be or are used. Any provision or publication of any third party’s products or services does not constitute Wolfson’s approval, licence, warranty or endorsement thereof. Any third party trade marks contained in this document belong to the respective third party owner. Reproduction of information from Wolfson datasheets is permissible only if reproduction is without alteration and is accompanied by all associated copyright, proprietary and other notices (including this notice) and conditions. Wolfson is not liable for any unauthorised alteration of such information or for any reliance placed thereon. Any representations made, warranties given, and/or liabilities accepted by any person which differ from those contained in this datasheet or in Wolfson’s standard terms and conditions of sale, delivery and payment are made, given and/or accepted at that person’s own risk. Wolfson is not liable for any such representations, warranties or liabilities or for any reliance placed thereon by any person. ADDRESS: Wolfson Microelectronics plc Westfield House 26 Westfield Road Edinburgh EH11 2QB Tel :: +44 (0)131 272 7000 Fax :: +44 (0)131 272 7001 Email :: [email protected] w PTD, Rev 2.0, October 2012 11 WM7132 Preliminary Technical Data REVISION HISTORY DATE REV ORIGINATOR 23/07/12 2.0 KC/JMacD w CHANGES PTD, Rev 2.0, October 2012 12