MAXIM MAX9744 Technical data
General Description
The MAX9744 20W stereo Class D audio power amplifier provides Class AB amplifier performance with Class
D efficiency, conserving board space and eliminating
the need for a bulky heatsink. This device features single-supply operation, adjustable gain, shutdown mode,
a SYNC output, speaker mute, and industry-leading
click-and-pop suppression.
The MAX9744 features a 64-step dual-mode (analog or
digital), programmable volume control and mute function. The MAX9744 operates from a 4.5V to 14V single
supply and can deliver up to 20W per channel into a
4Ω speaker with a 14V supply.
The MAX9744 offers two modulation schemes: a fixedfrequency modulation mode that allows one of several
preset switching frequencies to be selected, and a
spread-spectrum modulation mode that helps to
reduce EMI-radiated emissions.
The MAX9744 features high 75dB PSRR, low 0.04%
THD+N, and SNR in excess of 90dB. Robust short-circuit and thermal-overload protection prevent device
damage during a fault condition. The MAX9744 is available in a 44-pin thin QFN-EP (7mm x 7mm x 0.8mm)
package and is specified over the extended -40°C to
+85°C temperature range.
Applications
Flat-Panel Televisions
PC Speaker Systems
Multimedia Docking Stations
Features
♦ Wide 4.5V to 14V Power-Supply Voltage Range
♦ Filterless Spread-Spectrum Modulation Lowers
Radiated RF Emissions from Speaker Cables
♦ 20W Stereo Output (4Ω, VDD= 12V, THD+N = 10%)
♦ Integrated Volume Control (I2C or Analog)
♦ Low 0.04% THD+N
♦ High 75dB PSRR
♦ High 93% Efficiency
♦ Integrated Click-and-Pop Suppression
♦ Low-Power Shutdown Mode
♦ Short-Circuit and Thermal-Overload Protection
♦ Available in a 44-Pin Thin QFN-EP (7mm x 7mm x
0.8mm)
MAX9744
20W Stereo Class D Speaker Amplifier
with Volume Control
________________________________________________________________
Maxim Integrated Products
1
19-4078; Rev 1; 9/08
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.
Pin Configuration appears at end of data sheet.
EVALUATION KIT
AVAILABLE
MAX9744
BIAS
SYNCOUTSYNC
VOLUME
CONTROL
CLASS D
MODULATOR
CLASS D
MODULATOR
MUTE
SHUTDOWN
CONTROL
I
2
C
ANALOG
CONTROL
OSCILLATOR
3V TO 3.6V 4.5V TO 14V
MAX9744 EMI WITH FERRITE BEAD FILTERS
(V
DD
= 12V, 1m CABLE, 8Ω LOAD)
FREQUENCY (MHz)
220
200
60
80
100
140
160
120
180
5
10
15
20
25
30
35
40
30
240
260
280
300
OUTPUT MAGNITUDE (dBV)
EN5022 B LIMIT
Simplified Block Diagram
+
Denotes a lead-free/RoHS-compliant package.
*
EP = Exposed pad.
PART TEMP RANGE PIN-PACKAGE
MAX9744ETH+ -40°C to +85°C 44 TQFN-EP*
Ordering Information
MAX9744
20W Stereo Class D Speaker Amplifier
with Volume Control
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
PVDD
= 12V, V
DD
= 3.3V, V
GND
= V
PGND
= 0V, V
MUTE
= 0V; max volume setting; all speaker load resistors connected between
OUT_+ and OUT_-, R
L
= ∞, unless otherwise stated, C
BOOT_
= 0.1µF, C
BIAS
= 2.2µF, CIN= 0.47µF, RIN= 20kΩ, RF_= 20kΩ, spread-
spectrum mode, filterless modulation mode, see the
Functional Diagrams/Typical Application Circuits.
