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MAX98358
PDM Input Class D Audio Power Amplifier
General Description
The MAX98358 is a digital pulse-density modulated
(PDM) input Class D power amplifier that provides Class
AB audio performance with Class D efficiency. This IC
offers five selectable gain settings (3dB, 6dB, 9dB, 12dB,
and 15dB) set by a single gain-select input (GAIN). The IC
can be configured to produce a left channel, right channel,
or (left/2 + right/2) output from the stereo input data.
The MAX98358 takes a stereo pulse density modulated
(SPDM) input signal directly into the DAC. Data on the
rising edge of PDM_CLK is considered left-channel data
while data on the falling PDM_CLK edge is right channel.
A mono sum feature is also implemented with SPDM data
input by summing the data from both rising and falling
clock edges.
Active emissions-limiting, edge-rate limiting, and overshoot control circuitry greatly reduce EMI. A filterless
spread-spectrum modulation scheme eliminates the need
for output filtering found in traditional Class D devices and
reduces the component count of the solution.
Features
●● Single-Supply Operation (2.5V to 5.5V)
●● 3.2W Output Power into 4Ω at 5V
●● 1.8mA Quiescent Current (VDD = 3.7V)
●● 92% Efficiency (RL = 8Ω, POUT = 1.5W)
●● 29µVRMS Output Noise (AV = 6dB)
●● Low 0.013% THD+N at 1kHz
●● Supported PDM_CLK Rates of 1.84MHz–4.32MHz
and 5.28MHz–8.64MHz
●● Supports Left, Right, or Left/2 + Right/2 Outputs
●● Sophisticated Edge Rate Control Enables Filterless
Class D Outputs
●● 77dB PSRR at 217Hz
●● Low RF Susceptibility Rejects TDMA
Noise from GSM Radios
●● Extensive Click-and-Pop Reduction Circuitry
●● Robust Short-Circuit and Thermal Protection
The IC is available in 9-pin WLP (1.345mm x 1.435mm
x 0.64mm) and 16-pin TQFN (3mm x 3mm x 0.75mm)
packages and is specified over the -40°C to +85°C temperature range.
●● Available in Space-Saving Packages:
1.345mm x 1.435mm WLP (0.4mm Pitch)
3mm x 3mm TQFN
Applications
Simplified Block Diagram
●●
●●
●●
●●
Notebook and Netbook Computers
Cellular Phones
Tablets
Portable Media Players
Ordering Information and Functional Diagram appears at
end of data sheet.
PDM
INPUT
19-6786; Rev 6; 10/19
SHUTDOWN
AND
CHANNEL
SELECT
MAX98358
GAIN
CONTROL
DIGITAL
AUDIO
INTERFACE
DAC
CLASS D
OUTPUT
STAGE
MAX98358
PDM Input Class D Audio Power Amplifier
TABLE OF CONTENTS
General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Simplified Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Package Thermal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Typical Operating Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Speaker Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Bump/Pin Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Bump/Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Detailed Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Digital Audio Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Supported PDM_CLK Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
PDM_CLK Jitter Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
PDM Timing Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Standby Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
SD_MODE Pin and Shutdown Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Class D Speaker Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Ultra-Low EMI Filterless Output Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Speaker Current Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Gain Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Click-and-Pop Suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Filterless Class D Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Power-Supply Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Layout and Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
WLP Applications Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Functional Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
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Maxim Integrated │ 2
MAX98358
PDM Input Class D Audio Power Amplifier
LIST OF FIGURES
Figure 1. PDM Audio Interface Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 2. PDM Digital Audio Interface Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 3. SD_MODE Resistor Connection Using Open-Drain Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 4. SD_MODE Resistor Connection Using Push-Pull Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 5. EMI with 12in of Speaker Cable and No Output Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 6. Left-Channel Operation with 6dB Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 8. Right-Channel Operation with 6dB Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 7. Left-Channel Operation with 12dB Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 9. Stereo Operation Using Two MAX98358s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 10. Monomix (Left/2 + Right/2) PDM Operation with 6dB Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 11. MAX98358 WLP Ball Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
LIST OF TABLES
Table 1. PDM_CLK Channel Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 2. PDM_CLK Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 3. Calculated PDM_CLK Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 4. RMS Jitter Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 5. SD_MODE Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Table 6. Examples of SD_MODE Pullup Resistor Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Table 7. Gain Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
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Maxim Integrated │ 3
MAX98358
PDM Input Class D Audio Power Amplifier
Absolute Maximum Ratings
VDD, PDM_CLK and PDM_DATA to GND...............-0.3V to +6V
All Other Pins to GND............................... -0.3V to (VDD + 0.3V)
Continuous Current In/Out of VDD/GND/OUT_..................±1.6A
Continuous Input Current (all other pins)..........................±20mA
Duration of OUT_ Short Circuit to GND or VDD….....Continuous
Duration of OUTP Short to OUTN..............................Continuous
Continuous Power Dissipation ...............................(TA = +70°C)
WLP (derate 13.7mW/°C above +70°C).....................1096mW
TQFN (derate 20.8mW/°C above +70°C)..................1666mW
Junction Temperature.......................................................+150°C
Operating Temperature Range............................ -40°C to +85°C
Storage Temperature Range............................. -65°C to +150°C
Soldering Temperature (reflow)........................................+260°C
Lead Temperature (soldering, 10s, TQFN)...................... +300°C
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 (θJA)...........73°C/W
Junction-to-Case Thermal Resistance (θJC)................50°C/W
TQFN
Junction-to-Ambient Thermal Resistance (θJA)...........48°C/W
Junction-to-Case Thermal Resistance (θJC)..................7°C/W
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.maximintegrated.com/thermal-tutorial.
