19-3769; Rev 0; 9/05
KIT
ATION
EVALU
BLE
AVAILA
25W/50W, Filterless, Spread-Spectrum,
Stereo/Mono, Class D Amplifier
General Description
The MAX9709 stereo/mono, Class D audio power amplifi-
er delivers up to 2 x 25W into an 8Ω stereo mode and
1 x 50W into a 4Ω load in mono mode while offering up to
87% efficiency. The MAX9709 provides Class AB amplifi-
er performance with the benefits of Class D efficiency,
eliminating the need for a bulky heatsink and conserving
power. The MAX9709 operates from a single +10V to
+22V supply, driving the load in a BTL configuration.
The MAX9709 offers two modulation schemes: a fixed-fre-
quency modulation (FFM) mode, and a spread-spectrum
modulation (SSM) mode that reduces EMI-radiated emis-
sions. The MAX9709 can be synchronized to an external
clock from 600kHz to 1.2MHz. A synchronized output
allows multiple units to be cascaded in the system.
Features include fully differential inputs, comprehensive
click-and-pop suppression, and four selectable-gain set-
tings (22dB, 25dB, 29.5dB, and 36dB). A pin-program-
mable thermal flag provides seven different thermal
warning thresholds. Short-circuit and thermal-overload
protection prevent the device from being damaged
during a fault condition.
The MAX9709 is available in 56-pin TQFN (8mm x 8mm
x 0.8mm) and 64-pin TQFP (10mm x 10mm x 1.4mm)
packages, and is specified over the extended
-40°C to +85°C temperature range.
Features
♦
2 x 25W Output Power in Stereo Mode
(8Ω, THD = 10%)
♦
1 x 50W Output Power in Mono Mode
(4Ω, THD = 10%)
♦
High Efficiency: Up to 87%
♦
Filterless Class D Amplifier
♦
Unique Patented Spread-Spectrum Mode
♦
Programmable Gain (+22dB, +25dB, +29.5dB,
+36dB)
♦
High PSRR (90dB at 1kHz)
♦
Differential Inputs Suppress Common-Mode
Noise
♦
Shutdown and Mute Control
♦
Integrated Click-and-Pop Suppression
♦
Low 0.1% THD+N
♦
Current Limit and Thermal Protection
♦
Programmable Thermal Flag
♦
Clock Synchronization Input and Output
♦
Available in Thermally Efficient, Space-Saving
Packages: 56-Pin TQFN and 64-Pin TQFP
MAX9709
Ordering Information
PART
MAX9709ETN+
TEMP RANGE
PIN-PACKAGE
PKG
CODE
T5688-3
C64E-6
Applications
LCD TVs
Automotive
PDP TVs
PC/HiFi Audio Solutions
-40°C to +85°C 56 TQFN-EP**
MAX9709ECB+* -40°C to +85°C 64 TQFP-EP**
Pin Configurations appear at end of data sheet.
+Denotes
lead-free package.
*Future
product—Contact factory for availability.
**EP
= Exposed paddle.
Simplified Block Diagram
FS1, FS2
SYNC
RIGHT
CHANNEL
LEFT
CHANNEL
MONO
2
2
MAX9709
SYNCOUT
FS1, FS2
SYNC
AUDIO
INPUT
2
MAX9709
SYNCOUT
CLASS D
MODULATOR
GAIN
CONTROL
OUTPUT
PROTECTION
CLASS D
MODULATOR
GAIN
CONTROL
2
3
TEMP
OUTPUT
PROTECTION
V
DIGITAL
MONO
3
TEMP
G1, G2
TH0, TH1,
TH2
G1, G2
TH0, TH1,
TH2
STEREO MODE
MONO MODE
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
25W/50W, Filterless, Spread-Spectrum,
Stereo/Mono, Class D Amplifier
MAX9709
ABSOLUTE MAXIMUM RATINGS
PV
DD
, V
DD
to PGND, GND .......................................-0.3 to +30V
PV
DD
to V
DD
..........................................................-0.3V to +0.3V
OUTR+, OUTR-, OUTL+,
OUTL- to PGND, GND..........................-0.3V to (PV
DD
+ 0.3V)
C1N to GND .............................................-0.3V to (PV
DD
+ 0.3V)
C1P to GND..............................(PV
DD
- 0.3V) to (CPV
DD
+ 0.3V)
CPV
DD
to GND ..........................................(PV
DD
- 0.3V) to +40V
All Other Pins to GND.............................................-0.3V to +12V
Continuous Input Current (except PV
DD
, V
DD
, OUTR+,
OUTR-, OUTL+, and OUTL-) ..........................................20mA
Continuous Power Dissipation (T
A
= +70°C)
56-Pin Thin QFN (derate 47.6mW/°C above +70°C) .....3.81W
