WM7230, WM7230E w Bottom Port Digital Silicon Microphone DESCRIPTION FEATURES The WM7230 is a low-profile silicon digital microphone. It offers high Signal to Noise Ratio (SNR) and low power consumption and is suited to a wide variety of consumer applications. • • High SNR; selectable sensitivity tolerance options WM7230 – SNR 61dB, Sensitivity +/-3dB WM7230E – SNR 61dB, Sensitivity +/-1dB Low power - The WM7230 incorporates Wolfson’s proprietary CMOS/MEMS membrane technology, offering high reliability and high performance in a miniature, low-profile package. The WM7230 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 WM7230 incorporates a high performance ADC, which outputs a single-bit Pulse Density Modulated (PDM) audio data stream. The WM7230 supports selectable left/right channel assignment for a two-channel digital microphone interface, enabling efficient connection of multiple microphones in stereo/array configurations. • • Low profile packaging Support for automated flow solder assembly • • PDM Digital audio output Stereo/array operation • Proprietary ADC technology Reduced clock jitter sensitivity - The WM7230E 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. Sleep Mode - 2μA Normal Operation - 700μA Low noise floor modulation Stable in overload condition • • Bottom Port Package 1.64V to 3.7V supply • 4.00 mm x 3.00 mm x 1.00mm Thin Package Design APPLICATIONS • • Mobile telephone handsets Portable computers • • Portable media players Digital still cameras • • Digital video cameras Bluetooth headsets • Portable navigation devices BLOCK DIAGRAM VDD CHARGE PUMP Transducer (CMOS MEMS) CLK AMP ADC CONTROL DAT LRSEL WM7230 GND WOLFSON MICROELECTRONICS plc Preliminary Technical Data, October 2012, Rev 2.4 Copyright ©2012 Wolfson Microelectronics plc WM7230 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 AUDIO INTERFACE TIMING ........................................................................................... 6 TYPICAL PERFORMANCE ................................................................................... 7 FREQUENCY RESPONSE .............................................................................................. 7 THD RATIO ...................................................................................................................... 7 APPLICATIONS INFORMATION .......................................................................... 8 RECOMMENDED EXTERNAL COMPONENTS .............................................................. 8 OPTIMISED SYSTEM RF DESIGN ................................................................................. 8 CONNECTION TO A WOLFSON AUDIO CODEC .......................................................... 8 RECOMMENDED PCB LAND PATTERNS ..................................................................... 9 PACKAGE DIMENSIONS (LGA) ......................................................................... 10 IMPORTANT NOTICE ......................................................................................... 11 ADDRESS: ..................................................................................................................... 11 REVISION HISTORY ........................................................................................... 12 w PTD, Rev 2.4, October 2012 2 WM7230 Preliminary Technical Data PIN CONFIGURATION PIN DESCRIPTION PIN NAME TYPE 1 CLK Digital Input DESCRIPTION 2 DAT Digital Output 3 VDD Supply Power Supply 4 GND Supply Ground 5 LRSEL Digital Input Clock input PDM Data Output Channel Select 0 = Data output following falling CLK edge 1 = Data output following rising CLK edge ORDERING INFORMATION DEVICE DESCRIPTION Standard WM7230IMS/V MOISTURE SENSITIVITY LEVEL PEAK SOLDERING TEMPERATURE o MSL2A +260 C o MSL2A +260 C o MSL2A +260 C o MSL2A +260 C TEMPERATURE RANGE -40 to +100 C WM7230IMS/RV Standard (tape and reel) -40 to +100 C WM7230IMSE/V Standard Enhanced -40 to +100 C WM7230IMSE/RV Standard Enhanced (tape and reel) -40 to +100 C o o o o Note: Reel quantity = 4800 All devices are Pb-free and Halogen free. w PTD, Rev 2.4, October 2012 3 WM7230 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 <30°C / 85% Relative Humidity. Not normally stored in moisture barrier bag. MSL2 = out of bag storage