Electrical Characteristics
(VDD = 5V, VGND = 0V, GAIN = VDD (+6dB). PDM_CLK = 3.072MHz, speaker loads (ZSPK) connected between OUTP and OUTN,
ZSPK = ∞, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
Supply Voltage Range
VDD
Undervoltage Lockout
UVLO
Quiescent Current
IDD
Shutdown Current
ISHDN
Standby Current
ISTNDBY
CONDITIONS
MAX
UNITS
5.5
V
1.8
2.3
V
TA = +25°C
2.2
2.7
TA = +25°C, VDD = 3.7V
1.8
2.2
SD_MODE = 0V, TA = +25°C
0.6
2
µA
SD_MODE = 1.8V, no PDM_CLK,
TA = +25°C
340
400
µA
Guaranteed by PSSR test
MIN
TYP
2.5
1.4
mA
Turn-On Time
tON
Time from receipt of first clock cycle to full
operation
0.6
0.7
ms
Output Offset Voltage
VOS
TA = +25°C, gain = 15dB
±0.3
±2.5
mV
-72
KCP
Peak voltage, TA = Into shutdown
+25°C, A-weighted,
32 samples per
Out of shutdown
second (Note 3)
Click-and-Pop Level
VDD = 2.5V to 5.5V, TA = +25°C
Power-Supply Rejection Ratio
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PSRR
TA = +25°C
(Notes 3, 4)
dBV
-66
60
75
f = 217Hz,
200mVP-P ripple
77
f = 10kHz,
200mVP-P ripple
60
dB
Maxim Integrated │ 4
MAX98358
PDM Input Class D Audio Power Amplifier
Electrical Characteristics (continued)
(VDD = 5V, VGND = 0V, GAIN = VDD (+6dB). PDM_CLK = 3.072MHz, speaker loads (ZSPK) connected between OUTP and OUTN,
ZSPK = ∞, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
THD+N 10%
Output Power (Note 3)
POUT
THD+N = 1%
Total Harmonic Distortion +
Noise
THD+N
3.2
ZSPK = 8Ω + 68µH
1.8
ZSPK = 8Ω + 68µH,
VDD = 3.7V
0.93
ZSPK = 4Ω + 33µH
2.5
ZSPK = 8Ω + 68µH
1.4
ZSPK = 8Ω + 68µH,
VDD = 3.7V
0.77
f = 1kHz, POUT = 1W, TA = +25°C,
ZSPK = 4Ω + 33µH (WLP)
0.02
f = 1kHz, POUT = 1W, TA = +25°C,
ZSPK = 4Ω + 33µH (TQFN)
0.02
f = 1kHz, POUT = 0.5W, TA = +25°C,
ZSPK = 8Ω + 68FH
0.013
99
DR
A-weighted, PDM_CLK = 6.144MHz,
VRMS = 2.54V
Output Noise
VN
A-weighted (Note 4)
AV
Current Limit
ILIM
Efficiency
h
MAX
0.06
%
dB
29
µVRMS
14.4
15
15.6
GAIN = GND
11.4
12
12.6
GAIN = unconnected
8.4
9
9.6
GAIN = VDD
5.4
6
6.6
GAIN = VDD through 100kΩ
2.4
3
3.6
ZSPK = 8Ω + 68µH, THD+N = 10%,
f = 1kHz, gain = 12dB
Frequency Response
fOSC
Spread-Spectrum Bandwidth
UNITS
W
GAIN = GND through 100kΩ
DAC Gain Error
Class D Oscillator Frequency
TYP
ZSPK = 4Ω + 33µH
Dynamic Range
Gain (Relative to a 2.1dBV
Reference Level)
MIN
dB
2.8
A
92
%
1
%
±0.5
dB
330
kHz
±20
kHz
DIGITAL AUDIO INTERFACE
PDM_CLK High Frequency
Range
fCLKH
5.28
8.64
MHz
PDM_CLK Low Frequency
Range
fCLKL
1.84
4.32
MHz
PDM_CLK High Time
tPDM_CLKH
40
ns
PDM_CLK Low Time
tPDM_CLKL
40
ns
Maximum Low-Frequency
PDM_CLK Jitter
RMS jitter below 40kHz
0.5
ns
Maximum Low-Frequency
PDM_CLK Jitter
RMS jitter above 40kHz
12
ns
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Maxim Integrated │ 5
MAX98358
PDM Input Class D Audio Power Amplifier
Electrical Characteristics (continued)
(VDD = 5V, VGND = 0V, GAIN = VDD (+6dB). PDM_CLK = 3.072MHz, speaker loads (ZSPK) connected between OUTP and OUTN,
ZSPK = ∞, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
Input High Voltage
VIH
Digital audio inputs
Input Low Voltage
VIL
Digital audio inputs
Input Leakage Current
IIH, IIL
Input Capacitance
VIN = 0V, VDD = 5.5V, TA = +25°C
MIN
PDM_DATA to PDM_CLK
Setup Time
tSETUP
PDM_DATA to PDM_CLK
Hold Time
tHOLD
MAX
1.3
UNITS
V
-1
CIN
PDM Ones Density
TYP
0.6
V
+1
µA
3
Maximum
75
Minimum
25
pF
%
10
ns
10
SD_MODE COMPARATOR TRIP POINTS
B0
See SD_MODE and shutdown operation
for details
B1
B2
SD_MODE Pulldown Resistor
RPD
0.08
0.16
0.355
0.65
0.77
0.825
1.245
1.4
1.5
92
100
108
V
kΩ
GAIN COMPARATOR TRIP POINTS
VGAIN
AV = 3dB gain
0.65 x
VDD
0.85 x
VDD
AV = 6dB gain
0.9 x
VDD
VDD
AV = 9dB gain
0.4 x
VDD
0.6 x
VDD
AV = 12dB gain
0
0.1 x
VDD
AV = 15dB gain
0.15 x
VDD
0.35 x
VDD
V
Note 2: 100% production tested at TA = +25°C. Specifications over temperature limits are guaranteed by design.
Note 3: Class D amplifier testing performed with a resistive load in series with an inductor to simulate an actual speaker load. For
RL = 8Ω, LL = 68µH. For RL = 4Ω, LL = 33µH.
Note 4: Digital silence used for input signal.
Note 5: Dynamic range is measured using the EIJA method. -60dbFS 1kHz output signal. A-weighted and normalized to 0dBFS.
f = 20Hz to 20kHz.
