19-5494; Rev 0; 9/10
EVALUATION KIT
AVAILABLE
Stereo 3.1W Class D Amplifier
General Description
The MAX98303 stereo 3.1W Class D amplifier provides
Class AB audio performance with Class D efficiency.
This device offers five selectable gain settings (6dB,
9dB, 12dB, 15dB, and 18dB) set by a single gain-select
input (GAIN).
Active emissions limiting, edge-rate, and overshoot control circuitry greatly reduces EMI. A filterless spreadspectrum modulation scheme eliminates the need for
output filtering found in traditional Class D devices. These
features reduce application component count.
The IC's 2.0mA at 3.7V, 2.7mA at 5V, quiescent current
extends battery life in portable applications.
The IC is available in a 16-bump WLP (1.68mm x 1.68mm
x 0.64mm) package specified over the extended -40NC
to +85NC temperature range.
Applications
Notebook and Netbook
Computers
Tablets
Cellular Phones
MP3 Players
Portable Audio Players
VoIP Phones
Features
S Low Quiescent Current: 2.0mA at 3.7V, 2.7mA
at 5V
S Spread Spectrum and Active Emissions Limiting
S Five Pin-Selectable Gains
S Click-and-Pop Suppression
S Thermal and Overcurrent Protection
S Low-Current Shutdown Mode
S Space-Saving, 1.68mm x 1.68mm x 0.64mm,
16-Bump WLP (0.4mm Pitch)
Ordering Information
PART
MAX98303EWE+
+Denotes a lead(Pb)-free/RoHS-compliant package.
TEMP
RANGE
-40NC to
+85NC
PIN-
PACKAGE
16 WLP AAA
MARK
TOP
MAX98303
Typical Application Circuit
+2.6V TO +5.5V
10µF
OUTL-
OUTR+
OUTR-
1µF
INL+ OUTL+
1µF
INL-
PVDD
GAIN GAIN
1µF
INR+
1µF
INR-
PVDD
SHDN
PVDD
CONTROL
MAX98303
PGND
0.1µF
_______________________________________________________________ Maxim Integrated Products 1
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.
Stereo 3.1W Class D Amplifier
ABSOLUTE MAXIMUM RATINGS
PVDD to PGND ........................................................-0.3V to +6V
OUT_+, OUT_- to PGND .......................-0.3V to (V
All Other Pins to PGND ........................................... -0.3V to +6V
Continuous Current for PVDD, PGND,
OUTL_, OUTR_ ........................................................ Q1600mA
Continuous Input Current (all other pins) ........................ Q20mA
Duration of Short Circuit Between
OUTL_, OUTR_ to PVDD or PGND ........................Continuous
OUTL+ to OUTL-, OUTR+ to OUTR- .................... Continuous
MAX98303
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
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.
PVDD
+ 0.3V)
ELECTRICAL CHARACTERISTICS
(V
= V
PVDD
AC measurement bandwidth, TA = T
Supply Voltage Range V
Undervoltage Lockout UVLO 2.3 V
Quiescent Supply Current I
Shutdown Supply Current
Turn-On Time t
Bias Voltage V
Voltage Gain A
Channel-to-Channel Gain
Tracking
Input Resistance R
Output Offset Voltage V
= 3.7V, V
SHDN
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
= 0V, AV = 12dB (GAIN = PVDD), RL = J, RL connected between OUT_+ to OUT_-, 20Hz to 22kHz
PGND
MIN
to T
PVDD
DD
I
SHDN
ON
BIAS
OS
, unless otherwise noted. Typical values are at TA = +25NC.) (Notes 2, 3)
MAX
Inferred from PSRR test 2.6 5.5 V
V
= 5.0V 2.7
PVDD
V
= 0V, TA = +25NC
SHDN
Connect GAIN to PGND 17.5 18 18.5
