19-4217; Rev 1; 6/10
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
General Description
The MAX9791 combines a stereo 2W Class D power
amplifier, a stereo 180mW DirectDrive
®
headphone
amplifier, and a 120mA low-dropout (LDO) linear regu-
lator in a single device. The MAX9792 combines a
mono 3W Class D power amplifier, a stereo 180mW
DirectDrive headphone amplifier, and a 120mA LDO
linear regulator in a single device.
The MAX9791/MAX9792 feature Maxim’s DirectDrive
headphone amplifier architecture that produces a
ground-referenced output from a single supply, eliminat-
ing the need for large DC-blocking capacitors, saving
cost, board space, and component height. High 107dB
DC PSRR and low 0.006% THD+N ensure clean, low-
distortion amplification of the audio signal.
The ground sense feature senses and corrects for the
voltage difference between the output jack ground and
device signal ground. This feature minimizes head-
phone amplifier crosstalk by sensing the impedance in
the ground return trace and correcting for it at the out-
put jack. This feature also minimizes ground-loop noise
when the output socket is used as a line out connection
to other grounded equipment (for example, a PC con-
nected to a home hi-fi system).
The MAX9791/MAX9792 feature low RF susceptibility,
allowing the amplifiers to successfully operate in close
proximity to wireless applications. The MAX9791/
MAX9792 Class D amplifiers feature Maxim’s spread-
spectrum modulation and active emissions limiting cir-
cuitry. Industry-leading click-and-pop suppression
eliminates audible transients during power-up and shut-
down cycles.
The MAX9791/MAX9792 wake-on-beep feature wakes
up the speaker and headphone amplifiers when a qual-
ified beep signal is detected at the BEEP input.
For maximum flexibility, separate speaker and head-
phone amplifier control inputs provide independent
shutdown of the speaker and headphone amplifiers.
Additionally the LDO can be enabled independently of
the audio amplifiers.
The MAX9791/MAX9792 feature thermal-overload and
output short-circuit protection. The devices are avail-
able in 28-pin TQFN packages and are specified over
the -40°C to +85°C extended temperature range.
Features
o
Windows Vista® Premium Compliant
o
Low EMI Filterless Class D Speaker Amplifiers
Pass EN55022B Emissions Limit with 30cm of
Speaker Cable
o
180mW DirectDrive Headphone Amplifier
o
Excellent RF Immunity
o
Integrated 120mA LDO
o
Eliminates Headphone Ground Loop Noise
o
Wake-on-Beep Function
o
Click-and-Pop Suppression
o
Short-Circuit and Thermal-Overload Protection
o
Thermally Efficient, Space-Saving Package
28-Pin TQFN-EP (4mm x 4mm x 0.75mm)
MAX9791/MAX9792
Ordering Information
PART
MAX9791AETI+
MAX9791BETI+
MAX9791CETI+
MAX9792AETI+
MAX9792CETI+
STEREO/
MONO
Stereo
Stereo
Stereo
Mono
Mono
LDO
OUTPUT
4.75V
3.3V
1.8V
4.75V
1.8V
PIN-PACKAGE
28 TQFN-EP*
28 TQFN-EP*
28 TQFN-EP*
28 TQFN-EP*
28 TQFN-EP*
Note:
All devices are specified over the -40°C to +85°C
extended temperature range.
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed pad.
Simplified Block Diagrams
SPEAKER AND LDO
SUPPLY
2.7V TO 5.5V
HEADPHONE SUPPLY
2.7V TO 5.5V
CLASS D
AMP
MAX9791
CLASS D
AMP
Applications
Notebook Computers
Tablet PCs
Portable Multimedia Players
DirectDrive is a registered trademark of Maxim Integrated
Products, Inc.
Windows Vista is a registered trademark of Microsoft Corp.
SPKR_EN
HP_EN
LDO_EN
BEEP
AVDD
LDO
1.8V, 3.3V, OR 4.75V
Simplified Block Diagrams continued at end of data sheet.
1
________________________________________________________________
Maxim Integrated Products
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.
