19-3006; Rev 3; 8/04
2.6W Stereo Audio Power Amplifiers and
DirectDrive Headphone Amplifiers
General Description
The MAX9750/MAX9751/MAX9755 combine a stereo,
2.6W audio power amplifier and stereo DirectDrive
110mW headphone amplifier in a single device. The
headphone amplifier uses Maxim’s patented DirectDrive
architecture that produces a ground-referenced output
from a single supply, eliminating the need for large DC-
blocking capacitors, saving cost, space, and component
height. A high 90dB PSRR and low 0.01% THD+N
ensures clean, low-distortion amplification of the audio
signal.
The MAX9750 features an analog volume control, and a
BEEP input. The MAX9751 features a 2:1 input multiplexer,
allowing multiple audio sources to be selected. All devices
feature a single-supply voltage, a shutdown mode, logic-
selectable gain, and a headphone sense input. Industry-
leading click-and-pop suppression eliminates audible
transients during power and shutdown cycles.
The MAX9750/MAX9751/MAX9755 are offered in space-
saving, thermally efficient 28-pin thin QFN (5mm x 5mm
x 0.8mm) and 28-pin TSSOP packages. Both devices
have thermal-overload and output short-circuit protec-
tion, and are specified over the extended -40°C to +85°C
temperature range.
Features
o
No DC-Blocking Capacitors Required—Provides
Industry’s Most Compact Notebook Audio
Solution
o
PC2001 Compliant
o
5V Single-Supply Operation
o
Class AB 2.6W Stereo BTL Speaker Amplifiers
o
110mW DirectDrive Headphone Amplifiers
o
High 90dB PSRR
o
Low-Power Shutdown Mode
o
Industry-Leading Click-and-Pop Suppression
o
Low 0.01% THD+N at 1kHz
o
Short-Circuit and Thermal Protection
o
Selectable Gain Settings
o
Analog Volume Control (MAX9750)
o
Beep Input with Glitch Filter (MAX9750)
o
2:1 Stereo Input MUX (MAX9751)
o
±8kV ESD-Protected Headphone Driver Outputs
o
Available in Space-Saving, Thermally Efficient
Packages
28-Pin Thin QFN (5mm x 5mm x 0.8mm)
28-Pin TSSOP
MAX9750/MAX9751/MAX9755
Applications
Notebook PCs
Tablet PCs
Flat-Panel TVs
PC Displays
Portable DVD Players LCD Projectors
Simplified Block Diagrams
PART
MAX9750AETI
†
MAX9750AEUI*
MAX9750BETI
†
MAX9750BEUI*
MAX9750CETI
†
MAX9750CEUI*
MAX9751ETI
†
MAX9751EUI*
VOL
Ordering Information
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
28 Thin QFN
28 TSSOP
28 Thin QFN
28 TSSOP
28 Thin QFN
28 TSSOP
28 Thin QFN
28 TSSOP
28 Thin QFN
28 TSSOP
MAXIMUM
GAIN (dB)
13.5
13.5
19.5
19.5
10.5
10.5
10.5
10.5
10.5
10.5
MAX9755ETI
†
MAX9755EUI*
BEEP
*Future
product—contact factory for availability.
†
Lead-free
package.
MAX9750
Simplified Block Diagrams continued 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.
