19-3691; Rev 1; 10/05
KIT
ATION
EVALU
E
BL
AVAILA
3.2W, High-Efficiency, Low-EMI,
Filterless, Class D Audio Amplifier
General Description
Features
♦
3.2W into 4Ω Load (THD+N = 10%)
♦
Filterless Amplifier Passes FCC Radiated
Emissions Standards with 7.6cm of Cable
♦
92% Efficiency
♦
High PSRR (81dB at 1kHz)
♦
Low 0.02% THD+N
♦
External Clock Synchronization for Multiple,
Cascaded Maxim Class D Amplifiers
♦
3.0V to 5.5V Single-Supply Operation
♦
Pin-Selectable Gain (6dB, 12dB, 18dB, 24dB)
♦
Integrated Click-and-Pop Suppression
♦
Low Quiescent Current (8.4mA)
♦
Low-Power Shutdown Mode (10µA)
♦
Mute Function
♦
Short-Circuit and Thermal-Overload Protection
♦
Available in Thermally Efficient Package
16-Pin TQFN (4mm x 4mm x 0.8mm)
MAX9759
The MAX9759 mono Class D, audio power amplifier
provides Class AB amplifier audio performance with the
benefits of Class D efficiency, eliminating the need for a
heatsink and extending battery life. The MAX9759 deliv-
ers up to 3.2W of continuous power into a 4Ω load while
offering greater than 90% efficiency. Maxim’s next-gen-
eration, low-EMI modulation scheme allows the amplifi-
er to operate without an external LC filter while still
meeting FCC EMI-radiated emission levels.
The MAX9759 offers two modulation schemes: a fixed-
frequency modulation (FFM) mode and a spread-spec-
trum modulation (SSM) mode. The SSM mode flattens
the wideband spectral components, reducing EMI-radi-
ated emissions due to the modulation frequency.
Furthermore, the MAX9759 oscillator can be synchro-
nized to an external clock through the SYNC input,
allowing the switching frequency to range from
1000kHz to 1600kHz. The SYNC input and SYNC_OUT
output of the MAX9759 allow multiple Maxim Class D
amplifiers to be cascaded and frequency locked, mini-
mizing interference due to clock intermodulation. The
MAX9759 utilizes fully differential input amplifiers, a full-
bridged output, comprehensive click-and-pop suppres-
sion, and features four selectable gain settings (6dB,
12dB, 18dB, 24dB).
The MAX9759 features high 81dB PSRR, low 0.02%
THD+N, and SNR in excess of 90dB. Short-circuit and
thermal-overload protection prevents damage to the
device during a fault condition. The MAX9759 operates
from a single 5V supply, consumes 8.4mA of supply
current, and is available in a 16-pin thin QFN package
(4mm x 4mm x 0.8mm). The MAX9759 is fully specified
over the extended -40°C to +85°C temperature range.
Ordering Information
PART
MAX9759ETE+
TEMP RANGE
-40°C to +85°C
PIN-
PACKAGE
16 TQFN-EP*
PKG
CODE
T1644-4
+Denotes
lead-free package.
*EP
= Exposed paddle.
Simplified Block Diagram
Applications
Cell Phones/PDAs
Notebook PCs
Portable DVD Players
Flat-Panel PC Monitors
LCD TVs
LCD Projectors
SYNC
INPUT
SYNC
OUTPUT
OSCILLATOR
GAIN
CONTROL
SHDN
CONTROL
G1
G2
SHDN
MUTE
DIFFERENTIAL
AUDIO INPUT
MODULATOR
AND H-BRIDGE
MONO SPEAKER
OUTPUT
V
DD
MAX9759
MUTE
CONTROL
Pin Configurations appear at end of data sheet.
________________________________________________________________
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.
