LMV1012
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LMV1012 Analog Series: Pre-Amplified IC's for High Gain 2-Wire Microphones
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FEATURES
DESCRIPTION
•
The LMV1012 is an audio amplifier series for small
form factor electret microphones. This 2-wire portfolio
is designed to replace the JFET amplifier currently
being used. The LMV1012 series is ideally suited for
applications requiring high signal integrity in the
presence of ambient or RF noise, such as in cellular
communications. The LMV1012 audio amplifiers are
specified to operate over a 2.2V to 5.0V supply
voltage range with fixed gains of 7.8 dB, 15.6 dB,
20.9 dB, and 23.8 dB. The devices offer excellent
THD, gain accuracy and temperature stability as
compared to a JFET microphone.
1
2
•
•
•
•
•
•
•
•
Typical LMV1012-15, 2.2V Supply, RL = 2.2 kΩ,
C = 2.2 μF, VIN = 18 mVPP, Unless Otherwise
Specified
Supply Voltage: 2V - 5V
Supply Current: 1000
GΩ
LMV1012-07
6.4
5.5
7.8
9.5
10.0
LMV1012-15
14.0
13.1
15.6
16.9
17.5
LMV1012-20
19.5
17.4
20.9
22.0
23.3
LMV1012-25
22.5
21.4
23.8
25.0
25.7
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 specification 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.
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5V Electrical Characteristics (1)
Unless otherwise specified, all limits are specified for TJ = 25°C, VDD = 5V, VIN = 18 mV, RL = 2.2 kΩ and C = 2.2 μF.
Boldface limits apply at the temperature extremes.
Symbol
IDD
Parameter
Supply Current
SNR
VIN
Signal to Noise Ratio
Max Input Signal
Min (2)
Typ (3)
Max (2)
LMV1012-07
158
250
300
LMV1012-15
200
300
325
LMV1012-20
188
260
310
LMV1012-25
160
250
300
LMV1012-07
59
LMV1012-15
60
LMV1012-20
61
LMV1012-25
61
LMV1012-07
170
LMV1012-15
100
LMV1012-20
55
Conditions
VIN = GND
f = 1 kHz, VIN = 18 mV,
A-Weighted
f = 1 kHz and THD+N <
1%
LMV1012-25
VOUT
Output Voltage
VIN = GND
Units
μA
dB
mVPP
28
LMV1012-07
4.45
4.38
4.65
4.80
4.85
LMV1012-15
4.34
4.28
4.56
4.74
4.80
LMV1012-20
4.40
4.30
4.58
4.75
4.85
LMV1012-25
4.45
4.39
4.65
4.83
4.86
V
fLOW
Lower −3dB Roll Off Frequency
RSOURCE = 50Ω
67
Hz
fHIGH
Upper −3dB Roll Off Frequency
RSOURCE = 50Ω
150
kHz
en
Output Noise
A-Weighted
THD
Total Harmonic Distortion
CIN
Input Capacitance
ZIN
Input Impedance
AV
Gain
(1)
(2)
(3)
4
f = 1 kHz,
VIN = 18 mV
f = 1 kHz,
RSOURCE = 50Ω
LMV1012-07
−96
LMV1012-15
−89
LMV1012-20
−84
LMV1012-25
−82
LMV1012-07
0.12
LMV1012-15
0.13
LMV1012-20
0.18
LMV1012-25
0.21
dBV
%
2
pF
>1000
GΩ
LMV1012-07
6.4
5.5
8.1
9.5
10.7
LMV1012-15
14.0
13.1
15.6
16.9
17.5
LMV1012-20
19.2
17.0
21.1
22.3
23.5
LMV1012-25
22.5
21.2
23.9
25.0
25.8
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 specification 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.
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Connection Diagram
B2
GND
A2
OUTPUT
X
B1
INPUT
A1
GND
4-Bump DSBGA (Top View)
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.
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Typical Performance Characteristics
Unless otherwise specified, VS = 2.2V, RL = 2.2 kΩ, C = 2.2 μF, single supply, TA = 25°C
Supply Current vs. Supply Voltage (LMV1012-07)
Supply Current vs. Supply Voltage (LMV1012-15)
180
260
240
SUPPLY CURRENT (PA)
SUPPLY CURRENT (PA)
170
85°C
160
25°C
150
140
130
120
220
85°C
25°C
200
180
160
140
110
-40°C
-40°C
100
120
2
3
2.5
3.5
4
4.5
5
2
5.5
4
4.5
5.5
5
Figure 1.
Figure 2.
Supply Current vs. Supply Voltage (LMV1012-20)
Supply Current vs. Supply Voltage (LMV1012-25)
220
200
SUPPLY CURRENT (PA)
220
85°C
200
25°C
180
160
140
-40°C
85°C
180
25°C
160
140
120
120
-40°C
100
100
2
2.5
3
3.5
4
4.5
5
2
5.5
2.5
3.5
4
4.5
5.5
5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Figure 3.