64-Pin TQFP (derate 43.5mW/°C above +70°C)............3.48W
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature ......................................................+150°C
Thermal Resistance (θ
JC
)
56-Pin Thin QFN… ......................................................0.6°C/W
64-Pin TQFP…................................................................2°C/W
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
(PV
DD
= V
DD
= +20V, PGND = GND = 0V, C
SS
= 0.47µF, C
REG
= 0.01µF, C1 = 0.1µF, C2 = 1µF, R
LOAD
=
∞,
MONO = low (stereo
mode),
SHDN
=
MUTE
= high, G1 = low, G2 = high (A
V
= 22dB), FS1 = FS2 = high (SSM), SYNCIN = low. All load resistors (R
L
) are
connected between OUT_+ and OUT_-, unless otherwise stated. T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Supply Voltage Range
Shutdown Current
Shutdown to Full Operation
Mute to Full Operation
SYMBOL
V
DD
I
SHDN
t
SON
t
MUTE
G1 = 0, G2 = 1
Input Impedance
R
IN
G1 = 1, G2 = 1
G1 = 1, G2 = 0
G1 = 0, G2 = 0
Output Pulldown Resistance
Output Offset Voltage
V
OS
SHDN
= GND
AC-coupled input, measured between
OUT_+ and OUT_-
PV
DD
= 10V to 22V
Power-Supply Rejection Ratio
PSRR
200mV
P-P
ripple
(Note 2)
DC, input referred
f = 20Hz to 20kHz, input referred
One power switch
FS1
0
Switching Frequency
f
SW
1
1
0
Oscillator Spread Bandwidth
SYNCIN Lock Range
Equal to f
SW
x 4
FS2
0
1 (SSM)
0
1
600
180
200
200
160
250
±2
1200
%
kHz
220
kHz
f
RIPPLE
= 1kHz
f
RIPPLE
= 20kHz
49
67
50
40
25
12
SHDN
= low
CONDITIONS
Inferred from PSRR test
MIN
10
0.1
100
100
85
63
43
21
600
3
90
90
52
70
60
0.3
0.6
dB
Ω
dB
±40
125
90
60
30
kΩ
mV
kΩ
TYP
MAX
22
1
UNITS
V
µA
ms
ms
Common-Mode Rejection Ratio
Switch On-Resistance
CMRR
R
DS
FS1 = FS2 = high (SSM)
2
_______________________________________________________________________________________
25W/50W, Filterless, Spread-Spectrum,
Stereo/Mono, Class D Amplifier
ELECTRICAL CHARACTERISTICS (continued)
(PV
DD
= V
DD
= +20V, PGND = GND = 0V, C
SS
= 0.47µF, C
REG
= 0.01µF, C1 = 0.1µF, C2 = 1µF, R
LOAD
=
∞,
MONO = low (stereo
mode),
SHDN
=
MUTE
= high, G1 = low, G2 = high (A
V
= 22dB), FS1 = FS2 = high (SSM), SYNCIN = low. All load resistors (R
L
) are
connected between OUT_+ and OUT_-, unless otherwise stated. T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
SYMBOL
G1 = 0, G2 = 1
Gain
A
V
G1 = 1, G2 = 1
G1 = 1, G2 = 0
G1 = 0, G2 = 0
TH2
0
0
0
TEMP
Flag Threshold
T
FLAG
0
1
1
1
1
TEMP
Flag Accuracy
TEMP
Flag Hysteresis
STEREO MODE (R
LOAD
= 8Ω, Note 3)
Quiescent Current
MUTE
= 1, R
LOAD
=
∞
MUTE
= 0
P
VDD
= 20V
Output Power
P
OUT
f = 1kHz, THD =
10%, T
A
= +25°C
P
VDD
= 22V
P
VDD
= 12V,
R
LOAD
= 4Ω
25
29
15
0.1
91
96
87
0.2
%
dB
%
%
W
20
6.5
33
13
mA
TH1
0
0
1
1
0
0
1
1
TH0
0
1
0
1
0
1
0
1
±6
2
°C
°C
80
90
100
110
120
129
139
°C
CONDITIONS
MIN
21.6
24.9
29.2
35.9
TYP
22.0
25.0
29.5
36.0
MAX
22.3
25.6
29.9
36.6
dB
UNITS
MAX9709
From +80°C to +140°C
Total Harmonic Distortion Plus
Noise
Signal-to-Noise Ratio
Efficiency
Left-Right Channel Gain
Matching
THD+N
SNR
η
f = 1kHz, BW = 22Hz to 22kHz,
P
OUT
= 12W
P
OUT
= 10W
P
OUT
= 25W + 25W, f = 1kHz
R
LOAD
=
∞
22Hz to 22kHz
A-weighted
_______________________________________________________________________________________
3
25W/50W, Filterless, Spread-Spectrum,
Stereo/Mono, Class D Amplifier
MAX9709
ELECTRICAL CHARACTERISTICS (continued)
(PV
DD
= V
DD
= +20V, PGND = GND = 0V, C
SS
= 0.47µF, C
REG
= 0.01µF, C1 = 0.1µF, C2 = 1µF, R
LOAD
=
∞,
MONO = low (stereo
mode),
SHDN
=
MUTE
= high, G1 = low, G2 = high (A
V
= 22dB), FS1 = FS2 = high (SSM), SYNCIN = low. All load resistors (R
L
) are
connected between OUT_+ and OUT_-, unless otherwise stated. T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Output Short-Circuit Current