Connect GAIN to PGND through 100kI
±5% resistor
Connect GAIN to PVDD 11.5 12 12.5
V
Connect GAIN to PVDD through 100kI
±5% resistor
GAIN unconnected 5.5 6 6.5
AV = 18dB 15 20 29
AV = 15dB 15 20 29
AV = 12dB 15 20 29
IN
AV = 9dB 20 28 40
AV = 6dB 30 40 58
TA = +25NC (Note 4)
Continuous Power Dissipation for Multilayer Board (TA = +70NC)
16-Bump WLP (derate 17.2mW/NC above +70NC) ........1.38W
B
(Note 1) ..................................................................58NC/W
JA
B
(Note 1) .................................................................15NC/W
JC
Junction Temperature .....................................................+150NC
Operating Temperature Range .......................... -40NC to +85NC
Storage Temperature Range ............................ -65NC to +150NC
Soldering Temperature (reflow) ......................................+260NC
2.0 3.1
≤ 0.1 10
3.4 10 ms
1.3 V
14.5 15 15.5
8.5 9 9.5
±0.1
±0.3 ±3
mA
FA
dB
%
kI
mV
2 ______________________________________________________________________________________
Stereo 3.1W Class D Amplifier
ELECTRICAL CHARACTERISTICS (continued)
(V
= V
PVDD
AC measurement bandwidth, TA = T
Click and Pop K
Common-Mode Rejection Ratio CMRR
Crosstalk
Power-Supply Rejection Ratio
(Note 4)
Output Power P
Total Harmonic Distortion Plus
Noise
Oscillator Frequency f
Spread-Spectrum Bandwidth
Efficiency
Output Noise V
Signal-to-Noise Ratio SNR P
SHDN
= 3.7V, V
= 0V, AV = 12dB (GAIN = PVDD), RL = J, RL connected between OUT_+ to OUT_-, 20Hz to 22kHz
PGND
MIN
to T
, unless otherwise noted. Typical values are at TA = +25NC.) (Notes 2, 3)
MAX
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Peak voltage, A-weighted,
CP
32 samples per second,
RL = 8I + 68FH
(Notes 4, 5)
fIN = 1kHz,
input referred
P
= 300mW,
OUT
RL = 8I + 68FH
V
= 2.6V to 5.5V, TA = +25NC
PVDD
PSRR
V
RIPPLE
= 200mV
P-P
RL = 8I + 68FH
THD+N = 10%, f = 1kHz,
RL = 4I + 33µH
THD+N = 1%, f = 1kHz,
RL = 4I + 33µH
OUT
THD+N = 10%, f = 1kHz,
RL = 8I + 68µH
THD+N = 1%, f = 1kHz,
RL = 8I + 68µH
THD+N fIN = 1kHz
OSC
E THD+N = 10%, f = 1kHz, RL = 8I + 68FH
AV = 6dB, A weighted (Note 4) 37
N
= 3.1W, V
OUT
PVDD
Into shutdown -74
dBV
Out of shutdown -59
AV = 18dB 67
AV = 15dB 72
AV = 12dB 67
AV = 9dB 65
AV = 6dB 62
f = 1kHz 100
f = 10kHz 95
51 78
f = 217Hz 66
,
f = 1kHz 66
f = 10kHz 63
V
= 5.0V 3.1
PVDD
V
= 4.2V 2.2
PVDD
V
= 3.7V 1.7
PVDD
V
= 5.0V 2.5
PVDD
V
= 4.2V 1.7
PVDD
V
= 3.7V 1.3
PVDD
V
= 5.0V 1.8
PVDD
V
= 4.2V 1.2
PVDD
V
= 3.7V 1.0
PVDD
V
= 5.0V 1.4
PVDD
V
= 4.2V 1.0
PVDD
V
= 3.7V 0.7
PVDD
RL = 4I + 33FH,
P
= 1W
OUT
RL = 8I + 68FH,
P
= 0.5W
OUT
0.047
0.04
300 kHz
±15
kHz
93 %
FV
= 5.0V, AV = 6dB 99.6 dB
MAX98303
dB
dB
dB
W
%
RMS
_______________________________________________________________________________________ 3
Stereo 3.1W Class D Amplifier
ELECTRICAL CHARACTERISTICS (continued)
(V
= V
PVDD
AC measurement bandwidth, TA = T
Output Current Limit I
Thermal Shutdown Level 145
Thermal Shutdown Hysteresis 15
DIGITAL INPUT (SHDN)
MAX98303
Input Voltage High V
Input Voltage Low V
Input Leakage Current
Note 2: This device is 100% production tested at TA = +25NC. All temperature limits are guaranteed by design.
