TLV1018 www.ti.com .......................................................................................................................................... SLVS664A – OCTOBER 2008 – REVISED NOVEMBER 2008 AMPLIFIER FOR THREE-WIRE ANALOG ELECTRET MICROPHONES FEATURES APPLICATIONS • Output Voltage Noise (A Weighted): –89 dBV (Typ) • Low Supply Current: 70 µA (Typ) • Wide Supply Voltage Range: 1.7 V to 5 V • PSRR: 70 dB (Typ) • Signal-to-Noise Ratio: 61 dB (Typ) • Input Capacitance: 2 pF (Typ) • Input Impedance: >100 MΩ (Typ) • Output Impedance: <100 Ω (Typ) • Maximum Input Signal: 170 mVPP (Typ) • • • • • 1 2 Mobile Communications, Bluetooth Automotive Accessories Cellular Phones PDAs Accessory Microphone Products YDC PACKAGE (TOP VIEW) OUTPUT A2 B2 VCC GND A1 B1 INPUT DESCRIPTION/ORDERING INFORMATION The TLV1018 is an audio amplifier for small-form-factor electret microphones and is designed to replace the currently implemented JFET preamplifiers. The TLV1018 is ideal for extended battery-life applications, such as a Bluetooth™ communication link. The addition of a third pin to an electret microphone that incorporates a TLV1018 allows for a dramatic reduction in supply current compared to a JFET-equipped electret microphone. Microphone supply current is reduced to 70 µA, assuring longer battery life. The TLV1018 is specified for supply voltages from 1.7 V to 5 V and has fixed voltage gains of 15 dB and 25 dB. It offers low output impedance over the voice bandwidth, excellent power supply rejection (PSRR), and stability over temperature. The TLV1018 is offered in a space-saving four-terminal ultra-thin lead-free package (YDC) and is ideally suited for the form factor of miniature electret microphone packages. The TLV1018 is characterized for operation over a free-air temperature range of –40°C to 85°C. ORDERING INFORMATION (1) TA –40°C to 85°C (1) (2) PACKAGE (2) AV 15 dB 25 dB NanoStar™ WCSP (DSBGA) – YDC Reel of 3000 ORDERABLE PART NUMBER TOP-SIDE MARKING TLV1018-15YDCR Y28 TLV1018-25YDCR YW8 For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI web site at www.ti.com. Package drawings, thermal data, and symbolization are available at www.ti.com/packaging. 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. Bluetooth is a trademark of Bluetooth SIG. 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 © 2008, Texas Instruments Incorporated TLV1018 SLVS664A – OCTOBER 2008 – REVISED NOVEMBER 2008 .......................................................................................................................................... www.ti.com FUNCTIONAL BLOCK DIAGRAM VCC INPUT 1× Gain OUTPUT VDC GND ABSOLUTE MAXIMUM RATINGS (1) over operating free-air temperature range (unless otherwise noted) VCC Supply voltage VIN Input voltage –0.3 V to 5.5 V –0.3 V to 0.3 V θJA Thermal impedance, junction to free air TA Operating free-air temperature range –40°C to 85°C Tstg Storage temperature range –65°C to 150°C (1) (2) (2) 230.47°C/W Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. Package thermal impedance is calculated according to JESD 51-7. RECOMMENDED OPERATING CONDITIONS MIN MAX VCC Supply voltage 1.7 5 V TA Operating free-air temperature –40 85 °C 2 Submit Documentation Feedback UNIT Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TLV1018 TLV1018 www.ti.com .......................................................................................................................................... SLVS664A – OCTOBER 2008 – REVISED NOVEMBER 2008 ELECTRICAL CHARACTERISTICS over recommended operating conditions (unless otherwise noted) PARAMETER ICC SNR Supply current Signal-to-noise ratio TEST CONDITIONS VIN = GND Power-supply rejection ratio TLV1018-25 25°C 61 VCC = 5 V, VIN = 18 mVPP, f = 1 kHz TLV1018-15 25°C 61 TLV1018-25 25°C 62 VCC = 1.7 V to 5 V RSOURCE = 50 Ω, VIN = 18 mVPP en Output noise A-weighted 25°C 70 25°C 75 TLV1018-25 25°C 75 TLV1018-15 25°C –89 TLV1018-25 25°C –80 f = 1 kHz Output current VCC = 5 V, VOUT = 1.7 V, Sinking VCC = 5 V, VOUT = 0 V, Sourcing Input capacitance Input impedance Gain 25°C Hz kHz dBV 750 Full range 400 25°C 0.9 Full range 0.5 25°C 0.3 Full range 0.2 25°C 0.9 Full range 0.5 25°C 0.4 Full range 0.1 Ω 2.3 1.5 2.6 0.13 0.2 25°C 14.8 25°C Full range 24 % 2 pF >100 MΩ 15.4 16 25.5 26.2 14 24.8 mA 2.9 25°C Full