3.2W, High-Efficiency, Low-EMI,
Filterless, Class D Audio Amplifier
MAX9759
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND..............................................................................6V
PV
DD
to PGND .........................................................................6V
GND to PGND .......................................................-0.3V to +0.3V
All Other Pins to GND.................................-0.3V to (V
DD
+ 0.3V)
Continuous Current Into/Out of PV
DD
/PGND/OUT+/OUT-....1.7A
Duration of OUT+ or OUT- Short Circuit to
V
DD
/GND/PV
DD
/PGND............................................Continuous
Duration of Short Circuit Between OUT+ and OUT- ..Continuous
Continuous Power Dissipation (T
A
= +70°C)
16-Pin TQFN (derate 16.9mW/°C above +70°C) .....1349.1mW
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
ESD Protection (+IBM).........................................................±2kV
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
DD
= 5.0V)
(V
DD
= PV
DD
=
SHDN
=
MUTE
= 5V, GND = PGND = 0V, SYNC = 0V (FFM). Gain = 12dB (G1 = 0, G2 = 1). Speaker load resistor
(R
L
) connected between OUT+ and OUT-, unless otherwise noted, R
L
=
∞,
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical val-
ues are at T
A
= +25°C.) (Notes 1, 2)
PARAMETER
GENERAL
Supply Voltage Range
Quiescent Current
Mute Current
Shutdown Current
Shutdown to Full Operation
Mute to Full Operation
Common-Mode Rejection Ratio
Input DC Bias Voltage
V
DD
I
DD
I
MUTE
I
DD(SHDN)
t
SON
t
MUTE
CMRR
V
CM
Gain = +24dB
Input Resistance
R
IN
Gain = +18dB
Gain = +12dB
Gain = +6dB
G1 = 0, G2 = 0
Voltage Gain
A
V
G1 = 1, G2 = 0
G1 = 0, G2 = 1
G1 = 1, G2 = 1
Output Offset Voltage
V
OS
T
A
= +25°C
V
DD
= 4.5V to 5.5V
Power-Supply Rejection Ratio
(Note 3)
PSRR
f
RIPPLE
= 217Hz
200mV
P-P
ripple
f
RIPPLE
= 1kHz
f
RIPPLE
= 20kHz
62
f = 1kHz, input referred, V
IN
= 200mV
P-P
1.3
14
25
40
60
+22
+16
+10
+4
Inferred from PSRR test
No load
V
MUTE
= 0V
V
SHDN
= 0V
3.0
8.4
5.5
0.1
40
40
67
1.5
20
36
60
90
+24
+18
+12
+6
±10
90
79
81
70
dB
1.7
26
47
80
120
+26
+20
+14
+8
±50
mV
dB
kΩ
5.5
12
8
10
V
mA
mA
µA
ms
ms
dB
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
3.2W, High Efficiency, Low-EMI, Filterless,
Class D Audio Amplifier
ELECTRICAL CHARACTERISTICS (V
DD
= 5.0V) (continued)
(V
DD
= PV
DD
=
SHDN
=
MUTE
= 5V, GND = PGND = 0V, SYNC = 0V (FFM). Gain = 12dB (G1 = 0, G2 = 1). Speaker load resistor
(R
L
) connected between OUT+ and OUT-, unless otherwise noted, R
L
=
∞,
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical val-
ues are at T
A
= +25°C.) (Notes 1, 2)
PARAMETER
SYMBOL
THD+N = 1%
Output Power
P
OUT
THD+N = 10%
CONDITIONS
R
L
= 3Ω
R
L
= 4Ω
R
L
= 8Ω
R
L
= 3Ω
R
L
= 4Ω
R
L
= 8Ω
Total Harmonic Distortion Plus
Noise
THD+N
f
IN
= 1kHz, either
FFM or SSM,
P
OUT
= 1W
R
L
= 3Ω
R
L
= 4Ω
R
L
= 8Ω
FFM
SSM
FFM
SSM
1000
1102
MIN
TYP
3.4
2.6
1.4
4.3
3.2
1.8
0.08
0.05
0.02
93
89
96
92
1100
1500
1200
±70
1000
-50
dBV
Out of shutdown
-57
92
%
1600
kHz
1200
1837
kHz
dB
%
W
MAX
UNITS
MAX9759
Signal-to-Noise Ratio
SNR
P
OUT
= 1W,
R
L
= 8Ω
BW = 22Hz to
22kHz
A-weighted
SYNC = GND (FFM mode)
Oscillator Frequency
f
OSC
SYNC = FLOAT (FFM mode)
SYNC = V
DD
(SSM mode)
SYNC Frequency Lock Range
Click-and-Pop Level
K
CP
TTL-compatible clock input
Peak voltage,
A-weighted, 32 samples
per second (Notes 3, 4)
Into shutdown
Efficiency
η
P
OUT
= 1W, f
IN
= 1kHz, R
L
= 8Ω in series
with 68µH
V
DD
x 0.9
DIGITAL INPUTS (SHDN,
MUTE,
G1, G2, SYNC)
SYNC, G1, G2 Input Voltage High
SYNC, G1, G2 Input Voltage Low
SHDN, MUTE
Voltage High
SHDN, MUTE
Voltage Low
SYNC Input Resistance
SYNC Input Current
SHDN, MUTE,
G1, G2 Input
Current
SYNC Capacitance
DIGITAL OUTPUTS (SYNC_OUT)
Output Voltage High
Output Voltage Low
SYNC_OUT Capacitive Drive
V
OH
V
OL
I
OH
= 3mA
I
OL
= 3mA
TTL-compatible clock output
