19-0854; Rev 0; 9/07
10W Mono Class D Speaker
Amplifier with Volume Control
General Description
The MAX9768 mono 10W Class D speaker amplifier
provides high-quality, efficient audio power with an inte-
grated volume control function.
The MAX9768 features a 64-step dual-mode (analog or
digitally programmable) volume control and mute func-
tion. The audio amplifier operates from a 4.5V to 14V
single supply and can deliver up to 10W into an 8Ω
speaker with a 14V supply.
A selectable spread-spectrum mode reduces EMI-radiat-
ed emissions, allowing the device to pass EMC testing
with ferrite bead filters and cable lengths up to 1m. The
MAX9768 can be synchronized to an external clock,
allowing synchronization of multiple Class D amplifiers.
The MAX9768 features high 77dB PSRR, low 0.08%
THD+N, and SNR up to 97dB. Robust short-circuit and
thermal-overload protection prevent device damage
during a fault condition. The MAX9768 is available in a
24-pin thin QFN-EP (4mm x 4mm x 0.8mm) package
and is specified over the extended -40°C to +85°C tem-
perature range.
Features
♦
10W Output (8Ω, PV
DD
= 14V, THD+N = 10%)
♦
Patented Spread-Spectrum Modulation
♦
Meets EN55022B EMC with Ferrite Bead Filters
♦
Amplifier Operation from 4.5V to 14V Supply
♦
64-Step Integrated Volume Control (I
2
C or Analog)
♦
Low 0.08% THD+N (R
L
= 8Ω, P
OUT
= 6W)
♦
High 77dB PSRR
♦
Two t
ON
Times Offered
MAX9768—220ms
MAX9768B—15ms
♦
Low-Power Shutdown Mode (0.5µA)
♦
Short-Circuit and Thermal-Overload Protection
MAX9768
Ordering Information
PART
MAX9768ETG+
MAX9768BETG+
PIN-PACKAGE
24 TQFN-EP*
24 TQFN-EP*
t
ON
(ms)
220
15
PKG
CODE
T2444+4
T2444+4
Applications
Notebook Computers
Flat-Panel Displays
Multimedia Monitors
GPS Navigation
Systems
Security/Personal
Mobile Radio
Note:
All devices are specified over the -40°C to +85°C oper-
ating temperature range.
+Denotes
lead-free package.
*EP
= Exposed pad.
Pin Configuration located at end of data sheet.
Simplified Block Diagram
3.3V
4.5V TO 14V
MAX9768 EMI WITH FERRITE BEAD FILTERS
(V
DD
= 12V, 1m CABLE, 8Ω LOAD)
40
35
AMPLITUDE (dBµV/m)
30
25
20
15
10
5
OVER 20dB MARGIN
TO EN55022B LIMIT
SPEAKER
AUDIO
INPUT
FILTERLESS
CLASS D
SPEAKER
OUTPUT
SHDN
MUTE
ANALOG OR
I
2
C VOLUME
CONTROL
MAX9768
0
0 100 200 300 400 500 600 700 800 900 1000
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.
10W Mono Class D Speaker
Amplifier with Volume Control
MAX9768
ABSOLUTE MAXIMUM RATINGS
PV
DD
to PGND........................................................-0.3V to +16V
V
DD
to GND ..............................................................-0.3V to +4V
SCLK, SDA/VOL to GND ..........................................-0.3V to +4V
FB, SYNCOUT ............................................-0.3V to (V
DD
+ 0.3V)
BOOT_ to OUT_........................................................-0.3V to +4V
OUT_ to GND ...........................................-0.3V to (PV
DD
+ 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 Current (PV
DD
, PGND, OUT_) ..........................2.2A
Continuous Input Current (Any Other Pin) .......................±20mA
Continuous Input Current (FB_) .......................................±60mA
Continuous Power Dissipation (T
A
= +70°C)
Single-Layer Board:
24-Pin Thin QFN 4mm x 4mm,
(derate 20.8mW/°C above +70°C) .................................1.67W
Multilayer Board:
24-Pin Thin QFN 4mm x 4mm,
(derate 27.8mW/°C above +70°C) .................................2.22W
θ
JA
, Single-Layer Board…...........................................….48°C/W
θ
JA
, Multilayer Board ...................................................….36°C/W
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
(PV
DD
= 12V, V
DD
= 3.3V, GND = PGND = 0V, V
SHDN
= V
DD
, V
MUTE
= 0V; Max volume setting; speaker load resistor connected
between OUT+ and OUT-, R
L
=
∞,
unless otherwise noted. C
BIAS
= 2.2µF, C1 = C2 = 0.1µF, C
IN
= 0.47µF, R
IN
= 20kΩ, R
F
= 30kΩ,
SSM mode. Filterless modulation mode (see the
Functional Diagram/Typical Application Circuit).