for 1 year at <30°C / 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 <30°C / 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 GND-0.3V VDD+0.3V -40ºC +100ºC Voltage range digital inputs (LRSEL and CLK) Operating temperature range, TA Storage temperature prior to soldering 30°C 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 vapour phase re-flow process. The vapour can damage the device. Please refer to application note WAN0273 (MEMS MIC Assembly and Handling Guidelines) for further assembly and handling guidelines. RECOMMENDED OPERATING CONDITIONS SYMBOL MIN Digital Supply Range PARAMETER VDD 1.64 Ground GND Clock Frequency FCLK w TYP MAX UNIT 3.7 V 3.25 MHz 0 1 V PTD, Rev 2.4, October 2012 4 WM7230 Preliminary Technical Data ACOUSTIC AND ELECTRICAL CHARACTERISTICS Test Conditions: VDD=1.8V, 1kHz test signal, CLK=2.4MHz, TA = 25°C PARAMETER SYMBOL TEST CONDITIONS MIN Directivity TYP MAX UNIT dBFS Omni-directional Sensitivity (WM7230) S 94 dB SPL -29 -26 -23 Sensitivity (WM7230E) S 94 dB SPL -27 -26 -25 Acoustic Overload THD < 10% 120 dBFS dB SPL Signal to Noise Ratio SNR A-Weighted 61 Total Harmonic Distortion THD 100dB SPL 0.1 DR A-weighted noise floor to 1% THD 85 Frequency Response +3dB High frequency 17000 Hz Acoustic Noise Floor A-weighted 33 dB SPL A-weighted -87 dBFS 217Hz Square Wave -70 dBFS Dynamic Range Electrical Noise Floor Power Supply Rejection PSR dB 1 % dB 100mV pk-pk Digital Input / Output CLK Input HIGH Level VIH CLK Input LOW Level VIL DAT Output HIGH Level VOH IOH = +1mA DAT Output LOW Level VOL IOL = -1mA Input capacitance (CLK) Maximum load capacitance (DAT) 0.65 x VDD V 0.35 x VDD CIN 0.9 x VDD V ISC 0.1 x VDD V 100 pF 0.5 CLOAD Input Leakage Short Circuit Output Current V DAT connected to GND pF 1 μA 10 mA Miscellaneous Current Consumption Start-up Time CLK Sleep Frequency IVDD Active Mode 700 SLEEP Mode 2 From OFF 10 From SLEEP 10 μA 10 ms 1.0 kHz TERMINOLOGY 1. Sensitivity (dBFS) – Sensitivity is a measure of the microphone output response to the acoustic pressure of a 1kHz 94dB SPL (1Pa RMS) sine wave. This is referenced to the output Full Scale Range (FSR) of the microphone. 2. Full Scale Range (FSR) - Sensitivity, Electrical Noise Floor and Power Supply Rejection are measured with reference to the output Full Scale Range (FSR) of the microphone. FSR is defined as the amplitude of a 1kHz sine wave output whose positive peak value reaches 100% density of logic 1s and whose negative peak value reaches 0% density of logic 1s. This is the largest undistorted 1kHz sine wave that will fit in the digital output numerical range. Note that, because the definition of FSR is based on a sine wave, it is possible to support a square wave test signal output whose level is +3dBFS. 3. 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. Total Harmonic Distortion (%) – THD is the ratio of the RMS sum of the harmonic distortion products in the specified bandwidth (see note below) relative to the RMS amplitude of the fundamental (ie. test frequency) output. 4. 5. All performance measurements are carried out with 20kHz 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 brick wall filter removes out of band noise. w PTD, Rev 2.4, October 2012 5 WM7230 6. Preliminary Technical Data SLEEP Mode is enabled when the CLK input is below the CLK Sleep Frequency noted above. This is a power-saving mode. Normal operation resumes automatically when the CLK input is above the CLK Sleep Frequency. Note that the VDD supply is still required in SLEEP mode. AUDIO INTERFACE TIMING tCY CLK (input) DAT (LRSEL = 1) tL_DIS tL_EN DAT (LRSEL = 0) tR_DIS tR_EN DAT is high-impedance (hi-z) when not outputting data Figure 1 Digital Microphone Interface Timing Test Conditions The following timing information is valid across the full range of recommended operating conditions. PARAMETER SYMBOL MIN TYP MAX UNIT 308 1000 ns 60:40 40:60 Digital Microphone Interface Timing CLK cycle time tCY CLK duty cycle DAT enable from rising CLK edge (LRSEL = 1) tL_EN DAT disable from falling CLK edge (LRSEL = 1) tL_DIS DAT enable from falling CLK edge (LRSEL = 0) tR_EN DAT disable from rising CLK edge (LRSEL = 0) tR_DIS 18 ns 16 18 ns ns 16 ns Notes: 1. The DAT output is high-impedance when not outputting data; this