TA= T
MIN
to T
MAX
, unless oth-
erwise noted. Typical values are at T
A
= +25°C.) (Note 1)
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 to PGND ....................................................................+16V
V
DD
to GND ...........................................................................+4V
FB_, SYNCOUT, SYNC, SDA/VOL, ADDR1,
ADDR2 to GND........................................-0.3V to (V
DD
+ 0.3V)
BOOT_ to V
DD
..........................................................-0.3V to +6V
BOOT_ to OUT_........................................................-0.3V to +6V
OUT_ to GND ..........................................-0.3V to (PVDD + 0.3V)
PGND to GND .......................................................-0.3V to +0.3V
Any Other Pin to GND ..............................................-0.3V to +4V
OUT_, Short-Circuit Duration......................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
44-Pin Thin QFN (derate 27mW/°C above +70°C,
single-layer board) ...................................................2162mW
44-Pin Thin QFN (derate 37mW/°C above +70°C,
multilayer board) ......................................................2963mW
θ
JA
, Single-Layer Board................................................37°C/W
θ
JA
, Multilayer Board ................................................….27°C/W
Continuous Input Current (PVDD, PGND).............................6.4A
Continuous Output Current (OUT_) ......................................3.2A
Continuous Input Current (except OUT_).........................±20mA
Junction Temperature......................................................+150°C
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
GENERAL
Speaker Amplifier Supply Voltage
Range
Supply Voltage Range V
Quiescent Current
Shutdown Current
Turn-On Time t
Common-Mode Bias Voltage V
Input Amplifier Output-Voltage
Swing High
Input Amplifier Output-Voltage
Swing Low
Input Amplifier Output ShortCircuit Current Limit
Input Amplifier Gain-Bandwidth
Product
SPEAKER AMPLIFIERS
Gain A
Output Offset V
I
VDDSHDNTA
I
PVDDSHDNTA
PVDD Inferred from PSRR test 4.5 14 V
I
DD
I
DD
PVDD
ON
BIAS
V
OH
V
OL
GBW 1.8 MHz
VMAX
OS
Inferred from PSRR test 2.7 3.6 V
= +25°C 0.1 1
= +25°C 0.1 1
Specified as VDD – VOH, RL = 2kΩ
connected to 1.5V
Specified as VOL – GND, RL = 2kΩ
connected to 1.5V
Maximum
volume setting
TA = 25°C ±2 ±15 mV
Output stage gain 29.5
Total gain (Note 2) 29.5
20 35
10 20
200 ms
1.5 V
20 mV
20 mV
±60 mA
mA
µA
dB
MAX9744
20W Stereo Class D Speaker Amplifier
with Volume Control
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V
PVDD
= 12V, V
DD
= 3.3V, V
GND
= V
PGND
= 0V, V
MUTE
= 0V; max volume setting; all speaker load resistors connected between
OUT_+ and OUT_-, R
L
= ∞, unless otherwise stated, C
BOOT_
= 0.1µF, C
BIAS
= 2.2µF, CIN= 0.47µF, RIN= 20kΩ, RF_= 20kΩ, spread-
spectrum mode, filterless modulation mode, see the
Functional Diagrams/Typical Application Circuits.