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Maxim Integrated │ 6
MAX98358
PDM Input Class D Audio Power Amplifier
tPDM_CLK
tPDM_CLKH
tPDM_CLKL
PDM_CLK
tSETUP
LEFT
PDM_DATA
tHOLD
tSETUP
RIGHT
tHOLD
LEFT
RIGHT
Figure 1. PDM Audio Interface Timing Diagram
Typical Operating Characteristics
(VDD = 5V, VGND = 0V, GAIN = GND (12dB). PDM_CLK = 3.072MHz, speaker loads (ZSPK) connected between OUTP and OUTN,
TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
QUIECENT CURRENT
vs. SUPPLY VOLTAGE
4.0
VDDIO = 1.8V
3.0
2.5
2.0
1.5
1.0
0.5
0.0
-10
2.5
3.0
3.5
4.0
4.5
SUPPLY VOLTAGE (V)
0.7
0.6
0.5
0.4
0.3
0.2
5.0
0.0
5.5
2.5
3.0
3.5
4.0
4.5
SUPPLY VOLTAGE (V)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
toc03
0
VDD = 3.7V
ZSPK = 8Ω + 68μH
-10
-20
toc04
5.0
0
VDD = 4.2V
ZSPK = 8Ω + 68μH
-10
-20
-30
-30
-40
-40
-40
-50
-60
6kHz
-70
-80
-90
-100
0.001
-50
-60
THDN (dB)
-30
THDN (dB)
THDN (dB)
-20
0.8
0.1
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
0
6kHz
-70
1kHz
-80
100Hz
0.01
0.1
1
OUTPUT POWER (W)
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toc02
VDDIO = 1.8V
0.9
SHUTDOWN CURRENT (µA)
QUIECENT CURRENT (mA)
3.5
SHUTDOWN CURRENT
vs. SUPPLY VOLTAGE
1.0
toc01
-90
10
-100
0.001
5.5
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
toc05
VDD = 5V
ZSPK = 8Ω + 68μH
-50
-60
6kHz
-70
1kHz
-80
100Hz
0.01
0.1
1
OUTPUT POWER (W)
-90
10
-100
0.001
1kHz
100Hz
0.01
0.1
1
OUTPUT POWER (W)
10
Maxim Integrated │ 7
MAX98358
PDM Input Class D Audio Power Amplifier
Typical Operating Characteristics (continued)
(VDD = 5V, VGND = 0V, GAIN = GND (12dB). PDM_CLK = 3.072MHz, speaker loads (ZSPK) connected between OUTP and OUTN,
TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
0
VDD = 3.7V
ZSPK = 4Ω + 33μH
-10
-20
toc07
-20
-30
-40
-40
-40
6kHz
-50
-70
-80
-80
-100
0.001
100Hz
-100
0.001
10
VDD = 3.7V
ZSPK = 8Ω + 68μH
-10
-20
-20
THD+N RATIO(dB)
-40
-50
-60
POUT = 75mW
-70
0.01
0.1
1
OUTPUT POWER (W)
-50
POUT = 100mW
-70
POUT = 350mW
-90
10
100
1000
10000
FREQUENCY (Hz)
www.maximintegrated.com
100000
-100
VDD = 5V
ZSPK = 8Ω + 68μH
-30
-40
-50
-60
POUT = 850mW
-70
-80
POUT = 500mW
-90
10
100
POUT = 150mW
-90
1000
10000
FREQUENCY (Hz)
100000
10
toc11
0
-20
-40
0.01
0.1
1
OUTPUT POWER (W)
100Hz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT FREQUENCY
-10
-80
-80
-100
0.001
10
-30
-60
1kHz
-90
VDD = 4.2V
ZSPK = 8Ω + 68μH
-10
-30
-100
0
toc09
6kHz
-60
-80
100Hz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT FREQUENCY toc10
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT FREQUENCY
0
1kHz
-90
0.01
0.1
1
OUTPUT POWER (W)
-50
-70
THD+N RATIO(dB)
1kHz
6kHz
-60
-70
THDN (dB)
-30
-60
VDD = 5V
ZSPK = 4Ω + 33μH
-10
-30
-50
toc08
0
VDD = 4.2V
ZSPK = 4Ω + 33μH
-20
-90
THD+N RATIO(dB)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
-10
THDN (dB)
THDN (dB)
0
toc06
-100
10
100
1000
10000
FREQUENCY (Hz)
100000
Maxim Integrated │ 8
MAX98358
PDM Input Class D Audio Power Amplifier
Typical Operating Characteristics (continued)
(VDD = 5V, VGND = 0V, GAIN = GND (12dB). PDM_CLK = 3.072MHz, speaker loads (ZSPK) connected between OUTP and OUTN,
TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
THD+N RATIO(dB)
THD+N RATIO(dB)
-20
-40
-50
-60
POUT = 150mW
-70
POUT = 600mW
-90
10
100
-50
POUT = 250mW
-70
10000
-100
100000
10
100
OUTPUT POWER vs.
LOAD RESISTANCE
2.5
VDD = 3.7V
OUTPUT POWER (W)
OUTPUT POWER (W)
1.5
10% THD+N
1.0
1% THD+N
0.5
100000
toc16
10
LOAD RESISTANCE
www.maximintegrated.com
100
POUT = 1.5W
-70
POUT = 350mW
10
100
1000
10000
FREQUENCY (Hz)
OUTPUT POWER
vs. LOAD RESISTANCE
4.5
100000
toc18
VDD = 5V
3.5
2.0
10% THD+N
1.5
1% THD+N
1.0
3.0
2.5
10% THD+N
2.0
1% THD+N
1.5
1.0
0.5
1
-60
4.0
2.5
0.0
-50
-100
VDD = 4.2V
3.0
2.0
0.0
OUTPUT POWER vs.
LOAD RESISTANCE
3.5
toc15
-40
-90
1000
10000
FREQUENCY (Hz)
FREQUENCY (Hz)
-30
-80
POUT = 850mW
-90
1000
-20
-40
-60
VDD = 5V
ZSPK = 4Ω + 33μH
-10
-30
-80
-80
-100
VDD = 4.2V
ZSPK = 4Ω + 33μH
-10
-30
0
THD+N RATIO(dB)
VDD = 3.7V
ZSPK = 4Ω + 33μH
-20
toc13
0
OUTPUT POWER (W)
0
-10
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT FREQUENCY toc14
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT FREQUENCY
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT FREQUENCY
toc12
0.5
1
10
LOAD RESISTANCE
100
0.0
1
10
LOAD RESISTANCE
100
Maxim Integrated │ 9
MAX98358
PDM Input Class D Audio Power Amplifier
Typical Operating Characteristics (continued)
(VDD = 5V, VGND = 0V, GAIN = GND (12dB). PDM_CLK = 3.072MHz, speaker loads (ZSPK) connected between OUTP and OUTN,
TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
2.5
4.0
toc18
ZSPK = 8Ω + 68µH
1.5
OUTPUT POWER (W)
THD+N = 10%