T
A
= T
MIN
to T
MAX
, unless otherwise
noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
GENERAL
Speaker Supply Voltage
Range
Supply Voltage Range
Quiescent Current
Shutdown Current
Output Offset
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
Internal Gain
A
VMAX
Max volume setting; from FB to amplifier outputs
|(OUT+) - (OUT-)|; excludes external gain
resistors
29.27
30.1
31.00
dB
GBW
PV
DD
V
DD
I
VDD
I
PVDD
I
SHDN
V
OS
t
ON
V
BIAS
V
OH
V
OL
Specified as
V
DD
- V
OH
Specified as
V
OL
- GND
R
L
= 2kΩ connect to 1.5V
R
L
= 2kΩ connect to 1.5V
Filterless modulation
Classic PWM modulation
I
SHDN
= I
PVDD
+ I
DD
,
SHDN
= GND
Filterless modulation, V
MUTE
= V
DD
, T
A
= +25°C
Filterless modulation, V
MUTE
= 0V, T
A
= +25°C
MAX9768
MAX9768B
Inferred from PSRR test
Inferred from PSRR and UVLO test
4.5
2.7
7
4
4
0.5
±2
±2
220
15
1.5
3.6
6
±60
1.8
100
50
14.0
3.6
14.2
7.6
7.6
50
±12.5
±14
µA
mV
ms
V
mV
mV
mA
MHz
mA
V
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
10W Mono Class D Speaker
Amplifier with Volume Control
ELECTRICAL CHARACTERISTICS (continued)
(PV
DD
= 12V, V
DD
= 3.3V, GND = PGND = 0V, V
SHDN
= V
DD
, V
MUTE
= 0V; Max volume setting; speaker load resistor connected
between OUT+ and OUT-, R
L
=
∞,
unless otherwise noted. C
BIAS
= 2.2µF, C1 = C2 = 0.1µF, C
IN
= 0.47µF, R
IN
= 20kΩ, R
F
= 30kΩ,
SSM mode. Filterless modulation mode (see the
Functional Diagram/Typical Application Circuit).
T
A
= T
MIN
to T
MAX
, unless otherwise
noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Efficiency (Note 2)
SYMBOL
η
P
OUT
= 8W, f
IN
=
1kHz, R
L
= 8Ω
CONDITIONS
Filterless modulation
Classic PWM modulation
R
L
= 8Ω, THD+N = 1%,
filterless modulation
PV
DD
= 5V
R
L
= 8Ω, THD+N = 10%,
filterless modulation
R
L
= 8Ω, THD+N = 10%,
classic PWM modulation
Output Power (Note 2)
P
OUT
PV
DD
= 12V
R
L
= 8Ω, THD+N = 10%,
filterless modulation
R
L
= 8Ω, THD+N = 10%,
classic PWM modulation
PV
DD
= 14V
R
L
= 8Ω, THD+N = 10%,
filterless modulation
1.75
f = 1kHz, R
L
= 8Ω,
P
OUT
= 5W
0dB = 8W, R
L
=
8Ω, BW = 22Hz to
22kHz, filterless
modulation mode
SNR
0dB = 8W, R
L
=
8Ω, BW = 22Hz to
22kHz, classic
PWM modulation
0dB = 8W, f = 1kHz
V
DD
= 2.7V to 3.6V, filterless modulation,
T
A
= +25°C
Power-Supply Rejection
Ratio
PSRR
PV
DD
= 4.5V to 14V, filterless modulation,
T
A
= +25°C
f = 1kHz, V
RIPPLE
= 200mV
P-P
on PV
DD
f = 1kHz, V
RIPPLE
= 100mV
P-P
on V
DD
SYNC = GND
Oscillator Frequency
f
OCS
SYNC = unconnected
SYNC = V
DD
(spread-spectrum modulation
mode)
1060
1296
52
67
Unweighted
A-weighted
Filterless modulation
Classic PWM modulation
Unweighted
A-weighted
FFM
SSM
FFM
SSM
FFM
SSM
FFM
SSM
MIN
TYP
87
85
1.3
1.7
9
W
9
10
10
2
2.5
0.09
0.08
94
93
97
97
93
89
97
91
115
68
84
77
60
1200
1440
1200
±30
1320
1584
kHz
dB
dB
dB
A
A
%
MAX
UNITS
%
MAX9768
Soft Output Current Limit
Hard Output Current Limit
Total Harmonic Distortion
Plus Noise (Note 2)
I
LIM
I
SC
THD+N
Signal-to-Noise Ratio
(Note 2)
MUTE Attenuation (Note 3)
_______________________________________________________________________________________
3
10W Mono Class D Speaker
Amplifier with Volume Control
MAX9768
ELECTRICAL CHARACTERISTICS (continued)
(PV
DD
= 12V, V
DD
= 3.3V, GND = PGND = 0V, V
SHDN
= V
DD
, V
MUTE
= 0V; Max volume setting; speaker load resistor connected
between OUT+ and OUT-, R
L
=
∞,
unless otherwise noted. C
BIAS
= 2.2µF, C1 = C2 = 0.1µF, C
IN
= 0.47µF, R
IN
= 20kΩ, R
F
= 30kΩ,
SSM mode. Filterless modulation mode (see the
Functional Diagram/Typical Application Circuit).
