LMV1031 www.ti.com SNOSAP8B – SEPTEMBER 2005 – REVISED MAY 2013 LMV1031-20 Amplifier for Internal 3-Wire Analog Microphones and External Preamplifier Check for Samples: LMV1031 FEATURES DESCRIPTION • The LMV1031 audio amplifier is an ideal replacement for the JFET preamplifier that is currently used in the electret microphones. The LMV1031 is optimized for applications that require extended battery life, such as Bluetooth communication links. The supply current for the LMV1031 is only 72 μA. This is a dramatic reduction from that required for a JFET equipped microphone. The LMV1031, with its separate output and supply pins, offers a higher PSRR and eliminates the need for additional external components. 1 2 • • • • • • • • • (Typical LMV1031-20, 2V Supply; Unless Otherwise Noted) Signal to Noise Ratio 62 dB Output Voltage Noise (A-Weighted) −86 dBV Low Supply Current 72 μA Supply Voltage 2V to 5V Input Impedance >100 MΩ Max Input Signal 108 mVPP Output Voltage 1.09V Temperature Range −40°C to 85°C Large Dome 4-Bump DSBGA Package with Improved Adhesion Technology The LMV1031 has less than 200Ω of output impedance over the full audio bandwidth. The gain response of the LMV1031 is flat within the audio band and is stable over the temperature range. APPLICATIONS • • • • The LMV1031 is ensured to operate from 2V to 5V supply voltage over the full temperature range, has a fixed voltage gain of 20 dB and enhanced SNR performance. The LMV1031 is optimized for an output biasing of 1.09V. Mobile Communications - Bluetooth Accessory Microphone Products Cellular Phones PDAs The LMV1031 is available in a large dome 4-bump ultra thin DSBGA package that can easily fit on the PCB inside the miniature microphone metal can (package). This package is designed for microphone PCBs requiring 1 kg adhesion criteria. Block Diagram Electret Microphone DIAPHRAGM VDD xx xxx x x ELECTRET VIN VOUT 1x GAIN CONNECTOR x x IC VDC x GND AIRGAP BACKPLATE LMV1031 VCC x VOUT GND 1 2 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2005–2013, Texas Instruments Incorporated LMV1031 SNOSAP8B – SEPTEMBER 2005 – REVISED MAY 2013 www.ti.com These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. Absolute Maximum Ratings (1) (2) Human Body Model ESD Tolerance (3) 2500V Machine Model 250V Supply Voltage VDD - GND 5.5V −65°C to 150°C Storage Temperature Range Junction Temperature (4) 150°C max Mounting Temperature (1) (2) (3) (4) Infrared or Convection (20 sec.) 235°C Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but specific performance is not ensured. For specified specifications and the test conditions, see the Electrical Characteristics. If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and specifications. The human body model (HBM) is 1.5 kΩ in series with 100 pF. The machine model is 0Ω in series with 200 pF. The maximum power dissipation is a function of TJ(MAX) , θJA and TA. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(MAX) - TA)/θJA. All numbers apply for packages soldered directly onto a PC board. Operating Ratings (1) Supply Voltage 2V to 5V −40°C to +85°C Temperature Range (1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but specific performance is not ensured. For specified specifications and the test conditions, see the Electrical Characteristics. 2V and 5V Electrical Characteristics (1) Unless otherwise specified, all limits are specified for TJ = 25°C and VDD = 2V and 5V. Boldface limits apply at the temperature extremes. Symbol Parameter Conditions Min (2) Typ (3) Max (2) Units 72 90 100 μA IDD Supply Current VIN = GND SNR Signal to Noise Ratio f = 1 kHz, VIN = 18 mVPP 62 THD Total Harmonic Distortion f = 1 kHz, VIN = 18 mVPP 0.18 % en Output Noise A-Weighted −86 dBV AV Gain f = 1 kHz, VIN = 18 mVPP fLOW Lower −3 dB Roll Off Frequency RSOURCE = 50Ω, VIN = 18 mVPP 72 Hz fHIGH Upper −3 dB Roll Off Frequency RSOURCE = 50Ω, VIN = 18 mVPP 52 kHz VIN Max Input Signal f = 1 kHz and THD+N < 1% 108 mVPP ZIN Input Impedance >100 MΩ CIN Input Capacitance Output Voltage VIN = GND RO Output Impedance f = 1 kHz PSRR Power Supply Rejection Ratio 2V < VDD < 5V (2) (3) 2 20.1 20.90 21.00 2 VOUT (1) 19.18 19.00 dB 890 875 1090 dB pF 1310 1325 mV <200 Ω 56 dB Electrical table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very limited self-heating of the device such that TJ = TA. No ensuring of parametric performance is indicated in the electrical tables under conditions of internal self-heating where TJ > TA. All limits are specified by design or statistical analysis. Typical values represent the most likely parametric norm at the time of characterization. Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated Product Folder Links: LMV1031 LMV1031 www.ti.com SNOSAP8B – SEPTEMBER 2005 – REVISED MAY 2013 Connection Diagram A2 OUTPUT X A1 GND B2 VCC B1 INPUT Note: - Pin numbers are referenced to package marking text orientation. - The actual physical placement of the package marking will vary slightly from part to part. The package will designate the date code and will vary considerably. Package marking does not correlate to device type in any way. Figure 1. 4-Bump Ultra Thin DSBGA Top View Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated Product Folder Links: LMV1031 3 LMV1031 SNOSAP8B – SEPTEMBER 2005 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics Unless otherwise specified, VS = 2V, single supply, TA = 25°C Supply Current vs. Supply Voltage Output Voltage vs. Supply Voltage Figure 2. Figure 3. Gain vs. Supply Voltage Closed Loop Gain and Phase vs. Frequency 25 200 100 GAIN 15 0 10 -100 PHASE (o) GAIN (dB) 20 PHASE -200 5 0 10 100 1k 10k 100k -300 1M FREQUENCY (Hz) 4 Figure 4. Figure 5. Power Supply Rejection Ratio vs. Frequency Total Harmonic Distortion vs. Frequency Figure 6. Figure 7. Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated Product Folder Links: LMV1031 LMV1031 www.ti.com SNOSAP8B – SEPTEMBER 2005 – REVISED MAY 2013 Typical Performance Characteristics (continued) Unless otherwise specified, VS = 2V, single supply, TA = 25°C Total Harmonic Distortion vs. Input Voltage Output Voltage Noise vs. Frequency Figure 8. Figure 9. Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated Product Folder Links: LMV1031 5 LMV1031 SNOSAP8B – SEPTEMBER 2005 – REVISED MAY 2013 www.ti.com APPLICATION SECTION LOW CURRENT The LMV1031 has a low supply current which allows for a longer battery life. The low supply current of 72 μA makes this amplifier optimal for microphone applications which need to be always on. BUILT-IN GAIN The LMV1031 is offered in the space saving small DSBGA package which fits perfectly into the metal can of a microphone. This allows the LMV1031 to be placed on the PCB inside the microphone. The bottom side of the PCB has the pins that connect the supply voltage to the amplifier and make the output available. The input of the amplifier is connected to the microphone via the PCB. DIAPHRAGM xx xxx x x ELECTRET AIRGAP BACKPLATE CONNECTOR x x IC x LMV1031 VCC x VOUT GND Figure 10. Built-in Gain EXTERNAL PREAMPLIFIER APPLICATION The LMV1031 can also be used outside of an ECM as a space saving external preamplifier. In this application, the LMV1031 follows a phantom biased JFET microphone in the circuit. This is shown in Figure 11. The input of the LMV1031 is connected to the microphone via a 2.2 µF capacitor. The advantages of this circuit over one with only a JFET microphone are the additional gain and the high pass filter supplied by the LMV1031. The high pass filter makes the output signal more robust and less sensitive to low frequency disturbances. In this configuration the LMV1031 should be placed as close as possible to the microphone. VDD VDD 2.2 k: VDD VIN 2.2 PF JFET Microphone VOUT VOUT GND LMV1031 GND Figure 11. LMV1031 as external preamplifier 6 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated Product Folder Links: LMV1031 LMV1031 www.ti.com SNOSAP8B – SEPTEMBER 2005 – REVISED MAY 2013 A-WEIGHTED FILTER The human ear has a frequency range from 20 Hz to about 20 kHz. Within this range the sensitivity of the human ear is not equal for each frequency. To approach the hearing response weighting filters are introduced. One of those filters is the A-weighted filter. 10 0 -10 dBV -20 -30 -40 -50 -60 -70 10 1k 100 100k 10k FREQUENCY (Hz) Figure 12. A-Weighted Filter The A-weighted filter is commonly used in signal-to-noise ratio measurements, where sound is compared to device noise. It improves the correlation of the measured data to the signal-to-noise ratio perceived by the human ear. OUTPUT CURRENT The LMV1031 is designed for driving high ohmic loads with several milli amperes of output current. Figure 13 shows the gain performance of the LMV1031 versus the sinking and sourcing current. The gain remains constant within the shown output current range. This sets the operating range of the LMV1031 with respect to the output current. 