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
MAX9791/MAX9792
ABSOLUTE MAXIMUM RATINGS
Supply Voltage
(AVDD, PVDD, HPVDD to GND)........................-0.3V to +6.0V
(AVDD to PVDD) .............................................................±0.3V
GND to PGND, CPGND ......................................................±0.3V
CPVSS, C1N to GND ............................................-6.0V to + 0.3V
HPL, HPR to CPVSS ...........................................-0.3V to lower of
(HPVDD - CPVSS + 0.3V) and +9V
HPL, HPR to HPVDD..................................+0.3V to the higher of
(CPVSS - HPVDD - 0.3V) and -9V
COM, SENSE........................................................-0.3V to + 0.3V
Any Other Pin ..........................................-0.3V to (AVDD + 0.3V)
Duration of Short Circuit between OUT_+, OUT_- and GND,
PGND, AVDD, or PVDD..........................................Continuous
Duration of Short Circuit between LDO_OUT and AVDD,
GND (Note 1) .........................................................Continuous
Duration of Short Circuit between HPR, HPL and
GND .......................................................................Continuous
Continuous Current (PVDD, OUT_+, OUT_-, PGND)............1.7A
Continuous Current (C1N, C1P, CPVSS, AVDD, HPVDD,
LDO_OUT, HPR, HPL) ..................................................850mA
Continuous Input Current (All Other Pins) ........................±20mA
Continuous Power Dissipation (T
A
= +70°C)
28-Pin Thin QFN Single-Layer Board (derate 20.8mW/°C
above +70°C)..........................................................1667mW
Junction-to-Ambient Thermal Resistance (θ
JA
)
(Note 2) .....................................................................40°C/W
Junction-to-Case Thermal Resistance (θ
JC
)
(Note 2) ....................................................................2.7°C/W
28-Pin Thin QFN Multilayer Board (derate 28.6mW/°C
above +70°C)..........................................................2286mW
Junction-to-Ambient Thermal Resistance (θ
JA
)
(Note 2) .....................................................................35°C/W
Junction-to-Case Thermal Resistance (θ
JC
)
(Note 2) ....................................................................2.7°C/W
ESD Protection, Human Body Model ...................................±2kV
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1:
If short is present at power-up.
Note 2:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to
www.maxim-ic.com/thermal-tutorial.
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
AVDD
= V
PVDD
= V
HPVDD
= 5V, V
GND
= V
PGND
= V
CPGND
= 0, I
LDO_OUT
= 0, C
LDO
= 2µF (C
LDO
= 4µF for 1.8V LDO option),
C1 = C2 = 1µF. R
L
=
∞,
unless otherwise specified. R
IN1
= 20kΩ (A
VSPKR
= 12dB), R
IN2
= 40.2kΩ (A
VHP
= 0dB), C
IN1
= 470nF,
C
IN2
= C
COM
= 1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 3)
PARAMETER
GENERAL
Supply Voltage
Headphone Supply Voltage
Undervoltage Lockout
V
AVDD
,
V
PVDD
V
HPVDD
UVLO
SPKR_EN
1
MAX9791
Quiescent Current
I
AVDD
+
I
PVD
+
I
HPVDD
MAX9792
1
0
0
1
1
0
0
Shutdown Current