T
A
= T
MIN
to T
MAX
, unless otherwise
noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Class D Switching
Frequency
SYMBOL
SYNC = GND
SYNC = unconnected
SYNC = V
DD
(spread-spectrum modulation
mode)
1000
40
60
Full volume (ideal matching for R
IN
and R
F
)
Peak voltage, 32 samples
per second, A-weighted, R
IN
x C
IN
≤
10ms to guarantee
clickless/popless operation
Into shutdown
Out of shutdown
Into mute
Out of mute
2
52.6
48
dBV
67
57
100
11
0.1 x V
DD
0.9 x V
DD
2.33
0.7 x V
DD
0.8
0.3 x V
DD
±7.5
All other digital inputs
Load = 1mA
Load = 1mA
C
L
= 10pF
5
V
DD
- 0.3
0.3
±13
±1
MΩ
mV
V
V
CONDITIONS
MIN
265
324
TYP
300
360
300
±7.5
1600
kHz
%
%
%
MAX
330
396
kHz
UNITS
SYNC Frequency Lock
Range
Minimum SYNC Frequency
Lock Duty Cycle
Maximum SYNC Frequency
Lock Duty Cycle
Gain Matching
Click-and-Pop Level (Note 2)
K
CP
Input Impedance
Input Hysteresis
9.5dB Gain Voltage
Full Mute Voltage
DC volume control mode (SDA/VOL)
DC volume control mode (SDA/VOL)
DC volume control mode (SDA/VOL)
DC volume control mode (SDA/VOL)
SYNC
All other pins
SYNC
All other pins
DIGITAL INPUTS (SHDN, MUTE, ADDR1, ADDR2, SYNC)
Input-Voltage High
Input-Voltage Low
Input Leakage Current
DIGITAL OUTPUT (SYNCOUT)
Output-Voltage High
Output-Voltage Low
Rise/Fall Time
V
V
ns
V
IH
V
IL
I
SYNC
I
LK
V
V
µA
4
_______________________________________________________________________________________
10W Mono Class D Speaker
Amplifier with Volume Control
ELECTRICAL CHARACTERISTICS (continued)
(PV
DD
= 12V, V
DD
= 3.3V, GND = PGND = 0V, V
SHDN
= V
DD
, V
MUTE
= 0V; Max volume setting; speaker load resistor connected
between OUT+ and OUT-, R
L
=
∞,
unless otherwise noted. C
BIAS
= 2.2µF, C1 = C2 = 0.1µF, C
IN
= 0.47µF, R
IN
= 20kΩ, R
F
= 30kΩ,
SSM mode. Filterless modulation mode (see the
Functional Diagram/Typical Application Circuit).
T
A
= T
MIN
to T
MAX
, unless otherwise
noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
THERMAL PROTECTION
Thermal Shutdown
Threshold
Thermal Shutdown
Hysteresis
DIGITAL INPUTS (SCLK, SDA/VOL)
Input-Voltage High
Input-Voltage Low
Input High Leakage Current
Input Low Leakage Current
Input Hysteresis
Input Capacitance
DIGITAL OUTPUTS (SDA/VOL)
Output High Current
Output Low Voltage
Serial Clock
Bus Free Time Between a
STOP and 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
I
OH
V
OH
= V
DD
1
0.4
400
1.3
µA
V
kHz
µs
V
OL
I
OL
= 3mA
2
C TIMING CHARACTERISTICS (Figure 3)
I
f
SCL
t
BUF
C
IN
V
IH
V
IL
I
IH
I
IL
V
IN
= V
DD
V
IN
= GND
0.1 x V
DD
5
0.7 x V
DD
0.3 x V
DD
±1
±1
V
V
µA
µA
V
pF
150
15
°C
°C
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX9768
t
HD,STA
t
SU,STA
t
SU,STO
t
HD,DAT
t
SU,DAT
t
LOW
t
HIGH
t
R
t
F
(Note 4)
(Note 4)
0.6
0.6
0.6
0
100
1.3
0.6
20 +
0.1Cb
20 +
0.1Cb
300
300
0.9
µs
µs
µs
µs
ns
µs
µs
ns
ns
_______________________________________________________________________________________
5
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