19-5912; Rev 0; 6/11
EVALUATION KIT AVAILABLE
MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
General Description
The MAX98309/MAX98310 mono 1.4W class AB audio
amplifiers offer low quiescent current while maintaining
excellent SNR and low 0.008% THD+N. These ICs feature excellent 90dB PSRR and state of the art click-andpop suppression.
The ICs are offered with an internally fixed 0dB, 3dB,
6dB, and 9dB gain (MAX98310) or an externally set gain
(MAX98309) through external resistors.
The MAX98309 feature a 10ms or 100ms pin-selectable
turn-on time, while the MAX98310 has a preset 5ms turnon time.
The MAX98309/MAX98310 are available in a (1.0mm x
1.0mm) 9-bump, 0.3mm pitch WLP, and are specified over
the extended -40NC to +85NC temperature range.
Applications
Cell Phones/Smartphones
Digital Cameras
GPS
Portable Media Players
e-Readers
Tablets
Benefits and Features
S Enhances System Performance
Differential Input Improves Noise Immunity
Industry-Leading Click-and-Pop Suppression
High 90dB PSRR (fIN = 217Hz)
SSmaller Solution Size
1mm x 1mm WLP Footprint
SExtends Battery Life
Low Quiescent Current
SDelivers Robust System Design
Thermal Overload Protection
Short-Circuit Protection
S1.2mA Supply Current (VDD = 3.7V)
S750mW into 8I (VDD = 3.7V)
S2.5V to 5.5V Supply Operation
SPin-Selectable, Internally-Fixed Gain (MAX98310)
S1.8V Logic-Compatible SHDN Input
Ordering Information appears at end of data sheet.
For related parts and recommended products to use with this part,
refer to www.maxim-ic.com/MAX98309.related.
Simplified Block Diagram
2.5V TO 5.5V
RF
2.5V TO 5.5V
0.1µF
0.1µF
1µF
1µF
BIAS
VDD
BIAS
VDD
BIAS
BIAS
CIN
RIN
CIN
RIN
TON
RF
MAX98309
OUT+
INBIAS
IN+
OUTSHDN
CIN
CIN
MAX98310
VDD
IN-
IN+
RIN
RIN
OUT+
BIAS
OUTGND
GND
RF
GAIN
RF
SHDN
GND
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For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
ABSOLUTE MAXIMUM RATINGS
VDD to GND................................................................ -0.3V to 6V
SHDN to GND............................................................ -0.3V to 6V
All Other Pins to GND................................-0.3V to (VDD + 0.3V)
Continuous Current
VDD, GND, OUT_........................................................ Q750mA
IN_, SHDN, BIAS, GAIN, TON.......................................... Q20mA
OUT_ Short Circuit to GND or VDD Duration.............Continuous
OUT+ to OUT- Short Circuit Duration........................Continuous
Continuous Power Dissipation (TA = +70NC)
WLP (derate 11.9mW/NC above +70NC)......................848mW
Junction Temperature......................................................+150NC
Operating Temperature Range........................... -40NC to +85NC
Storage Temperature Range............................. -65NC to +150NC
Soldering Temperature (reflow).......................................+260NC
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 in the operational sections of the specifications is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
PACKAGE THERMAL CHARACTERISTICS (Note 1)
WLP
Junction-to-Ambient Thermal Resistance (BJA)......... 94°C/W
Junction-to-Case Thermal Resistance (BJC)................41°C/W
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
ELECTRICAL CHARACTERISTICS
(VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = VDD (0dB), CBIAS = 0.1µF, CIN = 0.47µF, no load: RIN = RF = 10kI (MAX98309),