1.0
THD+N = 1%
0.5
THD+N = 10%
2.5
2.0
THD+N = 1%
1.5
1.0
3.0
3.5
4.0
4.5
5.0
0.0
5.5
2.5
3.0
SUPPLY VOLTAGE (V)
EFFICIENCY
vs. OUTPUT POWER
100
VDD = 3.7V
80
VDD = 4.2V
VDD = 5V
4.0
4.5
5.0
EFFICIENCY vs. OUTPUT POWER
50
40
30
toc22
VDD = 4.2V
60
VDD = 5V
50
40
30
10
ZSPK = 8Ω + 68μH
0.5
1.0
1.5
OUTPUT POWER (W)
www.maximintegrated.com
10
2.0
0.20
0.18
VDD = 3.7V
20
20
0.0
-1
-3
5.5
ZSPK = 8Ω + 68μH
70
EFFICIENCY (%)
EFFICIENCY (%)
3.5
80
60
0
100
toc21
70
10
0
100
SUPPLY VOLTAGE (V)
90
90
1
-2
0.5
2.5
toc20
NORMALIZED TO 1kHz
2
0
0.0001
1000
10000
FREQUENCY (Hz)
POWER DISSIPATION
vs. OUTPUT POWER
100000
toc23
ZSPK = 8Ω + 68μH
0.16
POWER DISSIPATION (W)
OUTPUT POWER (W)
3.0
NORMALIZED GAIN
vs. FREQUENCY
3
toc19
ZSPK = 4Ω + 33µH
3.5
2.0
0.0
OUTPUT POWER
vs. SUPPLY VOLTAGE
NORMALIZED GAIN (dB)
OUTPUT POWER
vs. SUPPLY VOLTAGE
0.14
VDD = 5V
0.12
0.10
0.08
0.06
0.04
VDD = 4.2V
VDD = 3.7V
0.02
0.001
0.01
0.1
OUTPUT POWER (W)
1
0.00
0.001
0.01
0.1
1
OUTPUT POWER (W)
10
Maxim Integrated │ 10
MAX98358
PDM Input Class D Audio Power Amplifier
Typical Operating Characteristics (continued)
(VDD = 5V, VGND = 0V, GAIN = GND (12dB). PDM_CLK = 3.072MHz, speaker loads (ZSPK) connected between OUTP and OUTN,
TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
100
100
toc24
80
VDD = 3.7V
60
50
40
30
VDD = 4.2V
50
VDD = 5V
40
30
0
1
2
OUTPUT POWER (W)
3
0.001
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
toc27
VDD = 5V
0.35
0.30
VDD = 4.2V
0.25
0.20
0.15
0.10
0.01
0.1
0.00
0.001
1
OUTPUT POWER (W)
POWER-SUPPLY REJECTION RATIO
vs. SUPPLY VOLTAGE
toc28
100
VDD = 3.7V
0.01
0.1
1
OUTPUT POWER (W)
TURN-ON RESPONSE
60
60
PSRR (dB)
70
50
40
50
40
30
30
20
20
10
100
SD_MODE
1V/div
10
ZSPK = 8Ω + 68µH
10
toc29
OUTPUT
1V/div
80
70
10
ZSPK = 8Ω + 68µH
90
80
toc26
ZSPK = 4Ω + 33μH
0.05
0
0.0001
90
PSRR (dB)
VDD = 3.7V
60
10
ZSPK = 4Ω + 33μH
POWER DISSIPATION
vs. OUTPUT POWER
0.40
20
100
0
0.45
70
20
10
0.50
80
VDD = 5V
EFFICIENCY (%)
EFFICIENCY (%)
70
VDD = 4.2V
toc25
ZSPK = 4Ω + 33μH
90
90
0
EFFICIENCY vs. OUTPUT POWER
POWER DISSIPATION (W)
EFFICIENCY vs. OUTPUT POWER
1000
FREQUENCY (Hz)
www.maximintegrated.com
10000
100000
0
2.50
3.00
3.50
4.00
4.50
SUPPLY VOLTAGE (V)
5.00
5.50
2ms/div
Maxim Integrated │ 11
MAX98358
PDM Input Class D Audio Power Amplifier
Typical Operating Characteristics (continued)
(VDD = 5V, VGND = 0V, GAIN = GND (12dB). PDM_CLK = 3.072MHz, speaker loads (ZSPK) connected between OUTP and OUTN,
TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
INBAND OUTPUT SPECTRUM
20
toc30
-20
AMPLITUDE (dBV)
-40
-60
-80
1ms/div
-40
-60
-80
-100
-100
-120
-120
-140
0
5000
10000
15000
-140
20000
0
5000
FREQUENCY (Hz)
INBAND OUTPUT SPECTRUM
20
fPDMCLK = 6.144MHz
ZSPK = 8Ω + 68μH
0
toc34
0
-60
-80
-40
-60
-80
-40
-60
-80
-100
-100
-120
-120
-120
-140
-140
5000
10000
15000
FREQUENCY (Hz)
www.maximintegrated.com
20000
toc35
fPDMCLK = 5.6448MHz
ZSPK = 8Ω + 68μH
0
-100
0
20000
-20
AMPLITUDE (dBV)
AMPLITUDE (dBV)
-40
10000
15000
FREQUENCY (Hz)
INBAND OUTPUT SPECTRUM
20
fPDMCLK = 5.6448MHz
ZSPK = 8Ω + 68μH
-20
-20
AMPLITUDE (dBV)
INBAND OUTPUT SPECTRUM
20
toc33
toc32
fPDMCLK = 6.144MHz
ZSPK = 8Ω + 68μH
0
-20
SD_MODE
1V/div
INBAND OUTPUT SPECTRUM
20
fPDMCLK = 6.144MHz
ZSPK = 8Ω + 68μH
0
OUTPUT
1V/div
toc31
AMPLITUDE (dBV)
TURN-OFF RESPONSE
0
5000
10000
15000
FREQUENCY (Hz)
20000
-140
0
5000
10000
15000
FREQUENCY (Hz)
20000
Maxim Integrated │ 12
MAX98358
PDM Input Class D Audio Power Amplifier
Typical Operating Characteristics (continued)
(VDD = 5V, VGND = 0V, GAIN = GND (12dB). PDM_CLK = 3.072MHz, speaker loads (ZSPK) connected between OUTP and OUTN,
TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
INBAND OUTPUT SPECTRUM
20
fPDMCLK = 5.6448MHz
ZSPK = 8Ω + 68μH
0
-60
-80
-20
-40
-60
-80
-40
-60
-80
-100
-100
-100
-120
-120
-120
-140
-140
0
5000
10000
15000
FREQUENCY (Hz)
INBAND OUTPUT SPECTRUM
20
20000
5000
10000
15000
INBAND OUTPUT SPECTRUM
20
fPDMCLK = 3.072MHz
ZSPK = 8Ω + 68μH
0
0
-140
20000
toc40
-80
-40
-60
-80
-60
-80
-100
-100
-120
-120
-140
-140
FREQUENCY (Hz)
www.maximintegrated.com
20000
toc41
-40
-120
15000
20000
fPDMCLK = 2.8224MHz
ZSPK = 8Ω + 68μH
0
-100
10000
15000
-20
AMPLITUDE (dBV)
-60
10000
INBAND OUTPUT SPECTRUM
20
fPDMCLK = 2.8224MHz
ZSPK = 8Ω + 68μH
0
AMPLITUDE (dBV)
-40
5000
5000
FREQUENCY (Hz)
-20
-20
0
0
FREQUENCY (Hz)
toc39
toc38
fPDMCLK = 3.072MHz
ZSPK = 8Ω + 68μH
0
AMPLITUDE (dBV)
-40
INBAND OUTPUT SPECTRUM
20
-20
AMPLITUDE (dBV)
AMPLITUDE (dBV)
toc37
fPDMCLK = 3.072MHz
ZSPK = 8Ω + 68μH
0
-20
AMPLITUDE (dBV)
INBAND OUTPUT SPECTRUM
20
toc36
0
5000
10000
15000
FREQUENCY (Hz)
20000
-140
0
5000
10000
15000
FREQUENCY (Hz)
20000
