19-3608; Rev 1; 10/05
KIT
ATION
EVALU
BLE
AVAILA
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
General Description
The MAX9702 combines a highly efficient Class D
speaker amplifier with a high-linearity Class AB head-
phone amplifier. This ensures maximum battery life in
speaker mode and maximum performance in head-
phone mode. The MAX9702 delivers up to 1.1W per
channel into an 8Ω load and 1.8W into a 4Ω load from a
5V power supply. Maxim’s 2nd-generation, spread-
spectrum modulation scheme renders the traditional
Class D output filter unnecessary.
The MAX9702 speaker amplifier offers two modulation
schemes: a fixed-frequency (FFM) mode and a spread-
spectrum (SSM) mode that reduces EMI-radiated emis-
sions. The MAX9702 speaker amplifier features a fully
differential architecture, full-bridged (BTL) output, and
comprehensive click-and-pop suppression. The
MAX9702 speaker amplifier features high 75dB PSRR,
low 0.07% THD+N, and SNR in excess of 97dB. Short-
circuit and thermal-overload protection prevent the
device from being damaged during a fault condition.
The headphone amplifier uses Maxim’s DirectDrive
TM
architecture that produces a ground-referenced output
from a single supply, eliminating the need for large DC-
blocking capacitors, saving cost, board space, and
component height. A high 80dB PSRR and low 0.02%
THD+N ensures clean, low-distortion amplification of
the audio signal.
An I
2
C interface sets the speaker and headphone gain,
mono, stereo, and mute functions.
The MAX9702 is available in a 28-pin thin QFN-EP (5mm
x 5mm x 0.8mm) package. The MAX9702 is specified
over the extended -40°C to +85°C temperature range.
Features
♦
Spread-Spectrum Modulation Reduces EMI
Emissions
♦
Programmable Mono, Stereo, Mute, and Mix
Functions
♦
1.1W Stereo Output (8Ω, V
DD
= 5V)
♦
48mW Headphone Output (32Ω, V
DD
= 3.3V)
♦
1.8W Stereo Output (4Ω, V
DD
= 5V)
♦
94% Efficiency (R
L
= 8Ω, P
O
= 1.1W)
♦
High 73dB PSRR (f = 217Hz)
♦
I
2
C Programmable Gain Up to +21dB
♦
Integrated Click-and-Pop Suppression
♦
Low-Power Shutdown Mode (0.1µA)
♦
Short-Circuit and Thermal-Overload Protection
♦
±8kV (HBM) ESD-Protected Headphone Driver
Outputs
MAX9702
Ordering Information
PART
MAX9702ETI+
PIN–PACKAGE
28 TQFN-EP*
I
2
C SLAVE
ADDRESS
1001100
1001110
PKG
CODE
T2855-6
T2855-6
MAX9702BETI+ 28 TQFN-EP*
Note:
All devices specified for -40°C to +85°C operating tem-
perature range.
*EP
= Exposed paddle.
+
Denotes lead-free package.
Simplified Block Diagram
RIGHT MODULATOR
AND H-BRIDGE
Applications
Cellular Phones
INPUT MUX
Notebook PCs
PDAs
Handheld Gaming Consoles
INR
INM
INL
∑
GAIN
CONTROL
∑
LEFT MODULATOR
AND H-BRIDGE
SHDN
SDA
SCL
SYNC
I
2
C CONTROL
OSCILLATOR
Pin Configurations appear at end of data sheet.
SYNC_OUT
MAX9702
________________________________________________________________
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.
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
MAX9702
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND ...........................................................................+6V
PV
DD
to PGND .......................................................................+6V
CPV
DD
to CPGND..................................................................+6V
CPV
SS
to V
SS
......................................................................±0.3V
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)
HP_ 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_ ..............................................±600mA
Continuous Current In/Out of HP_ ..................................±120mA
Continuous Input Current CPV
SS
....................................+260mA
Continuous Input Current (all other pins) .........................±20mA
Duration of OUT_ Short Circuit to GND or PV
DD .........
