MAXIM MAX9792AETI+

19-4217; Rev 0; 11/08
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
Features
♦ Windows Vista® Premium Compliant
♦ Low EMI Filterless Class D Speaker Amplifiers
Pass EN55022B Emissions Limit with 30cm of
Speaker Cable
♦ 180mW DirectDrive Headphone Amplifier
♦ Excellent RF Immunity
♦ Integrated 120mA LDO
♦ Eliminates Headphone Ground Loop Noise
♦ Wake-on-Beep Function
♦ Click-and-Pop Suppression
♦ Short-Circuit and Thermal-Overload Protection
♦ Thermally Efficient, Space-Saving Package
28-Pin TQFN-EP (4mm x 4mm x 0.75mm)
Ordering Information
STEREO/
MONO
LDO
OUTPUT
MAX9791AETI+
Stereo
4.75V
MAX9791BETI+
Stereo
3.3V
28 TQFN-EP*
MAX9792AETI+
Mono
4.75V
28 TQFN-EP*
PART
PIN-PACKAGE
28 TQFN-EP*
Note: All devices are specified over the -40°C to +85°C
extended temperature range.
+Denotes a lead-free/RoHS-compliant package.
*EP = Exposed pad.
Simplified Block Diagrams
SPEAKER SUPPLY
4.5V TO 5.5V
HEADPHONE SUPPLY
2.7V TO 5.5V
CLASS D
AMP
MAX9791A
MAX9791B
CLASS D
AMP
Applications
Notebook Computers
SPKR_EN
Tablet PCs
LDO_EN
BEEP
Portable Multimedia Players
Windows Vista is a registered trademark of Microsoft Corp.
**U.S. Patent #7,061,327.
†U.S. Patent #6,847,257.
††U.S. Patent #7,190,225.
HP_EN
4.5V TO 5.5V
LDO
3.3V OR 4.75V
Simplified Block Diagrams continued at end of data sheet.
DirectDrive is a registered trademark of Maxim Integrated
Products, Inc.
________________________________________________________________ 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.
1
MAX9791/MAX9792
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 regulator 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 patented**
DirectDrive headphone amplifier 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. 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 headphone amplifier crosstalk by sensing the impedance in
the ground return trace and correcting for it at the output 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 connected 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 patented†
spread-spectrum modulation and patented †† active
emissions limiting circuitry. Industry-leading click-andpop suppression eliminates audible transients during
power-up and shutdown cycles.
The MAX9791/MAX9792 wake-on-beep feature wakes
up the speaker and headphone amplifiers when a qualified beep signal is detected at the BEEP input.
For maximum flexibility, separate speaker and headphone 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 available in 28-pin TQFN packages and are specified over
the -40°C to +85°C extended temperature range.
MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
ABSOLUTE MAXIMUM RATINGS
Supply Voltage
(AVDD, PVDD, HPVDD to GND)........................-0.3V to +6.0V
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 (TA = +70°C)
28-Pin Thin QFN Single-Layer Board (derate 20.8mW/°C
above +70°C)..........................................................1667mW
Junction-to-Ambient Thermal Resistance (θJA)
(Note 2) .....................................................................40°C/W
Junction-to-Case Thermal Resistance (θJC)
(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 (θJA)
(Note 2) .....................................................................35°C/W
Junction-to-Case Thermal Resistance (θJC)
(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
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
5.5
V
GENERAL
Supply Voltage
VAVDD,
VPVDD
Guaranteed by PSRR test
4.5
Headphone Supply Voltage
VHPVDD
Guaranteed by PSRR test
2.7
Undervoltage Lockout
Quiescent Current
UVLO
IAVDD +
IPVDD +
IHPVDD
Shutdown Current
ISHDN
Bias Voltage
VBIAS
Shutdown to Full Operation
Overtemperature Threshold
2
tON
5.5
V
2.65
V
SPKR_EN
HP_EN
LDO_EN
1
0
1
250
400
µA
1
1
0
4.4
6
mA
0
0
0
10.5
15
mA
0
1
0
14.4
21
mA
1
0
0
0.1
1
µA
HP_INR, HP_INL, SPKR_INR, SPKR_INL
0
V
0.4
ms
+150
°C
_______________________________________________________________________________________
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
SPEAKER AMPLIFIER
THD+N = 1%,
f = 1kHz,
TA = +25°C
(Note 4)
Output Power
THD+N = 10%,
f = 1kHz,
TA = +25°C
(Note 4)
THD+N
1.7
RL = 8Ω
(MAX9791)
1.2
RL = 3Ω
(MAX9792)
3
RL = 4Ω
(MAX9791)
2.2
RL = 8Ω
(MAX9791)
1.5
RL = 3Ω
(MAX9792)
3.7
W
POUT
Total Harmonic Distortion Plus
Noise
RL = 4Ω
(MAX9791)
RL = 8Ω, POUT = 500mW, f = 1kHz (Note 4)
0.04
RL = 4Ω, POUT = 500mW, f = 1kHz (Note 4)
0.03
VAVDD = VPVDD = 4.5V to 5.5V, TA = +25°C
Power-Supply Rejection Ratio
PSRR
Feedback Impedance
RFSKR
Gain
Click-and-Pop Level
Signal-to-Noise Ratio
Noise
Crosstalk
80
f = 217Hz, 200mVP-P
73
f = 1kHz, 200mVP-P
75
dB
f = 10kHz, 200mVP-P
62
Guaranteed by design
20
kΩ
RIN1 = 20kΩ
12
dB
VOS
Measured between OUT_+ and OUT_-,
TA = +25°C
±3
KCP
RL = 8Ω,
peak voltage,
A-weighted,
32 samples per second
(Notes 4, 5, and 6)
AV
Output Offset Voltage
60
%
SNR
VN
RL = 8Ω
POUT = 1.2W fIN = 1kHz,
(Note 4)
Into shutdown
±10
mV
-52.4
dBV
Out of
shutdown
-54
A-weighted
98
20Hz to 20kHz
94
dB
A-weighted
38
L to R, R to L, RL = 8Ω, VIN = -20dBFS =
100mVRMS, fIN = 1kHz (Note 4)
78
L to R, R to L, RL = 8Ω, VIN = -20dBFS =
100mVRMS, fIN = 15kHz (Note 4)
70
HP to SPKR, RLSPKR = 8Ω, PHP = 20mW,
RLHP = 32Ω, fIN = 1kHz (Note 4)
77
µVRMS
dB
_______________________________________________________________________________________
3
MAX9791/MAX9792
ELECTRICAL CHARACTERISTICS (continued)
MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.) (Note 3)