Maxim Integrated │ 13
MAX98358
PDM Input Class D Audio Power Amplifier
Typical Operating Characteristics (continued)
(VDD = 5V, VGND = 0V, GAIN = GND (12dB). PDM_CLK = 3.072MHz, speaker loads (ZSPK) connected between OUTP and OUTN,
TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
INBAND OUTPUT SPECTRUM
20
fPDMCLK = 2.8224MHz
ZSPK = 8Ω + 68μH
0
toc43
-20
-80
AMPLITUDE (dBV)
AMPLITUDE (dBV)
-60
-40
-60
-80
-40
-60
-80
-100
-100
-100
-120
-120
-120
-140
-140
0
5000
10000
15000
20000
0
5000
FREQUENCY (Hz)
INBAND OUTPUT SPECTRUM
20
10000
15000
FREQUENCY (Hz)
toc45
-80
-100
www.maximintegrated.com
5000
10000
15000
20000
FREQUENCY (Hz)
toc46
14
12
10
8
6
4
-120
-140
0
16
GROUP DELAY (µs)
AMPLITUDE (dBV)
-60
-140
18
-20
-40
20000
GROUP DELAY vs. FREQUENCY
20
fPDMCLK = 2.048MHz
ZSPK = 8Ω + 68μH
0
toc44
fPDMCLK = 2.048MHz
ZSPK = 8Ω + 68μH
0
-20
-40
INBAND OUTPUT SPECTRUM
20
fPDMCLK = 2.048MHz
ZSPK = 8Ω + 68μH
0
-20
AMPLITUDE (dBV)
INBAND OUTPUT SPECTRUM
20
toc42
2
0
5000
10000
15000
FREQUENCY (Hz)
20000
0
20
200
2000
FREQUENCY (Hz)
20000
Maxim Integrated │ 14
MAX98358
PDM Input Class D Audio Power Amplifier
OUTP
+
OUTN
TOP VIEW
MAX98358
GND
TOP VIEW
BUMP SIDE DOWN
N.C.
Bump/Pin Configurations
12
11
10
9
SD_MODE
VDD
OUTP
A1
A2
A3
N.C. 13
8
VDD
PDM_DATA
GAIN
OUTN
GND 14
7
VDD
B1
B2
B3
6
N.C.
PDM_CLK
GND
GND
C1
C2
C3
5
N.C.
MAX98358
GND 15
3
TQFN
4
SD_MODE
2
GND
1
GAIN
WLP
+
PDM_DATA
PDM_CLK 16
Bump/Pin Description
BUMP
PIN
WLP
TQFN
A1
4
SD_MODE
A2
7, 8
VDD
A3
9
B1
1
NAME
OUTP
FUNCTION
Shutdown and Channel Select. Determines left, right, or (left/2 + right/2) mix and also used for
shutdown. See Table 5.
Power-Supply Input
Positive Speaker Amplifier Output
PDM_DATA Digital Input Signal
Amplifier Gain
B2
2
Gain Connections
Gain (dB)
GND through 100kΩ resistor
15
GAIN
GND
12
Unconnected
9
VDD
6
VDD through 100kΩ resistor
3
B3
10
OUTN
C1
16
PDM_CLK
C2, C3
3, 11,
14, 15
GND
Ground
—
5, 6,
12, 13
N.C.
No Connection
—
—
EP
www.maximintegrated.com
Negative Speaker Amplifier Output
PDM Bit Clock Input Signal. Supports frequency ranges: 1.84MHz–4.32MHz and 5.28 MHz–
8.64MHz.
Exposed Pad. The exposed pad is not internally connected. Connect the exposed pad to a solid
ground plane for thermal dissipation.
Maxim Integrated │ 15
MAX98358
PDM Input Class D Audio Power Amplifier
Detailed Description
The output stage features low-quiescent current, 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
with edge-rate and overshoot control circuitry that offers
significant improvements in 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.
The MAX98358 is a digital PDM input Class D power
amplifier. The PDM modulation scheme uses the relative
density of digital pulses to represent the amplitude of an
analog signal. The IC accepts stereo PDM data through
PDM_DATA and PDM_CLK.
SD_MODE selects which audio channel is output by the
amplifier and is used to put the IC into shutdown. The
GAIN pin offers five gain settings and allows the output of
the amplifier to be tuned to the appropriate level.
Digital Audio Interface
Table 1. PDM_CLK Channel Select
PDM_CLK EDGE
DIRECTION
CHANNEL
Rising edge
Left
Falling edge
Right
The IC takes a stereo PDM input signal directly into the
DAC. Data read on the rising edge of PDM_CLK is leftchannel data while data read on the falling PDM_CLK
edge is right channel (Table 1).
Supported PDM_CLK Rates
Table 2 indicates the range of PDM_CLK rates that are
supported by the IC. Table 3 indicates the specific clock
rates to use based on the baseband rate and the oversample rate of the incoming PDM signal.
Table 2. PDM_CLK Rates
PDM_CLK Jitter Tolerance
SUPPORTED CLOCK RATES (MHz)
The IC features a very high PDM_CLK jitter tolerance of
0.5ns for RMS jitter below 40kHz and 12ns for wideband
RMS jitter while maintaining a dynamic range greater than
98dB (Table 4).
1.84–4.32
5.28–8.64
Table 3. Calculated PDM_CLK Rates
BASEBAND SAMPLE
RATE (kHz)
INPUT CLOCK RATES (MHz)
32x OVERSAMPLED
PDM
64x OVERSAMPLED
PDM
128x OVERSAMPLED
PDM
256x OVERSAMPLED
PDM
8
—
—
—
2.048
16
—
—
2.048
4.096
32
—
2.048
4.096
—
44.1
—
2.8224
5.6448*
—
48
—
3.072
6.144*
—
88.2
2.8224
5.6448*
—
—
96
3.072
6.144*
—
—
*The mono left/2 + right/2 feature is not supported at PDM_CLK rates of 5.28MHz and above.
Table 4. RMS Jitter Tolerance
FREQUENCY
RMS JITTER TOLERANCE (ns)
< 40kHz
0.5
40kHz–PDM_CLK
12
www.maximintegrated.com
Maxim Integrated │ 16
MAX98358
PDM Input Class D Audio Power Amplifier
SD_MODE Pin and Shutdown Operation
PDM Timing Characteristics
Figure 2 shows the PDM operation of the IC. The bitdepth is one bit and each bit alternates between leftchannel and right-channel data.