Continuous
Duration of Short Circuit Between OUT__ ..................Continuous
Duration of HP_ Short Circuit to GND
or PV
DD
..................................................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
28-Pin Thin QFN (derate 21.3mW/°C above +70°C)....1702mW
Junction Temperature ......................................................+150°C
Operating Temperature Range ...........................-40
o
C to +85°C
Storage Temperature Range .............................-65
o
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
= 3.3V)
(V
DD
= PV
DD
= CPV
DD
=
SHDN
= 3.3V, GND = PGND = CPGND = 0V, SYNC = V
DD
(SSM), speaker gain = +12dB, headphone gain
= +1dB. Speaker load R
L
connected between OUT+ and OUT-, unless otherwise noted, R
L
=
∞.
Headphone load R
LH
connected
between HPR/HPL to GND. C
BIAS
= 1µF to GND, 1µF capacitor between C1P and C1N, C
VSS
= 1µF. T
A
= T
MIN
to T
MAX
, unless oth-
erwise noted. Typical values are at T
A
= +25°C.) (Notes 1, 2)
PARAMETER
GENERAL
Supply Voltage Range
Quiescent Current
Shutdown Current
Input Resistance
Debounced Delay
V
DD
I
DD
I
SHDN
R
IN
t
DEBOUNCE
Inferred from PSRR test
HPS = GND, speaker mode
HPS = V
DD
, headphone mode
Hard shutdown,
SHDN
= GND
Soft shutdown (see
I C
section)
Stereo left and right
Mono channel
Delay from HPS transition to
headphone/speaker turn-on
Time from
SHDN
transition to full
operation
HPS = GND (SP mode)
HPS = V
DD
(HP mode)
16.5
8.4
2
SYMBOL
CONDITIONS
MIN
2.5
TYP
MAX
5.5
UNITS
V
mA
mA
µA
kΩ
ms
10
7
0.1
22
24
12
65
85
15
11
10
30
31.5
15.6
Turn-On Time
Turn-Off Time
Input Bias Voltage
SPEAKER AMPLIFIERS (HPS = GND)
Output Offset Voltage
Power-Supply Rejection Ratio
(Note 3)
t
ON
t
OFF
V
BIAS
ms
85
0
1.125
1.25
±9
54
f
RIPPLE
= 217Hz
f
RIPPLE
= 20kHz
75
75
55
dB
1.375
±40
±50
ms
V
V
OS
T
A
= +25°C
T
MIN
to T
MAX
V
DD
= 2.5V to 5.5V
100mV
P-P
ripple,
V
IN
= 0V, T
A
= +25°C
mV
PSRR
2
_______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
ELECTRICAL CHARACTERISTICS (V
DD
= 3.3V) (continued)
(V
DD
= PV
DD
= CPV
DD
=
SHDN
= 3.3V, GND = PGND = CPGND = 0V, SYNC = V
DD
(SSM), speaker gain = +12dB, headphone gain
= +1dB. Speaker load R
L
connected between OUT+ and OUT-, unless otherwise noted, R
L
=
∞.