PARAMETER
Class D Switching Frequency
SYMBOL
CONDITIONS
fSPK
MIN
Spread-Spectrum Bandwidth
Efficiency
η
TYP
948
MAX
UNITS
1158
kHz
±15
kHz
POUT = 1.5W, fIN = 1kHz, RL = 8Ω (Note 4)
83
%
THD+N = 1%,
f = 1kHz,
TA = +25°C
RL = 16Ω
100
RL = 32Ω
180
HEADPHONE AMPLIFIER
Output Power
Total Harmonic Distortion Plus
Noise
POUT
THD+N
mW
RL = 32Ω, fIN = 6kHz, 20kHz AES17,
VIN = -3dBFS = 212mVRMS
-78
RL = 10kΩ, fIN = 6kHz, 20kHz AES17,
VIN = -3dBFS = 500mVRMS
-87
RL = 32Ω, POUT = 100mW, f = 1kHz
0.006
RL = 16Ω, POUT = 75mW, f = 1kHz
0.014
VHPVDD = 2.7V to 5.5V, TA = +25°C
Power-Supply Rejection Ratio
Feedback Impedance
Gain
PSRR
Output Offset Voltage
VOS
Click-and-Pop Level
KCP
Signal-to-Noise Ratio
SNR
91
80
38.2
RIN2 = 40.2kΩ
40.2
dB
42.2
kΩ
±3
mV
0
TA = +25°C
RL = 32Ω,
peak voltage,
A-weighted, 32 samples
per second (Notes 5, 6)
RL = 32Ω, POUT = 40mW,
fIN = 1kHz
VN
A-weighted
Maximum Capacitive Load Drive
CL
No sustained oscillations
±0.3
Into shutdown
Out of
shutdown
dB
-81
dBV
-72.5
A-weighted
102
20Hz to 20kHz
94
dB
8
µVRMS
100
pF
L to R, R to L, fIN
= 1kHz, COM
and SENSE
connected
RL = 32Ω, VIN =
-20dBFS = 30mVRMS
82
RL = 10kΩ, VIN =
-20dBFS = 0.7mVRMS
89
L to R, R to L, fIN
= 15kHz, COM
and SENSE
connected
RL = 32Ω, VIN =
-20dBFS = 30mVRMS
64
RL = 10kΩ, VIN =
-20dBFS = 70.7mVRMS
70
SPKR to HP, RLSPKR = 8Ω, PSPKR = 1W,
RLHP = 32Ω, fIN = 1Hz
4
%
107
f = 1kHz, VRIPPLE = 200mVP-P
Noise
Crosstalk
70
f = 10kHz, VRIPPLE = 200mVP-P
RFHP
AV
dBFS
80
_______________________________________________________________________________________
dB
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
COM Input Range
VCOM
Inferred from CMRR test
Common-Mode Rejection Ratio
CMRR
-300mV < VCOM < +300mV
Slew Rate
Charge-Pump Frequency
MIN
TYP
-300
MAX
UNITS
+300
mV
60
dB
SR
0.38
V/µs
fOSC
530
kHz
BEEP INPUT (LDO_EN = 1)
Beep Signal Minimum Frequency
Amplifier Turn-On Time
Amplifier Hold Time
fBEEP
Four-cycle count
215
tONBEEP
Hz
400
tHOLDBEEP
221
246
µs
271
ms
5.5
V
LOW-DROPOUT LINEAR REGULATOR
Regulator Input Voltage Range
VAVDD
LDO Ground Current
ILDO
Output Current
IOUT
Current Limit
ILIM
Inferred from line regulation,
VLDO_OUT = 4.75V
4.5
0.25
Inferred from load regulation
Speaker to LDO, VLDO_OUT = 4.75V,
f =1kHz, ILDO_OUT = 10mA, speaker POUT
= 1.2W, RL = 8Ω
Crosstalk
Output-Voltage Accuracy
Dropout Voltage
VDO
0.4
mA
120
mA
300
mA
-80
dB
VLDO_OUT = 4.75V
±1.5
VLDO_OUT = 3.3V
±1.5
VLDO_OUT = 4.75V,
TA = +25°C (Note 7)
IOUT = 50mA
46
IOUT = 120mA
106
Startup Time
mV
30
VAVDD = 4.5V to
5.5V,
ILDO_OUT = 1mA
Line Regulation
µs
VLDO_OUT = 4.75V
-4.8
1.5
+4.8
VLDO_OUT = 3.3V
-4
0.2
+4
mV/V
Load Regulation
VLDO_OUT = 4.75V, 1mA < ILDO_OUT <
120mA
Ripple Rejection
VRIPPLE = 200mVP-P,
VLDO_OUT = 4.75V
ILDO_OUT = 10mA
0.22
f = 1kHz
56
f = 10kHz
40
mV/mA
dB
20Hz to 20kHz, CLDO_OUT = 2 x 1µF,
ILDO_OUT = 120mA
Output-Voltage Noise
%
130
µVRMS
DIGITAL INPUTS (SPKR_EN, HP_EN, LDO_EN, BEEP)
Input-Voltage High
VINH
Input-Voltage Low
VINL
Input Bias Current
2
-1
V
0.4
V
+1
µA
_______________________________________________________________________________________
5
MAX9791/MAX9792
ELECTRICAL CHARACTERISTICS (continued)
ELECTRICAL CHARACTERISTICS (continued)
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.) (Note 3)
Note 3: All devices are 100% production tested at room temperature. All temperature limits are guaranteed by design.
Note 4: Testing performed with a resistive load in series with an inductor to simulate an actual speaker load. For RL = 3Ω, L = 22µH.
For RL = 4Ω, L = 33µH. For RL = 8Ω, L = 68µH.
Note 5: Specified at TA = +25°C with an 8Ω + 68µH load connected across BTL output for speaker amplifier. Specified at TA = +25°C
with a 32Ω resistive load connected between HPR, HPL and GND for headphone amplifier. Speaker and headphone mode
transitions are controlled by SPKR_EN and HP_EN inputs, respectively.
Note 6: Amplifier Inputs AC-coupled to GND.
Note 7: Guaranteed by ATE characterization; limits are not production tested.
Typical Operating Characteristics
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2 x 1µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, measurement BW
= 20kHz AES17, TA = +25°C, unless otherwise noted. Speaker mode: SPKR_EN = 0, HP_EN = 0. Headphone mode: SPKR_EN = 1,
HP_EN = 1.)
SPEAKER
RL = 3Ω
VIN = -3dBFS
-20
-20
FS = 1VRMS
-50
-60
-70
-30
-40
FS = 707mVRMS
-50
-60
-80
FS = 707mVRMS
-90
1
10
100
-60
FS = 1VRMS
-90
-100
-100
0.1
0.01
FS = 707mVRMS
-50
-80
FS = 1VRMS
-90
-100
-40
-70
-70
-80
0.1
0.01
1
10
0.01
100
0.1
1
10
100
TOTAL HARMONIC DISTORTION + NOISE
vs. OUTPUT POWER (MAX9792 SPEAKER MODE)
TOTAL HARMONIC DISTORTION + NOISE
vs. OUTPUT POWER (MAX9791 SPEAKER MODE)
TOTAL HARMONIC DISTORTION + NOISE
vs. OUTPUT POWER (MAX9791 SPEAKER MODE)
100
100
100
10
RL = 4Ω
10
f = 6kHz
0.1
f = 6kHz
f = 1kHz
1
0.1
0.01
f = 100Hz
0.001
1.0
1.5
2.0
2.5
OUTPUT POWER (W)
3.0
3.5
4.0
1
f = 1kHz
0.1
0.01
f = 100Hz
f = 100Hz
0.001
0.001
0.5
10
THD+N (%)
THD+N (%)
f = 1kHz
0
RL = 8Ω
f = 6kHz
1
0.01
MAX9791 toc06
FREQUENCY (kHz)
MAX9791 toc05
FREQUENCY (kHz)
MAX9791 toc04
FREQUENCY (kHz)
RL = 3Ω
6
-20
THD+N (dBFS)
-40
RL = 8Ω
VIN = -3dBFS
-10
-30
THD+N (dBFS)
-30
THD+N (dBFS)
RL = 4Ω
VIN = -3dBFS
-10
0
MAX9791 toc02
0
MAX9791 toc01
0
-10
TOTAL HARMONIC DISTORTION + NOISE
vs. FREQUENCY (MAX9791 SPEAKER MODE)
TOTAL HARMONIC DISTORTION + NOISE
vs. FREQUENCY (MAX9791 SPEAKER MODE)
MAX9791 toc03
TOTAL HARMONIC DISTORTION + NOISE
vs. FREQUENCY (MAX9792 SPEAKER MODE)
