TI TLV1012

TLV1012
www.ti.com .......................................................................................................................................... SLCS154A – OCTOBER 2008 – REVISED NOVEMBER 2008
AMPLIFIER FOR HIGH-GAIN TWO-WIRE MICROPHONES
FEATURES
APPLICATIONS
•
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•
•
•
•
•
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1
Supply Voltage: 2 V to 5 V
Supply Current: <180 µA
Signal-to-Noise Ratio (A-Weighted): 60 dB
Output Voltage Noise (A-Weighted): −89 dBV
Total Harmonic Distortion: 0.013%
Voltage Gain: 15.6 dB
Cellular Phones
Headsets
Mobile Communications
Automotive Accessories
PDAs
Accessory Microphone Products
YDC PACKAGE
(TOP VIEW)
OUTPUT
A2
B2
GND
GND
A1
B1
INPUT
DESCRIPTION/ORDERING INFORMATION
The TLV1012 is an audio amplifier series for small-form-factor electret microphones. This two-wire amplifier is
designed to replace JFET amplifiers currently in use. The TLV1012 is ideally suited for applications that require
high signal integrity in the presence of ambient or RF noise, such as in cellular communications. The TLV1012
audio amplifier is specified for operation over a 2.2-V to 5-V supply voltage range with a fixed gain of 15.6 dB.
The device offers excellent THD, gain accuracy, and temperature stability compared to JFET microphones.
The TLV1012 enables a two-pin electret microphone solution, which provides direct pin-to-pin compatibility with
the existing JFET market.
The TLV1012 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 TLV1012 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)
(3)
AV (2)
15.6 dB
PACKAGE (3)
NanoStar™ WCSP
(DSBGA) – YDC
Reel of 3000
ORDERABLE PART NUMBER
TLV1012-15YDCR
TOP-SIDE MARKING
Y38
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.
Typical value measured at VDD = 2.2 V, VIN = 18 mV, RL = 2.2 kΩ, CL = 2.2 µF
Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.
1
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.
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
TLV1012
SLCS154A – OCTOBER 2008 – REVISED NOVEMBER 2008 .......................................................................................................................................... www.ti.com
FUNCTIONAL BLOCK DIAGRAM
VCC
OUTPUT
INPUT
–
+
–+
GND
ABSOLUTE MAXIMUM RATINGS (1)
over operating free-air temperature range (unless otherwise noted)
VCC
Supply voltage
–0.3 V to 5.5 V
VIN
Input voltage
–0.3 V to 0.3 V
θJA
Thermal impedance, junction to free air (2)
TA
Operating free-air temperature range
–40°C to 85°C
Tstg
Storage temperature range
–65°C to 150°C
(1)
(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 51-5.
RECOMMENDED OPERATING CONDITIONS
VCC
Supply voltage
TA
Operating free-air temperature
MIN
MAX
2
5
UNIT
V
–40
85
°C
2.2-V ELECTRICAL CHARACTERISTICS
VCC = 2.2 V, VIN = 18 mV, RL = 2.2 kΩ and CL = 2.2 µF (unless otherwise noted)
PARAMETER
TEST CONDITIONS
TJ
MIN
25°C
TYP
MAX
150
240
UNIT
µA
ICC
Supply current
VIN = GND
SNR
Signal-to-noise ratio
f = 1 kHz, VIN = 18 mVPP, A-weighted
25°C
60
dB
VIN
Maximum input signal
f = 1 kHz, THD+N < 1%
25°C
100
mVPP
VOUT
Output voltage
VIN = GND
fLOW
Lower –3-dB roll-off frequency
RSOURCE = 50 Ω
25°C
65
Hz
fHIGH
Upper –3-dB roll-off frequency
RSOURCE = 50 Ω
25°C
95
kHz
VN
Output noise
A-weighted
25°C
–89
dBV
THD
Total harmonic distortion
f = 1 kHz, VIN = 18 mVPP
25°C
0.013