Headphone load R
LH
connected
between HPR/HPL to GND. C
BIAS
= 1µF to GND, 1µF capacitor between C1P and C1N, C
VSS
= 1µF. T
A
= T
MIN
to T
MAX
, unless oth-
erwise noted. Typical values are at T
A
= +25°C.) (Notes 1, 2)
PARAMETER
Output Power
Total Harmonic Distortion Plus
Noise
SYMBOL
P
OUT
THD+N
CONDITIONS
THD+N = 1%, T
A
= +25°C,
f = 1kHz, V
DD
= 3.3V
R
L
= 8Ω
R
L
= 4Ω
MIN
TYP
470
700
0.07
0.13
86.5
87.5
91.5
91.5
1000
1250
1100
1340
1150
±50
1000
100
Peak voltage, 32
samples/second,
A-weighted (Note 3)
Into shutdown
Out of shutdown
56
48
94
0
+3
+6
+9
+12
+15
+18
+21
±0.2
L to R, R to L, f = 10kHz, R
L
= 8Ω,
P
OUT
= 300mW
65
%
dB
dB
dB
2000
kHz
pF
1200
1450
kHz
dB
MAX
UNITS
mW
%
MAX9702
R
L
= 8Ω (P
OUT
= 400mW), f = 1kHz
R
L
= 4Ω (P
OUT
= 600mW), f = 1kHz
V
OUT
=
2V
RMS
,
R
L
= 8Ω
BW = 22Hz
to 22kHz
A-weighted
FFM
SSM
FFM
SSM
Signal-to-Noise Ratio
SNR
SYNC = GND
Oscillator Frequency
f
S
SYNC = float
SYNC = V
DD
SYNC Frequency Lock Range
SYNC_OUT Capacitance Drive
Click-and-Pop Level
f
SYNC
C
SYNC_OUT
K
CP
Efficiency
η
P
OUT
= 2 x 500mW, f
IN
= 1kHz, R
L
= 8Ω,
L = 68µH
B2 = 0
B2 = 0
B2 = 0
B2 = 0
B2 = 1
B2 = 1
B2 = 1
B2 = 1
B1 = 0
B1 = 0
B1 = 1
B1 = 1
B1 = 0
B1 = 0
B1 = 1
B1 = 1
B0 = 0
B0 = 1
B0 = 0
B0 = 1
B0 = 0
B0 = 1
B0 = 0
B0 = 1
%
Gain (see
I
2
C
Section)
A
V
Channel-to-Channel Gain
Tracking
Crosstalk
_______________________________________________________________________________________
3
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
MAX9702
ELECTRICAL CHARACTERISTICS (V
DD
= 3.3V) (continued)
(V
DD
= PV
DD
= CPV
DD
=
SHDN
= 3.3V, GND = PGND = CPGND = 0V, SYNC = V
DD
(SSM), speaker gain = +12dB, headphone gain
= +1dB. Speaker load R
L
connected between OUT+ and OUT-, unless otherwise noted, R
L
=
∞.
Headphone load R
LH
connected
between HPR/HPL to GND. C
BIAS
= 1µF to GND, 1µF capacitor between C1P and C1N, C
VSS
= 1µF. T
A
= T
MIN
to T
MAX
, unless oth-
erwise noted. Typical values are at T
A
= +25°C.) (Notes 1, 2)
PARAMETER
SYMBOL
T
A
= +25°C
T
MIN
to T
MAX
V
DD
= 2.5V to 5.5V
PSRR
100mV
P-P
ripple,
V
IN
= 0V, T
A
= +25°C
THD+N = 1%, V
DD
=
3.3V, T
A
= +25°C
f
RIPPLE
= 217Hz
f
RIPPLE
= 20kHz
R
L
= 32Ω
R
L
= 16Ω
66
75
73
53
48
47
0.03
0.015
95.5
97.9
f
OSC
/2
Peak voltage, 32
samples/second,
A-weighted (Note 3)
±1V output step
B4 = 0
Gain (see
I
2
C
Section)
A
V
B4 = 0
B4 = 1
B4 = 1
Channel-to-Channel Gain
Tracking
Capacitance Drive
Crosstalk
HP_ Resistance to GND
Input Voltage High,
SHDN,
SYNC, HPS
Input Voltage High, SCL
Input Voltage Low,
SHDN,
SYNC,
HPS
C
L
No sustained oscillations
L to R, R to L, f = 10kHz, R
L
= 16Ω,
P
OUT
= 10mW
In speaker mode
B3 = 0
B3 = 1
B3 = 0
B3 = 1
Into shutdown
Out of shutdown
65
85
0.3
-2
+1
+4
+7
±0.2
300
70
1
%
pF
dB
kΩ
dB
dB
V/µs
mW
%
dB
kHz
dB
CONDITIONS
MIN
TYP
±1.8
MAX
±6
±8
UNITS
HEADPHONE AMPLIFIERS (HPS = V
DD
)
Output Offset Voltage
Power-Supply Rejection Ratio
(Note 4)
Output Power
Total Harmonic Distortion Plus
Noise
Signal-to-Noise Ratio
Charge-Pump Frequency
Click-and-Pop Level
Slew Rate
V
OS
mV
P
OUT
THD+N
SNR
f
CP
K
CP
SR
R
L
= 16Ω (P
OUT
= 40mW, f = 1kHz)
R
L
= 32Ω (P
OUT
= 32mW, f = 1kHz)
V
OUT
= 1V
RMS
,
R
L
= 32Ω
BW = 22Hz to 22kHz
A-weighted
DIGITAL INPUTS (SHDN, SYNC, SDA, SCL, HPS)
V
INH
V
INH
V
INL
2
0.7 x
V
DD
0.8
V
V
V
4
_______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
ELECTRICAL CHARACTERISTICS (V
DD
= 3.3V) (continued)
(V
DD
= PV
DD
= CPV
DD
=
SHDN
= 3.3V, GND = PGND = CPGND = 0V, SYNC = V
DD
(SSM), speaker gain = +12dB, headphone gain
= +1dB. Speaker load R
L
connected between OUT+ and OUT-, unless otherwise noted, R
L
=
∞.