range 17 Product Folder Link(s): TLV1018 dB 27 Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated mV 800 <100 25°C TLV1018-25 mVPP 600 TLV1018-25 f = 1 kHz, VIN = 18 mVPP dB 500 250 TLV1018-15 TLV1018-15 AV 25°C Full range 25°C VCC = 1.7 V, VOUT = 0 V, Sourcing ZIN 50 TLV1018-15 VCC = 1.7 V, VOUT = 1.7 V, Sinking CIN Full range µA dB 65 60 VIN = GND f = 1 kHz, VIN = 18 mVPP 55 170 TLV1018-25 Total harmonic distortion 50 25°C 25°C TLV1018-15 THD Full range UNIT 70 25°C RSOURCE = 50 Ω, VIN = 18 mVPP Upper –3-dB roll-off frequency 55 TLV1018-25 Lower –3-dB roll-off frequency fHIGH 25°C TLV1018-15 fLOW IOUT 100 61 f = 1 kHz, THD+N < 1% Output impedance 90 25°C Input voltage ZOUT MAX 70 TLV1018-15 VIN Output voltage TYP VCC = 1.7 V, VIN = 18 mVPP, f = 1 kHz TLV1018-25 VOUT MIN Full range TLV1018-15 PSRR TJ 25°C 3 TLV1018 SLVS664A – OCTOBER 2008 – REVISED NOVEMBER 2008 .......................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS SUPPLY CURRENT vs SUPPLY VOLTAGE CLOSED LOOP GAIN AND PHASE vs FREQUENCY 180 30 85 25 80 135 Gain 20 90 15 TA = 25°C 10 Gain – dB ICC – µA TA = 125°C TA = -40°C 70 5 0 0 Phase -5 -45 Phase – ° 45 75 -10 -90 -15 65 -20 -135 -25 -30 60 1.5 2.0 2.5 3.0 3.5 4.0 4.5 -180 10 5.0 100 1k 10k 100k 1M Frequency (Hz) VCC – V POWER SUPPLY REJECTION RATIO vs FREQUENCY TOTAL HARMONIC DISTORTION + NOISE vs FREQUENCY 120 0.6 VS = 1.7 V 100 0.5 80 0.4 THD+N – % PSRR – dB VIN = 18 mVpp 60 40 0.3 0.2 20 0.1 0 10 100 1k 1,000 Frequency – Hz 10k 10,000 100k 100,000 0 10 100 1,000 10,000 100,000 Frequency – Hz 4 Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TLV1018 TLV1018 www.ti.com .......................................................................................................................................... SLVS664A – OCTOBER 2008 – REVISED NOVEMBER 2008 TYPICAL CHARACTERISTICS (continued) TOTAL HARMONIC DISTORTION vs INPUT VOLTAGE OUTPUT NOISE VOLTAGE vs FREQUENCY -80 1.4 -90 Output Voltage Noise – dBV/rtHz 1.6 1.2 THD – % 1 0.8 0.6 0.4 -100 -110 -120 -130 -140 0.2 -150 0 10 0 10 20 30 40 50 60 70 80 100 1k 10k 100k Frequency – Hz Input Amplitude – mVpp Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TLV1018 5 TLV1018 SLVS664A – OCTOBER 2008 – REVISED NOVEMBER 2008 .......................................................................................................................................... www.ti.com APPLICATION INFORMATION Low Current The TLV1018 has a low supply current, which allows for a longer battery life. The low supply current of 70 µA makes this amplifier optimal for microphone applications that need to be always on. Built-In Gain The TLV1018 is offered in the space-saving YDC package, which fits perfectly into the metal can of a microphone. This allows the TLV1018 to be placed on the PCB inside the microphone. The bottom side of the PCB has 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 Airgap Electret Backplate Connector VCC OUTPUT GND Figure 1. Built-In Gain 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. The A-weighted filter is usually 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. 10 0 Filter – dBV -10 -20 -30 -40 -50 -60 -70 10 100 1000 10000 100000 Frequency – Hz Figure 2. A-Weighted Filter 6 Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TLV1018 TLV1018 www.ti.com .......................................................................................................................................... SLVS664A – OCTOBER 2008 – REVISED NOVEMBER 2008 Measuring Noise and SNR The overall noise of the TLV1018 is measured within the frequency band from 10 Hz to 22 kHz using an A-weighted filter. The input of the TLV1018 is connected to ground with a 5-pF capacitor. A-Weighted Filter 5 pF Figure 3. Noise Measurement 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 (SPL) of 94 dBSPL. No input capacitor is connected. Sound Pressure Level The volume of sound applied to a microphone is usually stated as the pressure level with respect to the threshold of hearing of the human ear. The sound pressure level (SPL) in decibels is defined by: Sound pressure level (dB) = 20 log Pm/PO Where Pm is the measured sound pressure, and PO is the threshold of hearing (20 µPa) To calculate the resulting output voltage of the microphone for a given SPL, the sound pressure in dBSPL needs to be converted to the absolute sound pressure in dBPa. This is the sound pressure level in decibels, which is referred to as 1 Pascal (Pa). The conversion is given by: dBPa = dBSPL + 20 log 20 µPa dBPa = dBSPL – 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 (dB Pa) –94 dB Sensitivity (dBV/Pa) Sound Pressure (dB SPL) Voltage (dBV) Figure 4. dBSPL to dBV Conversion Example: Busy traffic is 70 dBSPL VOUT = 70 – 94 – 44 = –68 dBV This is equivalent to 1.13 mVPP. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TLV1018 7 TLV1018 SLVS664A – OCTOBER 2008 – REVISED NOVEMBER 2008 .......................................................................................................................................... www.ti.com Because the TLV1018-15 has a gain of 5.6 (15 dB) over the JFET, the output voltage of the microphone is 6.35 mVPP. By replacing the JFET with the TLV1018-15, the sensitivity of the microphone is –29 dBV/Pa (–44 + 15). Low-Frequency Cut-Off Filter To reduce noise on the output of the microphone, a low-cut filter is implemented in the TLV1018. This filter reduces the effect of wind and handling noise. It is also helpful 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. 180 30 25 135 Gain 20 90 15 10 0 0 Phase -5 -45 Phase – ° Gain – dB 45 5 -10 -90 -15 -20 -135 -25 -30 -180 10 100 1k 10k 100k 1M Frequency (Hz) Figure 5. Gain vs. Frequency The TLV1018 is optimized to be used in audio-band applications. The TLV1018 provides a flat gain response within the audio band and offers linearity and excellent temperature stability. Advantage of Three Pins The TLV1018 ECM solution has three pins, instead of the two pins provided in the case of a JFET solution. The third pin provides the advantage of a low supply current, high PSRR, and eliminates the need for additional components. Noise pick-up by a microphone in a cell phone is a well known problem. A conventional JFET circuit is sensitive for noise pick-up because of its high output impedance. The output impedance is usually around 2.2 kΩ. By providing separate output and supply pins a much lower output impedance is achieved and therefore is less sensitive to noise pick-up. RF noise is one of the noises caused by non-linear behavior. The non-linear behavior of the amplifier at high frequencies, well above the usable bandwidth of the device, causes AM demodulation of high-frequency signals. The AM modulation contained in such signals folds back into the audio band, thereby disturbing the intended microphone signal. The GSM signal of a cell phone is such an AM-modulated signal. The modulation frequency of 216 Hz and its harmonics can be observed in the audio band. This type of noise is called bumblebee noise. 8 Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TLV1018 TLV1018 www.ti.com .......................................................................................................................................... SLVS664A – OCTOBER 2008 – REVISED NOVEMBER 2008 External Pre-Amplifier Application The TLV1018 can also be used outside of an ECM as a space saving external preamplifier. In this application, the TLV1018 follows a phantom biased JFET microphone in the circuit. This is shown in Figure 6. The input of the TLV1018 is connected to the microphone via the 2.2-µF capacitor. The advantage of this circuit over one with only a JFET microphone are the additional gain and the high-pass filter supplied by the TLV1018. The high-pass filter makes the output signal more robust and less sensitive to low frequency disturbances. In this configuration, the TLV1018 should be placed as close as possible to the microphone. VCC 2.2 kW VCC INPUT OUTPUT 2.2 µF JFET Microphone VOUT GND GND Figure 6. External Preamplifier Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TLV1018 9 PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2008 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty TLV1018-15YDCR ACTIVE DSBGA YDC 4 3000 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM TLV1018-25YDCR ACTIVE DSBGA YDC 4 3000 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM Lead/Ball Finish MSL Peak Temp (3) (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. 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. 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