TA= T
MIN
to T
MAX
, unless oth-
erwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Efficiency (Note 3)
Output Power P
Hard Output Current Limit I
Total Harmonic Distortion Plus
Noise
η
OUT
SC
THD+N
Signal-to-Noise Ratio SNR
Filterless
modulation
PWM
V
= 5V,
PVDD
f
= 1kHz
IN
V
= 12V,
PVDD
= 1kHz
f
IN
V
= 14V,
PVDD
= 1kHz
f
IN
f = 1kHz, R
8Ω, P
= 1kHz
f
IN
P
OUT
R
= 8Ω,
L
= 5W,
OUT
= 10W,
=
L
filterless
modulation
mode, BW =
22Hz to 22kHz
= 10W,
P
OUT
= 8Ω, PWM
R
L
mode, BW =
22Hz to 22kHz
P
= 10W, fIN = 1kHz,
OUT
8Ω load
P
= 15W, fIN = 1kHz,
OUT
4Ω load
P
= 10W, fIN = 1kHz,
OUT
8Ω load
P
= 15W, f
OUT
4Ω load
= 1kHz,
IN
93
87
92
88
RL = 8Ω, THD+N = 1% 1.4
RL = 8Ω, THD+N = 10% 1.8
RL = 4Ω, THD+N = 1% 2.6
R
= 4Ω, THD+N = 10% 3.6
L
RL = 8Ω, THD+N = 1% 8
RL = 8Ω, THD+N = 10% 10
RL = 4Ω, THD+N = 1% 14
R
= 4Ω, THD+N = 10% 17
L
RL = 8Ω, THD+N = 1% 10
RL = 8Ω, THD+N = 10% 13
RL = 4Ω, THD+N = 1% 17.5
R
= 4Ω, THD+N = 10% 22.5
L
3.9 5.5 A
Filterless modulation 0.04
PWM 0.04
Fixed-frequency
modulation, unweighted
Spread-spectrum,
unweighted
Fixed-frequency
modulation, A-weighted
Spread-spectrum,
A-weighted
Fixed-frequency
modulation, unweighted
Spread-spectrum,
unweighted
Fixed-frequency
modulation, A-weighted
Spread-spectrum,
A-weighted
91
90
94
94
91
81
94
89
%
%
W
%
dB
dB
MAX9744
20W Stereo Class D Speaker Amplifier
with Volume Control
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(V
PVDD
= 12V, V
DD
= 3.3V, V
GND
= V
PGND
= 0V, V
MUTE
= 0V; max volume setting; all speaker load resistors connected between
OUT_+ and OUT_-, R
L
= ∞, unless otherwise stated, C
BOOT_
= 0.1µF, C
BIAS
= 2.2µF, CIN= 0.47µF, RIN= 20kΩ, RF_= 20kΩ, spread-
spectrum mode, filterless modulation mode, see the
Functional Diagrams/Typical Application Circuits.
TA= T
MIN
to T
MAX
, unless oth-
erwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Crosstalk
Power-Supply Rejection Ratio PSRR
SYNC Frequency f
Class D Switching Frequency f
SYNC Frequency Lock Range 1000 1600 kHz
Minimum SYNC Frequency Lock
Duty Cycle
Maximum SYNC Frequency Lock
Duty Cycle
Gain Matching Full volume (ideal matching for R
Click-and-Pop Level K
VOLUME CONTROL
VOL Input Leakage Current ±5 µA
Input Hysteresis DC volume control mode 11 mV
9.5dB Gain Voltage DC volume control mode 0.1 x V
Full Mute Voltage DC volume control mode 0.9 x V
Full Mute Attenuation f = 1kHz, relative to 9.5dB setting -115 dB
DIGITAL INPUTS/OUTPUT (SHDN, MUTE, ADDR1, ADDR2, SCLK, SDA/VOL)
Input-Voltage High V
Input-Voltage Low V
Input Leakage Current I
Input Hysteresis SCLK, SDA/VOL 0.1 x V
Input Capacitance C
Output-Voltage Low V
SYNC
SW
CP
IH
IL
LK
IN
IL
1kHz 85
20Hz to 20kHz 68
VDD = 2.7V to 3.6V, TA = 25°C,
MUTE = high
PVDD = 4.5V to 14V 50 83
f = 1kHz, V
f = 1kHz, V
SYNC = GND 1020 1200 1355
SYNC = unconnected 1280 1440 1640
SYNC = VDD (spread-spectrum mode)
SYNC = GND 255 300 338
SYNC = unconnected 320 360 410
SYNC = VDD (spread-spectrum mode)
Peak voltage, 32
samples/second,
A-weighted (Note 4)
TA = +25°C ±1 µA
IOL = 3mA 0.4 V
= 100mV
RIPPLE
= 200mV
RIPPLE
on V
P-P
P-P
Into shutdown -43
Out of shutdown -43
Into mute -46
Out of mute -57
DD
on PVDD 75
and RF) 0.2 dB
IN
0.7 x V
DD
68
70
1200
±30
300
±6
40 %
60 %
DD
DD
0.3 x V
DD
5pF
DD
dB
dB
kHz
kHz
dBV
V
V
V
V
V
MAX9744
20W Stereo Class D Speaker Amplifier
with Volume Control
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICS (continued)
(V
PVDD
= 12V, V
DD
= 3.3V, V
GND
= V
PGND
= 0V, V
MUTE
= 0V; max volume setting; all speaker load resistors connected between
OUT_+ and OUT_-, R
L
= ∞, unless otherwise stated, C
BOOT_
= 0.1µF, C
BIAS
= 2.2µF, CIN= 0.47µF, RIN= 20kΩ, RF_= 20kΩ, spread-
spectrum mode, filterless modulation mode, see the
Functional Diagrams/Typical Application Circuits.
