19-3782; Rev 1; 1/06
N KIT
EVALUATIO
E
AVAILABL
2.3W Stereo Speaker Amplifiers and DirectDrive
Headphone Amplifiers with Automatic Level Control
General Description
The MAX9756/MAX9757/MAX9758 combine dual, 2.3W,
bridge tied load (BTL) stereo audio power amplifiers and
a DirectDrive
TM
headphone amplifier in a single device.
These devices feature single-supply voltage operation,
shutdown mode, logic-selectable gain, a headphone
sense input, a 31-step analog volume control, and indus-
try-leading click-and-pop suppression. The headphone
amplifier uses Maxim’s DirectDrive architecture that pro-
duces a ground-referenced output from a single supply,
eliminating the need for large DC-blocking capacitors.
The MAX9756/MAX9757 feature automatic level control
(ALC) that automatically limits output power to the speak-
er in the event of an overpowered output.
The MAX9756/MAX9758s’ 150mA internal linear regula-
tor provides a complete solution for DAC- or CODEC-
based designs.
The MAX9756/MAX9757/MAX9758 are offered in space-
saving, thermally efficient 32-pin (5mm x 5mm x 0.8mm)
and 36-pin thin QFN (6mm x 6mm x 0.8mm) packages.
All devices are specified over the extended -40°C to
+85°C temperature range.
♦
Analog Volume Control
♦
120mW DirectDrive Headphone Amplifiers (16Ω)
♦
150mA Adjustable LDO
♦
Class AB, 2.3W, Stereo BTL Speaker Amplifiers
(3Ω)
♦
High 95dB PSRR
♦
Low-Power Shutdown Mode
♦
Industry-Leading Click-and-Pop Suppression
♦
Short-Circuit and Thermal Protection
♦
Beep Input
Features
♦
Automatic Level Control—Protects Speakers
MAX9756/MAX9757/MAX9758
Ordering Information
PART
MAX9756ETX+
MAX9757ETJ+
MAX9758ETJ+
ALC
√
√
—
LDO
√
—
√
PIN-PACKAGE
36 Thin QFN-EP*
32 Thin QFN-EP*
32 Thin QFN-EP*
Applications
Notebook PCs
Tablet PCs
Portable DVD
Players
Flat-Panel TVs
PC Displays
LCD Projectors
Portable Audio
Note:
All devices specified for -40°C to +85°C operating
temperature range.
+Denotes
lead-free package.
*EP
= Exposed paddle.
Simplified Block Diagrams
SINGLE SUPPLY 4.5V TO 5.5V
SINGLE SUPPLY 4.5V TO 5.5V
SINGLE SUPPLY 4.5V TO 5.5V
ALC
ALC
ALC
ALC
VOL
BEEP
HPS
LDO
1.2V TO 5V
VOL
BEEP
HPS
VOL
BEEP
HPS
LDO
1.2V TO 5V
MAX9756
MAX9757
MAX9758
________________________________________________________________
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.
2.3W Stereo Speaker Amplifiers and DirectDrive
Headphone Amplifiers with Automatic Level Control
MAX9756/MAX9757/MAX9758
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V
DD
, PV
DD
, HPV
DD
, CPV
DD
, IN to GND) ....+6V
PGND, CPGND to GND ......................................................±0.3V
CPV
SS
, C1N, V
SS
to GND......................................-6.0V to +0.3V
HP_ to GND ...........................................................................±3V
Any Other Pin .............................................-0.3V to (V
DD
+ 0.3V)
Duration of OUT_ Short Circuit to GND or PV
DD
........Continuous
Duration of OUT_+ Short Circuit to OUT_- .................Continuous
Duration of HP_ Short Circuit to GND,
V
SS
, or HPV
DD
.........................................................Continuous
Duration of OUT Short Circuit to GND........................Continuous
Continuous Current (PV
DD