2.6W Stereo Audio Power Amplifiers and
DirectDrive Headphone Amplifiers
MAX9750/MAX9751/MAX9755
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V
DD
, PV
DD
, HPV
DD
, CPV
DD
to GND)..........+6V
GND to PGND.....................................................................±0.3V
CPV
SS
, C1N, V
SS
to GND .........................-6.0V to (GND + 0.3V)
HPOUT_ 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 HPOUT_ Short Circuit to GND,
V
SS
or HPV
DD
.........................................................Continuous
Continuous Current (PV
DD
, OUT_, PGND) ...........................1.7A
Continuous Current (CPV
DD
, C1N, C1P, CPV
SS
, V
SS
, HPV
DD
,
HPOUT_) .......................................................................850mA
Continuous Input Current (All Other Pins) ........................±20mA
Continuous Power Dissipation (T
A
= +70°C)
28-Pin Thin QFN (derate 20.8mW/°C above +70°C) ..1667mW
28-Pin TSSOP (derate 13mW/°C above +70°C) .........1039mW
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
= HPV
DD
= 5V, GND = PGND = CPGND = 0V,
SHDN
= V
DD
, C
BIAS
= 1µF, C1 = C2 = 1µF, speaker load
terminated between OUT_+ and OUT_-, headphone load terminated between HPOUT_ and GND, GAIN1 = GAIN2 = VOL = GAIN = 0V,
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
Headphone Supply Voltage
Quiescent Supply Current
Shutdown Supply Current
Bias Voltage
Switching Time
Input Resistance
Turn-On Time
SPEAKER AMPLIFIER (HPS = GND)
Measured
MAX9750A/MAX9750B/
between OUT_+ MAX9751/MAX9755
and OUT_-,
MAX9750C
T
A
= +25°C
PV
DD
or V
DD
= 4.5V to 5.5V (T
A
= +25°C)
f = 1kHz, V
RIPPLE
= 200mV
P-P
f = 10kHz, V
RIPPLE
= 200mV
P-P
±1
±0.4
75
90
80
55
dB
±15
mV
±6
V
DD
, PV
DD
CPV
DD
,
HPV
DD
I
DD
I
SHDN
V
BIAS
t
SW
R
IN
t
SON
Gain or input switching
Amplifier inputs (Note 2)
10
Inferred from PSRR test
Inferred from PSRR test
HPS = GND, speaker mode, R
L
=
∞
HPS = V
DD
, headphone mode, R
L
=
∞
SHDN
= GND
1.7
4.5
3
14
7
0.2
1.8
10
20
25
30
5.5
5.5
29
13
5
1.9
V
V
mA
µA
V
µs
kΩ
ms
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Output Offset Voltage
V
OS
Power-Supply Rejection Ratio
(Note 3)
PSRR
2
_______________________________________________________________________________________
2.6W Stereo Audio Power Amplifiers and
DirectDrive Headphone Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
= CPV
DD
= HPV
DD
= 5V, GND = PGND = CPGND = 0V,
SHDN
= V
DD
, C
BIAS
= 1µF, C1 = C2 = 1µF, speaker load
terminated between OUT_+ and OUT_-, headphone load terminated between HPOUT_ and GND, GAIN1 = GAIN2 = VOL = GAIN = 0V,
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MAX9750A/
MAX9750B/
MAX9751/
MAX9755
MAX9750C
MAX9750A/
MAX9750B/
MAX9751/
MAX9755
MAX9750C
MAX9750A/
MAX9750B/
MAX9751/
MAX9755
MAX9750C
1.2
MIN
TYP
MAX
UNITS
MAX9750/MAX9751/MAX9755
R
L
= 8Ω
0.9
0.65
1.4
0.8
Output Power (Note 4)
P
OUT
THD+N = 1%,
f = 1kHz,
T
A
= +25°C
2.3
W
1.5
R
L
= 4Ω
R
L
= 3Ω
2.6
2.2
0.01
0.02
90
80
200
75
75
1.4
dB
V/µs
%
dB
µV
RMS
pF
Total Harmonic Distortion Plus
Noise
Signal-to-Noise Ratio
Noise
Capacitive-Load Drive
Crosstalk
Off-Isolation
Slew Rate
THD+N
SNR
V
n
C
L
R
L
= 8Ω, P
OUT
= 500mW, f = 1kHz
R
L
= 4Ω, P
OUT
= 1W, f = 1kHz
R
L
= 8Ω, P
OUT
= 500mW, BW = 22Hz to
22kHz
BW = 22Hz to 22kHz, A-weighted
No sustained oscillations
L to R, R to L, f = 10kHz
Any unselected input to any active input,
f = 10kHz (MAX9751), input referred
SR
GAIN1 = 0, GAIN2 = 0
GAIN1 = 1, GAIN2 = 0
MAX9750A
GAIN1 = 0, GAIN2 = 1
GAIN1 = 1, GAIN2 = 1
