19-0746; Rev 4; 8/08
2 x 1.5W, Stereo Class D Audio Subsystem
with DirectDrive Headphone Amplifier
General Description
The MAX9775/MAX9776 combine a high-efficiency
Class D, stereo/mono audio power amplifier with a
mono DirectDrive
®
receiver amplifier and a stereo
DirectDrive headphone amplifier.
Maxim’s 3rd-generation, ultra-low-EMI, Class D audio
power amplifiers provide Class AB performance with
Class D efficiency. The MAX9775/MAX9776 deliver
1.5W per channel into a 4Ω load from a 5V supply and
offer efficiencies up to 79%. Active emissions limiting
circuitry and spread-spectrum modulation greatly
reduce EMI, eliminating the need for output filtering
found in traditional Class D devices.
The MAX9775/MAX9776 utilize a fully differential archi-
tecture, a full-bridged output, and comprehensive click-
and-pop suppression. A 3D stereo enhancement
function allows the MAX9775 to widen the stereo sound
field immersing the listener in a cleaner, richer sound
experience than typically found in portable applications.
The devices utilize a flexible, user-defined mixer archi-
tecture that includes an input mixer, volume control, and
output mixer. All control is done through I
2
C.
The mono receiver amplifier and stereo headphone
amplifier use Maxim’s DirectDrive architecture that pro-
duces a ground-referenced output from a single supply,
eliminating the need for large DC-blocking capacitors,
saving cost, space, and component height.
The MAX9775 is available in a 36-bump WLP (3mm x
3mm) package. The MAX9776 is available in a 32-pin
TQFN (5mm x 5mm) or a 36-bump WLP (3mm x 3mm)
package. Both devices are specified over the extended
-40°C to +85°C temperature range.
Features
♦
Unique Spread-Spectrum Modulation and Active
Emissions Limiting Significantly Reduces EMI
♦
3D Stereo Enhancement (MAX9775 Only)
♦
Up to 3 Stereo Inputs
♦
1.5W Stereo Speaker Output (4Ω, V
DD
= 5V)
♦
50mW Mono Receiver/Stereo Headphone Outputs
(32Ω, V
DD
= 3.3V)
♦
High PSRR (68dB at 217Hz)
♦
79% Efficiency (V
DD
= 3.3V, R
L
= 8Ω, P
OUT
=
470mW)
♦
I
2
C Control—Input Configuration, Volume Control,
Output Mode
♦
Click-and-Pop Suppression
♦
Low Total Harmonic Distortion (0.03% at 1kHz)
♦
Current-Limit and Thermal Protection
♦
Available in Space-Saving, 36-Bump WLP (3mm x
3mm) and 32-Pin TQFN (5mm x 5mm) Packages
MAX9775/MAX9776
Ordering Information
PART
MAX9775EBX+T
MAX9776ETJ+
PIN-PACKAGE
36 WLP*
32 TQFN-EP**
CLASS D
AMPLIFIER
Stereo
Mono
Applications
Cell Phones
Portable Multimedia Players
Handheld Gaming Consoles
MAX9776EBX+T
36 WLP*
Mono
Note:
All devices are specified over the -40°C to +85°C oper-
ating temperature range.
+Denotes
a lead-free/RoHS-compliant package.
*Four
center bumps depopulated.
**EP
= Exposed pad.
Pin Configurations appear at end of data sheet.
DirectDrive is a registered trademark of Maxim Integrated
Products, Inc.
Simplified Block Diagrams
SINGLE SUPPLY 2.7V TO 5.5V
SINGLE SUPPLY 2.7V TO 5.5V
GAIN
CONTROL
3D
SOUND
CONTROL
MIXER/
MUX
GAIN
CONTROL
MIXER/
MUX
I
2
C
INTERFACE
I
2
C
INTERFACE
MAX9775
MAX9776
________________________________________________________________
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.