TA = TMIN to TMAX. Typical values are at TA = +25°C, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
Supply Voltage Range
VDD
Undervoltage Lockout
UVLO
Quiescent Supply Current
IVDD
Shutdown Supply Current
IVDD_SD
Turn-On Time
tON
Gain
AV
CONDITIONS
Guaranteed by PSRR test
MIN
VDD falling
SHDN = VDD
1.8
MAX
UNITS
5.5
V
2.3
V
VDD = 3.7V
1.2
VDD = 5V
1.9
1.8
2
3
10
22.8
VSHDN = 0V, TA = +25NC
MAX98309 shutdown to TON = GND
full operation
TON = VDD
100
MAX98310 shutdown to full operation
5.7
11.5
MAX98310
-0.25
0
+0.25
GAIN = GND
2.75
3
3.25
GAIN = unconnected
5.75
6
6.25
GAIN = BIAS
8.75
9
9.25
GAIN = VDD
0.80 x
VDD
MAX98310
mA
FA
ms
GAIN = VDD
0.05 x
VDD
GAIN = GND
Gain Selection Threshold
TYP
2.5
GAIN = unconnected
0.16 x
VDD
0.24 x
VDD
GAIN = BIAS
0.35 x
VDD
0.69 x
VDD
dB
V
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MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = VDD (0dB), CBIAS = 0.1µF, CIN = 0.47µF, no load: RIN = RF = 10kI (MAX98309), TA
= TMIN to TMAX. Typical values are at TA = +25°C, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
RINDIFF
Input Bias Current
IINBIAS
Shutdown Input Bias Current
IINBIAS_
Output Offset Voltage
Click-and-Pop Level
SHDN
MAX98310
38.2
GAIN = 3dB
31.7
GAIN = 6dB
25.5
MAX98309/MAX98310, SHDN = VDD
SHDN = GND, IN_ = VDD or IN_ = GND
TA = +25NC (Note 3)
KCP
RL = 8I, 32 samples per
second, A-weighted,
TA = +25NC (Notes 3, 4)
Common-Mode Bias Voltage
VBIAS
Voltage at BIAS
Input Common-Mode Voltage
Range
VCM
Inferred from CMRR test
Common-Mode Rejection Ratio
GAIN = 0dB
VOS
CMRR
MAX98310/MAX98310
-5
Q0.2
Into shutdown
-66
Out of shutdown
-66
0.475
x VDD
VRIPPLE = 200mVP-P
(Note 3)
VDD = 3.7V, 1% THD+N
VDD = 3.7V, 10% THD+N
Output Power
POUT
VDD = 5V, 1% THD+N
(Note 5)
VDD = 5V, 10% THD+N
(Note 5)
0.5 x
VDD
0.5
Guaranteed over
input commonmode voltage
range
DC 2.5V to 5.5V
PSRR
UNITS
kI
Q1
FA
+5
FA
Q1
mV
dBV
-50
0.525
x VDD
V
VDD 0.6
V
-76
dB
fIN = 1kHz,
RL = 8I + 33FH
Power-Supply Rejection Ratio
MAX
1000
MAX98309, SHDN = VDD
Differential Input Resistance
TYP
-62
73
93
fIN = 217Hz
90
fIN = 1kHz
90
fIN = 10kHz
72
RL = 8I + 68FH
0.750
RL = 4I + 33FH
1.2
RL = 8I + 68FH
0.9
RL = 4I + 33FH
1.5
RL = 8I + 68FH
1.4
RL = 4I + 33FH,
thermally limited
2.1
RL = 8I + 68FH
1.7
RL = 4I + 33FH,
thermally limited
2.7
dB
W
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MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = VDD (0dB), CBIAS = 0.1µF, CIN = 0.47µF, no load: RIN = RF = 10kI (MAX98309),
TA = TMIN to TMAX. Typical values are at TA = +25°C, unless otherwise noted.) (Note 2)
PARAMETER
Total Harmonic Distortion Plus
Noise
SYMBOL
THD+N
CONDITIONS
fIN = 1kHz, BW = 22Hz to
22kHz
fIN = 6kHz, BW = 22Hz to
22kHz
Signal-to-Noise Ratio
SNR
Output Noise Voltage
VN
MIN
RL = 8I + 68FH,
POUT = 375mW
RL = 4I + 33FH,
POUT = 750mW
TYP
MAX
UNITS
0.008
0.06
RL = 8I + 68FH,
POUT = 375mW
0.02
%
0.01
A-weighted, VDD = 5V, POUT = 1.4W,
RL = 8I + 33FH
110
dB
9
FV
2
A
Thermal-Protection Threshold
+160
NC
Thermal-Protection Hysteresis
15
NC
500
pF
A-weighted (Note 3)
Overcurrent Protection
Threshold
Maximum Capacitive Load
Drive
CL
Bridge-tied load capacitance
LOGIC INPUT (SHDN, TON) (MAX98309)
Input Logic-High
VIH
1.8V logic compliant
1.4
V
Input Logic-Low
VIL
1.8V logic compliant
0.4
V
Input Leakage Current High
IIH
TA = +25NC
1
FA
Input Leakage Current Low
IIL
TA = +25NC
1
FA
Note
Note
Note
Note
2: All specifications are 100% tested at TA = +25°C; temperature limits are guaranteed by design.