THD+N (%)
MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
0
0.5
1.0
1.5
2.0
OUTPUT POWER (W)
2.5
3.0
0
0.5
1.0
OUTPUT POWER (W)
_______________________________________________________________________________________
1.5
2.0
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
SPEAKER
3.5
3.0
2.5
THD+N = 1%
2.0
1.5
110
THD+N = 10%
100
RL = 8Ω
90
80
2.0
THD+N = 1%
1.5
1.0
70
RL = 3Ω
60
50
40
30
1.0
20
0.5
0.5
fIN = 1kHz
10
0
0
0
1
10
100
1
10
0.5
1.0
1.5
2.0
2.5
3.0
3.5
LOAD RESISTANCE (Ω)
OUTPUT POWER (W)
EFFICIENCY vs. OUTPUT POWER
(MAX9791 SPEAKER MODE)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (SPEAKER MODE)
CROSSTALK vs. FREQUENCY
(SPEAKER MODE)
VRIPPLE = 200mVP-P
RL = 8Ω
-20
RL = 4Ω
50
40
-40
-60
-70
20
-80
fIN = 1kHz
10
LEFT
-50
30
0.6
0.9
1.2
OUTPUT POWER (W)
1.5
1.8
-40
-50
-60
RIGHT TO LEFT
-70
-90
LEFT TO RIGHT
-100
-110
-100
0.3
FS = 1VRMS
VIN = -20dBFS
RL = 8Ω
-80
RIGHT
-90
0
-20
CROSSTALK (dB)
60
0
-10
-30
-30
PSRR (dB)
70
4.0
MAX9791 toc12
80
-10
MAX9791 toc11
0
MAX9791 toc10
RL = 8Ω
90
0
0
100
LOAD RESISTANCE (Ω)
100
EFFICIENCY (%)
MAX9791 toc09
2.5
OUTPUT POWER (W)
OUTPUT POWER (W)
THD+N = 10%
f = 1kHz
EFFICIENCY (%)
f = 1kHz
4.5
4.0
3.0
MAX9791 toc07
5.0
EFFICIENCY vs. OUTPUT POWER
(MAX9792 SPEAKER MODE)
OUTPUT POWER vs. LOAD RESISTANCE
(MAX9791 SPEAKER MODE)
MAX9791 toc08
OUTPUT POWER vs. LOAD RESISTANCE
(MAX9792 SPEAKER MODE)
0.01
0.1
1
FREQUENCY (kHz)
10
100
0.01
0.1
1
10
100
FREQUENCY (kHz)
_______________________________________________________________________________________
7
MAX9791/MAX9792
Typical Operating Characteristics (continued)
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2 x 1µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, measurement BW
= 20kHz AES17, TA = +25°C, unless otherwise noted. Speaker mode: SPKR_EN = 0, HP_EN = 0. Headphone mode: SPKR_EN = 1,
HP_EN = 1.)
Typical Operating Characteristics (continued)
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2 x 1µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, measurement BW
= 20kHz AES17, TA = +25°C, unless otherwise noted. Speaker mode: SPKR_EN = 0, HP_EN = 0. Headphone mode: SPKR_EN = 1,
HP_EN = 1.)
SPEAKER
SPEAKER STARTUP WAVEFORM
SPEAKER SHUTDOWN WAVEFORM
MAX9791 toc13
SPKR_EN
2V/div
SPKR_EN
2V/div
SPEAKER OUT
SPEAKER OUT
200μs/div
200μs/div
WIDEBAND OUTPUT SPECTRUM
(SPEAKER MODE)
OUTPUT FREQUENCY SPECTRUM
(SPEAKER MODE)
-40
-50
-60
-70
-80
-90
-100
MAX9791 toc16
0
MAX9791 toc15
0
-10
-20
-30
VOUT = -60dBV
f = 1kHz
RL = 8Ω
UNWEIGHTED
-20
-40
-60
-80
-100
-120
RBW = 1kHz
INPUT AC GROUNDED
-110
-120
-140
0
1
10
FREQUENCY (MHz)
8
MAX9791 toc14
OUTPUT MAGNITUDE (dBV)
OUTPUT AMPLITUDE (dBV)
MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
100
1
5
10
15
20
FREQUENCY (kHz)
_______________________________________________________________________________________
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
HEADPHONE
FS = 300mVRMS
-80
FS = 300mVRMS
-70
-80
FS = 1VRMS
RL = 32Ω
VIN = -3dBFS
-60
THD+N (dBFS)
-70
VHPVDD = 3V
RL = 16Ω
VIN = -3dBFS
-60
THD+N (dBFS)
-60
-50
MAX9791 toc18
RL = 16Ω
VIN = -3dBFS
THD+N (dBFS)
-50
MAX9791 toc17
-50
TOTAL HARMONIC DISTORTION + NOISE
vs. FREQUENCY (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION + NOISE
vs. FREQUENCY (HEADPHONE MODE)
MAX9791 toc19
TOTAL HARMONIC DISTORTION + NOISE
vs. FREQUENCY (HEADPHONE MODE)
-70
FS = 300mVRMS
-80
FS = 1VRMS
-90
-90
-90
FS = 1VRMS
-100
10
1
100
0.1
0.01
10
1
0.1
0.01
100
10
1
100
FREQUENCY (kHz)
FREQUENCY (kHz)
FREQUENCY (kHz)
TOTAL HARMONIC DISTORTION + NOISE
vs. FREQUENCY (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION + NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION + NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
FS = 300mVRMS
-80
1
f = 6kHz
0.1
MAX9791 toc22
10
RL = 32Ω
10
THD+N (%)
-70
100
MAX9791 toc21
RL = 16Ω
THD+N (%)
VHPVDD = 3V
RL = 32Ω
VIN = -3dBFS
-60
100
MAX9791 toc20
-50
THD+N (dBFS)
-100
-100
0.1
0.01
1
f = 1kHz
0.1
f = 1kHz
f = 100Hz
-90
FS = 1VRMS
f = 100Hz
-100
10
1
100
40
0
80
120
160
0
200
50
100
200
150
250
OUTPUT POWER (mW)
OUTPUT POWER (mW)
TOTAL HARMONIC DISTORTION + NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION + NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
OUTPUT POWER vs. LOAD RESISTANCE
(HEADPHONE MODE)
VHPVDD = 3V
RL = 32Ω
1
f = 100Hz
0.1
f = 1kHz
1
0.1
f = 1kHz
f = 6kHz
f = 100Hz
0.01
0.01
f = 1kHz
THD+N = 10%
200
OUTPUT POWER (mW)
10
THD+N (%)
10
250
MAX9791 toc24A
100
MAX9791 toc23
VHPVDD = 3V
RL = 16Ω
MAX9791 toc25
FREQUENCY (kHz)
100
THD+N (%)
0.001
0.001
0.1
0.01
f = 6kHz
0.01
0.01
150
THD+N = 1%
100
50
f = 6kHz
0.001
0
0.001
0
10
20
30
40
50
60
OUTPUT POWER (mW)
70
80
90
0
10
20
30
40
50
OUTPUT POWER (mW)
60
70
1
10
100
LOAD RESISTANCE (Ω)
_______________________________________________________________________________________
9
MAX9791/MAX9792
Typical Operating Characteristics (continued)
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2 x 1µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, measurement BW
= 20kHz AES17, TA = +25°C, unless otherwise noted. Speaker mode: SPKR_EN = 0, HP_EN = 0. Headphone mode: SPKR_EN = 1,
HP_EN = 1.)
Typical Operating Characteristics (continued)
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2 x 1µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, measurement BW
= 20kHz AES17, TA = +25°C, unless otherwise noted. Speaker mode: SPKR_EN = 0, HP_EN = 0. Headphone mode: SPKR_EN = 1,
HP_EN = 1.)