, OUT_, PGND) ...........................1.7A
Continuous Current (CPV
DD
, C1N, CPGND, C1P, CPV
SS
,
V
SS
, HPV
DD
, HP_, IN, OUT) .............................................0.85A
Continuous Input Current (all other pins) .........................±20mA
Continuous Power Dissipation (T
A
= +70°C, single-layer board)
32-Pin Thin QFN (derate 18.6mW/°C above +70°C).....1490mW
36-Pin Thin QFN (derate 20.4mW/°C above +70°C).....1633mW
Continuous Power Dissipation (T
A
=+70°C, multilayer board)
32-Pin Thin QFN (derate 24.9mW/°C above +70°C).....1990mW
36-Pin Thin QFN (derate 27.7mW/°C above +70°C).....2180mW
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
= HPV
DD
= CPV
DD
= IN = +5.0V, GND = PGND = CPGND = 0,
SHDN
= V
DD
, REGEN = V
DD
, DR = SET = GND, C
BIAS
= 1µF, C
PVSS
= 1µF, C1 = C2 = 1µF, PREF = unconnected, speaker loads terminated between OUT_+ and OUT_-, headphone load
terminated between HP_ and GND, GAIN1 = GAIN2 = GAIN3 = VOL = 0 (A
V(SP)
= 15dB, A
V(HP)
= 0dB), T
A
= -40°C to +85°C, unless
otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
GENERAL
Supply Voltage Range
Headphone Supply Voltage
V
DD
, PV
DD
Inferred from PSRR test
HPV
DD
Inferred from PSRR test
I
DD
= I
VDD
+
I
HPVDD
+ I
CPVDD
HPS = GND, speaker
mode, R
L
=
∞
HPS = 5V, headphone
mode, R
L
=
∞
2.2
Gain or input switching
INL and INR
10
4.5
3.0
14
7
0.2
2.43
10
20
25
Measured between OUT_+ and OUT_-,
T
A
= +25°C
PV
DD
= 4.5V to 5.5V, T
A
= +25°C
PSRR
f = 1kHz, V
RIPPLE
= 200mV
P-P
f = 10kHz, V
RIPPLE
= 200mV
P-P
Output Power (Note 3)
Total Harmonic Distortion Plus
Noise
Signal-to-Noise Ratio
P
OUT
THD+N = 1%, f = 1kHz
(T
A
= +25°C)
R
L
= 8Ω
R
L
= 4Ω
R
L
= 3Ω
0.9
75
30
5.5
5.5
29
mA
13
5
2.65
µA
V
µs
kΩ
ms
V
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Quiescent Supply Current
I
DD
I
SHDN
V
BIAS
t
SW
R
IN
t
SON
Shutdown Supply Current
Bias Voltage
Switching Time
Input Resistance
Turn-On Time
SHDN
= REGEN = GND
SPEAKER AMPLIFIERS (HPS = GND)
Output Offset Voltage
Power-Supply Rejection Ratio
(Note 2)
V
OS
±0.4
95
83
68
1.3
2.0
2.3
0.009
0.015
92
95
%
W
dB
±15
mV
THD+N
R
L
= 8Ω, BTL P
OUT
= 1W, f = 1kHz
R
L
= 4Ω, BTL P
OUT
= 1W, f = 1kHz
R
L
= 8Ω, BTL P
OUT
= 1W, BW = 22Hz to
22kHz, unweighted
R
L
= 8Ω, BTL P
OUT
= 1W, A weighted
SNR
dB
2
_______________________________________________________________________________________
2.3W Stereo Speaker Amplifiers and DirectDrive
Headphone Amplifiers with Automatic Level Control
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
= HPV
DD
= CPV
DD
= IN = +5.0V, GND = PGND = CPGND = 0,
SHDN
= V
DD
, REGEN = V
DD
, DR = SET = GND, C
BIAS
= 1µF, C
PVSS
= 1µF, C1 = C2 = 1µF, PREF = unconnected, speaker loads terminated between OUT_+ and OUT_-, headphone load
terminated between HP_ and GND, GAIN1 = GAIN2 = GAIN3 = VOL = 0 (A
V(SP)
= 15dB, A
V(HP)
= 0dB), T
A
= -40°C to +85°C, unless
otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Noise
Capacitive-Load Drive
Crosstalk
Slew Rate
SR
SYMBOL
V
n
C
L
CONDITIONS
BW = 22Hz to 22kHz, unweighted,
measured at output, input at AC GND
No sustained oscillations
L to R, R to L, f = 10kHz
Measured between OUT_+ and OUT_-
GAIN3 = 0
GAIN3 = 0
GAIN3 = 0
Gain (Maximum Volume Settings)