3: Inputs AC-coupled to GND.
4: Mode transitions controlled by SHDN.
5: Thermally limited by package.
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MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
Typical Operating Characteristics
(VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = GND (RF = RIN = 10kI), CBIAS = 0.1µF, CIN = 1µF, no load, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
0.1
0.01
1k
10k
0.01
0.001
0.001
100k
100
1k
10k
100k
10
100
1k
100k
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
POUT = 50mW
fIN = 6kHz
1
fIN = 300Hz
0.1
0.01
0.01
MAX98309 toc06
VDD = 5V
RL = 8I
10
THD+N (%)
POUT = 500mW
VDD = 4.2V
RL = 4I
10
100
MAX98309 toc05
100
MAX98309 toc04
1
1
0.01
0.001
0.001
1k
10k
0
100k
500
1000
2000
1500
VDD = 3.7V
RL = 4I
100
fIN = 6kHz
0.01
VDD = 3.7V
RL = 8I
10
THD+N (%)
1
fIN = 300Hz
500
750
1000 1250 1500 1750
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
MAX98309 toc07
100
THD+N (%)
250
OUTPUT POWER (mW)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
0.1
0
OUTPUT POWER (mW)
FREQUENCY (Hz)
10
fIN = 1kHz
0.001
MAX98309 toc08
100
fIN = 6kHz
fIN = 300Hz
0.1
fIN = 1kHz
10
10k
FREQUENCY (Hz)
THD+N (%)
THD+N (%)
10
FREQUENCY (Hz)
VDD = 3.7V
RL = 8I
0.1
POUT = 800mW
0.1
FREQUENCY (kHz)
100
10
POUT = 200mW
1
POUT = 50mW
0.001
100
POUT = 1.2W
0.01
POUT = 50mW
10
1
0.1
VDD = 3.7V
RL = 4I
10
THD+N (%)
POUT = 300mW
VDD = 5V
RL = 8I
10
THD+N (%)
1
100
MAX98309 toc02
VDD = 4.2V
RL = 4I
THD+N (%)
100
MAX98309 toc01
10
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
MAX98309 toc03
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
1
fIN = 6kHz
0.1
fIN = 300Hz
0.01
fIN = 1kHz
fIN = 1kHz
0.001
0
400
0.001
800
1200
OUTPUT POWER (mW)
1600
0
200
400
600
800
1000
OUTPUT POWER (mW)
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MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
Typical Operating Characteristics (continued)
(VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = GND (RF = RIN = 10kI), CBIAS = 0.1µF, CIN = 1µF, no load, unless otherwise noted.)