HEADPHONE
THD+N = 1%
50
40
30
20
10
300
250
200
150
100
RL = 32Ω
50
100
10
0
1000
200
150
RL = 32Ω
100
50
25
50
75
20
0
100 125 150 175 200
40
80
PER CHANNEL OUTPUT POWER (mW)
PER CHANNEL OUTPUT POWER (mW)
HEADPHONE OUTPUT POWER
vs. HPVDD VOLTAGE
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (HEADPHONE MODE)
CROSSTALK vs. FREQUENCY
(HEADPHONE MODE)
0
200
-20
-30
-40
RL = 32Ω
PSRR (dB)
150
100
-50
-60
-70
RIGHT
4.5
5.0
5.5
0.1
LEFT TO RIGHT
COM AND SENSE
1
10
100
0.01
0.1
1
10
FREQUENCY (kHz)
STARTUP WAVEFORM
MAX9791 toc33
MAX9791 toc32
OUTPUT FREQUENCY SPECTRUM (dB)
RIGHT TO LEFT
COM AND SENSE
-70
FREQUENCY (kHz)
OUTPUT FREQUENCY SPECTRUM
(HEADPHONE MODE)
RIGHT AND LEFT
FS = 707mVRMS
VIN = -60dBFS
RL = 32Ω
-20
-60
-100
0.01
VHPVDD (V)
0
-50
RL = 32Ω
RIGHT TO LEFT
FS = 300mVRMS
COM AND SENSE
VIN = -20dBFS
DISABLED
RIGHT TO LEFT
COM AND SENSE
DISABLED
-90
LEFT
-120
4.0
-30
-40
HP_EN
2V/div
-60
-80
HP_
500mV/div
-100
-120
-140
0
5
10
100
-80
-100
-110
3.5
-20
-40
-80
-90
RL = 16Ω
50
VRIPPLE = 200mVP-P
RL = 32Ω
-10
CROSSTALK (dB)
MAX9791 toc29
THD+N = 1%
f = 1kHz
0
15
20
200μs/div
FREQUENCY (kHz)
10
60
LOAD RESISTANCE (Ω)
250
3.0
RL = 16Ω
250
0
0
0
VHPVDD = 3V
MAX9791 toc28
MAX9791 toc27
RL = 16Ω
300
MAX9791 toc31
THD+N = 10%
60
350
MAX9791 toc30
OUTPUT POWER (mW)
70
POWER DISSIPATION PER CHANNEL (mW)
VHPVDD = 3V
f = 1kHz
80
400
MAX9791 toc26
90
POWER DISSIPATION vs. OUTPUT POWER
(HEADPHONE MODE)
POWER DISSIPATION vs. OUTPUT POWER
(HEADPHONE MODE)
POWER DISSIPATION PER CHANNEL (mW)
OUTPUT POWER vs. LOAD RESISTANCE
(HEADPHONE MODE)
HEADPHONE OUTPUT POWER (mW)
MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
______________________________________________________________________________________
100
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
HEADPHONE
MAX9791 toc34
MAX9791 toc35
HEADPHONE RF IMMUNITY
vs. FREQUENCY
SHUTDOWN WAVEFORM
RL = 32Ω
-10
HP_
500mV/div
AMPLITUDE (dBV)
-30
HP_EN
2V/div
-50
LEFT
-70
-90
RIGHT
-110
200μs/div
-130
500
1000
1500
2000
2500
3000
FREQUENCY (MHz)
______________________________________________________________________________________
11
MAX9791/MAX9792
Typical Operating Characteristics (continued)
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2 x 1µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, measurement BW
= 20kHz AES17, TA = +25°C, unless otherwise noted. Speaker mode: SPKR_EN = 0, HP_EN = 0. Headphone mode: SPKR_EN = 1,
HP_EN = 1.)
Typical Operating Characteristics (continued)
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2 x 1µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, measurement BW
= 20kHz AES17, TA = +25°C, unless otherwise noted. Speaker mode: SPKR_EN = 0, HP_EN = 0. Headphone mode: SPKR_EN = 1,
HP_EN = 1.)
LINE OUT
-20
RL = 10kΩ
10
-30
-40
-50
-60
FS = 707mVRMS
-70
FS = 1VRMS
-80
1
-40
THD+N (%)
THD+N (dBFS)
-50
-60
FS = 707mVRMS
-70
FS = 1VRMS
f = 6kHz
0.1
f = 100Hz
0.01
-80
-90
-90
-100
-100
-110
-110
0.01
0.1
1
10
100
0.001
f = 1kHz
0.0001
0.01
0.1
1
10
0
100
0.5
1.0
1.5
2.0
2.5
3.0
3.5
OUTPUT POWER (mW)
TOTAL HARMONIC DISTORTION + NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
CROSSTALK vs. FREQUENCY
(HEADPHONE MODE)
OUTPUT FREQUENCY SPECTRUM
(HEADPHONE MODE)
1
0.1
f = 6kHz
f = 100Hz
0.01
RL = 10kΩ
FS = 707mVRMS
VIN = -20dBFS
-30
-40
CROSSTALK (dB)
VHPVDD = 3V
RL = 10kΩ
10
-20
MAX9791 toc39
100
-50
-60
RIGHT TO LEFT
COM AND SENSE
-70
-80
-90
-100
0.001
LEFT TO RIGHT
COM AND SENSE
-110
f = 1kHz
0.0001
0.5
1.0
1.5
2.0
OUTPUT POWER (mW)
2.5
3.0
-20
-40
-60
-80
-100
-120
-140
-120
0
RIGHT AND LEFT
RL = 10kΩ
FS = 300mVRMS
VIN = -60dBFS
0
4.0
MAX9791 toc41
FREQUENCY (kHz)
OUTPUT FREQUENCY SPECTRUM (dB)
FREQUENCY (kHz)
MAX9791 toc40
THD+N (dBFS)
-30
12
VHPVDD = 3V
RL = 10kΩ
VIN = -3dBFS
-10
100
MAX9791 toc37
RL = 10kΩ
VIN = -3dBFS
-20
0
MAX9791 toc36
0
-10
TOTAL HARMONIC DISTORTION + NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION + NOISE
vs. FREQUENCY (HEADPHONE MODE)
MAX9791 toc38
TOTAL HARMONIC DISTORTION + NOISE
vs. FREQUENCY (HEADPHONE MODE)
THD+N (%)
MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
0.01
0.1
1
FREQUENCY (kHz)
10
100
0
5
10
FREQUENCY (kHz)
______________________________________________________________________________________
15
20
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
GENERAL
SHUTDOWN CURRENT vs. SUPPLY VOLTAGE
SUPPLY CURRENT vs. SUPPLY VOLTAGE
SUPPLY CURRENT (mA)
15
10
SPKR_EN = 0
HP_EN = 0
SPKR_EN = 0
HP_EN = 1
5
MAX9791 toc43
LDO_EN = 1
0.20
SHUTDOWN CURRENT (μA)
MAX9791 toc42
20
SPKR_EN = 1
HP_EN = 0
LDO_EN = 0
0.16
0.12
0.08
0.04
0
SPKR_EN = 1
HP_EN = 0
SPKR_EN = 1
HP_EN = 1
0
-5
4.50
4.75
5.00
5.25
SUPPLY VOLTAGE (V)
5.50
4.50
4.75
5.00
5.25
5.50
SUPPLY VOLTAGE (V)
______________________________________________________________________________________
13
MAX9791/MAX9792
Typical Operating Characteristics (continued)
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2 x 1µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, measurement BW
= 20kHz AES17, TA = +25°C, unless otherwise noted. Speaker mode: SPKR_EN = 0, HP_EN = 0. Headphone mode: SPKR_EN = 1,
HP_EN = 1.)
Typical Operating Characteristics (continued)
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2 x 1µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, measurement BW
= 20kHz AES17, TA = +25°C, unless otherwise noted. Speaker mode: SPKR_EN = 0, HP_EN = 0. Headphone mode: SPKR_EN = 1,
HP_EN = 1.)