Threshold
Click-and-Pop Level
SYMBOL
I
SC
R
LOAD
= 0Ω
Peak voltage, 32
samples/second,
A-weighted (Notes 2, 5)
MUTE
= 1, R
LOAD
=
∞
MUTE
= 0
P
OUT
THD+N
SNR
η
I
SC
f = 1kHz,
THD = 10%
R
LOAD
= 8Ω
R
LOAD
= 4Ω
Into shutdown
Out of shutdown
CONDITIONS
MIN
TYP
3
-63
dBV
-55
MAX
UNITS
A
K
CP
MONO MODE (R
LOAD
= 4Ω, MONO = HIGH) (Note 6)
Quiescent Current
Output Power
Total Harmonic Distortion Plus
Noise
Signal-to-Noise Ratio
Efficiency
Output Short-Circuit Current
Threshold
Click-and-Pop Level
20
6.5
25
50
0.09
91
95
86
6
Into shutdown
Out of shutdown
-60
dBV
-63
1
2.5
0.8
I
SINK
= 3mA
V
PULLUP
= 5.5V
0.2
0.4
µA
V
V
V
µA
mA
W
%
dB
%
A
f = 1kHz, BW = 22Hz to 22kHz,
P
OUT
= 22W
P
OUT
= 10W
P
OUT
= 54W, f = 1kHz
R
LOAD
= 0Ω
Peak voltage, 32
samples/second,
A-weighted (Notes 2, 5)
20Hz to 20kHz
A-weighted
K
CP
DIGITAL INPUTS (SHDN,
MUTE,
G1, G2, FS1, FS2, TH0, TH1, TH2, SYNCIN, MONO)
Logic-Input Current
I
IN
0 to 12V
Logic-Input High Voltage
Logic-Input Low Voltage
Open-Drain Output Low Voltage
Leakage Current
V
IH
V
IL
V
OL
I
LEAK
OPEN-DRAIN OUTPUTS (TEMP, SYNCOUT)
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
All devices are 100% production tested at +25°C. All temperature limits are guaranteed by design.
Inputs AC-coupled to GND.
Testing performed with an 8Ω resistive load in series with a 68µH inductive load across the BTL outputs.
Minimum output power is guaranteed by pulse testing.
Testing performed with an 8Ω resistive load in series with a 68µH inductive load connected across BTL outputs. Mode tran-
sitions are controlled by
SHDN.
Note 6:
Testing performed with a 4Ω resistive load in series with a 33µH inductive load across the BTL outputs.
4
_______________________________________________________________________________________
25W/50W, Filterless, Spread-Spectrum,
Stereo/Mono, Class D Amplifier
Typical Operating Characteristics
(PV
DD
= V
DD
= +20V, PGND = GND = 0V, C
SS
= 0.47µF, C
REG
= 0.01µF, C1 = 0.1µF, C2 = 1µF, R
LOAD
= 8Ω,
SHDN
= high, MONO
= low,
MUTE
= high, G1 = low, G2 = high, FS1 = FS2 = high (SSM), SYNCIN = low. All load resistors (R
L
) are between OUT_+ and
OUT_-, T
A
= +25°C, unless otherwise stated.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (STEREO MODE)
MAX9709 toc01
MAX9709
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (STEREO MODE)
MAX9709 toc02
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (STEREO MODE)
P
OUT
= 12W
MAX9709 toc03
100
f
IN
= 1kHz
10
THD+N (%)
100
PV
DD
= 12V
R
LOAD
= 8Ω
1
10
THD+N (%)
THD+N (%)
25
1
1
R
LOAD
= 4Ω
0.1
0.1
0.1
0.01
0
5
10
15
20
25
30
35
OUTPUT POWER (W)
0.01
0
5
10
15
20
OUTPUT POWER (W)
0.01
10
100
1k
FREQUENCY (Hz)
10k
100k
EFFICIENCY vs. OUTPUT POWER
(STEREO MODE)
MAX9709 toc04
OUTPUT POWER vs. SUPPLY VOLTAGE
(STEREO MODE)
MAX9709 toc05
NO-LOAD SUPPLY CURRENT
vs. SUPPLY VOLTAGE (STEREO MODE)
MAX9709 toc06
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
0
5
10
15
20
25
35
30
OUTPUT POWER (W)
25
THD+N = 10%
20
15
10
5
0
THD+N = 1%
24
22
SUPPLY CURRENT (mA)
20
18
16
14
12
10
T
A
= -40°C
T
A
= +85°C
T
A
= +25°C
30
10
12
14
16
18
20
22
24
10
12
14
16
18
20
22
OUTPUT POWER (W)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SHUTDOWN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX9709 toc07
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (MONO MODE)
R
LOAD
= 4Ω
f
IN
= 1kHz
10
THD+N (%)
MAX9709 toc08
4.0
3.5
SUPPLY CURRENT (nA)
3.0
2.5
2.0
1.5
1.0
0.5
0
10
12
14
16
18
20
SHDN = 0
100
1
0.1
0.01
22
0
10
20
30
40
50
60
SUPPLY VOLTAGE (V)
OUTPUT POWER (W)
_______________________________________________________________________________________
5
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