OFFSET VOLTAGE
vs. COMMON-MODE VOLTAGE
OFFSET VOLTAGE
vs. COMMON-MODE VOLTAGE
3
2
VOS (mV)
1
0
-1
-2
-2
-3
-3
-4
-4
-5
1
2
3
0
5
4
COMMON-MODE VOLTAGE (V)
OUTPUT POWER vs. SUPPLY VOLTAGE
fIN = 1kHz
RL = 8I
THD+N = 10%
1500
1000
THD+N = 10%
500
fIN = 1kHz
RL = 4I
3000
OUTPUT POWER (mW)
OUTPUT POWER (mW)
2000
3.5
2500
THD+N = 10%
2000
1500
THERMALLY
LIMITED
1000
THD+N = 1%
500
0
0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.5
SUPPLY VOLATGE (V)
THERMALLY
LIMITED
2.0
1.5
THD+N = 10%
THD+N = 1%
1.0
4.0
4.5
5.0
5.5
OUTPUT POWER vs. LOAD
VDD = 3.7V
fIN = 1kHz
ZLOAD = LOAD + 68µH
1.6
1.4
OUTPUT POWER (mW)
2.5
3.5
1.8
MAX98309 toc13
VDD = 5V
fIN = 1kHz
ZLOAD = LOAD + 68µH
3.0
SUPPLY VOLATGE (V)
OUTPUT POWER vs. LOAD
3.0
OUTPUT POWER (W)
1.0 1.5 2.0 2.5 3.0
COMMON-MODE VOLTAGE (V)
OUTPUT POWER vs. SUPPLY VOLTAGE
3500
MAX98309 toc11
2500
0.5
MAX98309 toc12
0
1.2
1.0
0.8
THD+N = 10%
0.6
0.4
0.5
MAX98309 toc14
VOS (mV)
0
-1
VDD = 3.7V
RL = 8I
3
2
1
MAX98309 toc10
VDD = 5V
RL = 8I
4
4
MAX98309 toc09
5
THD+N = 1%
0.2
0
0
1
10
100
LOAD RESISTANCE (I)
1k
1
10
100
1k
LOAD RESISTANCE (I)
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MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
Typical Operating Characteristics (continued)
(VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = GND (RF = RIN = 10kI), CBIAS = 0.1µF, CIN = 1µF, no load, unless otherwise noted.)
POWER DISSIPATION
vs. OUTPUT POWER
RL = 8I
600
400
200
RL = 4I
500
400
300
RL = 8I
200
100
0
0
1000
1500
0
2000
300
600
900
1200
1500
0
-10
MAX98309 toc18
10
100
1k
10k
-70
VDD = 3.7V
100k
VDD = 5V
10
100
1k
10k
FREQUENCY (Hz)
CMRR vs. FREQUENCY
(MAX98309)
CMRR vs. FREQUENCY
(MAX98310)
-20
1000k
-60
FREQUENCY (Hz)
RL = 8I
THD + N = 1%
100k
10k
-40
-50
-80
-90
-100
-110
-120
VDD = 3.7V
100
1k
RL = 8I
VRIPPLE = 200mV
-20
-30
PSRR (dB)
VDD = 5V
0
AV = 0dB
PSRR vs. FREQUENCY
(MAX98310)
0
MAX98309 toc20
PSRR (dB)
RL = 8I
VRIPPLE = 200mV
-10
AV = 3dB
FREQUENCY (Hz)
PSRR vs. FREQUENCY
(MAX98309)
10
AV = 6dB
OUTPUT POWER (mW)
OUTPUT POWER (mW)
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
-140
AV = 9dB
MAX98309 toc19
500
0
VDD = 3.7V
fIN = 1kHz
POUT = POUTL + POUTR
12
11
10
9
8
7
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
RL = 8I
THD + N = 1%
-10
-20
-30
100k
MAX98309 toc21
800
600
GAIN (dB)
RL = 4I
MAX98309 toc16
700
1000
-30
-40
CMRR (dB)
CMRR (dB)
POWER DISSIPATION (mW)
1200
800
POWER DISSIPATION (mW)
VDD = 5V
fIN = 1kHz
POUT = POUTL + POUTR
MAX98309 toc15
1400
GAIN vs. FREQUENCY
(MAX98310)
MAX98309 toc17
POWER DISSIPATION
vs. OUTPUT POWER
VDD = 3.7V
-50
-60
-70
-40
VDD = 3.7V
-50
-60
-70
-80
VDD = 5V
-80
VDD = 5V
-90
-90
-100
-100
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
10k
100k
FREQUENCY (Hz)
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MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
Typical Operating Characteristics (continued)
(VDD = 3.7V, VGND = 0V, SHDN = VDD, GAIN = GND (RF = RIN = 10kI), CBIAS = 0.1µF, CIN = 1µF, no load, unless otherwise noted.)