LDO
0.5
0
-0.5
-1.0
-1.5
0.06
0.05
0.04
0.03
0.02
MAX9791 toc46
MAX9791 toc45
0.07
0.5
LDO_OUT = 3.3V
0
LDO_OUT = 4.75V
-0.5
0.01
-1.0
0
25
75
50
100
125
0
150
300
600
900
1200
LOAD CURRENT (mA)
AMPLIFIER OUTPUT POWER (mW)
LDO DROPOUT VOLTAGE vs. LOAD
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY LDO
40
MAX9791 toc47
300
LDO_OUT = 4.75V
250
20
VRIPPLE = 200mVP-P
ILOAD = 10mA
PSRR (dB)
100
-20
LDO_OUT = 4.74V
-60
50
LDO_OUT = 3.3V
-80
0
50
100
150
ILOAD (mA)
200
250
300
35
85
60
200
CLOAD = 2 x 1μF
ILOAD = 120mA
175
150
125
100
75
50
-100
0
10
LDO OUTPUT NOISE
0
-40
-15
TEMPERATURE (°C)
200
150
-40
1500
LDO OUTPUT NOISE (μV)
0
MAX9791 toc49
-2.0
14
0.08
1.0
LDO OUTPUT ACCURACY (%)
1.0
0.09
MAX9791 toc48
LDO OUTPUT ACCURACY (%)
1.5
0.10
LDO OUTPUT ACCURACY (%)
MAX9791 toc44
2.0
LDO OUTPUT ACCURACY
vs. TEMPERATURE
LDO OUTPUT ACCURACY
vs. AMPLIFIER OUTPUT POWER
LDO OUTPUT ACCURACY
vs. LOAD CURRENT
LDO DROPOUT VOLTAGE (mV)
MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
0.01
0.1
1
FREQUENCY (kHz)
10
100
0.01
0.1
1
FREQUENCY (kHz)
______________________________________________________________________________________
10
100
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
LDO
LOAD-TRANSIENT RESPONSE
LINE-TRANSIENT RESPONSE
MAX9791 toc51
MAX9791 toc50
ILDO_OUT
50mV/div
CH1 LOW
4.560V
CH1 HIGH
5.500V
CH2 LOW
800.0μV
AC-COUPLED
VLDO_OUT
10mV/div
CH2 HIGH
1.000mV
100ms/div
SHUTDOWN RESPONSE
CROSSTALK vs. FREQUENCY
SPEAKER TO LDO
LDO_EN
2V/div
VLDO_EN
2V/div
200μs/div
CROSSTALK (dB)
MAX9791 toc52
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
MAX9791 toc53
1.00ms/div
BOTH SPEAKERS WITH SIGNAL
PSPKR = 1.2W
RLSPKR = 8W
ILDO = 10mA
LEFT CHANNEL TO LDO
RIGHT CHANNEL TO LDO
0.01
0.1
1
10
100
FREQUENCY (kHz)
______________________________________________________________________________________
15
MAX9791/MAX9792
Typical Operating Characteristics (continued)
(VAVDD = VPVDD = VHPVDD = 5V, VGND = VPGND = VCPGND = 0, ILDO_OUT = 0, CLDO = 2 x 1µF, C1 = C2 = 1µF. RL = ∞, unless otherwise specified. RIN1 = 20kΩ (AVSPKR = 12dB), RIN2 = 40.2kΩ (AVHP = 0dB), CIN1 = 470nF, CIN2 = CCOM = 1µF, measurement BW
= 20kHz AES17, TA = +25°C, unless otherwise noted. Speaker mode: SPKR_EN = 0, HP_EN = 0. Headphone mode: SPKR_EN = 1,
HP_EN = 1.)
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
MAX9791/MAX9792
MAX9791 Pin Description
16
PIN
NAME
1
SPKR_INL
FUNCTION
2
HP_INR
Right-Channel Headphone Amplifier Input
3
HP_INL
Left-Channel Headphone Amplifier Input
4
COM
Common-Mode Voltage Sense Input
5
GND
Signal Ground. Star connect to PGND.
6
LDO_OUT
7
AVDD
8
LDO_EN
Left-Channel Speaker Amplifier Input
LDO Output. Bypass with two 1µF ceramic low ESR capacitors to GND.
Positive Power-Supply and LDO Input. Bypass with a 0.1µF and two 1µF capacitors to GND.
LDO Enable. Connect LDO_EN to AVDD to enable the LDO.
9
HPR
Right-Channel Headphone Amplifier Output
10
HPL
Left-Channel Headphone Amplifier Output
11
SENSE
12
CPVSS
Headphone Amplifier Negative Power Supply. Connect a 1µF capacitor between CPVSS and PGND.
13
C1N
Charge-Pump Flying Capacitor Negative Terminal. Connect a 1µF capacitor between C1P and C1N.
14
CPGND
Headphone Ground Sense
Charge-Pump Ground. Connect directly to PGND plane.
15
C1P
Charge-Pump Flying Capacitor Positive Terminal. Connect a 1µF capacitor between C1P and C1N.
16
HPVDD
Headphone Amplifier Positive Power Supply. Connect a 10µF capacitor between HPVDD and PGND.
17, 26
PVDD
Speaker Amplifier Power-Supply Input. Bypass with a 0.1µF capacitor to PGND.
18
OUTL-
Left-Channel Speaker Amplifier Output, Negative Phase
19
OUTL+
Left-Channel Speaker Amplifier Output, Positive Phase
20, 23
PGND
Power Ground. Star connect to GND.
21
BEEP
PC Beep Input. Connect to GND if beep detection function is disabled.
22
HP_EN
24
OUTR+
Right-Channel Speaker Amplifier Output, Positive Phase
25
OUTR-
Right-Channel Speaker Amplifier Output, Negative Phase
27
SPKR_EN
28
SPKR_INR
—
EP
Active-High Headphone Amplifier Enable
Active-Low Speaker Amplifier Enable
Right-Channel Speaker Amplifier Input
Exposed Pad. Connect to GND.
______________________________________________________________________________________
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
PIN
NAME
FUNCTION
1, 5
GND
2
HP_INR
Right-Channel Headphone Amplifier Input
3
HP_INL
Left-Channel Headphone Amplifier Input
4
COM
6
LDO_OUT
7
AVDD
8
LDO_EN
9
HPR
Signal Ground. Star connect to PGND.
Common-Mode Voltage Sense Input
LDO Output. Bypass with two 1µF ceramic low ESR capacitors to GND.
Positive Power Supply and LDO Input. Bypass with a 0.1µF and two 1µF capacitors to GND.
LDO Enable. Connect LDO_EN to AVDD to enable the LDO.
Right-Channel Headphone Amplifier Output
10
HPL
11
SENSE
Headphone Ground Sense
Left-Channel Headphone Amplifier Output
12
CPVSS
Headphone Amplifier Negative Power Supply. Connect a 1µF capacitor between CPVSS and PGND.
13
C1N
Charge-Pump Flying Capacitor Negative Terminal. Connect a 1µF capacitor between C1P and C1N.
14
CPGND
15
C1P
Charge-Pump Ground. Connect directly to PGND plane.
Charge-Pump Flying Capacitor Positive Terminal. Connect a 1µF capacitor between C1P and C1N.
16
HPVDD
17, 26
PVDD
Speaker Amplifier Power-Supply Input. Bypass with a 0.1µF capacitor to PGND.
Headphone Amplifier Positive Power Supply. Connect a 10µF capacitor between HPVDD and PGND.
18, 25
OUT-
Speaker Amplifier Output, Negative Phase
19, 24
OUT+
Speaker Amplifier Output, Positive Phase
20, 23
PGND
Power Ground. Star connect to GND.
21
BEEP
PC Beep Input. Connect to GND if beep detection function is disabled.
22
HP_EN
27
SPKR_EN
Active-Low Speaker Amplifier Enable
Active-High Headphone Amplifier Enable
28
SPKR_IN
Speaker Amplifier Input
—
EP
Exposed Pad. Connect to GND.