The IC features a low-power shutdown mode, drawing
less than 0.6µA (typ) of supply current. During shutdown,
all internal blocks are turned off, including setting the
output stage to a high-impedance state. Drive SD_MODE
low to put the IC into shutdown.
If the PDM generator produces data that is stuck at logichigh or logic-low, then the output of the IC is railed, forcing DC at the load. Therefore, it is recommended that the
PDM generator includes protection to detect this invalid
condition. If such a condition is detected, then the IC
should either be put into shutdown or PDM_CLK should
be stopped.
The state of SD_MODE determines the audio channel
that is sent to the amplifier output (Table 5).
Drive SD_MODE high to select the left channel of the
stereo input data. Drive SD_MODE high through a sufficiently small resistor to select the right channel of
the stereo input data. Drive SD_MODE high through a
sufficiently large resistor to select monomix mode where
both the left and right words of the stereo input data are
summed (left/2 + right/2). The monomix (left/2 + right/2)
mode is not supported for PDM_CLK rates 5.28MHz.
and above. RLARGE and RSMALL are determined by
the VDDIO voltage (logic voltage from control interface)
that is driving SD_MODE according to the following two
equations:
Standby Mode
The MAX98358 automatically enters standby mode when
PDM_CLK is removed. In standby mode, the Class D
speaker amplifier is turned off and the outputs go into
a high-impedance state, ensuring that the unwanted
current is not transferred to the load during this condition. Standby mode should not be used in place of the
shutdown mode because the shutdown mode provides
the lowest power consumption and the best power-on/off
click-and-pop performance.
RSMALL (kΩ) = 94.0 x VDDIO - 100
RLARGE (kΩ) = 222.2 x VDDIO - 100
SD_MODE = LOGIC-HIGH
PDM_CLK
PDM_DATA
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
RIGHT CHANNEL IGNORED
SD_MODE = PULLUP THROUGH RSMALL
PDM_CLK
PDM_DATA
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
LEFT CHANNEL IGNORED
SD_MODE = PULLUP THROUGH RLARGE
PDM_CLK
PDM_DATA
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
L
R
LEFT AND RIGHT CHANNELS AVERAGED
Figure 2. PDM Digital Audio Interface Timing
Table 5. SD_MODE Control
SD_MODE STATUS
SELECTED CHANNEL
High
VSD_MODE > B2 trip point
Left
Pullup through RSMALL
B2 trip point (1.4V typ) > VSD_MODE >
B1 trip point
Right
Pullup through RLARGE*
B1 trip point (0.77V typ) > VSD_MODE >
B0 trip point
(Left/2 + right/2)
Low
B0 trip point (0.16V typ) > VSD_MODE
Shutdown
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Maxim Integrated │ 17
MAX98358
Figure 3 and Figure 4 show how to connect an external
resistor to SD_MODE when using an open-drain driver or
a pullup/down driver.
When the device is configured in left channel mode
(SD_MODE is directly driven to logic-high by the control interface) care must be taken to avoid violating
the Absolute Maximum Ratings limits for SD_MODE.
Ensuring that VDD is always greater than VDDIO is one
way to prevent SD_MODE from violating the Absolute
Maximum Ratings limits. If this is not possible in the
application (e.g., if VDD < 3.0V and VDDIO = 3.3V), then
it is necessary to add a small resistance (~2kΩ) in series
with SD_MODE to limit the current into the SD_MODE
pin. This is not a concern when using the right channel or
monomix modes.
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 reduces EMI emissions while maintaining up to 92% 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 ICs’ spread-spectrum modulator randomly varies the
switching frequency by ±20kHz around the center frequency (330kHz). Above 10MHz, the wideband spectrum
looks like noise for EMI purposes (Figure 5).
Speaker Current Limit
If the output current of the speaker amplifier exceeds the
current limit (2.8A typ), the IC disables the outputs for
approximately 100µs. At the end of the 100µs, the outputs
are re-enabled. If the fault condition still exists, the IC continues to disable and re-enable the outputs until the fault
condition is removed.
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PDM Input Class D Audio Power Amplifier
Gain Selection
The IC offers five programmable gain selections through
a singel gain input (GAIN). Gain is referenced to the
full-scale output of the DAC, which is 2.1dBV (Table 7).
Assuming that the desired output swing is not limited by
the supply voltage rail, the IC’s output level can be calculated based on the PDM input ones’s density and selected
amplifier gain according to the following equation:
Output signal level (dBV) = 20 x log[abs(PDM one’s
density(%) - 50) /25] (dBFS) + 2.1dB + selected
speaker amplifier gain (dB)
where the one’s density of the PDM input ranges from
75% (maximum positive magnitude) to 25% (maximum
negative magnitude). 0dFBS is referenced to 0dBV.
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 audible transient sources internal to the device. To achieve optimal
click-and-pop reduction at startup, it is recommended
that idle data be sent to the digital audio interface for the
first 0.5ms of turn-on time. When entering shutdown, the
differential speaker outputs simultaneously drop to GND.
Table 6. Examples of SD_MODE Pullup
Resistor Values
LOGIC VOLTAGE
LEVEL (VDDIO) (V)
RSMALL (kΩ)
RLARGE (kΩ)
1.8
69.8
300
3.3
210
634
Table 7. Gain Selection
GAIN
GAIN (dB)
Connect to GND through
100kΩ ±5% resistor
15
Connect to GND
12
Unconnected
9
Connect to VDD
6
Connect to VDD through
100kΩ ±5% resistor
3
Maxim Integrated │ 18
MAX98358
PDM Input Class D Audio Power Amplifier
PROCESSOR
VDDIO
LEFT MODE
MAX98358
R
VSD_MODE
GPIO
100kΩ
±8%
B2 (1.4V typ)
RIGHT MODE
B1 (0.77V typ)
LEFT/2 + RIGHT/2 MODE
B0 (0.16V typ)
Figure 3. SD_MODE Resistor Connection Using Open-Drain Driver
PROCESSOR
VDDIO
GPIO
LEFT MODE
MAX98358
R
VSD_MODE
100kΩ
±8%
B2 (1.4V typ)
RIGHT MODE
B1 (0.77V typ)
LEFT/2 + RIGHT/2 MODE
B0 (0.16V typ)
Figure 4. SD_MODE Resistor Connection Using Push-Pull Driver
EMISSION LEVEL (dBµV/m)
90
70
50
30
10
-10
0 100 200 300 400 500 600 700 800 900 1000
FREQUENCY (MHz)
Figure 5. EMI with 12in of Speaker Cable and No Output Filtering
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Maxim Integrated │ 19
MAX98358
PDM Input Class D Audio Power Amplifier
2.5V TO 5.5V
2.5V TO 5.5V
10µF
10µF
0.1µF
CODEC
GPIO*
SD_MODE
A1
A2
A3
PDM CLOCK
PDM DATA OUT
PDM_CLK
PDM_DATA
C1
GPIO*
OUTP
SD_MODE
A1
VDD
GAIN
B2
A2
A3
MAX98358
B3
B1
CODEC
VDD
GAIN
B2
0.1µF
PDM CLOCK
OUTN
PDM DATA OUT
C2, C3
PDM_CLK
PDM_DATA
GND
C1
MAX98358
B3
B1
OUTP
OUTN
C2, C3
GND
*RESPONDS TO LEFT CHANNEL WHEN GPIO IS HIGH.
