19-4078; Rev 1; 9/08
KIT
ATION
EVALU
BLE
AVAILA
20W Stereo Class D Speaker Amplifier
with Volume Control
General Description
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, V
DD
= 12V, THD+N = 10%)
♦
Integrated Volume Control (I
2
C 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
The MAX9744 20W stereo Class D audio power amplifi-
er provides Class AB amplifier performance with Class
D efficiency, conserving board space and eliminating
the need for a bulky heatsink. This device features sin-
gle-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 func-
tion. 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 fixed-
frequency 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-cir-
cuit and thermal-overload protection prevent device
damage during a fault condition. The MAX9744 is avail-
able 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.
Ordering Information
PART
MAX9744ETH+
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
44 TQFN-EP*
+Denotes
a lead-free/RoHS-compliant package.
*EP
= Exposed pad.
Applications
Flat-Panel Televisions
PC Speaker Systems
Multimedia Docking Stations
Pin Configuration appears at end of data sheet.
Simplified Block Diagram
3V TO 3.6V
4.5V TO 14V
CLASS D
MODULATOR
MAX9744
MAX9744 EMI WITH FERRITE BEAD FILTERS
(V
DD
= 12V, 1m CABLE, 8Ω LOAD)
40
35
OUTPUT MAGNITUDE (dBV)
EN5022 B LIMIT
30
25
20
15
10
5
BIAS
VOLUME
CONTROL
CLASS D
MODULATOR
MUTE
SHUTDOWN
CONTROL
I
2
C
ANALOG
CONTROL
OSCILLATOR
SYNC
SYNCOUT
30
60
80
100
140 180 220 260
300
120 160 200 240 280
FREQUENCY (MHz)
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
20W Stereo Class D Speaker Amplifier
with Volume Control
MAX9744
ABSOLUTE MAXIMUM RATINGS
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
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.
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, C
IN
= 0.47µF, R
IN
= 20kΩ, R
F_
= 20kΩ, spread-
spectrum mode, filterless modulation mode, see the
Functional Diagrams/Typical Application Circuits.
T
A
= T
MIN
to T
MAX
, unless oth-
erwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
GENERAL
Speaker Amplifier Supply Voltage
Range
Supply Voltage Range
Quiescent Current
Shutdown Current
Turn-On Time
Common-Mode Bias Voltage
Input Amplifier Output-Voltage
Swing High
Input Amplifier Output-Voltage
Swing Low
Input Amplifier Output Short-
Circuit Current Limit
Input Amplifier Gain-Bandwidth
Product
SPEAKER AMPLIFIERS
Gain
Output Offset
A
VMAX
V
OS
Maximum
volume setting
T
A
= 25°C
Output stage gain
Total gain (Note 2)
29.5
29.5
±2
±15
dB
mV
GBW
PVDD
V
DD
I
DD
I
PVDD
I
VDDSHDN
I
PVDDSHDN
t
ON
V
BIAS
V
OH
V
OL
Specified as V
DD
– V
OH
, R
L
= 2kΩ
connected to 1.5V
Specified as V
OL
– GND, R
L
= 2kΩ
connected to 1.5V
T
A
= +25°C
T
A
= +25°C
Inferred from PSRR test
Inferred from PSRR test
4.5
2.7
20
10
0.1
0.1
200
1.5
20
20
±60
1.8
14
3.6
35
20
1
1
V
V
mA
µA
ms
V
mV
mV
mA
MHz
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
20W Stereo Class D Speaker Amplifier
with Volume Control
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, C
IN
= 0.47µF, R
IN
= 20kΩ, R
F_
= 20kΩ, spread-
spectrum mode, filterless modulation mode, see the
Functional Diagrams/Typical Application Circuits.
T
A
= T
MIN
to T
MAX
, unless oth-
erwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
SYMBOL
Filterless
modulation
Efficiency (Note 3)
η
MAX9744
CONDITIONS
P
OUT
= 10W, f
IN
= 1kHz,
8Ω load
P
OUT
= 15W, f
IN
= 1kHz,
4Ω load
P
OUT
= 10W, f
IN
= 1kHz,
8Ω load
P
OUT
= 15W, f
IN
= 1kHz,
4Ω load
R
L
= 8Ω, THD+N = 1%
V
PVDD
= 5V,
f
IN
= 1kHz
R
L
= 8Ω, THD+N = 10%
R
L
= 4Ω, THD+N = 1%
R
L
= 4Ω, THD+N = 10%
R
L
= 8Ω, THD+N = 1%
V
PVDD
= 12V,
f
IN
= 1kHz
R
L
= 8Ω, THD+N = 10%
R
L
= 4Ω, THD+N = 1%
R
L
= 4Ω, THD+N = 10%
R
L
= 8Ω, THD+N = 1%
V
PVDD
= 14V,
f
IN
= 1kHz
R
L
= 8Ω, THD+N = 10%
R
L
= 4Ω, THD+N = 1%
R
L
= 4Ω, THD+N = 10%
MIN
TYP
93
MAX
UNITS
%
87
92
%
88
1.4
1.8
2.6
3.6
8
10
14
17
10
13
17.5
22.5
3.9
5.5
0.04
0.04
91
90
dB
94
94
91
81
dB
94
89
%
A
W
PWM
Output Power
P
OUT
Hard Output Current Limit
Total Harmonic Distortion Plus
Noise
I
SC
THD+N
f = 1kHz, R
L
=
8Ω, P
OUT
= 5W,
f
IN
= 1kHz
P
OUT
= 10W,
R
L
= 8Ω,
filterless
modulation
mode, BW =
22Hz to 22kHz
Filterless modulation
PWM
Fixed-frequency
modulation, unweighted
Spread-spectrum,
unweighted
Fixed-frequency
modulation, A-weighted
Spread-spectrum,
A-weighted
Fixed-frequency
modulation, unweighted
P
OUT
= 10W,
R
L
= 8Ω, PWM
mode, BW =
22Hz to 22kHz
Spread-spectrum,
unweighted
Fixed-frequency
modulation, A-weighted
Spread-spectrum,
A-weighted
Signal-to-Noise Ratio
SNR
_______________________________________________________________________________________
3
20W Stereo Class D Speaker Amplifier
with Volume Control
MAX9744
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, C
IN
= 0.47µF, R
IN
= 20kΩ, R
F_
= 20kΩ, spread-
spectrum mode, filterless modulation mode, see the
Functional Diagrams/Typical Application Circuits.