Note 3: Testing performed with a resistive load in series with an inductor to simulate an actual speaker load. For RL = 4I,
L = 33FH. For RL = 8I, L = 68FH.
Note 4: Amplifier inputs AC-coupled to ground.
Note 5: Mode transitions controlled by SHDN.
SHDN
= 3.7V, V
= 0V, AV = 12dB (GAIN = PVDD), RL = J, RL connected between OUT_+ to OUT_-, 20Hz to 22kHz
PGND
MIN
to T
, unless otherwise noted. Typical values are at TA = +25NC.) (Notes 2, 3)
MAX
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
LIM
INH
INL
V
= 2.5V to 5.5V 1.4 V
PVDD
V
= 2.5V to 5.5V 0.4 V
PVDD
2 A
TA = +25NC
±1
NC
NC
FA
Typical Operating Characteristics
(V
= V
PVDD
bandwidth, TA = +25NC, unless otherwise noted.)
10
1
THD+N (%)
0.1
0.01
10 100k
SHDN
= 5.0V, V
= 0V, AV = 12dB, RL = J, RL connected between OUT_+ to OUT_-, 20Hz to 22kHz AC measurement
PGND
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
V
= 5V
PVDD
= 4I + 33µH
Z
LOAD
P
= 2W
OUT
P
= 1.5W
OUT
10k1k100
FREQUENCY (Hz)
MAX98303 toc01
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
10
V
= 4.2V
PVDD
= 4I + 33µH
Z
LOAD
P
= 0.2W
1
THD+N (%)
0.1
0.01
10 100k
OUT
P
= 1W
OUT
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
10
V
= 3.7V
PVDD
= 4I + 33µH
Z
MAX98303 toc02
THD+N (%)
10k1k100
LOAD
1
P
= 0.8W
0.1
0.01
OUT
P
= 0.2W
OUT
10 100k
FREQUENCY (Hz)
10k1k100
MAX98303 toc03
4 ______________________________________________________________________________________
Stereo 3.1W Class D Amplifier
Typical Operating Characteristics (continued)
(V
= V
PVDD
bandwidth, TA = +25NC, unless otherwise noted.)
SHDN
= 5.0V, V
= 0V, AV = 12dB, RL = J, RL connected between OUT_+ to OUT_-, 20Hz to 22kHz AC measurement
PGND
MAX98303
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
10
V
= 5V
PVDD
= 8I + 68µH
Z
LOAD
1
P
= 1.2W
THD+N (%)
0.1
0.01
10 100k
OUT
P
= 0.2W
OUT
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
100
V
= 5V
PVDD
= 4I + 33µH
Z
LOAD
10
1
THD+N (%)
0.1
f = 6000Hz
f = 1000Hz
10k1k100
f = 100Hz
MAX98303 toc04
MAX98303 toc07
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
10
V
= 4.2V
PVDD
= 8I + 68µH
Z
LOAD
P
OUT
= 0.6W
OUT
= 0.2W
1
P
THD+N (%)
0.1
0.01
10 100k
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
100
V
= 4.2V
PVDD
= 4I + 33µH
Z
LOAD
10
1
THD+N (%)
0.1
f = 6000Hz
f = 1000Hz
10k1k100
f = 100Hz
MAX98303 toc05
MAX98303 toc08
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
10
V
= 3.7V