THE MAX98358 IS SHUTDOWN WHEN GPIO IS LOW.
*RESPONDS TO LEFT CHANNEL WHEN GPIO IS HIGH.
THE MAX98358 IS SHUTDOWN WHEN GPIO IS LOW.
Figure 6. Left-Channel Operation with 6dB Gain
Figure 7. Left-Channel Operation with 12dB Gain
2.5V TO 5.5V
10µF
CODEC
RSMALL
(69.8kΩ)**
GPIO*
PDM CLOCK
PDM DATA OUT
0.1µF
VDD
GAIN
SD_MODE
PDM_CLK
A1
C1
PDM_DATA B1
B2
A2
A3
OUTP
MAX98358
B3
OUTN
C2, C3
GND
*RESPONDS TO RIGHT CHANNEL WHEN GPIO IS HIGH.
**69.8kΩ ASSUMES VGPIO = 1.8V.
THE MAX98358 IS SHUTDOWN WHEN GPIO IS LOW.
Figure 8. Right-Channel Operation with 6dB Gain
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Maxim Integrated │ 20
MAX98358
PDM Input Class D Audio Power Amplifier
2.5V TO 5.5V
10µF
0.1µF
VDD
GAIN
SD_MODE
A1
B2
A2
A3
PDM_CLK
PDM_DATA
OUTP
MAX98358
C1
B3
B1
OUTN
C2
GND
CODEC
*RESPONDS TO LEFT CHANNEL WHEN GPIO IS HIGH.
THE MAX98358 IS SHUTDOWN WHEN GPIO IS LOW.
GPIO*
2.5V TO 5.5V
PDM CLOCK
10µF
PDM DATA OUT
RSMALL
(69.8kΩ)**
0.1µF
VDD
GAIN
SD_MODE
A1
B2
A2
A3
PDM_CLK
PDM_DATA
C1
MAX98358
B3
B1
OUTP
OUTN
C2, C3
GND
*RESPONDS TO RIGHT CHANNEL WHEN GPIO IS HIGH.
**69.8kΩ ASSUMES VGPIO = 1.8V.
THE MAX98358 IS SHUTDOWN WHEN GPIO IS LOW.
Figure 9. Stereo Operation Using Two MAX98358s
www.maximintegrated.com
Maxim Integrated │ 21
MAX98358
Filterless Class D Operation
Traditional Class D amplifiers require an output filter
to recover the audio signal from the amplifier’s output.
The filter adds cost, size, and decreases efficiency and
THD+N performance. The MAX98358’s filterless modulation scheme does not require an output filter. The device
relies on the inherent inductance of the speaker coil and
the natural filtering of both the speaker and the human ear
to recover the audio component of the square-wave output.
Because the switching frequency of the IC is well beyond
the bandwidth of most speakers, voice coil movement due
to the switching frequency is very small. Use a speaker
with a series inductance > 10µH. Typical 8Ω speakers
exhibit series inductances in the 20µH to 100µH range.
Power-Supply Input
VDD, which ranges from 2.5V to 5.5V, powers the IC,
including the speaker amplifier. Bypass VDD with a 0.1µF
and 10µF capacitor to GND. Some applications might
require only the 10µF bypass capacitor, making it possible to operate with a single external component. Apply
additional bulk capacitance at the IC if long input traces
between VDD and the power source are used.
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 load impedance decreases, the current drawn from the device
outputs increases. At higher current, the resistance of
the output traces decreases the power delivered to the
load. For example, if 2W is delivered from the speaker
output to a 4Ω load through 100mΩ of total speaker
trace, 1.904W is being delivered to the speaker. If power
is delivered through 10mΩ of total speaker trace, 1.951W
is being delivered to the speaker. Wide output, supply,
and ground traces also improve the power dissipation of
the IC. Parasitic capacitance on the output causes higher
quiescent current by VDD x 330kHz x CPARASITIC.
For example, at VDD and a total parasitic capacitance of
100pF (50pF on each output trace), the increase in quiescent current is: 5 x 330kHz x 100pF = 165µA.
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.
www.maximintegrated.com
PDM Input Class D Audio Power Amplifier
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 the Application Note 1891: Wafer-Level
Packaging (WLP) and Its Applications. Figure 11 shows
the dimensions of the WLP balls used on the IC.
2.5V TO 5.5V
10µF
CODEC
GPIO*
PDM CLOCK
PDM DATA OUT
RLARGE
(300kΩ)**
SD_MODE
0.1µF
A1
VDD
GAIN
B2
A2
A3
PDM_CLK
PDM_DATA
C1
OUTP
MAX98358
B3
B1
OUTN
C2, C3
GND
*LEFT AND RIGHT ARE SUMMED WHEN GPIO IS HIGH.
**300kΩ ASSUMES VGPIO = 1.8V.
THE MAX98358 IS SHUTDOWN WHEN GPIO IS LOW.
Figure 10. Monomix (Left/2 + Right/2) PDM Operation with 6dB
Gain
0.24mm
0.21mm
Figure 11. MAX98358 WLP Ball Dimensions
Maxim Integrated │ 22
MAX98358
PDM Input Class D Audio Power Amplifier
Functional Diagram
2.5V TO 5.5V
10µF
0.1µF
VDD
A2
(7, 8)
C1
PDM_CLK (16)
PDM_DATA B1 (1)
SD_MODE A1 (3)
GAIN
B2
(2)
MAX98358
DIGITAL
AUDIO
INTERFACE
DAC
(3, 11, 14, 15)
C2, C3
CLASS D
OUTPUT
STAGE
A3 (9) OUTP
B3
(10) OUTN
GND
() APPLIES TO TQFN PACKAGE
Ordering Information
PART
MAX98358EWL+T
MAX98358ETE+
TEMP RANGE
PIN-PACKAGE
-40°C to +85°C
-40°C to +85°C
9 WLP
16 TQFN
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
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Maxim Integrated │ 23
MAX98358
PDM Input Class D Audio Power Amplifier
Package Information
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.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
W91F1+1
21-0896
Refer to Application Note 1891
16 TQFN
T1633+4
21-0136
90-0031
0.05 S
0.05
www.maximintegrated.com
AB
maxim
integrated
TM
Maxim Integrated │ 24
MAX98358
PDM Input Class D Audio Power Amplifier
Package Information (continued)
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.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.
