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w WM7120A,WM7120Ae top port analogue silicon microphone wolfson microelectronics plc to receive regular email updates, sign up at http://www.wolfsonmicro.com/enews pre-production, april 2012, rev 3.1 copyright ? 2012 wolfson microelectronics plc description the WM7120A 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 WM7120A incorporates wolfson?s proprietary cmos/mems membrane technology, offering high reliability and high performance in a miniature, low-profile package. the WM7120A 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 WM7120Ae 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. features ? high snr; selectable sensitivity tolerance options - WM7120A - snr 57db, sensitivity +/-3db - WM7120Ae - snr 57db, sensitivity +/-1db ? low supply current 140a ? low profile packaging ? support for automated flow solder assembly ? analogue output ? top port package ? 1.5v to 3.7v supply ? 3.76mm x 2.95mm 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
WM7120A pre-production w pp, rev 3.1, april 2012 2 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 ? connection to a wolfson audio codec .......................................................... 8 ? recommended pcb land patterns ..................................................................... 9 ? package dimensions .................................................................................... 10 ? important notice ......................................................................................... 11 ? address: ..................................................................................................................... 11 ? revision history ........................................................................................... 12 ?
pre-production WM7120A w pp, rev 3.1, april 2012 3 pin configuration pin description pin name type description 1 vdd supply analogue supply 2 gnd supply analogue ground 3 gnd supply analogue ground 4 output analogue output microphone analogue output ordering information device description temperature range moisture sensitivity level peak soldering temperature WM7120Aims/v standard -40 to +100 o c msl2a +260 o c WM7120Aims/rv standard (tape and reel) -40 to +100 o c msl2a +260 o c WM7120Aimse/v enhanced -40 to +100 o c msl2a +260 o c WM7120Aimse/rv enhanced (tape and reel) -40 to +100 o c msl2a +260 o c note: reel quantity = 5700 all devices are pb-free and halogen free.
WM7120A pre-production w pp, rev 3.1, april 2012 4 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 guar anteed 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 <30c / 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 -0.3v +4.2v operating temperature range, t a -40oc +100oc 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. for information on recommended pick and place vacuum point, refer to the package dimension drawing. 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 wan_0273 for further assembly and handling guidelines. recommended operating conditions parameter symbol min typ max unit analogue supply range vdd 1.5 3.7 v ground gnd 0 v
pre-production WM7120A w pp, rev 3.1, april 2012 5 acoustic and electrical characteristics test conditions: vdd=2.1v, 1khz test signal, t a = 25c parameter symbol test conditions min typ max unit directivity omni-directional sensitivity (WM7120A) s 94db spl -45 -42 -39 dbv sensitivity (WM7120Ae) s 94db spl -43 -42 -41 dbv acoustic overload no load thd < 10% 131 db spl signal to noise ratio snr a-weighted 57 db total harmonic distortion thd 104db spl 0.25 % dynamic range dr a-weighted, noise floor to 1% thd 88 db frequency response -3db low frequency +3db high frequency 62 9300 hz hz acoustic noise floor a-weighted 37 db spl electrical noise floor a-weighted -99 dbv power supply rejection ratio psrr 100mv rms, 217hz 50 db current consumption i vdd 140 190 a output dc impedance z out 100 ? 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 rms 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.
WM7120A pre-production w pp, rev 3.1, april 2012 6 typical performance frequency response \ 10.00 \ 8.00 \ 6.00 \ 4.00 \ 2.00 0.00 2.00 4.00 6.00 8.00 10.00 10.0 100.0 1000.0 10000.0 sensitivity (db) frequency (hz) sensitivity vs frequency (relative to sensitivity @ 1khz) thd ratio 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 90.0 95.0 100.0 105.0 110.0 115.0 120.0 125.0 130.0 135.0 thd (%) input sound pressure level (db spl) thd vs input sound pressure level
pre-production WM7120A w pp, rev 3.1, april 2012 7 applications information recommended external components figure 1 wm7120 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. t he 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 20k ? 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.
WM7120A pre-production w pp, rev 3.1, april 2012 8 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 WM7120A. the recommended connection of a WM7120A 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 1f decoupling capacitor is also recommended; this should be positioned close to the vdd pin of the WM7120A. 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 WM7120A silicon microphone single-ended connection to wm8994 figure 3 WM7120A silicon microphone pseudo-differential connection to wm8994
pre-production WM7120A w pp, rev 3.1, april 2012 9 recommended pcb land patterns 1.65 mm ?0.8 mm figure 4 recommended customer pcb land pattern (note that all other dimensions can be obtained from the package dimensions)
WM7120A pre-production w pp, rev 3.1, april 2012 10 package dimensions dm100.b d m e l a k j bottom view top view 0.1 c 0.1 c 0.05 -c- c side view d e dimensions (mm) symbols min nom max note a 3.66 3.76 3.86 2.95 2.85 3.05 1.10 1.03 1.17 notes: 1. the seating plane is represented by primary datum -c- 2. the deviation from the seating plane due to warpage or twist is specified as max 50 ? m (flatness). 3. lid should be parallel to the seating plane 50 ? m. f h p g 3 ms4: package 3.76 x 2.95 x 1.10 mm body 0.55 0.50 0.60 0.80 3 0.65 0.95 1 2 1 pnp vacuum point n 2 1.31 gasket area r 0.3 r 0.45 r 0.1 r 0.35 r 0.55 t s s 0.86 t 0.70 0.81 0.91 g 0.65 0.55 0.75 p 2.41 2.46 2.51 1.65 1.60 1.70 h 0.65 f 0.55 0.75 k 1.475 n 1.16 l 2.70 2.60 m 3.51 3.41 pin 1 corner pnp vacuum point j 1.18 1.33 1.03 1.325 1.625 21 3 4
pre-production WM7120A w pp, rev 3.1, april 2012 11 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 specific ations 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 informati on 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 nece ssarily 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. wolfs on 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 sy stems, 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 per missible only if reproduction is without alteration and is accompanied by all associated copyright, proprietary and other noti ces (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 :: sales@wolfsonmicro.com
WM7120A pre-production w pp, rev 3.1, april 2012 12 revision history date rev originator changes 02/05/11 2.0 jmacd first release of ae variant 2.0 kc added the WM7120Ae updated the features for WM7120Ae electrical noise floor to 101dbv updated the frequency response curve, the thd curves, updated the +3db frequency response to 9300hz. updated WM7120Ae frequency response performance, and sensitivity performance updated the reel quantity to 4800 remove the 20kohms test condition. modified the wording for 1uf and 20kohms to ensure 10hz low frequency cut off 2.0 jmacd package diagram updated to dm058e - tolerances adjusted and dimensions standardized - updated tolerances for measurements g and j 06/05/11 2.0 jmacd/mr acoustic and electrical char: acoustic overload updated to 131. 10/05/11 2.0 mr updated the -3db frequency response to 40hz. 07/06/11 2.1 kc change on the pin configuration and top view. 01/07/11 2.1 jmacd/mr package drawing update to reflect new pin numbering. 04/07/11 2.2 jmacd/mr order code for enhanced, 62hz roll off updated to: WM7120Aimse/v WM7120Aimse/rv 11/10/11 2.3 jmacd package diagram changed to dm100b. 09/09/11 3.0 kc added reference to wan_0273. updated the interface codec to wm8994. snr updated to 57db, noise floor to -99dbv and acoustic noise floor to 37 db spl. 20/02/12 3.1 kc/jmacd acoustic and electrical characteristics: sensitivity unit changed from db to dbv. updated the terminology 1. dynamic range added. dr definition added

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