Figure 4.
Gain and Phase vs. Frequency (LMV1012-07)
Gain and Phase vs. Frequency (LMV1012-15)
300
18
8
250
16
6
200
14
10
GAIN
150
2
100
0
50
0
-2
0
GAIN
-40
-80
-120
12
GAIN (dB)
PHASE
PHASE (°C )
4
3
PHASE
10
-160
8
-200
6
-240
-4
-50
-6
-100
4
-280
-8
-150
2
-320
-200
0
-10
10
100
1k
10k
100k
1M
10
FREQUENCY (Hz)
Figure 5.
100
100k
1k
10k
FREQUENCY (Hz)
PHASE (°)
SUPPLY CURRENT (PA)
240
GAIN (dB)
3.5
SUPPLY VOLTAGE (V)
260
6
3
2.5
SUPPLY VOLTAGE (V)
-360
1M
Figure 6.
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Typical Performance Characteristics (continued)
Unless otherwise specified, VS = 2.2V, RL = 2.2 kΩ, C = 2.2 μF, single supply, TA = 25°C
Gain and Phase vs. Frequency (LMV1012-20)
Gain and Phase vs. Frequency (LMV1012-25)
25
300
GAIN
300
GAIN
250
20
20
200
200
150
50
10
0
GAIN (dB)
100
15
150
PHASE
PHASE (°)
PHASE
GAIN (dB)
250
100
15
50
0
10
-50
5
-50
5
-100
-100
-150
-150
-200
0
100
10
1k
10k
100k
PHASE (°C )
25
-200
0
100
10
1M
1k
10k
100k
1M
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 7.
Figure 8.
Total Harmonic Distortion vs. Frequency (LMV1012-07)
Total Harmonic Distortion vs. Frequency (LMV1012-15)
0.7
0.6
VIN = 18 mVPP
VIN = 18 mVPP
0.6
0.5
0.5
THD+N (%)
THD+N (%)
0.4
0.4
0.3
0.3
0.2
0.2
0.1
0.1
0.0
0.0
10
100
1k
10k
100k
10
1k
100
10k
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 9.
Figure 10.
Total Harmonic Distortion vs. Frequency (LMV1012-20)
Total Harmonic Distortion vs. Frequency (LMV1012-25)
0.6
0.6
VIN = 18 mVPP
0.5
0.5
0.4
0.4
THD+N (%)
THD+N (%)
VIN = 18 mVPP
0.3
0.3
0.2
0.2
0.1
0.1
0.0
0.0
10
100
1k
10k
100k
FREQUENCY (Hz)
10
100
1k
10k
100k
FREQUENCY (Hz)
Figure 11.
Figure 12.
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Typical Performance Characteristics (continued)
Unless otherwise specified, VS = 2.2V, RL = 2.2 kΩ, C = 2.2 μF, single supply, TA = 25°C
Total Harmonic Distortion vs. Input Voltage (LMV1012-07)
Total Harmonic Distortion vs. Input Voltage (LMV1012-15)
1.0
1.0
f = 1 kHz
0.9
0.8
0.8
0.7
0.7
THD+N (%)
THD+N (%)
f = 1 kHz
0.9
0.6
0.5
0.4
0.6
0.5
0.4
0.3
0.3
0.2
0.2
0.1
0.1
0.0
0.0
0
50
100
150
200
250
0
INPUT VOLTAGE (mVPP)
20
40
60
80
100
Figure 14.
Total Harmonic Distortion vs. Input Voltage (LMV1012-20)
Total Harmonic Distortion vs. Input Voltage (LMV1012-25)
1.0
1.0
0.9
0.9
0.8
0.8
0.7
0.7
THD+N (%)
THD+N (%)
Figure 13.
0.6
0.5
0.4
0.6
0.5
0.4
0.3
0.3
0.2
0.2
0.1
0.1
f = 1 kHz
f = 1 kHz
0.0
0.0
0
10
20
30
40
50
0
60
10
20
Figure 15.
40
Figure 16.
Output Noise vs. Frequency (LMV1012-07)
Output Noise vs. Frequency (LMV1012-15)
-100
-100
INPUT IS CONNECTED
TO GND
-105
-110
-110
-115
-115
-120
-125
-130
-135
INPUT IS CONNECTED TO
GND
-105
NOISE (dBV/ Hz)
NOISE (dBV/ Hz)
30
INPUT VOLTAGE (mVPP)
INPUT VOLTAGE (mVPP)
-120
-125
-130
-135
-140
-140
-145
-145
-150
-150
10
100
1k
10k
100k
10
100
1k
10k
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 17.
8
120
INPUT VOLTAGE (mVPP)
Figure 18.