Bias Voltage
I
SHDN
V
BIAS
SPKR_EN
= 1.8V
HP_INR, HP_INL, SPKR_INR, SPKR_INL
HP_EN
0
1
0
1
0
1
0
1
LDO_EN
1
0
0
0
1
0
0
0
250
4.4
10.5
14.4
250
4.4
10.5
14.4
3.3
0
400
6
15
21
400
6
18
24
7..3
µA
V
mA
µA
mA
µA
Guaranteed by PSRR test (Note 4)
Guaranteed by PSRR test
2.7
2.7
5.5
5.5
2.65
V
V
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
AVDD
= V
PVDD
= V
HPVDD
= 5V, V
GND
= V
PGND
= V
CPGND
= 0, I
LDO_OUT
= 0, C
LDO
= 2µF (C
LDO
= 4µF for 1.8V LDO option),
C1 = C2 = 1µF. R
L
=
∞,
unless otherwise specified. R
IN1
= 20kΩ (A
VSPKR
= 12dB), R
IN2
= 40.2kΩ (A
VHP
= 0dB), C
IN1
= 470nF,
C
IN2
= C
COM
= 1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 3)
PARAMETER
Shutdown to Full Operation
Overtemperature Threshold
SPEAKER AMPLIFIER
R
L
= 4
(MAX9791)
R
L
= 8
(MAX9791)
R
L
= 3
(MAX9792)
1.7
1.2
3
W
2.2
1.5
3.7
0.04
0.03
60
80
73
75
62
20
12
±3
-52.4
dBV
Out of
shutdown
A-weighted
20Hz to 20kHz
-54
98
dB
94
38
78
70
77
dB
µV
RMS
±10
k
dB
mV
dB
%
SYMBOL
t
ON
CONDITIONS
MIN
TYP
0.4
+150
MAX
UNITS
ms
°C
MAX9791/MAX9792
THD+N = 1%,
f = 1kHz,
T
A
= +25°C
(Note 5)
Output Power
P
OUT
R
L
= 4
THD+N = 10%, (MAX9791)
f = 1kHz,
R
L
= 8
T
A
= +25°C
(MAX9791)
(Note 5)
R
L
= 3
(MAX9792)
R
L
= 8 , P
OUT
= 500mW, f = 1kHz (Note 5)
R
L
= 4 , P
OUT
= 500mW, f = 1kHz (Note 5)
V
AVDD
= V
PVDD
= 2.7V to 5.5V, T
A
= +25°C
f = 217Hz, 200mV
P-P
f = 1kHz, 200mV
P-P
f = 10kHz, 200mV
P-P
Guaranteed by design
R
IN1
= 20k
Measured between OUT_+ and OUT_-,
T
A
= +25°C
R
L
= 8 ,
peak voltage,
A-weighted,
32 samples per second
(Notes 5, 6, and 7)
R
L
= 8
P
OUT
= 1.2W f
IN
= 1kHz,
(Note 5)
A-weighted
L to R, R to L, R
L
= 8 , V
IN
= -20dBFS =
100mV
RMS
, f
IN
= 1kHz (Note 5)
Into shutdown
Total Harmonic Distortion Plus
Noise
THD+N
Power-Supply Rejection Ratio
PSRR
Feedback Impedance
Gain
Output Offset Voltage
R
FSKR
A
V
V
OS
Click-and-Pop Level
K
CP
Signal-to-Noise Ratio
Noise
SNR
V
N
Crosstalk
L to R, R to L, R
L
= 8 , V
IN
= -20dBFS =
100mV
RMS
, f
IN
= 15kHz (Note 5)
HP to SPKR, R
LSPKR
= 8 , P
HP
= 20mW,
R
LHP
= 32 , f
IN
= 1kHz (Note 5)
_______________________________________________________________________________________
3
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
MAX9791/MAX9792
ELECTRICAL CHARACTERISTICS (continued)
(V
AVDD
= V
PVDD
= V
HPVDD
= 5V, V
GND
= V
PGND
= V
CPGND
= 0, I
LDO_OUT
= 0, C
LDO
= 2µF (C
LDO
= 4µF for 1.8V LDO option),
C1 = C2 = 1µF. R
L
=
∞,
unless otherwise specified. R
IN1
= 20kΩ (A
VSPKR
= 12dB), R
IN2
= 40.2kΩ (A
VHP
= 0dB), C
IN1
= 470nF,
C
IN2
= C
COM
= 1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 3)
PARAMETER
Class D Switching Frequency
Spread-Spectrum Bandwidth
Efficiency
HEADPHONE AMPLIFIER
Output Power
P
OUT
THD+N = 1%,
f = 1kHz,
T
A
= +25°C
R
L
= 16
R
L
= 32
100
mW
180
-78
dBFS
-87
0.006
0.014
70
107
91
80
38.2
R
IN2
= 40.2k
T
A
= +25°C
R
L
= 32 ,
peak voltage,
A-weighted, 32 samples
per second (Notes 6, 7)
Into shutdown
Out of
shutdown
40.2
0
±0.3
-81
dBV
-72.5
102
94
8
100
82
89
64
70
80
dB
R
L
= 32 , V
IN
=
-20dBFS = 30mV
RMS
R
L
= 10k , V
IN
=
-20dBFS = 0.7mV
RMS
R
L
= 32 , V
IN
=
-20dBFS = 30mV
RMS
R
L
= 10k , V