(Note 4)
A
VMAX
(SPKR)
MAX9756/MAX9757/MAX9758
MIN
TYP
71
200
80
1.3
15
16.5
18
19.5
21
22.5
24.0
25.5
65
MAX
UNITS
µV
RMS
pF
dB
V/µs
GAIN2 = 0
GAIN2 = 0
GAIN2 = 1
GAIN2 = 1
GAIN2 = 0
GAIN2 = 0
GAIN2 = 1
GAIN2 = 1
GAIN1 = 0
GAIN1 = 1
GAIN1 = 0
GAIN1 = 1
GAIN1 = 0
GAIN1 = 1
GAIN1 = 0
GAIN1 = 1
Into
shutdown
Out of
shutdown
GAIN3 = 0
GAIN3 = 1
GAIN3 = 1
GAIN3 = 1
GAIN3 = 1
dB
Click-and-Pop Level
K
CP
Peak voltage, 32
samples/second,
A weighted (Note 5)
dBV
38.5
HEADPHONE AMPLIFIERS (HPS = V
DD
)
Output Offset Voltage
Power-Supply Rejection Ratio
(Note 2)
Output Power (Note 3)
Total Harmonic Distortion Plus
Noise
V
OS(HP)
PSRR
T
A
= +25°C
HPV
DD
= 3V to 5.5V, T
A
= +25°C
f = 1kHz, V
RIPPLE
= 200mV
P-P
f = 10kHz, V
RIPPLE
= 200mV
P-P
P
OUT
THD+N
THD+N = 1%, f = 1kHz
(T
A
= +25°C)
R
L
= 32Ω
R
L
= 16Ω
40
70
±2
90
72
70
68
130
0.02
0.04
97
dB
100
20.4
200
60
1.4
GAIN2 = 0, HPS = 1
GAIN2 = 1, HPS = 1
Peak voltage, 32
samples/second,
A weighted (Note 4)
Into shutdown
Out of shutdown
0
3.0
62
dBV
50
µV
RMS
pF
dB
V/µs
dB
mW
%
dB
±7
mV
R
L
= 32Ω, V
OUT
= 1V
RMS
, f = 1kHz
R
L
= 16Ω, V
OUT
= 1V
RMS
, f = 1kHz
R
L
= 32Ω, BTL P
OUT
= 65mW,
BW = 22Hz to 22kHz, unweighted
R
L
= 32Ω, BTL P
OUT
= 65W,
BW = 22Hz to 22kHz, A weighted
BW = 22Hz to 22kHz
No sustained oscillations
L to R, R to L, f = 10kHz
Signal-to-Noise Ratio
SNR
Noise
Capacitive-Load Drive
Crosstalk
Slew Rate
Gain (Maximum Volume Settings)
(Note 6)
Click-and-Pop Level
V
n
C
L
SR
A
VMAX(HP)
K
CP
_______________________________________________________________________________________
3
2.3W Stereo Speaker Amplifiers and DirectDrive
Headphone Amplifiers with Automatic Level Control
MAX9756/MAX9757/MAX9758
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
= HPV
DD
= CPV
DD
= IN = +5.0V, GND = PGND = CPGND = 0,
SHDN
= V
DD
, REGEN = V
DD
, DR = SET = GND, C
BIAS
= 1µF, C
PVSS
= 1µF, C1 = C2 = 1µF, PREF = unconnected, speaker loads terminated between OUT_+ and OUT_-, headphone load
terminated between HP_ and GND, GAIN1 = GAIN2 = GAIN3 = VOL = 0 (A
V(SP)
= 15dB, A
V(HP)
= 0dB), T
A
= -40°C to +85°C, unless
otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
CHARGE PUMP
Charge-Pump Frequency
VOLUME CONTROL
VOL Input Impedance
VOL Input Hysteresis
Full Mute Voltage
Full Mute Attenuation
Input Impedance
Channel Matching
BEEP INPUT
Beep Signal Amplitude Threshold
Beep Signal Frequency
Threshold
PREF Threshold Accuracy
Maximum Gain Compression
Attack Time
Hold Time
Release Time (Note 9)
DR INPUT (TRI-STATE INPUT)
DR Input Voltage High
DR Input Voltage Middle
DR Input Voltage Low
Input Leakage Current
LOGIC INPUTS (GAIN_,
SHDN,
REGEN)
Input High Voltage
Input Low Voltage
Input Leakage Current
V
IH
V
IL
I
IN
2
0.8
±1
V
V
µA
V
DRH
V
DRM
V
DRL
0V
≤
V
DR
≤
V
DD
0.8 x
V
DD
0.4 x
V
DD
0
V
DD
0.6 x
V
DD
0.3 x
V
DD
±1
V
V
V
µA
C
T
= 1µF (Note 8)
Time between attack and release phases
C
T
= 1µF,
release from
6dB
0V < V
DR
< (0.3V x V
DD
)
0.4V < V
DR
< (0.6V x V
DD
)
0.8V < V
DR
< V
DD
T
A
= +25°C, R
B
= 47kΩ (see
BEEP Input
section)
T
A
= +25°C
0.3
300
V
Hz
R
VOL_
(Note 7)
f
IN
= 1kHz
Any gain setting
A
V
= +15dB to 0dB
A
V
= -2dB to -20dB
A
V
= -22dB to -56dB
R
VOL
100
10
0.858 x
HPV
DD
-85
100
±0.2
±0.3
±1.0
dB
MΩ