Detailed Description
The MAX9791 combines a stereo 2W Class D power
amplifier, a stereo 175mW DirectDrive headphone
amplifier, and a 120mA LDO linear regulator in a single
device. The MAX9792 combines a mono 3W Class D
power amplifier, a stereo 175mW DirectDrive headphone amplifier, and a 120mA LDO linear regulator in a
single device.
The MAX9791/MAX9792 feature wake-on-beep detection, comprehensive click-and-pop suppression, lowpower shutdown mode, and excellent RF immunity.
These devices incorporate an integrated LDO that
serves as a clean power supply for CODEC or other circuits. The MAX9791/MAX9792 are Windows Vista
Premium compliant. See Table 1 for a comparison of the
Windows Vista Premium specifications and MAX9791/
MAX9792 specifications.
The MAX9791/MAX9792 feature spread-spectrum modulation and active emission limiting circuitry that offers
significant improvements to switch-mode amplifier technology. These devices offer Class AB performance with
Class D efficiency in a minimal board-space solution.
The headphone amplifiers use Maxim’s patented
DirectDrive architecture to eliminate the bulky output
DC-blocking capacitors required by traditional headphone amplifiers. A charge pump inverts the positive
supply (HPVDD) to create a negative supply (CPVSS).
The headphone amplifiers operate from these bipolar
supplies with their outputs biased about GND. The benefit of the GND bias is that the amplifier outputs no
longer have a DC component (typically VDD/2). This
feature eliminates the large DC-blocking capacitors
required with conventional headphone amplifiers to
______________________________________________________________________________________
17
MAX9791/MAX9792
MAX9792 Pin Description
Table 1. Windows Premium Mobile Vista Specifications vs. MAX9791/MAX9792
Specifications
DEVICE TYPE
Analog Line-Out Jack
(RL = 10kΩ, FS =
0.707VRMS)
Analog Headphone-Out
Jack (RL = 32Ω, FS =
0.300VRMS)
REQUIREMENT
WINDOWS PREMIUM
MOBILE VISTA
SPECIFICATIONS
MAX9791/MAX9792
TYPICAL PERFORMANCE
THD+N
≤ -65dB FS [100Hz, 20kHz]
Dynamic range with signal
present
≤ -80dBV, A-weighted [20Hz,
20kHz]
87dBFS [100Hz, 20kHz]
Line output crosstalk
≤ -50dB [20Hz, 15kHz]
THD+N
≤ -45dB FS [100Hz, 20kHz]
Dynamic range with signal
present
≤ -60dBV, A-weighted [20Hz,
20kHz]
Headphone output
crosstalk
≤ -50dB [20Hz, 15kHz]
-98.9dB A-weighted [20Hz, 20kHz]
64dB [20Hz, 15kHz]
82dBFS [100Hz, 20kHz]
-91.5dB A-weighted [20Hz, 20kHz]
64dB [20Hz, 15kHz]
Note: THD+N, dynamic range with signal present, and crosstalk should be measured in accordance with AES17 audio measurements standards.
conserve board space and system cost, as well as
improve low-frequency response and distortion.
The MAX9791/MAX9792 amplifiers feature an undervoltage lockout that prevents operation from an insufficient power supply and click-and-pop suppression that
eliminates audible transients on startup and shutdown.
The amplifiers include thermal overload and short-circuit protection.
Class D Speaker Amplifier
The MAX9791/MAX9792 integrate a filterless class D
amplifier that offers much higher efficiency than class AB
amplifiers. The high efficiency of a Class D amplifier is
due to the switching operation of the output stage transistors. In a Class D amplifier, the output transistors act
as current steering switches and consume negligible
additional power. Any power loss associated with the
Class D output stage is mostly due to the I2R loss of the
MOSFET on-resistance and quiescent current overhead.
The theoretical best efficiency of a linear amplifier is
78%, however, that efficiency is only exhibited at peak
output power. Under normal operating levels (typical
music reproduction levels), efficiency falls below 45%,
whereas the MAX9791/MAX9792 exhibit 67% efficiency
under the same conditions (Figure 1).
18
EFFICIENCY vs. IDEAL
CLASS AB EFFICIENCY
90
80
70
EFFICIENCY (%)
MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
60
MAX9791
50
40
IDEAL CLASS AB
30
20
10
0
0
0.25
0.50
0.75
1.00
1.25
1.50
OUTPUT POWER (W)
Figure 1. MAX9791 Efficiency vs. Class AB Efficiency
Ultra-Low EMI Filterless Output Stage
In traditional Class D amplifiers, the high dv/dt of the
rising and falling edge transitions resulted in increased
electromagnetic-interference (EMI) emissions, which
required the use of external LC filters or shielding to
meet EN55022B EMI regulation standards. Limiting the
dv/dt normally results in decreased efficiency. Maxim’s
active emissions limiting circuitry actively limits the
dv/dt of the rising and falling edge transitions, providing
reduced EMI emissions while maintaining up to 83%
efficiency.
______________________________________________________________________________________
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
40
35
AMPLITUDE (dBμV/m)
VOUT
VDD/2
30
25
GND
20
CONVENTIONAL AMPLIFIER BIASING SCHEME
15
+VDD
10
5
30
100
1000
FREQUENCY (MHz)
VOUT
GND
Figure 2. EMI with 30cm of Speaker Cable
In addition to active emission limiting, the MAX9791/
MAX9792 feature patented spread-spectrum modulation
that flattens the wideband spectral components.
Proprietary techniques ensure that the cycle-to-cycle
variation of the switching period does not degrade audio
reproduction or efficiency (see the Typical Operating
Characteristics). In spread-spectrum modulation mode,
the switching frequency varies randomly by ±15kHz
around the center frequency (530kHz). The effect is to
reduce the peak energy at harmonics of the switching
frequency. Above 10MHz, the wideband spectrum looks
like noise for EMI purposes (see Figure 2).
Speaker Current Limit
When the output current of the speaker amplifier
exceeds the current limit (2A, typ) the MAX9791/
MAX9792 disable the outputs for approximately 100µs.
At the end of 100µs, the outputs are re-enabled. If the
fault condition still exists, the MAX9791/MAX9792 continue to disable and re-enable the outputs until the fault
condition is removed.
DirectDrive Headphone Amplifier
Traditional single-supply headphone amplifiers bias the
outputs at a nominal DC voltage (typically half the supply). Large coupling capacitors are needed to block
this DC bias from the headphone. Without these capacitors, a significant amount of DC current flows to the
headphone, resulting in unnecessary power dissipation
and possible damage to both headphone and headphone amplifier.
-VDD
DirectDrive AMPLIFIER BIASING SCHEME
Figure 3. Traditional Amplifier Output vs. MAX9791/MAX9792
DirectDrive Output
Maxim’s patented DirectDrive architecture uses a
charge pump to create an internal negative supply voltage. This allows the headphone outputs of the
MAX9791/MAX9792 to be biased at GND while operating from a single supply (Figure 3). Without a DC component, there is no need for the large DC-blocking
capacitors. Instead of two large (220µF, typ) capacitors, the MAX9791/MAX9792 charge pump requires two
small 1µF ceramic capacitors, conserving board space,
reducing cost, and improving the frequency response
of the headphone amplifier.
The MAX9791/MAX9792 feature a low-noise charge
pump. The nominal switching frequency of 530kHz is
well beyond the audio range, and thus does not interfere with audio signals. The switch drivers feature a
controlled switching speed that minimizes noise generated by turn-on and turn-off transients. By limiting the
switching speed of the charge pump, the di/dt noise
caused by the parasitic trace inductance is minimized.