TA= T
MIN
to T
MAX
, unless oth-
erwise noted. Typical values are at T
A
= +25°C.) (Note 1)
Note 1: All devices are 100% production tested at +25°C. All temperature limits are guaranteed by design.
Note 2: See the
Gain-Setting Resistors
section.
Note 3: Measured on the MAX9744 Evaluation Kit.
Note 4: Testing performed with an 8Ω resistive load connected across BTL output. Mode transitions are controlled by SHDN or
MUTE pin, respectively.
Note 5: A master device must provide a hold time of at least 300ns for the SDA signal in order to bridge the undefined region of the
SCL’s falling edge.
Note 6: C
B
= total capacitance of one bus line in pF.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DIGITAL INPUT (SYNC)
Input-Voltage High V
Input-Voltage Low V
SYNC Input Leakage I
SYNCIH
SYNCIL
SYNCIN
TA = +25°C ±7.5 ±13 µA
2.3 V
0.8 V
DIGITAL OUTPUT (SYNCOUT)
-
V
Output-Voltage High V
Output-Voltage Low V
SYNCOUTIH
SYNCOUTILISINK
I
SOURCE
= 1mA
= 1mA 0.3 V
DD
0.3
Rise/Fall Time CL = 10pF 50 V/µs
THERMAL PROTECTION
Thermal-Shutdown Threshold +165 °C
Thermal-Shutdown Hysteresis 15 °C
I2C TIMING CHARACTERISTICS (Figure 3)
Serial Clock f
Bus Free Time Between a STOP
and a START Condition
Hold Time (Repeated) START
Condition
Repeated START Condition
Setup Time
STOP Condition Setup Time t
Data Hold Time t
Data Setup Time t
t
HD, STA
t
SU, STA
SU, STO
HD,DAT
SU,DAT
SCL Clock Low Period t
SCL Clock High Period t
Rise Time of SDA and SCL,
Receiving
Fall Time of SDA and SCL,
Receiving
Pulse Width of Spike Suppressed t
Capacitive Load for Each Bus
Line
SCL
t
BUF
LOW
HIGH
t
R
t
F
SP
C
B
1.3 µs
(Note 5) 0.6 µs
0.6 µs
0.6 µs
0 0.9 µs
100 ns
1.3 µs
0.6 µs
(Note 6)
(Note 6)
20 +
0.1C
20 +
0.1C
B
B
050ns
400 kHz
300 ns
300 ns
400 pF
V
MAX9744
20W Stereo Class D Speaker Amplifier
with Volume Control
6 _______________________________________________________________________________________
Typical Operating Characteristics
(V
PVDD
= 12V, VDD= 3.3V, V
GND
= V
PGND
= 0V, V
MUTE
= 0V; max volume setting; all speaker load resistors connected between
OUT_+ and OUT_- with an inductor in series, 8Ω load, L = 68µH, 4Ω load, L= 33µH. R
L
= ∞, unless otherwise stated, C
BIAS
= 2.2µF,
C
IN
= 0.47µF, RIN= 20kΩ, RF_= 20kΩ, spread-spectrum mode, TA= +25°C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX9744 toc01
OUTPUT POWER (W)
THD+N (%)
18161412108642
0.01
0.1
1
10
100
0.001
020
fIN = 6kHz
fIN = 100Hz
fIN = 1kHz
PVDD = 12V
R
L
= 4Ω
FILTERLESS MODULATION
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX9744 toc02
