EVALUATION KIT AVAILABLE
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 over-
shoot 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.
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 tem-
perature range.
Features
●
Single-Supply Operation (2.5V to 5.5V)
● 3.2W Output Power into 4Ω at 5V
●
1.8mA Quiescent Current (V
DD
= 3.7V)
●
92% Efficiency (R
L
= 8Ω, P
OUT
= 1.5W)
●
29µV
RMS
Output Noise (A
V
= 6dB)
●
Low 0.015% 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
●
Available in Space-Saving Packages:
1.345mm x 1.435mm WLP (0.4mm Pitch)
3mm x 3mm TQFN
Applications
●
●
●
●
Notebook and Netbook Computers
Cellular Phones
Tablets
Portable Media Players
Simplified Block Diagram
Ordering Information
and
Functional Diagram
appears at
end of data sheet.
PDM
INPUT
SHUTDOWN
AND
CHANNEL
SELECT
DIGITAL
AUDIO
INTERFACE
MAX98358
GAIN
CONTROL
DAC
CLASS D
OUTPUT
STAGE
19-6786; Rev 5; 8/17
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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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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MAX98358
PDM Input Class D Audio Power Amplifier
Absolute Maximum Ratings
V
DD
, PDM_CLK and PDM_DATA to GND ..............-0.3V to +6V
All Other Pins to GND .............................. -0.3V to (V
DD
+ 0.3V)
Continuous Current In/Out of V
DD
/GND/OUT_ ..................±1.6A
Continuous Input Current (all other pins) .........................±20mA
Duration of OUT_ Short Circuit to GND or V
DD
….....Continuous
Duration of OUTP Short to OUTN .............................Continuous
Continuous Power Dissipation ..............................(T
A
= +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 (θ
JA
) ..........73°C/W
Junction-to-Case Thermal Resistance (θ
JC
) ...............50°C/W
TQFN
Junction-to-Ambient Thermal Resistance (θ
JA
) ..........48°C/W
Junction-to-Case Thermal Resistance (θ
JC
) .................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
PARAMETER
Supply Voltage Range
Undervoltage Lockout
Quiescent Current
Shutdown Current
Standby Current
Turn-On Time
Output Offset Voltage
(V
DD
= 5V, V
GND
= 0V, GAIN = V
DD
(+6dB). PDM_CLK = 3.072MHz, speaker loads (Z
SPK
) connected between OUTP and OUTN,
Z
SPK
= ∞, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 2)
SYMBOL
V
DD
UVLO
I
DD
I
SHDN
I
STNDBY
t
ON
V
OS
T
A
= +25°C
T
A
= +25°C, V
DD
= 3.7V
SD_MODE
= 0V, T
A
= +25°C
SD_MODE
= 1.8V, no PDM_CLK,
T
A
= +25°C
Time from receipt of first clock cycle to full
operation
T
A
= +25°C, gain = 15dB
Peak voltage, T
A
= Into shutdown
+25°C, A-weighted,
32 samples per
Out of shutdown
second (Note 3)
V
DD
= 2.5V to 5.5V, T
A
= +25°C
Power-Supply Rejection Ratio
PSRR
T
A
= +25°C
(Notes 3, 4)
f = 217Hz,
200mV
P-P
ripple
f = 10kHz,
200mV
P-P
ripple
60
CONDITIONS
Guaranteed by PSSR test
MIN
2.5
1.4
1.8
2.2
1.8
0.6
340
0.6
±0.3
-72
dBV
-66
75
77
60
dB
TYP
MAX
5.5
2.3
2.7
2.2
2
400
0.7
±2.5
UNITS
V
V
mA
µA
µA
ms
mV
Click-and-Pop Level
K
CP
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MAX98358
PDM Input Class D Audio Power Amplifier
Electrical Characteristics (continued)
PARAMETER
SYMBOL
(V
DD
= 5V, V
GND
= 0V, GAIN = V
DD
(+6dB). PDM_CLK = 3.072MHz, speaker loads (Z
SPK
) connected between OUTP and OUTN,
Z
SPK
= ∞, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 2)
CONDITIONS
Z
SPK
= 4Ω + 33µH
THD+N 10%
Output Power (Note 3)
P
OUT
THD+N = 1%
Z
SPK
= 8Ω + 68µH
Z
SPK
= 8Ω + 68µH,
V
DD
= 3.7V
Z
SPK
= 4Ω + 33µH
Z
SPK
= 8Ω + 68µH
Z
SPK
= 8Ω + 68µH,
V
DD
= 3.7V
MIN
TYP
3.2
1.8
0.93
2.5
1.4
0.77
0.02
0.02
0.013
99
29
14.4
11.4
8.4
5.4
2.4
15
12
9
6
3
2.8
Z
SPK
= 8Ω + 68µH, THD+N = 10%,
f = 1kHz, gain = 12dB
92
1
±0.5
f
OSC
330
±20
15.6
12.6
9.6
6.6
3.6
A
%
%
dB
kHz
kHz
dB
dB
µV
RMS
0.06
%
W
MAX
UNITS
f = 1kHz, P
OUT
= 1W, T
A
= +25°C,
Z
SPK
= 4Ω + 33µH (WLP)
Total Harmonic Distortion +
Noise
THD+N
f = 1kHz, P
OUT
= 1W, T
A
= +25°C,
Z
SPK
= 4Ω + 33µH (TQFN)
f = 1kHz, P
OUT
= 0.5W, T
A
= +25µC,
Z
SPK
= 8Ω + 68FH
Dynamic Range
Output Noise
DR
V
N
A-weighted, PDM_CLK = 6.144MHz,
V
RMS
= 2.54V
A-weighted (Note 4)
GAIN = GND through 100kΩ
Gain (Relative to a 2.1dBV
Reference Level)
GAIN = GND
A
V
GAIN = unconnected
GAIN = V
DD
GAIN = V
DD
through 100kΩ
Current Limit
Efficiency
DAC Gain Error
Frequency Response
Class D Oscillator Frequency
Spread-Spectrum Bandwidth
DIGITAL AUDIO INTERFACE
PDM_CLK High Frequency
Range
PDM_CLK Low Frequency
Range
PDM_CLK High Time
PDM_CLK Low Time
Maximum Low-Frequency
PDM_CLK Jitter
Maximum Low-Frequency
PDM_CLK Jitter
f
CLKH
f
CLKL
t
PDM_CLKH
t
PDM_CLKL
RMS jitter below 40kHz
RMS jitter above 40kHz
5.28
1.84
40
40
I
LIM
h
8.64
4.32
MHz
MHz
ns
ns
0.5
12
ns
ns
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