2 x 1.5W, Stereo Class D Audio Subsystem
with DirectDrive Headphone Amplifier
MAX9775/MAX9776
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND..............................................................................6V
PV
DD
to PGND .........................................................................6V
CPV
DD
to CPGND ....................................................................6V
CPV
SS
to CPGND .....................................................-6V to +0.3V
V
SS
to CPGND..........................................................-6V to +0.3V
C1N .......................................(CPV
SS
- 0.3V) to (CPGND + 0.3V)
C1P.......................................(CPGND - 0.3V) to (CPV
DD
+ 0.3V)
HPL, HPR to GND...................(CPV
SS
- 0.3V) to (CPV
DD
+ 0.3V)
GND to PGND and CPGND................................................±0.3V
V
DD
to PV
DD
and CPV
DD
....................................................±0.3V
SDA, SCL to GND.....................................................-0.3V to +6V
All other pins to GND..................................-0.3V to (V
DD
+ 0.3V)
Continuous Current In/Out of PV
DD
, PGND, CPV
DD
, CPGND,
OUT__, HPR, and HPL..................................................±800mA
Continuous Input Current CPV
SS
......................................260mA
Continuous Input Current (all other pins) .........................±20mA
Duration of Short Circuit Between
OUT_+ and OUT_- ..................................................Continuous
Duration of HP_, OUT_ Short Circuit to
GND or PV
DD
..........................................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
36-Bump (3mm x 3mm) UCSP Multilayer Board
(derate 17.0mW/°C above +70°C) ...........................1360.5mW
32-Pin (5mm x 5mm) TQFN Single-Layer Board
(derate 21.3mW/°C above +70°C) ...........................1702.1mW
32-Pin TQFN Multilayer Board (derate 34.5mW/°C
above +70°C)...........................................................2758.6mW
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
DD
= PV
DD
= CPV
DD
= 3.3V, V
GND
= V
PGND
= V
CPGND
= 0V,
SHDN
= V
DD
, I
2
C settings (INA gain = +20dB, INB gain = INC gain =
0dB, volume setting = 0dB, mono path gain = 0dB,
SHDN
= 1, SSM = 1). Speaker load resistors (R
LSP
) are terminated between
OUT_+ and OUT_-, headphone load resistors are terminated to GND, unless otherwise noted. C1 = C2 = C3 = 1µF. T
A
= T
MIN
to
T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
GENERAL
Supply Voltage Range
V
DD
, P
VDD
,
Inferred from PSRR test
C
PVDD
Output mode 1, 6, 11 (Rx mode)
Quiescent Current (Mono)
I
DD
Output mode 4, 9, 14 (HP mode)
Output mode 2, 7, 12 (SP mode)
Output mode 3, 8, 13 (SP and HP mode)
Output mode 1, 6, 11 (Rx mode)
Quiescent Current (Stereo)
I
DD
Output mode 4, 9, 14 (HP mode)
Output mode 2, 7, 12 (SP mode)
Output mode 3, 8, 13 (SP and HP mode)
Mute Current
Shutdown Current
I
MUTE
I
SHDN
Current in mute (low power)
Hard shutdown
Soft shutdown
SHDN
= GND
See the
I
2
C Interface
section
2.7
6.3
8
9.5
12.9
7
9
16.5
20
4.7
0.1
8.5
30
17.5
3.5
45
1.12
28
5.5
50
1.25
41.0
8.0
60
1.38
10
10