______________________________________________________________________________________
19
MAX9791/MAX9792
VDD
CLASS D EMI PLOT
MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
RFHP
CROSSTALK
vs. GROUND RESISTANCE (RG)
-40
CIN2
HP_INL
HPL
RIN2
COM
RFHP
SENSE
RCOM
CROSSTALK (dB)
-50
HPR
CCOM
RS = 5Ω
RL = 32Ω
-45
-55
-60
-65
-70
CIN2
-75
HP_INR
-80
RIN2
0
RFHP
0.025
0.050
0.075
0.100
0.125
0.150
RG (Ω)
Figure 4. Connecting COM for Ground Sense
Figure 5. Crosstalk vs. Ground Resistance
Common-Mode Sense
Windows Vista-compliant platforms are restricted to only
115mΩ of ground return impedance. If the headphone
jack ground is connected close to the audio device
ground using a solid ground plane, the return path resistance can be quite low. However, it is often necessary to
locate some jacks far from the audio device. The
MAX9791/MAX9792 COM and SENSE inputs allow the
headphone jack to be placed further away from the
device without degrading crosstalk performance.
The headphone amplifier output impedance, trace
resistance, and contact resistance of the jack are
grouped together to represent the source resistance,
RS. The resistance between the load and the sleeve,
the sleeve contact resistance, and the system ground
return resistance are grouped together to represent the
ground resistance, RG.
Assuming a typical source resistance of 5Ω, the ground
return impedance would need to be limited to 115mΩ
to meet Windows Vista’s crosstalk specification of 50dB
(Figure 5). This is further complicated by the fact that
the impedance of the sleeve connection in the 3.5mm
stereo jack can make up 30mΩ–90mΩ alone.
The MAX9791/MAX9792 COM and SENSE inputs
reduce crosstalk performance by eliminating effects of
28.5mΩ of ground return path resistance. If ground
sensing is not required, connect COM directly to GND
and leave SENSE unconnected (Figure 6).
The MAX9791/MAX9792 SENSE and COM inputs sense
and correct for the difference between the headphone
return and device ground. When using common-mode
sense, connect COM through a resistor to GND of the
device (Figure 4). For optimum common-mode rejection, use the same value resistors for RIN2 and RCOM.
To improve AC CMRR, add a capacitor equal to CIN2
between GND and RCOM.
Configuring SENSE and COM in this way improves system crosstalk performance by reducing the negative
effects of the headphone jack ground return resistance.
⎛ RG ⎞
Crosstalk in dB = 20 log ⎜
⎟
⎝ RL + RS ⎠
20
Wake-on-Beep
The MAX9791/MAX9792 beep-detection circuit wakes
up the device (speaker and headphone amplifiers)
once a qualified beep signal is detected at BEEP and
the LDO is enabled. The amplifier wake command from
the beep-detection circuit overrides the logic signal
applied at HP_EN and SPKR_EN.
______________________________________________________________________________________
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
MAX9791/MAX9792
CROSSTALK vs. FREQUENCY
(HEADPHONE MODE)
-20
-30
RL = 32Ω
FS = 300mVRMS
VOUT = -20dBFS
RIGHT TO LEFT
COM AND SENSE
DISABLED
-40
CROSSTALK (dB)
A qualified BEEP signal consists of a 3.3V typical,
215Hz minimum signal that is present at BEEP for four
consecutive cycles. Once the first rising edge transition
is detected at BEEP, the beep circuit wakes up and
begins counting the beep cycles. Once four consecutive cycles of a qualified beep signal are counted, the
device (speaker and headphone amplifiers) enables
within 400µs. If the first rising edge is not followed by
three consecutive rising edges within 16ms, the device
remains shutdown (i.e., glitch protection).
The device (speaker and headphone amplifiers) returns
to its programmed logic state once 246ms has elapsed
from the time the last rising edge was detected. This
246ms amplifier hold time ensures complete beep profiles are passed to the amplifier outputs (Figure 7).
Ground BEEP when the wake-on-beep feature is not
used. Do not leave BEEP unconnected.
LEFT TO RIGHT
COM AND SENSE
DISABLED
-50
-60
RIGHT TO LEFT
COM AND SENSE
-70
-80
LEFT TO RIGHT
COM AND SENSE
-90
-100
0.01
0.1
1
10
100
FREQUENCY (kHz)
Low-Dropout Linear Regulator
The LDO regulator can be used to provide a clean
power supply to a CODEC or other circuitry. The LDO
can be enabled independently of the audio amplifiers.
Set LDO_EN = AVDD to enable the LDO or set LDO_EN
= GND to disable the LDO. The LDO can provide up to
120mA of continuous current.
Figure 6. MAX9791/MAX9792 COM and SENSE Inputs Reduce
Crosstalk
time, connect SPKR_EN and HP_EN together, allowing
a single logic voltage to enable either the speaker or
the headphone amplifier as shown in Figure 8.
Speaker and Headphone Amplifier Enable
The MAX9791/MAX9792 feature control inputs for the
independent enabling of the speaker and headphone
amplifiers, allowing both to be active simultaneously
if required. Driving SPKR_EN high disables the speaker
amplifiers. Driving HP_EN low independently disables
the headphone amplifiers. For applications that
require only one of the amplifiers to be on at a given
Shutdown
The MAX9791/MAX9792 feature a low-power shutdown
mode, drawing 0.1µA of supply current. By disabling
the speaker, headphone amplifiers, and the LDO, the
MAX9791/MAX9792 enter low-power shutdown mode.
Set SPKR_EN to AVDD and HP_EN and LDO_EN to
GND to disable the speaker amplifiers, headphone
amplifiers, and LDO, respectively.
16ms
BEEP
1
2
3
4
240ms
SPKR AND HP
AMPS ENABLE
400μs
Figure 7. Qualified BEEP Signal Timing
______________________________________________________________________________________
21
MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
MAX9791
RFB
20kΩ
MAX9791A/B
MAX9792A
SINGLE
CONTROL
SPKR_EN
CIN1
RIN1
SPKR_IN_
MONO
CLASS D
AMPLIFIER
OUT_+
OUT_-
HP_EN
Figure 8. Enabling Either the Speaker or Headphone Amplifier
with a Single Control Pin
Click-and-Pop Suppression
The MAX9791/MAX9792 feature a common-mode bias
voltage of 0V. A 0V BIAS allows the MAX9791/MAX9792
to quickly turn on/off with no resulting clicks and pops.
With the HDA CODEC outputs biased and the
MAX9791/MAX9792 inputs sitting as 0V in shutdown
and normal operation, the RIN x CIN time constant is
eliminated.
Speaker Amplifier
The MAX9791/MAX9792 speaker amplifiers feature
Maxim’s comprehensive, industry leading click-andpop suppression. During startup and shutdown, the
click-and-pop suppression circuitry eliminates any
audible transient sources internal to the device.
Headphone Amplifier
In conventional single-supply headphone amplifiers,
the output-coupling capacitor is a major contributor of
audible clicks and pops. Upon startup, the amplifier
charges the coupling capacitor to its bias voltage, typically V DD/2. During shutdown, the capacitor is discharged to GND; a DC shift across the capacitor
results, which in turn appears as an audible transient at
the speaker. Because the MAX9791/MAX9792 do not
require output-coupling capacitors, no audible transient
occurs.
The MAX9791/MAX9792 headphone amplifiers feature
extensive click-and-pop suppression that eliminates
any audible transient sources internal to the device.
22
Figure 9. Setting Speaker Amplifier Gain
Applications Information
Filterless Class D Operation
Traditional Class D amplifiers require an output filter to
recover the audio signal from the amplifier’s output. The
filters add cost and size and can decrease efficiency
and THD+N performance. The traditional PWM scheme
uses large differential output swings (2 x PVDD peakto-peak) causing large ripple currents. Any parasitic
resistance in the filter components results in a loss of
power, lowering the efficiency.
The MAX9791/MAX9792 do not require an output filter.
The devices rely on the inherent inductance of the speaker coil and the natural filtering of both the speaker and
the human ear to recover the audio component of the
square-wave output. Eliminating the output filter results in
a smaller, less costly, and more efficient solution.