TURN-ON TIME (MAX98309) 10ms
TURN-ON TIME (MAX98309) 100ms
MAX98309 toc22
TURN-ON TIME MAX98310
MAX98309 toc23
2ms/div
MAX98309 toc24
20ms/div
1ms/div
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SUPPLY CURRENT vs. TEMPERATURE
2.0
1.5
1.0
1.5
VDD = 3.7V
1.0
0.5
0.5
0
0
3.5
4.0
4.5
5.0
5.5
-40
-15
10
35
60
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
SHUTDOWN CURRENT
vs. SUPPLY VOLTAGE
SHUTDOWN CURRENT
vs. TEMPERATURE
MAX98309 toc27
9
8
7
6
5
4
3
2
10
85
MAX98309 toc28
3.0
9
SHUTDOWN CURRENT (µA)
2.5
SHUTDOWN CURRENT (µA)
MAX98309 toc26
VDD = 5V
2.0
SUPPLY CURRENT (mA)
2.5
SUPPLY CURRENT (mA)
2.5
MAX98309 toc25
3.0
8
VDD = 5V
7
6
5
4
VDD = 3.7V
3
2
1
1
0
0
2.5
3.0
3.5
4.0
4.5
SUPPLY VOLTAGE (V)
5.0
5.5
-40
-15
10
35
60
85
TEMPERATURE (°C)
����������������������������������������������������������������� Maxim Integrated Products 8
MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
Pin Configurations
TOP VIEW
(BUMP SIDE DOWN)
TOP VIEW
(BUMP SIDE DOWN)
MAX98309
1
2
3
+
MAX98310
1
2
3
+
A
OUT+
SHDN
IN-
A
OUT+
SHDN
IN-
B
GND
TON
VDD
B
GND
GAIN
VDD
C
OUT-
BIAS
IN+
C
OUT-
BIAS
IN+
WLP
WLP
Pin Descriptions
PIN
NAME
FUNCTION
MAX98309
MAX98310
A1
A1
OUT+
Amplifier Positive Output
A2
A2
SHDN
Active-Low Shutdown Input. Connect to GND to place the IC into shutdown. Connect
to VDD for normal operation.
A3
A3
IN-
B1
B1
GND
Ground
B2
—
TON
Turn-On Time Selection. Connect TON to GND for a 10ms turn-on time. Connect TON
to VDD for a 100ms turn on time.
—
B2
GAIN
Gain Select Input. See Table 1 for gain settings.
Inverting Audio Input
B3
B3
VDD
Power Supply Input. Connect a 1FF capacitor from VDD to GND.
C1
C1
OUT-
Amplifier Negative Output
C2
C2
BIAS
Common-Mode DC Bias Bypass. Connect a 0.1FF (min) capacitor to GND.
C3
C3
IN+
Noninverting Audio Input
����������������������������������������������������������������� Maxim Integrated Products 9
MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
Detailed Description
The MAX98309/MAX98310 mono 1.4W Class AB audio
amplifiers offer low quiescent current while maintaining
excellent SNR and low 0.008% THD+N. Both ICs feature
excellent 90dB PSRR and state-of-the-art click-and-pop
suppression.
Applications Information
BTL Amplifier
The ICs are offered with an internally fixed 0dB, 3dB,
6dB, and 9dB gain (MAX98310) or an externally set gain
(MAX98309) through external resistors.
The ICs are designed to drive a load differentially, a
configuration referred to as bridge-tied load, or BTL. The
BTL configuration (Figure 1) offers advantages over the
single-ended configuration, where one side of the load
is connected to ground. Driving the load differentially
doubles the output voltage compared to a single-ended
amplifier under similar conditions.
The MAX98309 features a 10ms or 100ms pin-selectable
turn-on time, while the MAX98310 has a preset 5ms turnon time.