15
µA
mA
mA
5.5
10
12.6
15
18
mA
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Turn-On Time
t
ON
Time from shutdown or power-on to full
operation
B and C pair inputs, T
A
= +25°C,
VOL = max
A pair inputs, T
A
= +25°C, +20dB
T
A
= +25°C, f
IN
= 1kHz (Note 2)
IN_ inputs
ms
kΩ
kΩ
dB
V
Input Resistance
Common-Mode Rejection Ratio
Input DC Bias Voltage
R
IN
CMRR
V
BIAS
2
_______________________________________________________________________________________
2 x 1.5W, Stereo Class D Audio Subsystem
with DirectDrive Headphone Amplifier
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
= CPV
DD
= 3.3V, V
GND
= V
PGND
= V
CPGND
= 0V,
SHDN
= V
DD
, I
2
C settings (INA gain = +20dB, INB gain = INC gain =
0dB, volume setting = 0dB, mono path gain = 0dB,
SHDN
= 1, SSM = 1). Speaker load resistors (R
LSP
) are terminated between
OUT_+ and OUT_-, headphone load resistors are terminated to GND, unless otherwise noted. C1 = C2 = C3 = 1µF. T
A
= T
MIN
to
T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
SPEAKER AMPLIFIERS
Output Offset Voltage
V
OS
T
A
= +25°C
T
MIN
≤
T
A
≤
T
MAX
Peak voltage,
T
A
= +25°C,
A-weighted, 32
samples per second
(Notes 2, 3)
Into shutdown
Out of shutdown
Into mute
Out of mute
V
DD
= 2.7V to 5.5V
f = 217Hz,
100mV
P-P
ripple
Power-Supply Rejection Ratio
(Note 3)
PSRR
T
A
= +25°C
f = 1kHz,
100mV
P-P
ripple
f = 20kHz,
100mV
P-P
ripple
Output Power (Note 4)
Current Limit
Total Harmonic Distortion Plus
Noise (Note 4)
R
L
= 8Ω,
P
OUT
= 125mW
R
L
= 4Ω,
P
OUT
= 250mW
BW = 20Hz to 20kHz
A-weighted
P
OUT
THD+N = 1%,
T
A
= +25°C
R
L
= 4Ω, V
DD
= 5V
R
L
= 8Ω, V
DD
= 3.3V
R
L
= 8Ω, V
DD
= 5V
48
-62
-60
-63
-62
70
68
60
50
1500
450
1115
1.6
0.03
%
0.04
81
dB
84
1100
1100 ±30
79
12
T
A
= +25°C
R
3D
Used with 22nF and 2.2nF external
capacitors
L to R, R to L, f = 10kHz, R
L
= 8Ω,
V
OUT
= 300mV
RMS
5
±1
7
73
9
kHz
%
dB
%
kΩ
dB
A
mW
dB
dB
±5.5
±23.5
±40
mV
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX9775/MAX9776
Click-and-Pop Level
K
CP
THD+N
f = 1kHz
Signal-to-Noise Ratio
SNR
V
OUT
= 1.8V
RMS
,
R
L
= 8Ω, 3D not
active (Note 3)
Output Frequency
Efficiency
Gain
Channel-to-Channel Gain
Tracking (Note 5)
3D Sound Resistors (Note 5)
Crosstalk (Notes 4, 5)
f
OSC
η
A
V
Fixed-frequency modulation
Spread-spectrum modulation
P
OUT
= 470mW, f = 1kHz both channels
driven, L = 68µH in series with 8Ω load
_______________________________________________________________________________________
3
2 x 1.5W, Stereo Class D Audio Subsystem
with DirectDrive Headphone Amplifier
MAX9775/MAX9776
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
= CPV
DD
= 3.3V, V
GND
= V
PGND
= V
CPGND
= 0V,
SHDN
= V
DD
, I
2
C settings (INA gain = +20dB, INB gain = INC gain =
0dB, volume setting = 0dB, mono path gain = 0dB,
SHDN
= 1, SSM = 1). Speaker load resistors (R
LSP
) are terminated between
OUT_+ and OUT_-, headphone load resistors are terminated to GND, unless otherwise noted. C1 = C2 = C3 = 1µF. T
A
= T
MIN
to
T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
RECEIVER AMPLIFIER
Output Offset Voltage
V
OS
T
A
= +25°C
Peak voltage, T
A
=
+25°C, A-weighted,
32 samples per
