EVALUATION KIT AVAILABLE
MAX98400A/MAX98400B
Stereo, High-Power, Class D Amplifiers
General Description
The MAX98400A/MAX98400B Class D amplifiers provide
high-performance, thermally efficient amplifier solutions. The
MAX98400A delivers 2x20W into 8Ω loads or 1x40W into a
4Ω load. The MAX98400B delivers 2x12W into 8Ω loads.
An integrated limiting circuit prevents output clipping
distortion, protects small speakers from transient voltages,
and reduces power dissipation.
A thermal-foldback feature can be enabled to automatically
reduce the output power at above a junction temperature
of +120°C. Traditional thermal protection is also available in
addition to robust overcurrent protection.
The ICs operate from a single 8V to 28V supply and provide
a high 67dB PSRR, eliminating the need for a regulated
power supply. They offer up to 90% efficiency from a 12V
supply.
Filterless modulation allows the ICs to pass EN55022B EMI
limits with 1m cables using only a low-cost ferrite bead and
small-value capacitor on each output.
Both devices feature eight digitally controlled gain settings.
Comprehensive click-and-pop reduction circuitry minimizes
noise coming into and out of shutdown.
The MAX98400A/MAX98400B are available in 36-pin and
24-pin TQFN packages, respectively, and are specified over
the -40°C to +85°C temperature range.
Features
●
Wide 8V to 28V Supply Voltage Range
●
Single-Supply Operation
●
Low EMI: Active Emissions Limiting
●
Clipping Limiter
●
Low Quiescent Current
●
Thermal Foldback
●
Thermal and Overcurrent Protection
Applications
●
●
●
●
LCD/PDP Televisions
LCD Monitors
MP3 Docking Stations
Notebook PCs
Ordering Information
PART
MAX98400AETX+
MAX98400BETG+
PIN-PACKAGE
36 TQFN-EP*
24 TQFN-EP*
SPEC
2x20W
2x12W
Note:
Devices operate over the -40°C to +85°C temperature
range.
*EP
= Exposed pad.
Simplified Block Diagram
INL-
CLIPPING
LIMITER
PGA
CLASS D
MODULATOR
AND H-BRIDGE
OUTL-
INL+
OUTL+
MONO*
MAX98400A/B
INR-
CLIPPING
LIMITER
PGA
CLASS D
MODULATOR
AND H-BRIDGE
OUTR-
INR+
OUTR+
*MAX98400A ONLY
19-5286; Rev 1; 4/15
MAX98400A/MAX98400B
Stereo, High-Power, Class D Amplifiers
TABLE OF CONTENTS
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Typical Operating Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Pin Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Stereo Configuration for MAX98400A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Mono Configuration for MAX98400A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Detailed Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Click-and-Pop Suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Mono Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Clipping Limiter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Limiter Threshold Control (LIM_TH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Release Time Control (RELEASE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Preamplifier Gain Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Thermal Foldback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Overtemperature Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Overcurrent Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Applications Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Filterless Class D Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Inductor-Based Output Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Component Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Input Capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Internal Regulator V
S
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Supply Bypassing, Layout, and Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Chip Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Functional Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
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MAX98400A/MAX98400B
Stereo, High-Power, Class D Amplifiers
LIST OF FIGURES
Figure 1 . MAX98400B EMI Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 2 . MAX98400A Efficiency vs . Class AB Effifciency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 3 . Limiter Control, Mode3 Configuration (Table 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 4 . Output Filter for PWM Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
LIST OF TABLES
Table 1 . Limiter Control Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Table 2 . Gain Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Table 3 . Filter Component Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
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Maxim Integrated
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MAX98400A/MAX98400B
Stereo, High-Power, Class D Amplifiers
Absolute Maximum Ratings
PVDD to PGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0 .3V to +30V
V
S
to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0 .3V to +6V
SHDN,
MONO to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0 .3V to +6V
IN_ to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0 .3V to +6V
G1, G2, RELEASE, TEMPLOCK,
LIM_TH to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0 .3V to (V
S
+ 0 .3V)
OUT_ to PGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0 .3V to (V
PVDD
+ 0 .3V)
PGND to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0 .3V to +0 .3V
Continuous Current into OUT_ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +2 .4A
Continuous Current into PVDD, PGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +4 .8A
Continuous Current into All Other Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . +10mA
Duration of OUT_ Short Circuit to PVDD or PGND . . .Continuous
Duration of Short Circuit Between
OUT_+ and OUT_- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Continuous
Continuous Power Dissipation (T
A
= +70NC)
36-Pin TQFN Multilayer Board
(derate 35 .7mW/NC above +70NC) . . . . . . . . . . . . . . . . . . . . . . . . .2857 .1mW
B
JA
(Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28NC/W
B
JC
(Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1NC/W
24-Pin TQFN Multilayer Board
(derate 27 .8mW/NC above +70NC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35 .7mW
B
JA
(Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36NC/W
B
JC
(Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3NC/W
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+150NC
Operating Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . -40NC to +85NC
Storage Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . -65NC to +150NC
Lead Temperature (soldering, 10s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+300NC
Soldering Temperature (reflow) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+260NC
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 .
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion 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.