PVDD
= 8I + 68µH
Z
LOAD
P
OUT
OUT
= 0.4W
= 0.2W
1
P
THD+N (%)
0.1
0.01
10 100k
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
100
V
= 3.7V
PVDD
= 4I + 33µH
Z
LOAD
10
1
THD+N (%)
0.1
f = 6000Hz
f = 1000Hz
MAX98303 toc06
10k1k100
MAX98303 toc09
f = 100Hz
0.01
0 3.5
OUTPUT POWER (W)
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
100
V
= 5V
PVDD
= 8I + 68µH
Z
LOAD
10
1
THD+N (%)
0.1
0.01
0 2.0
f = 6000Hz
f = 1000Hz
OUTPUT POWER (W)
_______________________________________________________________________________________ 5
1.51.00.5
3.02.52.01.51.00.5
f = 100Hz
MAX98303 toc10
0.01
0 2.5
OUTPUT POWER (W)
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
100
V
= 4.2V
PVDD
= 8I + 68µH
Z
LOAD
10
1
THD+N (%)
0.1
0.01
0 1.5
f = 6000Hz
f = 1000Hz
OUTPUT POWER (W)
2.01.51.00.5
f = 100Hz
1.20.90.60.3
MAX98303 toc11
0.01
0 2.0
OUTPUT POWER (W)
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
100
V
= 3.7V
PVDD
= 8I + 68µH
Z
LOAD
10
1
THD+N (%)
0.1
0.01
0 1.2
f = 6000Hz
f = 1000Hz
OUTPUT POWER (W)
1.51.00.5
MAX98303 toc12
f = 100Hz
1.00.80.60.40.2
Stereo 3.1W Class D Amplifier
Typical Operating Characteristics (continued)
(V
= V
PVDD
bandwidth, TA = +25NC, unless otherwise noted.)
SHDN
= 5.0V, V
= 0V, AV = 12dB, RL = J, RL connected between OUT_+ to OUT_-, 20Hz to 22kHz AC measurement
PGND
OUTPUT POWER vs. LOAD RESISTANCE
3.5
3.0
MAX98303
2.5
2.0
1.5
OUTPUT POWER (W)
1.0
0.5
0
1 1000
THD+N = 10%
THD+N = 1%
R
LOAD
OUTPUT POWER vs. SUPPLY VOLTAGE
2.5
f = 1kHz
Z
= 8I + 68µH
LOAD
2.0
THD+N = 10%
1.5
1.0
0.5
OUTPUT POWER PER CHANNEL (W)
0
THD+N = 1%
SUPPLY VOLTAGE (V)
(I)
10010
V
PVDD
f = 1kHz
5.04.54.03.53.02.5 5.5
= 5V
1.8
1.6
MAX98303 toc13
1.4
1.2
1.0
0.8
0.6
OUTPUT POWER (W)
0.4
0.2
MAX98303 toc16
AMPLITUDE (dB)
-10
-20
-30
OUTPUT POWER vs. LOAD RESISTANCE
V
= 3.7V
PVDD
f = 1kHz
THD+N = 10%
THD+N = 1%
0
1 1000
R
LOAD
10010
(I)
GAIN vs. FREQUENCY
30
GAIN = PGND
20
10
GAIN = PVDD
0
GAIN = 100kI TO PVDD
10 100k
GAIN = 100kI TO PGND
GAIN = UNCONNECTED
10k1k100
FREQUENCY (Hz)
OUTPUT POWER vs. SUPPLY VOLTAGE
4.5
f = 1kHz
4.0
Z
= 4I + 33µH
MAX98303 toc14
LOAD
3.5
3.0
2.5
2.0
1.5
1.0
OUTPUT POWER PER CHANNEL (W)
0.5
0
2.5 5.5
EFFICIENCY vs. OUTPUT POWER
100
90
MAX98303 toc17
80
Z
LOAD
70
60
50
40
EFFICIENCY (%)
30
20
10
0
OUTPUT POWER PER CHANNEL (W)
THD+N = 10%
THD+N = 1%
SUPPLY VOLTAGE (V)
= 8I + 68µH
Z
LOAD
5.04.54.03.53.0
V
PVDD
= 4I + 33µH
MAX98303 toc15