(NE - 1) X e
E
MARKING
E/2
D2/2
(ND - 1) X e
D/2
AAAA
e
C
L
D
D2
k
C
L
b
0.10 M C A B
E2/2
L
E2
0.10 C
C
L
0.08 C
C
L
A
A2
A1
L
L
e
e
maxim
integrated
TM
PACKAGE OUTLINE,
8, 12, 16L THIN QFN, 3x3x0.75mm
21-0136
www.maximintegrated.com
V
1
3
Maxim Integrated │ 25
MAX98358
PDM Input Class D Audio Power Amplifier
Package Information (continued)
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.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.
PKG
8L 3x3
12L 3x3
16L 3x3
EXPOSED PAD VARIATIONS
REF. MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX.
A
0.70
b
0.80
0.70 0.75
0.80
0.25 0.30 0.35
0.20 0.25 0.30
0.20 0.25
0.30
D
3.00 BSC
3.00 BSC
3.00 BSC
E
e
3.00 BSC
0.65 BSC.
3.00 BSC
0.50 BSC.
3.00 BSC
0.50 BSC.
L
0.35
0.75
0.55
0.80
0.75
0.70
0.75
0.45
0.55
0.65
0.30 0.40
N
8
12
16
ND
2
3
4
NE
2
A1
A2
k
0
0.02
0.20 REF
0.25
0.02
0
0.50
4
3
0.05
PKG.
CODES
0.05
0
0.02
0.05
0.20 REF
0.25
0.20 REF
0.25
D2
E2
JEDEC
NOM. MAX.
TQ833-1
0.25
0.70
1.25
0.25
0.70
1.25
0.35 x 45°
WEEC
T1233-1
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-1
MIN.
NOM. MAX.
PIN ID
MIN.
T1233-1C
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-1
T1233-3
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-1
T1233-3C
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-1
T1633-2
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-2
T1633-2C
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-2
T1633F-3
0.65
0.80
0.95
0.65
0.80
0.95
0.225 x 45°
WEED-2
T1633FH-3
0.65
0.80
0.95
0.65
0.80
0.95
0.225 x 45°
WEED-2
T1633-4
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-2
T1633-4C
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-2
T1633MK-5
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-2
EXPOSED PAD VARIATIONS
PKG.
CODES
D2
E2
MIN.
NOM. MAX.
T1233-4
0.95
1.10
T1233-4C
T1233-5C
0.95
1.50
1.10
1.60
T1633-5
0.95
T1633-5C
0.95
T1633-7C
0.95
L
PIN ID
MIN.
NOM. MAX.
1.25
0.95
1.10
1.25
0.35
0.45
0.55
0.35 x 45°
1.25
1.70
0.95
1.50
1.10
1.60
1.25
1.70
0.35
0.40
0.45
0.45
0.55
0.50
0.35 x 45°
0.35 x 45°
1.10
1.25
0.95
1.10
1.25
0.25
0.35
0.45
0.35 x 45°
1.10
1.25
0.95
1.10
1.25
0.25
0.35
0.45
0.35 x 45°
1.10
1.25
0.95
1.10
1.25
0.25
0.35
0.45
0.35 x 45°
MIN. NOM.
MAX.
maxim
integrated
TM
PACKAGE OUTLINE,
8, 12, 16L THIN QFN, 3x3x0.75mm
21-0136
www.maximintegrated.com
V
2
3
Maxim Integrated │ 26
MAX98358
PDM Input Class D Audio Power Amplifier
Package Information (continued)
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.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.
NOTES:
1.
2.
3.
4.
ALL DIMENSIONS ARE IN MILLIMETERS. ANGLES ARE IN DEGREES.
DIMENSIONING & TOLERANCING CONFORM TO ASME Y14.5-2009.
N IS THE TOTAL NUMBER OF TERMINALS.
THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO JESD 95-1 SPP-012. DETAILS OF
TERMINAL #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE TERMINAL #1 IDENTIFIER
MAY BE EITHER A MOLD OR MARKED FEATURE.
5. DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.20 mm AND 0.25 mm FROM TERMINAL TIP.
6. ND AND NE REFER TO THE NUMBER OF TERMINALS ON EACH D AND E SIDE RESPECTIVELY.
7. DEPOPULATION IS POSSIBLE IN A SYMMETRICAL FASHION.
8. DRAWING CONFORMS TO JEDEC MO220 REVISION C. T1233-4, T1233-4C, T1233-5C, T1633-5, T1633-5C AND T1633-7C WITH
CUSTOM LEAD DIMENSION.
9. MARKING SHOWN IS FOR PACKAGE ORIENTATION REFERENCE ONLY.
10. NUMBER OF LEADS SHOWN ARE FOR REFERENCE ONLY.
11. WARPAGE NOT TO EXCEED 0.10mm.
12. MATERIAL MUST BE COMPLIANT WITH MAXIM SPECIFICATION 10-0131 FOR SUBSTANCE CONTENT, MUST BE Eu ROHS
COMPLIANT WITHOUT EXEMPTION AND PB-FREE.
13. ALL DIMENSIONS APPLY TO BOTH LEADED (-) AND Pb FREE (+) PARTS.
maxim
integrated
TM
PACKAGE OUTLINE,
8, 12, 16L THIN QFN, 3x3x0.75mm
21-0136
www.maximintegrated.com
V
3
3
Maxim Integrated │ 27
MAX98358
PDM Input Class D Audio Power Amplifier
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
DESCRIPTION
0
9/13
Initial release
—
1
11/13
Removed future product reference
21
2
8/14
Added THD+N TQFN typical only spec to Electrical Characteristics table
3
3
1/15
Added Table of Contents, updated SSM spec, replaced all typical operating
characteristics, and corrected typos
4
8/15
Corrected package outline for WLP package
24
5
8/17
Updated soldering temperature and added lead temperature in the Absolute Maximum
Ratings section
4
6
10/19
Updated Features section, corrected typo in Electrical Characteristics table, added
Group Delay vs. Frequency TOC
5–12, 16–18
1, 5, 14
For pricing, delivery, and ordering information, please visit Maxim Integrated’s online storefront at https://www.maximintegrated.com/en/storefront/storefront.html.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated 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 and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
© 2019 Maxim Integrated Products, Inc. │ 28
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