second (Notes 3, 6)
Into shutdown
Into mute
Out of shutdown
Out of mute
V
DD
= 2.7V to 5.5V
f = 217Hz,
100mV
P-P
ripple
Power-Supply Rejection Ratio
(Note 3)
PSRR
T
A
= +25°C
f = 1kHz,
100mV
P-P
ripple
f = 20kHz,
100mV
P-P
ripple
Output Power
Gain
Total Harmonic Distortion Plus
Noise
Signal-to-Noise Ratio
Slew Rate
Capacitive Drive
HEADPHONE AMPLIFIERS
Output Offset Voltage
V
OS
T
A
= +25°C
Peak voltage, T
A
=
+25°C, A-weighted,
32 samples per
second (Notes 2, 4)
HP_
Into shutdown
Into mute
Out of shutdown
Out of mute
Contact
Air
V
DD
= 2.7V to 5.5V
f = 217Hz,
100mV
P-P
ripple
Power-Supply Rejection Ratio
(Note 3)
PSRR
T
A
= +25°C
f = 1kHz,
100mV
P-P
ripple
f = 20kHz,
100mV
P-P
ripple
58
±1.8
-61
-65
-60
-64
±4
±8
80
80
70
62
dB
kV
dB
±5.5
mV
P
OUT
A
V
THD+N
SNR
SR
C
L
R
L
= 16Ω (V
OUT
= 800mV
RMS
, f = 1kHz)
R
L
= 32Ω (V
OUT
= 800mV
RMS
, f = 1kHz)
R
L
= 16Ω, V
OUT
=
800mV
RMS
(Note 3)
BW = 20Hz to 20kHz
A-weighted
T
A
= +25°C,
THD+N = 1%
R
L
= 16Ω
R
L
= 32Ω
58
±1.8
-62
-67
-63
-66
80
80
70
62
60
50
3
0.03
0.024
87
89
0.3
300
mW
dB
%
dB
V/µs
pF
dB
dB
±5.5
mV
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Click-and-Pop Level
K
CP
Click-and-Pop Level
K
CP
ESD Protection
4
_______________________________________________________________________________________
2 x 1.5W, Stereo Class D Audio Subsystem
with DirectDrive Headphone Amplifier
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
= CPV
DD
= 3.3V, V
GND
= V
PGND
= V
CPGND
= 0V,
SHDN
= V
DD
, I
2
C settings (INA gain = +20dB, INB gain = INC gain =
0dB, volume setting = 0dB, mono path gain = 0dB,
SHDN
= 1, SSM = 1). Speaker load resistors (R
LSP
) are terminated between
OUT_+ and OUT_-, headphone load resistors are terminated to GND, unless otherwise noted. C1 = C2 = C3 = 1µF. T
A
= T
MIN
to
T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Output Power
Current Limit
Gain
Channel-to-Channel Gain
Tracking
Total Harmonic Distortion Plus
Noise
Signal-to-Noise Ratio
Slew Rate
Capacitive Drive
Crosstalk
VOLUME CONTROL
HP gain (max)
IN+6dB = 0
(minimum gain
setting)
Volume Control
IN+6dB = 1
(maximum gain
setting)
SP gain (max)
HP gain (min)
SP gain (min)
HP gain (max)
SP gain (max)
HP gain (min)
SP gain (min)
Mono+6dB = 0
Mono Gain
All outputs
Mono+6dB = 1
Input Pair A Control
Mute Attenuation
(Minimum Volume)
DIGITAL INPUTS (SHDN, SDA, SCL)
Input-Voltage High
Input-Voltage Low
Input Hysteresis (SDA, SCL)
V
IH
V
IL
V
HYS
200
1.4
0.4
V
V
mV
INA+20dB = 0 (minimum gain setting)
INA+20dB = 1 (maximum gain setting)
V
IN
= 1V
RMS
6
Set by IN+6dB
20
80
dB
dB
3
12
-72
-63
9
18
-61
-57
0
dB
dB
THD+N
A
V
T
A
= +25°C
R
L
= 16Ω (V
OUT
= 800mV
RMS
, f = 1kHz)
R
L
= 32Ω (V
OUT
= 800mV
RMS
, f = 1kHz)
R
L
= 16Ω,
V
OUT
= 800mV
RMS
BW = 20Hz to
20kHz
A-weighted
SYMBOL
P
OUT
T
A
= +25°C,
THD+N = 1%
CONDITIONS
R
L
= 16Ω
R
L
= 32Ω
MIN
TYP
60
50
170
+3
±1
0.03
0.024
92
93
0.3
300
L to R, R to L, f = 10kHz, R
L
= 16Ω,
V
OUT
= 160mV
RMS
75
V/µs
pF
dB
MAX
UNITS
mW
mA
dB
%
%
MAX9775/MAX9776
SNR
SR
C
L
dB
_______________________________________________________________________________________
5
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