= 5.0V
MAX98303 toc18
3.53.02.0 2.51.0 1.50.50 4.0
EFFICIENCY vs. OUTPUT POWER
100
90
80
70
Z
= 8I + 68µH
LOAD
60
50
40
EFFICIENCY (%)
30
20
10
0
0 2.0
OUTPUT POWER PER CHANNEL (W)
Z
LOAD
= 4I + 33µH
V
1.51.00.5
PVDD
= 3.7V
MAX98303 toc19
SUPPLY CURRENT vs. SUPPLY VOLTAGE
4.0
3.5
3.0
2.5
2.0
1.5
SUPPLY CURRENT (mA)
1.0
0.5
0
2.5 5.5
SUPPLY VOLTAGE (V)
0
vs. FREQUENCY
V
= 200mV
RIPPLE
-10
Z
= 8I + 68µH
-20
-30
-40
-50
PSRR (dB)
-60
-70
-80
-90
-100
LOAD
FREQUENCY (Hz)
MAX98303 toc20
5.04.53.0 3.5 4.0
6 ______________________________________________________________________________________
POWER-SUPPLY REJECTION RATIO
P-P
MAX98303 toc21
10k1k10010 100k
Stereo 3.1W Class D Amplifier
Typical Operating Characteristics (continued)
(V
= V
PVDD
bandwidth, TA = +25NC, unless otherwise noted.)
SHDN
= 5.0V, V
= 0V, AV = 12dB, RL = J, RL connected between OUT_+ to OUT_-, 20Hz to 22kHz AC measurement
PGND
MAX98303
POWER-SUPPLY REJECTION RATIO
vs. SUPPLY VOLTAGE
0
f = 1kHz
-10
V
= 200mV
RIPPLE
Z
-20
LOAD
-30
-40
-50
PSRR (dB)
-60
-70
-80
-90
-100
2.5 5.5
P-P
= 8I + 68µH
SUPPLY VOLTAGE (V)
STARTUP RESPONSE
COMMON-MODE REJECTION RATIO
100
vs. FREQUENCY
Z
= 8I + 68µH
LOAD
90
MAX98303 toc22
80
70
60
50
CMRR (dB)
40
30
20
10
5.04.54.03.53.0
MAX98303 toc25
0
10 100k
V
SHDN
2V/div
I
SPEAKER
200mA/div
AV = 15dB
A
= 18dB
V
FREQUENCY (Hz)
A
= 9dB
V
AV = 12dB
A
= 6dB
V
10k1k100
-20
MAX98303 toc23
-40
-60
CROSSTALK (dB)
-80
-100
-120
SHUTDOWN RESPONSE
CROSSTALK vs. FREQUENCY
0
Z
= 8I + 68µH
LOAD
LEFT TO RIGHT
RIGHT TO LEFT
10 100k
FREQUENCY (Hz)
MAX98303 toc26
10k1k100
V
SHDN
2V/div
I
SPEAKER
200mA/div
MAX98303 toc24
1ms/div
WIDEBAND vs. FREQUENCY
20
0
-20
-40
-60
OUTPUT MAGNITUDE (dBV)
-80
-100
0.1 100
FREQUENCY (MHz)
101
_______________________________________________________________________________________ 7
RBW = 100Hz
MAX98303 toc27
1ms/div
IN-BAND vs. FREQUENCY
0
f = 1kHz
-20
-40
-60
-80
-100
OUTPUT MAGNITUDE (dBV)
-120
-140
10 100k
FREQUENCY (Hz)
MAX98303 toc28
10k1k100
Stereo 3.1W Class D Amplifier
Bump Configuration
TOP VIEW
(BUMP SIDE DOWN)
+
A
OUTL+
MAX98303
1
2 3 4
OUTL- GAIN INL+
MAX98303
B
PGND PGND PGND INL-
C
PVDD PVDD PVDD INR-
D
OUTR+ OUTR- SHDN INR+
(1.68mm O 1.68mm O 0.64mm,
WLP
0.4mm PITCH)
Bump Description
BUMP NAME FUNCTION
A1 OUTL+ Positive Left Speaker Output
A2 OUTL- Negative Left Speaker Output
A3 GAIN Gain Select. See Table 1 for Gain Settings.