T
A
= T
MIN
to T
MAX
, unless oth-
erwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Crosstalk
SYMBOL
1kHz
20Hz to 20kHz
V
DD
= 2.7V to 3.6V, T
A
= 25°C,
MUTE = high
Power-Supply Rejection Ratio
PSRR
PV
DD
= 4.5V to 14V
f = 1kHz, V
RIPPLE
= 100mV
P-P
on V
DD
f = 1kHz, V
RIPPLE
= 200mV
P-P
on PVDD
SYNC = GND
SYNC Frequency
f
SYNC
SYNC = unconnected
SYNC = V
DD
(spread-spectrum mode)
SYNC = GND
Class D Switching Frequency
f
SW
SYNC = unconnected
SYNC = V
DD
(spread-spectrum mode)
SYNC Frequency Lock Range
Minimum SYNC Frequency Lock
Duty Cycle
Maximum SYNC Frequency Lock
Duty Cycle
Gain Matching
Full volume (ideal matching for R
IN
and R
F
)
Into shutdown
Click-and-Pop Level
K
CP
Peak voltage, 32
samples/second,
A-weighted (Note 4)
Out of shutdown
Into mute
Out of mute
VOLUME CONTROL
VOL Input Leakage Current
Input Hysteresis
9.5dB Gain Voltage
Full Mute Voltage
Full Mute Attenuation
Input-Voltage High
Input-Voltage Low
Input Leakage Current
Input Hysteresis
Input Capacitance
Output-Voltage Low
C
IN
V
IL
I
OL
= 3mA
V
IH
V
IL
I
LK
T
A
= +25°C
SCLK, SDA/VOL
0.1 x V
DD
5
0.4
DC volume control mode
DC volume control mode
DC volume control mode
f = 1kHz, relative to 9.5dB setting
0.7 x V
DD
0.3 x V
DD
±1
±5
11
0.1 x V
DD
0.9 x V
DD
-115
µA
mV
V
V
dB
V
V
µA
V
pF
V
1000
40
60
0.2
-43
-43
-46
-57
dBV
255
320
1020
1280
50
CONDITIONS
MIN
TYP
85
68
68
83
70
75
1200
1440
1200
±30
300
360
300
±6
1600
kHz
%
%
dB
338
410
kHz
1355
1640
kHz
dB
MAX
UNITS
dB
DIGITAL INPUTS/OUTPUT (SHDN, MUTE, ADDR1, ADDR2, SCLK, SDA/VOL)
4
_______________________________________________________________________________________
20W Stereo Class D Speaker Amplifier
with Volume Control
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, C
IN
= 0.47µF, R
IN
= 20kΩ, R
F_
= 20kΩ, spread-
spectrum mode, filterless modulation mode, see the
Functional Diagrams/Typical Application Circuits.
T
A
= T
MIN
to T
MAX
, unless oth-
erwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
DIGITAL INPUT (SYNC)
Input-Voltage High
Input-Voltage Low
SYNC Input Leakage
DIGITAL OUTPUT (SYNCOUT)
Output-Voltage High
Output-Voltage Low
Rise/Fall Time
THERMAL PROTECTION
Thermal-Shutdown Threshold
Thermal-Shutdown Hysteresis
I
2
C TIMING CHARACTERISTICS (Figure 3)
Serial Clock
Bus Free Time Between a STOP
and a START Condition
Hold Time (Repeated) START
Condition
Repeated START Condition
Setup Time
STOP Condition Setup Time
Data Hold Time
Data Setup Time
SCL Clock Low Period
SCL Clock High Period
Rise Time of SDA and SCL,
Receiving
Fall Time of SDA and SCL,
Receiving
Pulse Width of Spike Suppressed
Capacitive Load for Each Bus
Line
f
SCL
t
BUF
t
HD, STA
t
SU, STA
t
SU, STO
t
HD,DAT
t
SU,DAT
t
LOW
t
HIGH
t
R
t
F
t
SP
C
B
(Note 6)
(Note 6)
(Note 5)
1.3
0.6
0.6
0.6
0
100
1.3
0.6
20 +
0.1C
B
20 +
0.1C
B
0
300
300
50
400
0.9
400
kHz
µs
µs
µs
µs
µs
ns
µs
µs
ns
ns
ns
pF
+165
15
°C
°C
V
SYNCOUTIH
I
SOURCE
= 1mA
V
SYNCOUTIL
I
SINK
= 1mA
C
L
= 10pF
50
V
DD
-
0.3
0.3
V
V
V/µs
V
SYNCIH
V
SYNCIL
I
SYNCIN
T
A
= +25°C
±7.5
2.3
0.8
±13
V
V
µA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX9744
All devices are 100% production tested at +25°C. All temperature limits are guaranteed by design.
See the
Gain-Setting Resistors
section.
Measured on the MAX9744 Evaluation Kit.
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.
Note 1:
Note 2:
Note 3:
Note 4:
_______________________________________________________________________________________
5
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