Substituting 2 x VOUT(P-P) for VOUT(P-P) into the following
equations yields four times the output power due to
doubling of the output voltage:
Bias
The ICs operate from a single 2.5V to 5.5V power supply
and feature an internally generated common-mode bias
voltage of VDD/2 reference to ground. BIAS provides both
click-and-pop suppression and sets the DC bias level
for the audio outputs. Choose the value of the bypass
capacitor as described in the BIAS Capacitor section. Do
not connect external loads to BIAS as this can affect the
overall performance.
Turn-On Time
The MAX98309 external gain amplifier features a selectable turn-on time for optimized click-and-pop performance. Connect TON to GND for a 10ms turn-on time.
Connect TON to VDD for a 100ms turn-on time. The
MAX98310 has a preset 5ms turn-on time.
Shutdown Mode
The ICs feature a 1.8FA low-power shutdown mode
that reduces quiescent current consumption. When the
active-low shutdown mode is entered, the ICs’ internal
bias circuitry is disabled, the amplifier outputs go high
impedance, and BIAS is driven to GND.
Click-and-Pop Suppression
The ICs feature Maxim’s industry-leading click-andpop suppression circuitry. During startup, the amplifier
common-mode bias voltage ramps to the DC bias point.
When entering shutdown, the amplifier outputs are high
impedance between both outputs. This scheme minimizes the energy present in the audio band.
VRMS =
VOUT (P −P)
2 2
VRMS 2
POUT =
RL
Because the differential outputs are biased at midsupply,
there is no net DC voltage across the load. This eliminates the need for DC-blocking capacitors required for
single-ended amplifiers. These capacitors can be large,
expensive, consume board space, and degrade lowfrequency performance.
Power Dissipation and Heatsinking
Under normal operating conditions, the ICs dissipate a
significant amount of power. The maximum power dissipation is given in the Absolute Maximum Ratings or can
be calculated by the following equation:
PD(MAX) =
TJ(MAX) − TA
θ JA
where TJ(MAX) is +150NC, TA is the ambient temperature,
and BJA is the reciprocal of the derating factor in C/W as
specified in the Absolute Maximum Ratings.
+1
VOUT(P-P)
2 x VOUT(P-P)
-1
VOUT(P-P)
Figure 1. BTL Configuration
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MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
The increase in power delivered by the BTL configuration
directly results in an increase in internal power dissipation over the single-ended configuration. The maximum
internal power dissipation for a given VDD and load is
given by the following equation:
PD(MAX) =
2VDD 2
π 2R L
If the internal power dissipation for a given application
exceeds the maximum allowed for a given package,
reduce power dissipation by increasing the ground plane
heatsinking capability and the size of the traces to the
device. See the Layout and Grounding section. Other
methods for reducing power dissipation are to reduce
VDD, increase load impedance, decrease ambient
temperature, reduce gain, or reduce input signal.
Thermal-overload protection limits total power dissipation
in the MAX98309/MAX98310. When the junction temperature exceeds +160NC, the thermal protection circuitry
disables the amplifier. Operation returns to normal once
the die cools by 15NC.
Amplifier Gain
Fixed Differential Gain (MAX98310)
The MAX98310 features four internally fixed differential
gain options selectable by GAIN (Table 1). This simplifies
design, decreases required application footprint size, and
eliminates external gain-setting resistors.
External Differential Gain (MAX98309)
The MAX98309 features an external gain option. Resistors
RF and RIN. See the Simplified Block Diagram and set the
gain of the amplifier as follows:
AV =
RF
RIN
Input Filter
The fully differential amplifier inputs can be biased at
voltages other than midsupply. The common-mode
feedback circuit adjusts for input bias, ensuring the outputs are still biased at midsupply. Input capacitors are
not required as long as the input voltage is within the
specified common-mode range listed in the Electrical
Characteristics table.
If input capacitors are used, input capacitor CIN, in conjunction with the input resistor RIN, forms a highpass filter
that removes the DC bias from an incoming signal. The
AC-coupling capacitor allows the amplifier to bias the signal to an optimum DC level. Assuming zero-source impedance, the -3dB point of the highpass filter is given by:
f−3dB =
1
2πRIN CIN
Setting f-3dB too high affects the low-frequency response
of the amplifier. Use capacitors with adequately low voltage coefficients, such as X7R ceramic capacitors with a
high voltage rating. Capacitors with higher voltage coefficients result in increased distortion at low frequencies.
