WM7121P WOLFSON | Alldatasheet
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w WM7121P, WM7121PE Top Port Analogue Silicon Microphone WOLFSON MICROELECTRONICS plc Pre-Production, June 2014, Rev 3.0 Copyright 2014 Wolfson Microelectronics plc
DESCRIPTION
The WM7121P 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 WM7121P incorporates Wolfson’s proprietary CMOS/MEMS membrane technology, offering high reliability and high performance in a miniature, low-profile package. The WM7121P 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 WM7121P Top Port microphone offers matched performance to the WM7132P Bottom Port microphone. The matched characteristics enable highly accurate sound pick- up in opposite directions, suitable for noise cancellation and other DSP algorithms. The WM7121PE 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 (65dB) Low variation in sensitivity - ±3dB tolerance (WM7121P) - ±1dB tolerance (WM7121PE) Matched pair with Bottom Port microphone WM7132P - Matched sensitivity, roll-off, and phase response Low current consumption (190µA) Analogue output Top Port LGA Package 1.5V to 3.7V supply
APPLICATIONS
Mobile phone handsets Portable media players Digital still cameras Digital video cameras Bluetooth headsets Portable navigation devices Portable games consoles BLOCK DIAGRAM 3D VIEW 3.76mm x 2.95mm x 1.10mm LGA package
WM7121P, WM7121PE Pre-Production w PP, June 2014, Rev 3.0 TABLE OF CONTENTS
Pre-Production WM7121P, WM7121PE w PP, June 2014, Rev 3.0 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 signal
ORDERING INFORMATION
DEVICE DESCRIPTION TEMPERATURE RANGE MOISTURE SENSITIVITY LEVEL PEAK SOLDERING TEMPERATURE WM7121PIMS/RV Standard (tape and reel) -40 to +100°C MSL2A +260°C WM7121PIMSE/RV Enhanced (tape and reel) -40 to +100°C MSL2A +260°C Note: Reel quantity = 5000 All devices are Pb-free and Halogen free.
WM7121P, WM7121PE Pre-Production w PP, June 2014, Rev 3.0 ABSOLUTE MAXIMUM RATINGS Absolute Maximum Ratings are stress ratings only. Permanent da mage 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 Operating temperature range, TA -40°C +100°C Storage temperature prior to soldering 30°C max / 60% RH max Storage temperature after soldering -40°C +100°C 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 (MEMS MIC Assembly and Handling Guidelines) 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 WM7121P, WM7121PE w PP, June 2014, Rev 3.0 ACOUSTIC AND ELECTRICAL CHARACTERISTICS Test Conditions: VDD=2.1V, 1kHz test signal, TA = 25°C, unless otherwise stated. PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT Directivity Omni-directional Polarity Positive sound pressure Positive output voltage Sensitivity (WM7121P) S 94dB SPL -41 -38 -35 dBV Sensitivity (WM7121PE) S 94dB SPL -39 -38 -37 dBV Acoustic Overload No Load, THD < 10% 126 dB SPL Total Harmonic Distortion THD 100dB SPL 0.1 1 % 114dB SPL 0.2 122dB SPL 1 Signal to Noise Ratio SNR A-weighted 65 dB Dynamic Range DR A-weighted 93 dB Frequency Response -3dB low frequency 62 Hz +3dB high frequency 15000 Frequency Response Flatness 200Hz to 6kHz -1 +1 dB Acoustic Noise Floor A-weighted 29 dB SPL Electrical Noise Floor A-weighted -103 dBV Power Supply Rejection Ratio PSRR 217Hz sine wave, 100mV (peak-peak) 46 dB Power Supply Rejection PSR 217Hz square wave, 100mV (peak-peak) -72 dBV Current Consumption I VDD 190 240 µA Output DC Impedance Z OUT 55 150 Ω TERMINOLOGY 1. Sensitivity (dBV) – Sensitivity is a measure of the micr ophone output response to the acoustic pressure of a 1kHz 94dB SPL (1Pa RMS) sine wave. 2. Total Harmonic Distortion (%) – THD is the ratio of the RMS sum of the harmonic distortion products in the specified bandwid th (see note below) relative to the amplitude of the fundamental (ie. test frequency) output. 3. Signal-to-Noise Ratio (dB) – SNR is a measure of the differ ence in level between the output response of a 1kHz 94dB SPL sine wave and the idle noise 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 within a 20Hz to 20kHz bandwidth 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.
WM7121P, WM7121PE Pre-Production w PP, June 2014, Rev 3.0 TYPICAL PERFORMANCE Sensitivity vs. Frequency PSRR vs. Frequency Sensitivity vs. Supply Voltage Current Consumption vs. Supply Voltage THD vs. Sound Pressure Level
Pre-Production WM7121P, WM7121PE w PP, June 2014, Rev 3.0 APPLICATIONS INFORMATION RECOMMENDED EXTERNAL COMPONENTS Figure 1 WM7121P 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 (Recommended PCB Layout for Microphone RF Immunity in Mobile Cell Phone Applications) for further information.
WM7121P, WM7121PE Pre-Production w PP, June 2014, Rev 3.0 PACKAGE DIMENSIONS
Pre-Production WM7121P, WM7121PE w PP, June 2014, Rev 3.0 IMPORTANT NOTICE Wolfson Microelectronics plc (“Wolfson”) products and services are sold subject to Wolfson’s terms and conditions of sale, deli very 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 righ t to make changes to its products and specifications or to disconti nue any product or service without notice. Customers should there fore 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 exte nt Wolfson deems necessary to support its warranty. Speci fic 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 safeguard s to minimise inherent or procedural hazards. Wolfson is not li able 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 c an 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 intellectua l 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, licen ce, 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 accompanie d 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 acc epted 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 the reon by any person. ADDRESS: Wolfson Microelectronics plc Westfield House
26 Westfield Road
Tel :: +44 (0)131 272 7000 Fax :: +44 (0)131 272 7001 Email :: sales@wolfsonmicro.com
WM7121P, WM7121PE Pre-Production w PP, June 2014, Rev 3.0
REVISION HISTORY
DATE REV DESCRIPTION OF CHANGES PAGE CHANGED BY 26/02/14 1.0 First Release IS 25/03/14 2.0 Formatting and miscellaneous updates throughout document Electrical Characteristics updated Package Outline Drawing updated 1-9 PH 13/06/14 3.0 Electrical Characteristics updated Typical Performance graphs added PCB Stencil drawings updated Package Outline Drawing updated PH
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