%
CIN
Input capacitance
25°C
2
pF
ZIN
Input impedance
25°C
AV
2
Gain
f = 1 kHz, RSOURCE = 50 Ω
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Full range
280
25°C
1.70
Full range
1.63
1.87
1.94
2.00
>1000
25°C
14.0
Full range
13.1
15.6
V
GΩ
16.9
17.5
dB
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TLV1012
TLV1012
www.ti.com .......................................................................................................................................... SLCS154A – OCTOBER 2008 – REVISED NOVEMBER 2008
5-V ELECTRICAL CHARACTERISTICS
VCC = 5 V, VIN = 18 mV, RL = 2.2 kΩ and CL = 2.2 µF (unless otherwise noted)
PARAMETER
TEST CONDITIONS
TJ
MIN
25°C
TYP
MAX
160
300
UNIT
µA
ICC
Supply current
VIN = GND
SNR
Signal-to-noise ratio
f = 1 kHz, VIN = 18 mVPP, A-weighted
25°C
60
dB
VIN
Maximum input signal
f = 1 kHz, THD+N < 1%
25°C
100
mVPP
VOUT
Output voltage
VIN = GND
fLOW
Lower –3-dB roll-off frequency
RSOURCE = 50 Ω
25°C
67
Hz
fHIGH
Upper –3-dB roll-off frequency
RSOURCE = 50 Ω
25°C
150
kHz
VN
Output noise
A-weighted
25°C
–89
dBV
THD
Total harmonic distortion
f = 1 kHz, VIN = 18 mVPP
25°C
0.013
%
CIN
Input capacitance
25°C
2
pF
ZIN
Input impedance
25°C
>1000
GΩ
AV
Gain
f = 1 kHz, RSOURCE = 50 Ω
Full range
325
25°C
4.34
Full range
4.28
25°C
14.0
Full range
13.1
4.56
4.74
4.80
15.6
16.9
17.5
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Product Folder Link(s): TLV1012
V
dB
3
TLV1012
SLCS154A – OCTOBER 2008 – REVISED NOVEMBER 2008 .......................................................................................................................................... www.ti.com
TYPICAL CHARACTERISTICS
CLOSED LOOP GAIN AND PHASE
vs
FREQUENCY
TOTAL HARMONIC DISTORTION + NOISE
vs
FREQUENCY
180
30
0.6
VS = 2.2 V
25
VIN = 18 mVpp
135
20
0.5
90
15
10
0.4
0
0
-5
-45
THD+N – %
5
Phase – °
Gain – dB
45
-10
0.3
0.2
-90
-15
-20
0.1
-135
-25
-30
-180
10
100
1k
10k
100k
0
1M
10
100
Frequency – Hz
TOTAL HARMONIC DISTORTION + NOISE
vs
INPUT VOLTAGE
10k
10,000
100k
100,000
TOTAL HARMONIC DISTORTION + NOISE
vs
INPUT VOLTAGE
1.6
1.6
VCC = 5 V
VCC = 2.2 V
1.4
1.4
1.2
1.2
1
1
THD+N – %
THD+N – %
1k
1,000
Frequency – Hz
0.8
0.6
0.8
0.6
0.4
0.4
0.2
0.2
0
0
0
20
40
60
80
100
120
0
Input Amplitude – mVpp
20
40
60
80
100
120
Input Amplitude – mVpp
Figure 1.
4
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Product Folder Link(s): TLV1012
TLV1012
www.ti.com .......................................................................................................................................... SLCS154A – OCTOBER 2008 – REVISED NOVEMBER 2008
TYPICAL CHARACTERISTICS (continued)
OUTPUT VOLTAGE NOISE
vs
FREQUENCY
-80
Output Voltage Noise – dBV/rtHz
-90
-100
-110
-120
-130
-140
-150
10
100
1k
1,000
10k
10,000
100k
100,000
Frequency – Hz
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Product Folder Link(s): TLV1012
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TLV1012
SLCS154A – OCTOBER 2008 – REVISED NOVEMBER 2008 .......................................................................................................................................... www.ti.com
APPLICATION INFORMATION
High Gain
The TLV1012 provides outstanding gain compared to JFET amplifiers and still maintains the same ease of
implementation, with improved gain, linearity, and temperature stability. A high gain eliminates the need for extra
external components.