BIAS Capacitor
BIAS is the output of the internally generated VDD/2 bias
voltage. The BIAS bypass capacitor, CBIAS, improves
PSRR and THD+N by reducing power supply and other
noise sources at the common-mode bias node, and also
generates the clickless/popless startup DC bias waveform for the speaker amplifiers. Bypass BIAS with a 0.1FF
capacitor to GND. Larger values of CBIAS (up to 1FF)
improve PSRR.
Supply Bypassing
where AV is the desired voltage gain. Hence, an RIN of
10kI and an RF of 20kI yields a gain of 2V/V or 6dB.
RF can be either fixed or variable, allowing the use of a
digitally controlled potentiometer to alter the gain under
software control.
Table 1. Fixed Differential Gain
GAIN CONNECTION
GAIN (dB)
VDD
0
GND
3
Unconnected
6
BIAS
9
Proper power-supply bypassing ensures low-noise, lowdistortion performance. Connect a 1FF ceramic capacitor
from VDD to GND. Add additional bulk capacitance as
required by the application. Locate the bypass capacitor
as close as possible to the device.
Layout and Grounding
Good PCB layout is essential for optimizing performance.
Use large traces for the power-supply inputs and amplifier
outputs to minimize losses due to parasitic trace resistance and route heat away from the device. Good grounding improves audio performance, and prevents any digital
switching noise from coupling into the audio signal.
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MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
Ordering Information
PART
TEMP RANGE
GAIN
PIN-PACKAGE
TOP MARK
MAX98309EWL+
-40NC to +85NC
External
9 WLP
+AIY
MAX98310EWL+
-40NC to +85NC
Fixed
9 WLP
+AIZ
+Denotes a lead(Pb)-free/RoHS-compliant package.
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MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
Package Information
For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or
“-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains
to the package regardless of RoHS status.
PACKAGE TYPE
PACKAGE CODE
OUTLINE NO.
LAND PATTERN NO.
9 WLP (0.3mm pitch)
W91D1+1
21-0486
Refer to Application Note 1891
COMMON DIMENSIONS
PIN 1
INDICATOR
MARKING
E
A3
1
A2
A
0.03
A2
0.48 REF
0.025 BASIC
0.21
A
See
Note 7
SIDE VIEW
E
0.03
0.60 BASIC
D1
S
TOP VIEW
0.05
0.16
b
0.05 S
D
0.64
A3
A1
AAAA
A
A1
E1
0.60 BASIC
e
0.30
BASIC
SD
0.00
BASIC
SE
0.00
BASIC
D
PKG. CODE
MIN
MAX
MIN
MAX
W91D1+1
0.95
0.98
0.95
0.98
DEPOPULATED
BUMPS
NONE
E1
e
SE
B
SD
C
D1
B
A
1
2
3
b
NOTES:
1. Terminal pitch is defined by terminal center to center value.
2. Outer dimension is defined by center lines between scribe lines.
3. All dimensions in millimeter.
4. Marking shown is for package orientation reference only.
5. Tolerance is ± 0.02 unless specified otherwise.
6. All dimensions apply to PbFree (+) package codes only.
7. Front - side finish can be either Black or Clear.
A
BOTTOM VIEW
TITLE
-DRAWING NOT TO SCALE-
APPROVAL
PACKAGE OUTLINE
9 BUMPS, WLP PKG. 0.3mm PITCH
DOCUMENT CONTROL NO.
21-0486
REV.
B
1
1
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MAX98309/MAX98310
Mono 1.4W Class AB Audio Amplifiers
Revision History
REVISION
NUMBER
REVISION
DATE
0
6/11
DESCRIPTION
Initial release
PAGES
CHANGED
—
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.
Maxim reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical
Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2011
Maxim Integrated Products 14
Maxim is a registered trademark of Maxim Integrated Products, Inc.