IN
=
-20dBFS = 70.7mV
RMS
dB
µV
RMS
pF
±3
42.2
k
dB
mV
dB
%
P
OUT
= 1.5W, f
IN
= 1kHz, R
L
= 8
(Note 5)
SYMBOL
f
SPK
CONDITIONS
MIN
948
±15
83
TYP
MAX
1158
UNITS
kHz
kHz
%
R
L
= 32 , f
IN
= 6kHz, 20kHz AES17,
V
IN
= -3dBFS = 212mV
RMS
Total Harmonic Distortion Plus
Noise
THD+N
R
L
= 10k , f
IN
= 6kHz, 20kHz AES17,
V
IN
= -3dBFS = 500mV
RMS
R
L
= 32 , P
OUT
= 100mW, f = 1kHz
R
L
= 16 , P
OUT
= 75mW, f = 1kHz
V
HPVDD
= 2.7V to 5.5V, T
A
= +25°C
Power-Supply Rejection Ratio
Feedback Impedance
Gain
Output Offset Voltage
Click-and-Pop Level
PSRR
R
FHP
A
V
V
OS
K
CP
f = 1kHz, V
RIPPLE
= 200mV
P-P
f = 10kHz, V
RIPPLE
= 200mV
P-P
Signal-to-Noise Ratio
Noise
Maximum Capacitive Load
SNR
V
N
C
L
R
L
= 32 , P
OUT
= 40mW, A-weighted
f
IN
= 1kHz
20Hz to 20kHz
A-weighted
No sustained oscillations
L to R, R to L, f
IN
= 1kHz, COM
and SENSE
connected
Crosstalk
L to R, R to L, f
IN
= 15kHz, COM
and SENSE
connected
SPKR to HP, R
LSPKR
= 8 , P
SPKR
= 1W,
R
LHP
= 32 , f
IN
= 1Hz
4
_______________________________________________________________________________________
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
AVDD
= V
PVDD
= V
HPVDD
= 5V, V
GND
= V
PGND
= V
CPGND
= 0, I
LDO_OUT
= 0, C
LDO
= 2µF (C
LDO
= 4µF for 1.8V LDO option),
C1 = C2 = 1µF. R
L
=
∞,
unless otherwise specified. R
IN1
= 20kΩ (A
VSPKR
= 12dB), R
IN2
= 40.2kΩ (A
VHP
= 0dB), C
IN1
= 470nF,
C
IN2
= C
COM
= 1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 3)
PARAMETER
COM Input Range
Common-Mode Rejection Ratio
Slew Rate
Charge-Pump Frequency
BEEP INPUT (LDO_EN = 1)
Beep Signal Minimum
Amplifier Turn-On Time
f
BEEP
t
ONBEEP
221
Four-cycle count
215
0.4
246
0.25
Inferred from load regulation
300
Speaker to LDO, V
LDO_OUT
= 4.75V,
f =1kHz, I
LDO_OUT
= 10mA, speaker P
OUT
= 1.2W, R
L
= 8 (Note 6)
V
LDO_OUT
= 4.75V
V
LDO_OUT
= 3.3V
V
DO
V
LDO_OUT
= 4.75V,
T
A
= +25°C (Note 8)
I
OUT
= 50mA
I
OUT
= 120mA
46
106
30
V
AVDD
= 5V to 5.5V, V
LDO_OUT
= 4.75V,
I
LDO_OUT
= 1mA, C
LDO
= 2µF
Line Regulation
V
AVDD
= 4.5V to 5.5V, V
LDO_OUT
= 3.3V,
I
LDO_OUT
= 1mA, C
LDO
= 2µF
V
AVDD
= 3V to 5.5V, V
LDO_OUT
= 1.8V,
I
LDO_OUT
= 1mA, C
LDO
= 4µF
Load Regulation
V
LDO_OUT
= 4.75V, 1mA < I
LDO_OUT
<
120mA
V
RIPPLE
= 200mV
P-P
,
V
LDO_OUT
= 4.75V
I
LDO_OUT
= 10mA
f = 1kHz
f = 10kHz
-4.8
-4
-6.4
1.5
0.2
2.5
0.22
56
dB
40
130
µV
RMS
+4.8
+4
+6.4
mV/mA
mV/V
-80
±1.5
±1.5
271
0.4
120
Hz
ms
ms
mA
mA
mA
dB
SYMBOL
V
COM
CMRR
SR
f
OSC
CONDITIONS
Inferred from CMRR test
-300mV < V
COM
< +300mV
MIN
-300
60
0.38
530
TYP
MAX
+300
UNITS
mV
dB
V/µs
kHz
MAX9791/MAX9792
Amplifier Hold Time
t
HOLDBEEP
LOW-DROPOUT LINEAR REGULATOR
LDO Ground Current
I
LDO
Output Current
Current Limit
Crosstalk
I
OUT
I
LIM
Output-Voltage Accuracy
Dropout Voltage
Startup Time
%
mV
µs
Ripple Rejection
Output-Voltage Noise
20Hz to 20kHz, C
LDO_OUT
= 2 x 1µF,
I
LDO_OUT
= 120mA
V
INH
V
INL
-1
1.4
DIGITAL INPUTS (SPKR_EN, HP_EN, LDO_EN, BEEP)
Input-Voltage High
Input-Voltage Low
Input Bias Current
V
0.4
+1
V
µA
_______________________________________________________________________________________
5
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