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Typical Performance Characteristics (continued)
Unless otherwise specified, VS = 2.2V, RL = 2.2 kΩ, C = 2.2 μF, single supply, TA = 25°C
Output Noise vs. Frequency (LMV1012-20)
Output Noise vs. Frequency (LMV1012-25)
-100
-100
INPUT IS CONNECTED
TO GND
-110
-110
-115
-115
-120
-125
-130
-135
-120
-125
-130
-135
-140
-140
-145
-145
-150
INPUT IS CONNECTED
TO GND
-105
NOISE (dBV/ Hz)
NOISE (dBV/ Hz)
-105
-150
10
100
1k
10k
100k
FREQUENCY (Hz)
10
100
1k
10k
100k
FREQUENCY (Hz)
Figure 19.
Figure 20.
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APPLICATION SECTION
HIGH GAIN
The LMV1012 series provides outstanding gain versus the JFET 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 LMV1012 is offered in 0.3 mm height space saving small 4-pin DSBGA packages in order to fit inside the
different size ECM canisters of a microphone. The LMV1012 is 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 VDD through a resistor.
This phantom biasing allows both supply voltage and output signal on one connection.
DIAPHRAGM
xxxx
xxx
x
x
ELECTRET
AIRGAP
BACKPLATE
CONNECTOR
x
x
LMV1012
IC
x
x
Figure 21. 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. This filter improves the correlation of the measured data to the signal to noise ratio perceived by the
human ear.
10
0
-10
dBV
-20
-30
-40
-50
-60
-70
10
100
1k
10k
100k
FREQUENCY (Hz)
Figure 22. A-Weighted Filter
10
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MEASURING NOISE AND SNR
The overall noise of the LMV1012 is measured within the frequency band from 10 Hz to 22 kHz using an Aweighted filter. The input of the LMV1012 is connected to ground with a 5 pF capacitor, as in Figure 23. Special
precautions in the internal structure of the LMV1012 have been taken to reduce the noise on the output.
A-WEIGHTED FILTER
5 pF
Figure 23. 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 SPL. No input capacitor is connected for the measurement.
SOUND PRESSURE LEVEL
The volume of sound applied to a microphone is usually stated as a pressure level referred 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
PO is the threshold of hearing (20 μPa).
(1)
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 referred to 1 Pascal (Pa).
The conversion is given by:
dBPa = dB SPL + 20*log 20 μPa
dBPa = dB SPL - 94 dB
(2)
(3)
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.
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ABSOLUTE
SOUND
PRESSURE
[dBPa]
-94 dB
SENSITIVITY
[dBV/Pa]
SOUND
PRESSURE
[dB SPL]
VOLTAGE
[dBV]
Figure 24. dB SPL to dBV Conversion
Example: Busy traffic is 70 dB SPL
VOUT = 70 −94 −44 = −68 dBV
(4)
This is equivalent to 1.13 mVPP
Since the LMV1012-15 has a gain of 6 (15.6 dB) over the JFET, the output voltage of the microphone is 6.78
mVPP. By implementing the LMV1012-15, the sensitivity of the microphone is -28.4 dBV/Pa (−44 + 15.6).
LOW FREQUENCY CUT OFF FILTER
To reduce noise on the output of the microphone a low frequency cut off filter has been implemented. This filter
reduces the effect of wind and handling noise.
It's 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.
20
GAIN (dB)
15
10
5
85°C
25°C
0
-40°C
VDD = 2.2V
-5
10
100
1k
10k
100k
1M
FREQUENCY (Hz)
Figure 25. LMV1012-15 Gain vs. Frequency Over Temperature
The LMV1012 is optimized to be used in audio band applications. By using the LMV1012, the gain response is
flat within the audio band and has linearity and temperature stability (see Figure 25).
12
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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 amongst other 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 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 26. One capacitor reduces the noise caused by the 900 MHz carrier and the other reduces the noise
caused by 1800/1900 MHz.
VDD
OUTPUT
INPUT
10 pF
33 pF
Figure 26. RF Noise Reduction
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REVISION HISTORY
Changes from Revision G (May 2013) to Revision H
•
14
Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 13
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PACKAGE OPTION ADDENDUM
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10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
(3)
Device Marking
(4/5)
(6)
LMV1012TP-25/NOPB
ACTIVE
DSBGA
YPB
4
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
LMV1012TPX-15/NOPB
ACTIVE
DSBGA
YPB
4
3000
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
LMV1012TPX-25/NOPB
ACTIVE
DSBGA
YPB
4
3000
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
LMV1012UP-07/NOPB
ACTIVE
DSBGA
YPC
4
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
LMV1012UP-15/NOPB
ACTIVE
DSBGA
YPC
4
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
LMV1012UP-20/NOPB
ACTIVE
DSBGA
YPC
4
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
LMV1012UP-25/NOPB
ACTIVE
DSBGA
YPC
4
250
RoHS & Green
SNAGCU
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)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