Electrical Characteristics
(V
PVDD
= 18V, C
IN
= 1FF, V
SHDN
= 5V, LIM_TH = V
S
, TEMPLOCK = unconnected; G1 = GND, G2 = open (gain = 20 .1dB), C
REL
=
1FF, C1 = C2 = 1FF, R
L
=
J,
AC measurement bandwidth 20Hz to 20kHz, differential input signal, T
A
= T
MIN
to T
MAX
, unless otherwise
noted . Typical values are at T
A
= +25NC .) (Notes 2, 3)
PARAMETER
PVDD Supply Voltage Range
V
S
Supply Input Voltage
Quiescent Current
Single-Supply
Quiescent Current
Shutdown Current
PVDD Undervoltage Lockout
V
S
Regulator Output Voltage
INPUT STAGE
Differential Input Voltage Range
Single-Ended Input Voltage
Range
Common-Mode Rejection Ratio
Input Resistance
CMRR
Differential V
LIM_TH
= 0V, gain = +35dB
20
60
32
2
1
V
RMS
V
RMS
dB
kΩ
SYMBOL
V
PVDD
V
S
I
PVDD
I
VS
I
PVDD
I
SHDN_PVDD
I
SHDN_VS
V
UVLO
V
S
CONDITIONS
Inferred from PVDD_PSRR
Inferred from I
VS
test
Dual-supply mode:
V
S
= 4 .75V, T
A
= +25NC
Single-supply mode:
T
A
= +25NC
R
L
= 8Ω (Note 3)
V
SHDN
= 0V, T
A
= +25NC,
V
S
= 5 .5V
4 .2
MIN
8
4 .75
10
6
16
17
8
3
7
4 .47
TYP
MAX
28
5 .5
15
8 .2
23
UNITS
V
V
mA
AMPLIFIER DC CHARACTERISTICS
mA
20
10
7 .9
4 .75
FA
V
V
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Maxim Integrated
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MAX98400A/MAX98400B
Stereo, High-Power, Class D Amplifiers
Electrical Characteristics (continued)
(V
PVDD
= 18V, C
IN
= 1FF, V
SHDN
= 5V, LIM_TH = V
S
, TEMPLOCK = unconnected; G1 = GND, G2 = open (gain = 20 .1dB), C
REL
=
1FF, C1 = C2 = 1FF, R
L
=
J,
AC measurement bandwidth 20Hz to 20kHz, differential input signal, T
A
= T
MIN
to T
MAX
, unless otherwise
noted . Typical values are at T
A
= +25NC .) (Notes 2, 3)
PARAMETER
POWER STAGE
Shutdown to Full Operation
Gain Accuracy
Left-to-Right Gain Matching
Crosstalk
Output Offset Voltage
V
OS
All gain settings
1kHz
10kHz
T
A
= +25NC
Peak voltage,
32 samples/s,
A-weighted,
T
A
= +25NC (Notes 4, 5)
V
PVDD
= 8V to 28V
PSRR
PVDD
1kHz, 100mV
P-P
ripple
10kHz, 100mV
P-P
ripple
V
S
= 4 .75V to 5 .5V
V
S
Power-Supply Rejection Ratio
PSRR
VS
1kHz, 100mV
P-P
ripple
10kHz, 100mV
P-P
ripple
Stereo, R
L
= 8Ω, 10% THD+N,
f
IN
= 1kHz (Note 3)
Mono, R
L
= 4Ω, 10% THD+N,
f
IN
= 1kHz (Note 3)
Stereo, R
L
= 8Ω, 10% THD+N,
f
IN
= 1kHz (Note 3)
P
OUT
= 0 .1W to P
OUT
/2, f
IN
= 20Hz to
20kHz, R
L
= 8Ω
P
OUT
/2, f
IN
= 1kHz, R
L
= 8Ω
V
N
E
I
LIM
R
DSON
f
SW
V
PVDD
= 28V
V
LIM_TH
= 0V
V
LIM_TH
= 0V
V
PVDD
= 14V (Note 6)
(Note 7)
V
LIM
_
TH
= 0V
V
LIM_TH
= 0V
A-weighted
P
OUT
= 2x20W, R
L
= 8Ω (MAX98400A)
f
IN
= 1kHz (Note 3)
3 .5
265
20
39
Into
shutdown
Out of
shutdown
52
-85
-68
Q8
-47
dBV
-56
63
67
57
55
50
40
22
44
15
0 .3
0 .03
100
90
5
0 .4
330
26
240
0 .8
4
-1
-12
0
-6
+1
FV
RMS
%
A
Ω
395
kHz
V
Fs
s
dBFS
dBFS
dBFS
dB
W
dB
dB
Q45
t
SON
Q0 .8
11
Q4
Q2
ms
%
%
dB
mV
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Click-and-Pop Level
K
CP
PVDD Power-Supply Rejection
Ratio
MAX98400A Output Power
P
OUT
MAX98400B Output Power
Total Harmonic Distortion Plus
Noise
Output Noise
Efficiency
Current Limit
Output FET Resistance
Switching Frequency
Peak Output Voltage
LIMITER
Attack Time
Release Time
Maximum Trigger Level
Minimum Trigger Level
Trigger Level
Compression Range
P
OUT
THD+N
%
500
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