100
2.4
0.4
V
V
pF
V
INH
V
INL
V
INH
V
INL
200
±35
±1
10
2
0.8
V
V
DD
x 0.1
V
V
V
kΩ
µA
µA
pF
_______________________________________________________________________________________
3
3.2W, High-Efficiency, Low-EMI,
Filterless, Class D Audio Amplifier
MAX9759
ELECTRICAL CHARACTERISTICS (V
DD
= 3.3V)
(V
DD
= PV
DD
=
SHDN
=
MUTE
= 3.3V, GND = PGND = 0V, SYNC = GND (FFM). Gain = 12dB (G1 = 0, G2 = 1). Speaker load resis-
tor (R
L
) connected between OUT+ and OUT-, unless otherwise noted. R
L
=
∞,
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical
values are at T
A
= +25°C.) (Notes 1, 2)
PARAMETER
Quiescent Current
Mute Current
Shutdown Current
Common-Mode Rejection Ratio
SYMBOL
I
DD
I
MUTE
I
SHDN
CMRR
V
MUTE
= 0V
V
SHDN
= 0V
f = 1kHz, input referred
V
DD
= 3.0V to 5.5V
Power-Supply Rejection Ratio
PSRR
f
RIPPLE
= 217Hz
200mV
P-P
ripple
f
RIPPLE
= 1kHz
f
RIPPLE
= 20kHz
R
L
= 3Ω
THD+N = 1%
Output Power
P
OUT
THD+N = 10%
R
L
= 4Ω
R
L
= 8Ω
R
L
= 3Ω
R
L
= 4Ω
R
L
= 8Ω
Total Harmonic Distortion Plus
Noise
THD+N
f = 1kHz, either
FFM or SSM,
P
OUT
= 500mW
R
L
= 3Ω
R
L
= 4Ω
R
L
= 8Ω
BW = 22Hz
to 22kHz
A-weighted
FFM
SSM
FFM
SSM
50
CONDITIONS
MIN
TYP
6
5
0.1
67
72
79
81
70
1.5
1.1
0.65
1.8
1.3
0.78
0.06
0.04
0.02
93
89
96
92
dB
%
W
MAX
UNITS
mA
A
µA
dB
dB
dB
Signal-to-Noise Ratio
SNR
P
OUT
= 500mW,
R
L
= 8Ω
Note 1:
All devices are 100% production tested at +25°C. All temperature limits are guaranteed by design.
Note 2:
Testing performed with a resistive load in series with an inductor to simulate an actual speaker load. For R
L
= 4Ω, L = 33µH.
For R
L
= 8Ω, L = 68µH.
Note 3:
Inputs AC-coupled to GND.
Note 4:
Testing performed with 8Ω resistive load in series with a 68µH inductive load across BTL outputs. Mode transitions are con-
trolled by the
SHDN
pin.
4
_______________________________________________________________________________________
3.2W, High-Efficiency, Low-EMI,
Filterless, Class D Audio Amplifier
MAX9759
Typical Operating Characteristics
(V
DD
= PV
DD
=
SHDN
=
MUTE
= 5V, GND = PGND = 0V, SYNC = V
DD
(SSM), unless otherwise noted. Gain = 12dB (G1 = 0, G2 = 1).
THD+N measurement bandwidth: 22Hz to 22kHz. Typical values are at T
A
= +25°C.) (See
Typical Operating Circuit)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX9759 toc01
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX9759 toc02
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
V
DD
= 5V
R
L
= 4Ω
1
THD+N (%)
MAX9759 toc03
10
V
DD
= 5V
R
L
= 3Ω
1
THD+N (%)
10
V
DD
= 3.3V
R
L
= 3Ω
1
THD+N (%)
10
P
OUT
= 1W
0.1
P
OUT
= 500mW
0.1
P
OUT
= 1W
0.1
0.01
P
OUT
= 2.6W
0.01
P
OUT
= 1.3W
0.01
P
OUT
= 2.2W
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX9759 toc04
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX9759 toc05
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
V
DD
= 3.3V
R
L
= 8Ω
1
THD+N (%)
MAX9759 toc06
10
V
DD
= 3.3V
R
L
= 4Ω
1
THD+N (%)
P
OUT
= 500mW
0.1
10
V
DD
= 5V
R
L
= 8Ω
1
THD+N (%)
10
0.1
P
OUT
= 600mW
0.1
P
OUT
= 300mW
0.01
P
OUT
= 700mW
0.01
P
OUT
= 1.2W
0.01
P
OUT
= 500mW
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
FREQUENCY (Hz)
10k
100k
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
0.001
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX9759 toc07
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX9759 toc08
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
V
DD
= 3.3V
R
L
= 3Ω
MAX9759 toc09
10
V
DD
= 5V
R
L
= 8Ω
P
OUT
= 1.2W
1
THD+N (%)
100
V
DD
= 5V
R
L
= 3Ω
10
100
10
THD+N (%)
THD+N (%)
1
0.1
f
IN
= 200Hz, 1kHz
1
f
IN
= 200Hz, 1kHz
0.1
f
IN
= 10kHz
SSM
0.1
0.01
FFM
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
0.01
f
IN
= 10kHz
0.01
0.001
0
1
2
3
4
OUTPUT POWER (W)
0.001
0
0.5
1.0
OUTPUT POWER (W)
1.5
2.0
_______________________________________________________________________________________
5