mV
V
dB
MΩ
f
OSC
500
550
600
kHz
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
AUTOMATIC LEVEL CONTROL SPEAKER AMPLIFIER (MAX9756/MAX9757)
R
PREF
= 180kΩ
6.0
5
6.3
15
50
30
9.5
3
s
8.1
%
dB
ms
ms
4
_______________________________________________________________________________________
2.3W Stereo Speaker Amplifiers and DirectDrive
Headphone Amplifiers with Automatic Level Control
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
= HPV
DD
= CPV
DD
= IN = +5.0V, GND = PGND = CPGND = 0,
SHDN
= V
DD
, REGEN = V
DD
, DR = SET = GND, C
BIAS
= 1µF, C
PVSS
= 1µF, C1 = C2 = 1µF, PREF = unconnected, speaker loads terminated between OUT_+ and OUT_-, headphone load
terminated between HP_ and GND, GAIN1 = GAIN2 = GAIN3 = VOL = 0 (A
V(SP)
= 15dB, A
V(HP)
= 0dB), T
A
= -40°C to +85°C, unless
otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
LOGIC INPUT HEADPHONE (HPS)
Input High Voltage
Input Low Voltage
HPS Pullup Current
LOW-DROPOUT LINEAR REGULATOR
Input Voltage Range
Supply (Ground) Current
Shutdown Current
Output Current
Fixed Output Voltage Accuracy
Adjustable Output Voltage Range
SET Reference Voltage
SET Dual-Mode Threshold
SET Input Leakage Current
Dropout Voltage (Note 10)
Output Current Limit
Startup Time
Line Regulation
Load Regulation
Ripple Rejection
Output Voltage Noise
V
IN
= 3.5V to 5.5V, V
OUT
= 2.5V,
I
OUT
= 1mA
V
OUT
= 4.65V, 1mA < I
OUT
< 150mA
V
RIPPLE
= 200mV
P-P
f = 1kHz
f = 10kHz
-0.1
I
SET
∆V
OD
I
LIM
V
OUT
= 4.65V (fixed
output operation)
I
OUT
= 50mA
I
OUT
= 150mA
V
SET
V
IN
I
Q
I
SHDN
I
OUT
I
OUT
= 1mA
V
SET
1.19
1.21
200
±20
25
100
300
20
+0.01
0.5
60
50
100
+0.1
±500
50
150
Inferred from line regulation
I
OUT
= 0mA,
SHDN
= GND
I
OUT
= 150mA
REGEN = 0V
150
±1.5
4.85
1.23
3.5
100
350
0.1
3
5.5
160
V
µA
µA
mA
%
V
V
mV
nA
mV
mA
µs
%/V
%
dB
µV
RMS
V
IH
V
IL
35
2
0.8
V
V
µA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX9756/MAX9757/MAX9758
20Hz to 22kHz, C
OUT
= 2 x 1µF,
I
OUT
= 150mA, V
OUT
= 4.65V
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:
Note 10:
All devices are 100% production tested at room temperature. All temperature limits are guaranteed by design.
PSRR is specified with the amplifier input connected to GND through R
IN
and C
IN
.
Output power levels are measured with the TQFN’s exposed paddle soldered to the ground plane.
Speaker path gain is defined as: A
VSPKR
= (V
OUT+
- V
OUT-
)/V
IN__
).
Speaker mode testing performed with 8Ω resistive load connected across BTL output. Headphone mode testing per-
formed with 32Ω resistive load connected between HP_ and GND. Mode transitions are controlled by
SHDN.
Headphone path gain is defined as: A
VHP
= V
HP_
/V
IN__
.
See Table 3 for detains on the mute levels.
Attack envelope is exponential. Attack time is defined as the 15 x 10
3
x C
T
.
Time for the gain to return to within 10% of nominal gain setting after the input signal has fallen below the PREF threshold.
Release is linear in dB. Release time is proportional to magnitude of gain compression.
Dropout voltage is defined as (V
IN
- V
OUT
) when V
OUT
is 2% below the value of V
OUT
for V
IN
= V
OUT(NOM)
+ 1V.
_______________________________________________________________________________________
5