A4 INL+ Noninverting Audio Left Input
B1, B2, B3 PGND Ground
B4 INL- Inverting Audio Left Input
C1, C2, C3 PVDD
C4 INR- Inverting Audio Right Input
D1 OUTR+ Positive Right Speaker Output
D2 OUTR- Negative Right Speaker Output
D3
D4 INR+ Noninverting Audio Right Input
SHDN Active-Low Shutdown Input. Drive SHDN low to place the device in shutdown.
Power Supply. Bypass PVDD to PGND with 0.1FF and 10FF capacitors.
8 ______________________________________________________________________________________
Stereo 3.1W Class D Amplifier
Detailed Description
The MAX98303 features low quiescent current, a lowpower shutdown mode, comprehensive click-and-pop
suppression, and excellent RF immunity.
The IC offers Class AB audio performance with Class D
efficiency in a minimal board-space solution.
The Class D amplifier features spread-spectrum modulation, edge-rate, and overshoot control circuitry that
offers significant improvements to switch-mode amplifier
radiated emissions.
The amplifier features click-and-pop suppression that
reduces audible transients on startup and shutdown.
The amplifier includes thermal-overload and short-circuit
protection.
Class D Speaker Amplifier
The filterless Class D amplifier offers much higher efficiency than Class AB amplifiers. The high efficiency of
a Class D amplifier is due to the switching operation of
the output stage transistors. Any power loss associated
with the Class D output stage is mostly due to the I2R
loss of the MOSFET on-resistance and quiescent current
overhead.
Ultra-Low-EMI Filterless Output Stage
Traditional Class D amplifiers require the use of external
LC filters, or shielding, to meet EN55022B electromagnetic-interference (EMI) regulation standards. Maxim’s active
emissions limiting edge-rate control circuitry and spreadspectrum modulation reduce EMI emissions, while maintaining up to 93% efficiency.
Maxim’s spread-spectrum modulation mode flattens
wideband spectral components, while proprietary techniques ensure that the cycle-to-cycle variation of the
switching period does not degrade audio reproduction
or efficiency. The IC’s spread-spectrum modulator randomly varies the switching frequency by Q15kHz around
the center frequency (300kHz). Above 10MHz, the
wideband spectrum looks like noise for EMI purposes
(Figure 1).
Speaker Current Limit
If the output current of the speaker amplifier exceeds
the current limit (2A typ), the IC disables the outputs for
approximately 100Fs. At the end of 100Fs, the outputs
are reenabled. If the fault condition still exists, the IC
continues to disable and reenable the outputs until the
fault condition is removed.
Selectable Gain
The IC offers five programmable gains selected using
the GAIN input.
Table 1. Gain Control Configuration
GAIN PIN MAXIMUM GAIN (dB)
Connect to PGND 18
Connect to PGND through
100kI ±5% resistor
Connect to PVDD 12
Connect to PVDD through
100kI ±5% resistor
Unconnected 6
90
70
50
EN55022B LIMIT
30
EMISSIONS LEVEL (dBµV/m)
10
-10
Figure 1. EMI with 30cm of Speaker Cable and No Output Filter
HORIZONTAL
VERTICAL
0 100 200 300 400 500 600 700 800 900 1000
FREQUENCY (MHz)
The IC features a low-power shutdown mode, drawing
P 0.1FA (typ) of supply current. Drive SHDN low to place
the MAX98303 into shutdown.
Click-and-Pop Suppression
The IC speaker amplifier features Maxim’s comprehensive click-and-pop suppression. During startup, the
click-and-pop suppression circuitry reduces any audible
transient sources internal to the device. When entering
shutdown, the differential speaker outputs ramp down to
PGND quickly and simultaneously.
15
9
Shutdown
MAX98303
_______________________________________________________________________________________ 9
Stereo 3.1W Class D Amplifier
Applications Information
Filterless Class D Operation
Traditional Class D amplifiers require an output filter.