Built-In Gain
The TLV1012 is offered in the space-saving YDC package, which fits perfectly into the metal can of a
microphone. This allows the TLV1012 to be placed on the PCB inside the microphone.
The bottom side of the PCB usually shows a bull's-eye pattern, where the outer ring, which is shorted to the
metal can, should be connected to the ground. The center dot on the PCB is connected to the VCC through a
resistor. This phantom biasing allows both supply voltage and output signal on one connection.
Diaphragm
Airgap
Electret
Backplate
Connector
TLV1012
Figure 2. 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 3. A-Weighted Filter
6
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Product Folder Link(s): TLV1012
TLV1012
www.ti.com .......................................................................................................................................... SLCS154A – OCTOBER 2008 – REVISED NOVEMBER 2008
Measuring Noise and SNR
The overall noise of the TLV1012 is measured within the frequency band from 10 Hz to 22 kHz using an
A-weighted filter. The input of the TLV1012 is connected to ground with a 5-pF capacitor.
5 pF
A-Weighted
Filter
Figure 4. 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 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 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 sound pressure level, 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
(dBPa)
–94 dB
Sensitivity
(dBV/Pa)
Sound
Pressure
(dBSPL)
Voltage
(dBV)
Figure 5. dB SPL to dBV Conversion
For example, busy traffic is 70 dBSPL:
VOUT = 70 – 94 – 44 = –68 dBV
This is equivalent to 1.13 mVPP.
Because the TLV1012-15 has a gain of 6 (15.6 dB) over the JFET, the output voltage of the microphone is
6.78 mVPP. By replacing the JFET with the TLV1012-15, the sensitivity of the microphone is –28.4 dBV/Pa (–44 +
15.6).
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TLV1012
SLCS154A – OCTOBER 2008 – REVISED NOVEMBER 2008 .......................................................................................................................................... www.ti.com
Low-Frequency Cut-Off Filter
To reduce noise on the output of the microphone, a low-cut filter is implemented in the TLV1012. 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
20
90
15
10
0
0
-5
-45
Phase – °
Gain – dB
45
5
-10
-90
-15
-20
-135
-25
-30
-180
10
100
1k
10k
100k
1M
Frequency – Hz
Figure 6. Gain and Phase vs Frequency
The TLV1012 is optimized to be used in audio-band applications. The TLV1012 provides a flat gain response
within the audio band and offers linearity and excellent temperature stability.
8
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Product Folder Link(s): TLV1012
TLV1012
www.ti.com .......................................................................................................................................... SLCS154A – OCTOBER 2008 – REVISED NOVEMBER 2008
Noise
Noise pick-up by a microphone in cell phones is a well known problem. A conventional JFET circuit is sensitive
for noise pick-up because of its high output impedance, which is usually around 2.2 kΩ.
RF noise is among other noises caused by nonlinear behavior. The nonlinear 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 kind of noise is called bumblebee noise.
RF noise caused by a GSM signal can be reduced by connecting two external capacitors to ground (see
Figure 7). One capacitor reduces the noise caused by the 900-MHz carrier, and the other reduces the noise
caused by 1800/1900 MHz.
VCC
Output
Input
10 pF
33 pF
Figure 7. RF Noise Reduction
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9
PACKAGE OPTION ADDENDUM
www.ti.com
24-Oct-2008
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
TLV1012-15YDCR
ACTIVE
DSBGA
YDC
Pins Package Eco Plan (2)
Qty
4
3000 Green (RoHS &
no Sb/Br)
Lead/Ball Finish
SNAGCU
MSL Peak Temp (3)
Level-1-260C-UNLIM
(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.
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Addendum-Page 1
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