Headphone load R
LH
connected
between HPR/HPL to GND. C
BIAS
= 1µF to GND, 1µF capacitor between C1P and C1N, C
VSS
= 1µF. T
A
= T
MIN
to T
MAX
, unless oth-
erwise noted. Typical values are at T
A
= +25°C.) (Notes 1, 2)
PARAMETER
Input Voltage Low, SDA, SCL
Input Hysteresis, SDA, SCL
Input Capacitance SDA, SCL
Input Leakage Current,
SHDN,
SCL
Input Leakage Current, HPS
SYNC Input Current
HPS Pullup Resistance
DIGITAL OUTPUTS (SYNC_OUT)
Output Voltage High
Output Voltage Low
Output Fall Time, SDA
V
OH
V
OL
t
F
I
OH
= 3mA
I
OL
= 3mA
2.4
0.4
300
V
V
ns
SYMBOL
V
INL
V
HYS
C
IN
I
IN
I
IN
In play mode
±10
25
600
0.05 x
V
DD
10
±1
CONDITIONS
MIN
TYP
MAX
0.3 x
V
DD
UNITS
V
V
pF
µA
µA
µA
kΩ
MAX9702
ELECTRICAL CHARACTERISTICS (V
DD
= 5V)
(V
DD
= PV
DD
= CPV
DD
=
SHDN
= 5V, GND = PGND = CPGND = 0V, SYNC = V
DD
(SSM), speaker gain = +12dB, headphone gain =
+1dB. Speaker load R
L
connected between OUT+ and OUT-, unless otherwise noted, R
L
=
∞.
Headphone load R
LH
connected
between HPR/HPL to GND. C
BIAS
= 1µF to GND, 1µF capacitor between C1P and C1N, C
VSS
= 1µF. T
A
= T
MIN
to T
MAX
, unless oth-
erwise noted. Typical values are at T
A
= +25°C.) (Notes 1, 2)
PARAMETER
GENERAL
Quiescent Current
Shutdown Current
I
DD
I
SHDN
HPS = GND, speaker mode
HPS = V
DD
, headphone mode
Hard shutdown,
SHDN
= GND
Soft shutdown (see
I C section)
2
SYMBOL
CONDITIONS
MIN
TYP
14
8
0.2
25
MAX
UNITS
mA
µA
SPEAKER AMPLIFIERS (HPS = GND)
Power-Supply Rejection Ratio
(Note 3)
PSRR
100mV
P-P
ripple,
V
IN
= 0V,
T
A
= +25°C
THD+N = 1%,
T
A
= +25°C,
f = 1kHz
f
RIPPLE
= 217Hz
f
RIPPLE
= 20kHz
R
L
= 8Ω
V
DD
= 5V
R
L
= 4Ω
1800
73
dB
50
1100
mW
Output Power
P
OUT
_______________________________________________________________________________________
5
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