OUTPUT POWER (W)
THD+N (%)
161284
0.01
0.1
1
10
100
0.001
020
PVDD = 12V
R
L
= 4Ω
PWM MODE
fIN = 6kHz
fIN = 100Hz
fIN = 1kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX9744 toc03
OUTPUT POWER (W)
THD+N (%)
963
0.01
0.1
1
10
100
0.001
012
PVDD = 12V
R
L
= 8Ω
FILTERLESS MODULATION
fIN = 6kHz
fIN = 100Hz
fIN = 1kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX9744 toc04
OUTPUT POWER (W)
THD+N (%)
963
0.01
0.1
1
10
100
0.001
012
PVDD = 12V
R
L
= 8Ω
PWM MODE
fIN = 6kHz
fIN = 100Hz
fIN = 1kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX9744 toc05
OUTPUT POWER (W)
THD+N (%)
321
0.01
0.1
1
10
100
0.001
04
fIN = 6kHz
fIN = 100Hz
fIN = 1kHz
PVDD = 5V
R
L
= 4Ω
FILTERLESS MODULATION
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX9744 toc06
OUTPUT POWER (W)
THD+N (%)
321
0.01
0.1
1
10
100
0.001
04
PVDD = 5V
R
L
= 4Ω
PWM MODE
fIN = 6kHz
fIN = 100Hz
fIN = 1kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX9744 toc08
OUTPUT POWER (W)
THD+N (%)
106842
0.01
0.1
1
10
100
0.001
012
PVDD = 12V
R
L
= 8Ω
f
IN
= 1kHz
FILTERLESS MODULATION
SSM
FFM
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX9744 toc07
OUTPUT POWER (W)
THD+N (%)
161284
0.01
0.1
1
10
100
0.001
020
PVDD = 12V
R
L
= 4Ω
f
IN
= 1kHz
FILTERLESS MODULATION
FFM
SSM
MAX9744
20W Stereo Class D Speaker Amplifier
with Volume Control
_______________________________________________________________________________________
7
Typical Operating Characteristics (continued)
(V
PVDD
= 12V, VDD= 3.3V, V
GND
= V
PGND
= 0V, V
MUTE
= 0V; max volume setting; all speaker load resistors connected between
OUT_+ and OUT_- with an inductor in series, 8Ω load, L = 68µH, 4Ω load, L= 33µH. R
L
= ∞, unless otherwise stated, C
BIAS
= 2.2µF,
C
IN
= 0.47µF, RIN= 20kΩ, RF_= 20kΩ, spread-spectrum mode, TA= +25°C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
100
PVDD = 12V
= 4Ω
R
L
= 1kHz
f
IN
10
PWM MODE
1
THD+N (%)
0.1
0.01
0.001
020
FFM
SSM
OUTPUT POWER (W)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
100
PVDD = 12V
= 8Ω
R
L
FILTERLESS MODULATION
10
161284
MAX9744 toc09
MAX9744 toc12
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
100
PVDD = 12V
= 4Ω
R
L
FILTERLESS MODULATION
10
1
OUTPUT POWER = 10W
THD+N (%)
0.1
0.01
0.001
10 100k
OUTPUT POWER = 5W
10k1k100
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
100
PVDD = 12V
= 8Ω
R
L
PWM MODE
10
MAX9744 toc10
MAX9744 toc13
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
100
PVDD = 12V
= 4Ω
R
L
PWM MODE
10
1
THD+N (%)
0.001
OUTPUT POWER = 10W