GAIN1 = 0, GAIN2 = 0
GAIN1 = 1, GAIN2 = 0
GAIN1 = 0, GAIN2 = 1
GAIN1 = 1, GAIN2 = 1
GAIN1 = 0, GAIN2 = 0
MAX9750C
GAIN1 = 1, GAIN2 = 0
GAIN1 = 0, GAIN2 = 1
GAIN1 = 1, GAIN2 = 1
GAIN = 1
GAIN = 0
9
10.5
12
13.5
15
16.5
18
19.5
6
7.5
9
10.5
9
10.5
dB
dB
Gain (Maximum Volume Setting)
A
VMAX(SPKR)
MAX9750B
Gain (MAX9751/MAX9755)
A
V
_______________________________________________________________________________________
3
2.6W Stereo Audio Power Amplifiers and
DirectDrive Headphone Amplifiers
MAX9750/MAX9751/MAX9755
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
= CPV
DD
= HPV
DD
= 5V, GND = PGND = CPGND = 0V,
SHDN
= V
DD
, C
BIAS
= 1µF, C1 = C2 = 1µF, speaker load
terminated between OUT_+ and OUT_-, headphone load terminated between HPOUT_ and GND, GAIN1 = GAIN2 = VOL = GAIN = 0V,
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Output Offset Voltage
Power-Supply Rejection Ratio
(Note 3)
SYMBOL
V
OS
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
Output Power
Total Harmonic Distortion Plus
Noise
Signal-to-Noise Ratio
Noise
Capacitive-Load Drive
Crosstalk
Off-Isolation
Slew Rate
ESD
Gain
CHARGE PUMP
Charge-Pump Frequency
VOLUME CONTROL (MAX9750_)
VOL Input Impedance
VOL Input Hysteresis
Full Mute Input Voltage
Channel Matching
BEEP INPUT (MAX9750_)
Beep Signal Minimum Amplitude
Beep Signal Minimum Frequency
V
BEEP
f
BEEP
R
B
= 33kΩ (Note 6)
0.8
400
V
P-P
Hz
(Note 5)
A
V
= -25dB to +13.5dB
R
VOL
100
10
0.858 x
HPV
DD
±0.2
MΩ
mV
V
dB
f
OSC
500
550
600
kHz
SR
ESD
A
V
IEC air discharge
GAIN2 = GAIN = 0, GAIN1 = X
GAIN2 = GAIN = 1, GAIN1 = X
P
OUT
THD+N = 1%,
f = 1kHz, T
A
= +25°C
R
L
= 32Ω
R
L
= 16Ω
40
60
CONDITIONS
MIN
TYP
±2
75
73
63
50
mW
110
0.007
0.03
95
12
200
88
74
0.4
±8
0
3
dB
V/µs
kV
dB
%
dB
µV
RMS
pF
dB
MAX
±7
UNITS
mV
HEADPHONE AMPLIFIER (HPS = V
DD
)
THD+N
SNR
V
n
C
L
R
L
= 32Ω, P
OUT
= 20mW, f = 1kHz
R
L
= 16Ω, P
OUT
= 75mW, f = 1kHz
R
L
= 32Ω, P
OUT
= 50mW, BW = 22Hz to
22kHz
BW = 22Hz to 22kHz
No sustained oscillations
L to R, R to L, f = 10kHz
Any unselected input to any active input,
f = 10kHz (MAX9751), input referred
4
_______________________________________________________________________________________
2.6W Stereo Audio Power Amplifiers and
DirectDrive Headphone Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
= CPV
DD
= HPV
DD
= 5V, GND = PGND = CPGND = 0V,
SHDN
= V
DD
, C
BIAS
= 1µF, C1 = C2 = 1µF, speaker load
terminated between OUT_+ and OUT_-, headphone load terminated between HPOUT_ and GND, GAIN1 = GAIN2 = VOL = GAIN = 0V,
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Current
LOGIC INPUT HEADPHONE (HPS)
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Current
V
IH
V
IL
I
IN
10
2
0.8
V
V
µA
SYMBOL
V
IH
V
IL
I
IN
CONDITIONS
MIN
2
0.8
±1
TYP
MAX
UNITS
V
V
µA
MAX9750/MAX9751/MAX9755
LOGIC INPUT (SHDN, GAIN1, GAIN2, GAIN, VOL, IN1/2)
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
All devices are 100% production tested at room temperature. All temperature limits are guaranteed by design.
Guaranteed by design. Not production tested.
PSRR is specified with the amplifier input connected to GND through C
IN
.
Output power levels are measured with the thin QFN’s exposed paddle soldered to the ground plane.
See Table 3 for details of the mute levels.
The value of R
B
dictates the minimum beep signal amplitude (see the
Beep Input
section).
_______________________________________________________________________________________
5
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