enables the outputs of two microphones to be connected together with the data from one microphone interleaved with the data from the other. (The microphones must be configured to transmit on opposite channels in this case.) 2. In a typical configuration, the Left channel is transmitted following the rising CLK edge (LRSEL = 1). In this case, the Left channel should be sampled by the receiving device on the falling CLK edge, 3. Similarly, the Right channel is typically transmitted following the falling CLK edge (LRSEL = 0). In this case, the Right channel should be sampled by the receiving device on the rising CLK edge. w PTD, Rev 2.4, October 2012 6 WM7230 Preliminary Technical Data TYPICAL PERFORMANCE FREQUENCY RESPONSE Sensitivity vs. Frequency (Relative to Sensitivity @ 1kHz) 11.0 9.0 7.0 Sensitivity (dB) 5.0 3.0 1.0 ‐1.0 ‐3.0 ‐5.0 ‐7.0 ‐9.0 ‐11.0 10 100 1000 10000 Frequency (Hz) THD RATIO w PTD, Rev 2.4, October 2012 7 WM7230 Preliminary Technical Data APPLICATIONS INFORMATION RECOMMENDED EXTERNAL COMPONENTS It is recommended to connect a 0.1µF decoupling capacitor between the VDD and GND pins of the WM7230. A ceramic 0.1µF capacitor with X7R dielectric or better is suitable. The capacitor should be placed as close to the WM7230 as possible. OPTIMISED SYSTEM RF DESIGN For optimised RF design please refer to document WAN0278 (Recommended PCB Layout for Microphone RF Immunity in Mobile Cell Phone Applications) for further information. CONNECTION TO A WOLFSON AUDIO CODEC Wolfson provides a range of audio CODECs incorporating a digital microphone input interface; these support direction connection to digital microphones such as the WM7230. Stereo connection of two WM7230 digital microphones to the WM8994 CODEC is illustrated in Figure 2. A 0.1µF decoupling capacitor is recommended; this should be positioned close to the VDD pin of the WM7230. A ceramic 0.1µF capacitor with X7R dielectric or better is suitable. 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 supporting a digital microphone interface. Figure 2 Stereo WM7230 Digital Microphone Connection to WM8994 w PTD, Rev 2.4, October 2012 8 WM7230 Preliminary Technical Data RECOMMENDED PCB LAND PATTERNS Figure 3 Recommended Customer PCB Land Pattern (Note that all dimensions can be obtained from the package dimensions) w PTD, Rev 2.4, October 2012 9 WM7230 Preliminary Technical Data PACKAGE DIMENSIONS (LGA) w PTD, Rev 2.4, October 2012 10 Preliminary Technical Data WM7230 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 2.4, October 2012 11 WM7230 Preliminary Technical Data REVISION HISTORY DATE REV ORIGINATOR 20/10/10 1.0/2.0 PH CHANGES Front page description and features re-worded. Description of LRSEL pin updated. Electrical Characteristics re-ordered, and terminology updated. Microphone interface timing drawing and descriptions updated. Frequency response graph added. Illustration of recommended external components replaced with text. Connection to Wolfson CODEC text and illustration updated. Recommended PCB land patterns moved to Applications Information. 26/10/10 1.0/2.0 23/11/10 JMacD CST Package Diagram DM089.D added Specification of FSR corrected. Specification for THD corrected Time to data valid changed to minimum Grammatical errors 28/01/11 2.0 JMacD Reel quantity added to order information 01/05/11 2.1 JMacD Updated the LRSEL pin description , Timing diagram and notes for the rising and falling clock edges. Sleep mode current updated to 2uA Updated the reel quantity Updated the start up time Updated the new freq response and THD curves 06/09/11 2.1 JMacD Updated +3dB frequency cut off Updated VDD to 1.64V Package Diagram updated to DM089.E. References and dimension letters changed to be consistent with all mems package diagrams. Lid dimensions updated. Swapped dimensions L and E. Added marking area boundary 16/12/11 2.2 KC Introduced E variant with sensitivity +/-1dB Added E variant ordering info Added voltage range digital input Updated the CODEC to WM8994 Added Reference to WAN_0273 22/06/12 2.3 MR/JMacD Dynamic Range added, p5 Active mode current changed to 700uA, p1 and p5 CLK cycle time min and max updated, p6 Package Diagram updated to DM089F 08/10/12 2.4 w JMacD Optimised System RF Design added. PTD, Rev 2.4, October 2012 12