0.1
0.01
10 100k
OUTPUT POWER = 5W
10k1k100
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
100
PVDD = 5V
= 4Ω
R
L
FILTERLESS MODULATION
10
MAX9744 toc11
MAX9744 toc14
1
OUTPUT POWER = 6W
THD+N (%)
0.1
0.01
0.001
OUTPUT POWER = 3W
10 100k
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
100
PVDD = 5V
= 4Ω
R
L
PWM MODE
10
1
OUTPUT POWER = 500mW
THD+N (%)
0.1
0.01
0.001
10 100k
10k1k100
OUTPUT POWER = 1.5W
10k1k100
FREQUENCY (Hz)
1
OUTPUT POWER = 6W
THD+N (%)
0.1
0.01
0.001
10 100k
MAX9744 toc15
OUTPUT POWER = 3W
FREQUENCY (Hz)
1
OUTPUT POWER = 1.5W
THD+N (%)
0.1
0.01
0.001
10k1k100
10 100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
100
PVDD = 12V
= 4Ω
R
L
FILTERLESS MODULATION
10
= 5W
P
OUT
1
THD+N (%)
0.1
0.01
0.001
10 100k
SSM
FREQUENCY (Hz)
OUTPUT POWER = 500mW
10k1k100
FREQUENCY (Hz)
MAX9744 toc16
FFM
10k1k100
MAX9744
20W Stereo Class D Speaker Amplifier
with Volume Control
8 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(V
PVDD
= 12V, VDD= 3.3V, V
GND
= V
PGND
= 0V, V
MUTE
= 0V; max volume setting; all speaker load resistors connected between
OUT_+ and OUT_- with an inductor in series, 8Ω load, L = 68µH, 4Ω load, L= 33µH. R
L
= ∞, unless otherwise stated, C
BIAS
= 2.2µF,
C
IN
= 0.47µF, RIN= 20kΩ, RF_= 20kΩ, spread-spectrum mode, TA= +25°C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX9744 toc17
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01
0.1
1
10
100
0.001
10 100k
PVDD = 12V
R
L
= 8Ω
FILTERLESS MODULATION
P
OUT
= 3W
FFM
SSM
EFFICIENCY vs. OUTPUT POWER
MAX9744 toc18
OUTPUT POWER (W)
EFFICIENCY (%)
POWER DISSIPATION (mW)
1284
10
20
30
40
50
60
70
80
90
100
0
1
2
3
4
5
6
7
8
9
10
0
016
PVDD = 12V, fIN = 1kHz, RL = 4Ω
FILTERLESS MODULATION
PWM MODE
EFFICIENCY vs. OUTPUT POWER
MAX9744 toc19
OUTPUT POWER (W)
(PER CHANNEL)
EFFICIENCY (%)
POWER DISSIPATION
10624
20
10
40
60
80
30
50
70
90
100
0
5W
0W
08
PWM MODE
FILTERLESS MODULATION
PVDD = 12V
f
IN
= 1kHz
R
L
= 8Ω
EFFICIENCY vs. OUTPUT POWER
MAX9744 toc20
OUTPUT POWER (W)
EFFICIENCY (%)
POWER DISSIPATION
3.01.50.5 1.0
20
10
40
60
80
30
50
70
90
100
0
2W
0W
0 2.0 2.5
PWM MODE
FILTERLESS MODULATION
PVDD = 5V
f
IN
= 1kHz
R
L
= 4Ω
EFFICIENCY vs. SUPPLY VOLTAGE
MAX9744 toc21
SUPPLY VOLTAGE (V)
EFFICIENCY (%)
141068
75
80
85
90
95
100
70
412
fIN = 1kHz
R
L
= 4Ω
FILTERLESS MODULATION
THD+N = 10%
THD+N = 1%
EFFICIENCY vs. SUPPLY VOLTAGE
MAX9744 toc22
SUPPLY VOLTAGE (V)
EFFICIENCY (%)
141068
75
80
85
90
95
100
70
412
fIN = 1kHz
R
L
= 8Ω
FILTERLESS MODULATION
THD+N = 10%
THD+N = 1%