2.0 NEGATIVE = SOURCING CURRENT POSITIVE = SINKING CURRENT 20 1.5 GAIN (dB) GAIN 1.0 15 VOUT 10 0.5 5 0.0 0 -2.0 OUTPUT VOLTAGE (V) 25 -0.5 -1.0 0.0 1.0 2.0 3.0 4.0 OUTPUT CURRENT (mA) Figure 13. Performance vs. Output Current Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated Product Folder Links: LMV1031 7 LMV1031 SNOSAP8B – SEPTEMBER 2005 – REVISED MAY 2013 www.ti.com MEASURING NOISE AND SNR The overall noise of the LMV1031 is measured within the frequency band from 10 Hz to 22 kHz using an Aweighted filter. The input of the LMV1031 is connected to ground with a 5 pF capacitor. A-WEIGHTED FILTER 5pF Figure 14. Noise Measurement Setup The signal-to-noise ratio (SNR) is measured with a 1 kHz input signal of 18 mVPP using an A-weighted filter. This represents a sound pressure level of 94 dB with a standard ECM sensitivity. No input capacitor is connected. SOUND PRESSURE LEVEL The volume of sound applied to a microphone is commonly stated as the pressure level with respect to the threshold of hearing of the human ear. This sound pressure level (SPL) in decibels is defined by: Sound pressure level (dB) = 20 log Pm/PO where • • Pm is the measured sound pressure PO is the threshold of hearing (20 µPa) In order to be able to calculate the resulting output voltage of the microphone for a given SPL, the sound pressure in dB SPL needs to be converted to the absolute sound pressure in dBPa. This is the sound pressure level in decibels which is referred to 1 Pascal (Pa). The conversion is given by: dBPa = dB SPL + 20*log 20 µPa dBPa = dB SPL - 94 dB Translation from absolute sound pressure level to a voltage is specified by the sensitivity of the microphone. A conventional microphone has a sensitivity of −44 dBV/Pa. ABSOLUTE SOUND PRESSURE [dBPa] -94dB SENSITIVITY [dBV/Pa] SOUND PRESSURE [dB SPL] VOLTAGE [dBV] Figure 15. dB SPL to dBV Conversion 8 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated Product Folder Links: LMV1031 LMV1031 www.ti.com SNOSAP8B – SEPTEMBER 2005 – REVISED MAY 2013 Example: Busy traffic is 70 dB VOUT = 70 −94 −44 = −68 dBV This is equivalent to 1.13 mVPP Since the LMV1031-20 has a gain of 10 times (20 dB) over the JFET, the output voltage of the microphone is 11.3 mVPP. By replacing the JFET with the LMV1031-20, the sensitivity of the microphone is −24 dBV/Pa (−44 + 20). LOW FREQUENCY CUT-OFF FILTER The LMV1031 has a low cut-off filter on the output of the microphone, to reduce low frequency noises, such as wind and vibration. This also helps to reduce the proximity effect in directional microphones. This effect occurs when the sound source is very close to the microphone. The lower frequencies are amplified which gives a bass sound. This amplification can cause an overload, which results in a distortion of the signal. Figure 16. Gain vs. Frequency The LMV1031 is optimized to be used in audio band applications. As shown in Figure 16, the LMV1031 provides a flat gain response within the audio band and offers excellent temperature stability. ADVANTAGE OF THREE PINS When implemented in an Electret Condenser Microphone (ECM) the LMV1031 adds the advantages of a three pin configuration. The third pin provides a low supply current, higher PSRR, and eliminates the need for additional external components. It is well known that cell phone microphones are sensitive to noise pick-up. A conventional JFET circuit is sensitive to noise pick-up because of its high output impedance, which is usually around 2.2 kΩ. The LMV1031 is less sensitive to noise pick-up because it provides separate output and supply pins. Using separate pins greatly reduces the output impedance. Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated Product Folder Links: LMV1031 9 LMV1031 SNOSAP8B – SEPTEMBER 2005 – REVISED MAY 2013 www.ti.com REVISION HISTORY Changes from Revision A (May 2013) to Revision B • 10 Page Changed layout of National Data Sheet to TI format ............................................................................................................ 9 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated Product Folder Links: LMV1031 PACKAGE OPTION ADDENDUM www.ti.com 3-May-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish (2) MSL Peak Temp Op Temp (°C) Top-Side Markings (3) LMV1031UR-20/NOPB ACTIVE DSBGA YPD 4 250 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM LMV1031URX-20/NOPB ACTIVE DSBGA YPD 4 3000 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM (4) -40 to 85 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) Multiple Top-Side Markings will be inside parentheses. Only one Top-Side Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Top-Side Marking for that device. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 1 Samples PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) LMV1031UR-20/NOPB DSBGA YPD 4 250 178.0 8.4 LMV1031URX-20/NOPB DSBGA YPD 4 3000 178.0 8.4 Pack Materials-Page 1 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 1.22 1.22 0.56 4.0 8.0 Q1 1.22 1.22 0.56 4.0 8.0 Q1 PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LMV1031UR-20/NOPB DSBGA YPD LMV1031URX-20/NOPB DSBGA YPD 4 250 210.0 185.0 35.0 4 3000 210.0 185.0 35.0 Pack Materials-Page 2 MECHANICAL DATA YPD0004 D 0.350±0.045 E URA04XXX (Rev D) D: Max = 1.184 mm, Min =1.123 mm E: Max = 1.184 mm, Min =1.123 mm 4215141/A NOTES: A. All linear dimensions are in millimeters. Dimensioning and tolerancing per ASME Y14.5M-1994. B. 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