The filter adds cost and size and decreases THD performance. The IC’s filterless modulation scheme does not
require an output filter.
Because the switching frequency of the IC is well
beyond the bandwidth of most speakers, voice coil
MAX98303
movement due to the switching frequency is very small.
Use a speaker with a series inductance > 10FH. Typical
8I speakers exhibit series inductances in the 20FH to
100FH range.
Component Selection
Power-Supply Input (PVDD)
PVDD powers the speaker amplifier. PVDD ranges from
2.6V to 5.5V. Bypass PVDD with 0.1FF and 10FF capacitors to PGND. Apply additional bulk capacitance at the
device if long input traces between PVDD and the power
source are used.
Input Filtering
The input-coupling capacitor (CIN), in conjunction with
the amplifier’s internal input resistance (RIN), forms a
highpass filter that removes the DC bias from the incoming signal. These capacitors allow the amplifier to bias
the signal to an optimum DC level.
Assuming zero source impedance with a gain setting of
12dB, 15dB, or 18dB, CIN is:
8
= µ
C [ F]
IN
f
3dB
−
Layout and Grounding
Proper layout and grounding are essential for optimum
performance. Good grounding improves audio performance and prevents switching noise from coupling into
the audio signal.
Use wide, low-resistance output traces. As the load
impedance decreases, the current drawn from the
device increases. At higher current, the resistance of the
output traces decrease the power delivered to the load.
For example, if 2W is delivered from the device output to
a 4I load through 100mI of total speaker trace, 1.904W
is delivered to the speaker. If power is delivered through
10mI of total speaker trace, 1.99W is delivered to the
speaker. Wide output, supply, and ground traces also
improve the power dissipation of the device.
The IC is inherently designed for excellent RF immunity.
For best performance, add ground fills around all signal
traces on top or bottom PCB planes.
WLP Applications Information
For the latest application details on WLP construction,
dimensions, tape carrier information, PCB techniques,
bump-pad layout, and recommended reflow temperature profile, as well as the latest information on reliability
testing results, refer to Application Note 1891: Wafer
level packaging (WLP) and its applications. Figure 2
shows the dimensions of the WLP balls used on the IC.
0.24mm
with a gain setting of 9dB, CIN is:
5.7
= µ
C [ F]
IN
f
3dB
−
with a gain setting of 6dB, CIN is:
4
= µ
C [ F]
IN
f
−
3dB
where f
tors with adequately low-voltage coefficients for best
low-frequency THD performance.
10 _____________________________________________________________________________________
is the -3dB corner frequency. Use capaci-
-3dB
Figure 2. MAX98303 WLP Ball Dimensions
0.21mm
Stereo 3.1W Class D Amplifier
Block Diagram
2.6V TO 5.5V
MAX98303
PVDD
PVDD
SHDN
INL-
GAINB4A3
0.1µF
PVDD
C1, C2, C3
D3
A4INL+
UVLO/POWER
MANAGEMENT
10µF
CLICK-AND-POP
SUPPRESSION
CLASS D
MODULATOR
LOW-EMI
DRIVER
LOW-EMI
DRIVER
MAX98303
PGND
PGND
PVDD
PVDD
PVDD
OUTL+
A1
A2
OUTL-
OUTR+
D1
D2
OUTR-
INR- C4
LOW-EMI
DRIVER
D4INR+
CLASS D
MODULATOR
B1, B2, B3
PGND
PGND
PVDD
LOW-EMI
DRIVER
PGND
Chip Information
PROCESS: CMOS
______________________________________________________________________________________ 11
Stereo 3.1W Class D Amplifier
Package Information
For the latest package outline information and land patterns, 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.
16 WLP W161B1+1
21-0491 —
MAX98303
12 _____________________________________________________________________________________
Stereo 3.1W Class D Amplifier
Revision History
MAX98303
REVISION
NUMBER
0 9/10 Initial release —
REVISION
DATE
DESCRIPTION
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 13
©
2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
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