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX9744 toc24
SUPPLY VOLTAGE (V)
OUTPUT POWER (W)
121086
4
8
12
16
20
24
0
414
fIN = 1kHz
R
L
= 4Ω
PWM MODE
THD+N = 10%
THD+N = 1%
EFFICIENCY vs. SUPPLY VOLTAGE
MAX9744 toc23
SUPPLY VOLTAGE (V)
EFFICIENCY (%)
121086
75
80
85
90
95
100
70
414
fIN = 1kHz
R
L
= 4Ω
PWM MODE
THD+N = 10%
THD+N = 1%
MAX9744
20W Stereo Class D Speaker Amplifier
with Volume Control
_______________________________________________________________________________________
9
Typical Operating Characteristics (continued)
(V
PVDD
= 12V, VDD= 3.3V, V
GND
= V
PGND
= 0V, V
MUTE
= 0V; max volume setting; all speaker load resistors connected between
OUT_+ and OUT_- with an inductor in series, 8Ω load, L = 68µH, 4Ω load, L= 33µH. R
L
= ∞, unless otherwise stated, C
BIAS
= 2.2µF,
C
IN
= 0.47µF, RIN= 20kΩ, RF_= 20kΩ, spread-spectrum mode, TA= +25°C, unless otherwise noted.)
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX9744 toc25
SUPPLY VOLTAGE (V)
OUTPUT POWER (W)
141068
4
8
12
16
0
412
RL = 8Ω
f
IN
= 1kHz
PWM MODE
THD+N = 10%
THD+N = 1%
OUTPUT POWER vs. LOAD RESISTANCE
MAX9744 toc26
LOAD RESISTANCE (Ω)
OUTPUT POWER (W)
3015510
4
8
12
20
16
0
02520
PVDD = 12V
f = 1kHz
FILTERLESS MODULATION
THD+N = 10%
THD+N = 1%
OUTPUT POWER vs. LOAD RESISTANCE
MAX9744 toc27
LOAD RESISTANCE (Ω)
OUTPUT POWER (W)
3015510
1
2
4
3
0
02520
PVDD = 5V
f = 1kHz
PWM MODE
THD+N = 10%
THD+N = 1%
CASE TEMPERATURE
vs. OUTPUT POWER
MAX9744 toc28
OUTPUT POWER (W)
CASE TEMPERATURE (°C)
18936
25
50
125
100
75
0
01512
fIN = 1kHz
R
L
= 4Ω
PVDD = 14V
PWM MODE
PVDD = 12V
PWM MODE
PVDD = 14V
FILTERLESS MODULATION
PVDD = 12V
FILTERLESS MODULATION
CASE TEMPERATURE
vs. OUTPUT POWER
MAX9744 toc29
OUTPUT POWER (W)
CASE TEMPERATURE (°C)
12624
25
75
50
0
0108
fIN = 1kHz
R
L
= 8Ω
PVDD = 12V
PWM MODE
PVDD = 14V
PWM MODE
PVDD = 14V
FILTERLESS MODULATION
PVDD = 12V
FILTERLESS MODULATION
POWER-SUPPLY REJECTION RATIO (PVDD)
vs. FREQUENCY
MAX9744 toc30
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
-100
10 100k
PWM MODE
FILTERLESS MODULATION
PVDD = 12V
V
RIPPLE
= 200mV
P-P
EMI WITH FERRITE BEAD FILTERS
(V
DD
= 12V, 1m CABLE, 8Ω LOAD)
MAX9744 toc32
OUTPUT MAGNITUDE (dBV)
5
10
15
20
25
30
35
40
FREQUENCY (MHz)
220
200
60
80
100
140
160
120
180
30
240
260
280
300
EN5022 B LIMIT
POWER-SUPPLY REJECTION RATIO (VDD)
vs. FREQUENCY
MAX9744 toc31
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
-100
10 100k
PWM MODE
FILTERLESS MODULATION
VDD = 3.3V
V
RIPPLE
= 100mV
P-P
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