Because the frequency of the MAX9791/MAX9792 output is well beyond the bandwidth of most speakers,
voice coil movement due to the square-wave frequency
is very small. For optimum results, use a speaker with a
series inductance > 10µH. Typical 8Ω speakers exhibit
series inductances in the 20µH to 100µH range.
______________________________________________________________________________________
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
L1*
MAX9791A/B
MAX9792A
⎛ 20kΩ ⎞
A VSPKR = -4 ⎜
V/V
⎝ RIN1 ⎟⎠
Component Selection
Optional Ferrite Bead Filter
In applications where speaker leads exceed 15cm, use
a filter constructed from a ferrite bead and a capacitor
to ground (Figure 10) to provide additional EMI suppression. Use a ferrite bead with low DC resistance,
high frequency (> 1.2MHz) impedance of 100Ω to
600Ω, and rated for at least 1A. The capacitor value
varies based on the ferrite bead chosen and the actual
speaker lead length. Select the capacitor value based
on EMI performance.
L2*
330pF
330pF
*L1 = L2 = WÜRTH 742792040
Figure 10. Optional Ferrite Bead Filter
TOTAL HARMONIC DISTORTION + NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
100
RL = 32Ω
10
THD+N (%)
where AVSPKR is the desired voltage gain. An RIN1 of
20kΩ yields a gain of 4V/V, or 12dB.
MAX9791/MAX9792
Setting Speaker Amplifier Gain
External input resistors in conjunction with the internal
feedback resistors (RFSPKR) set the speaker amplifier
gain of the MAX9791/MAX9792. Set gain by using
resistor RIN1 as follows (Figure 9):
OUT OF PHASE
1
IN PHASE
0.1
Output Power (Headphone Amplifier)
The headphone amplifiers are specified for the worstcase scenario when both inputs are in phase. Under
this condition, the drivers simultaneously draw current
from the charge pump, leading to a slight loss in headroom of CPVSS. In typical stereo audio applications, the
left and right signals have differences in both magnitude and phase, subsequently leading to an increase in
the maximum attainable output power. Figure 11 shows
the two extreme cases for in and out of phase. In most
cases, the available power lies between these
extremes.
Headphone Amplifier Gain
Gain-Setting Resistors
External input resistors in conjunction with the internal
feedback resistors (RFHP) set the headphone amplifier
gain of the MAX9791/MAX9792. Set gain by using
resistor RIN2 (Figure 4) as follows:
⎛ 40.2kΩ ⎞
A VHP = - ⎜
V/V
⎝ RIN2 ⎟⎠
0.01
0.001
0
50
100
150
200
250
OUTPUT POWER (mW)
Figure 11. Output Power vs. Supply Voltage with Inputs In/Out
of Phase; 32W Load Conditions and 3.5dB Gain
Power Supplies
The MAX9791/MAX9792 speaker amplifiers are powered from PVDD with a range from 4.5V to 5.5V. The
headphone amplifiers are powered from HPVDD and
CPVSS. HPVDD is the positive supply of the headphone
amplifiers and charge pump ranging from 2.7V to 5.5V.
CPVSS is the negative supply of the headphone amplifiers. The charge pump inverts the voltage at HPVDD,
and the resulting voltage appears at CPVSS. AVDD
powers the remainder of the device.
where AVHP is the desired voltage gain. An RIN2 of
40.2kΩ yields a gain of 1V/V, or 0dB.
______________________________________________________________________________________
23
SPEAKER RF IMMUNITY
vs. FREQUENCY
INPUT COUPLING CAPACITOR-INDUCED THD+N
vs. FREQUENCY (HEADPHONE MODE)
-50
-60
-70
VOUT - -3dBFS
FS = 1VRMS
RL =32Ω
AMPLITUDE (dBV)
0603 10V X7R 10% 1μF
THD+N (dBFS)
MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
0603 10V X5R 10% 1μF
-80
0805 50V X7R 10% 1μF
-90
0402 6.3V X5R 10% 1μF
-100
10
100
1000
FREQUENCY (kHz)
Figure 12. Input Coupling Capacitor-Induced THD+N vs.
Frequency
Component Selection
Speaker Amplifier Power-Supply Input (PVDD)
PVDD powers the speaker amplifiers. PVDD ranges
from 4.5V to 5.5V. Bypass PVDD with a 0.1µF capacitor
to PGND. Apply additional bulk capacitance at the
device if long input traces between PVDD and the
power source are used.
Headphone Amplifier Power-Supply Input
(HPVDD and CPVSS)
The headphone amplifiers are powered from HPVDD
and CPVSS. HPVDD is the positive supply of the headphone amplifiers and ranges from 2.7V to 5.5V. Bypass
HPVDD with a 10µF capacitor to PGND. CPVSS is the
negative supply of the headphone amplifiers. Bypass
CPVSS with a 1µF capacitor to PGND. The charge
pump inverts the voltage at HPVDD, and the resulting
voltage appears at CPVSS. A 1µF capacitor should be
connected between C1N and C1P.
Positive Power Supply and LDO Input (AVDD)
The internal LDO and the remainder of the device are
powered by AVDD. AVDD ranges from 4.5V to 5.5V.
Bypass AVDD with a 0.1µF capacitor to GND and two
1µF capacitors to GND. Note additional bulk capacitance is required at the device if long input traces
between AVDD and the power source are used.
Input Filtering
The input capacitor (C IN_ ), in conjunction with the
amplifier input resistance (RIN_), forms a highpass filter
that removes the DC bias from the incoming signal.
24
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
RIGHT
LEFT
0
500
1000
1500
2000
2500
3000
FREQUENCY (MHz)
Figure 13. Speaker RF Immunity
The AC-coupling capacitor allows the amplifier to bias
the signal to an optimum DC level. Assuming zero
source impedance, the -3dB point of the highpass filter
is given by:
f -3dB =
1
2πRIN _ CIN _
RIN_ is the amplifier’s external input resistance value.
Choose CIN_ such that f-3dB is well below the lowest frequency of interest. Setting f-3dB too high affects the amplifier’s low frequency response. Use capacitors with
adequately low-voltage coefficient dielectrics (see Figure
12). Capacitors with higher voltage coefficients, such as
ceramics, result in increased distortion at low frequencies.
Charge-Pump Capacitor Selection
Use capacitors with an ESR less than 100mΩ for optimum performance. Low ESR ceramic capacitors minimize the output resistance of the charge pump. For
best performance over the extended temperature
range, select capacitors with an X7R dielectric.
Flying Capacitor (C1)
The value of the flying capacitor (C1) affects the load
regulation and output resistance of the charge pump. A
C1 value that is too small degrades the device’s ability
to provide sufficient current drive, which leads to a loss
of output voltage. Connect a 1µF capacitor between
C1P and C1N.
______________________________________________________________________________________
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
Layout and Grounding
Proper layout and grounding are essential for optimum
performance. Use large traces for the power-supply
inputs and amplifier outputs to minimize losses due to
parasitic trace resistance, as well as route heat away
from the device. Good grounding improves audio performance, minimizes crosstalk between channels, and
prevents switching noise from coupling into the audio
signal. Connect PGND and GND together at a single
point on the PCB. Route PGND and all traces that carry
switching transients away from GND, and the traces
and components in the audio signal path.
Connect C2 to the PGND plane. Place the chargepump capacitors (C1, C2) as close as possible to the
device. Bypass PVDD with a 0.1µF capacitor to PGND.
Place the bypass capacitors as close as possible to the
device.
The MAX9791/MAX9792 is inherently designed for
excellent RF immunity. For best performance, add
ground fills around all signal traces on top or bottom
PCB planes.
Use large, low-resistance output traces. As load impedance decreases, the current drawn from the device outputs increase. At higher current, the resistance of the
output traces decrease the power delivered to the load.
For example, if 2W is delivered from the speaker output
to a 4Ω load through a 100mΩ trace, 49mW is wasted
in the trace. If power is delivered through a 10mΩ
trace, only 5mW is wasted in the trace. Large output,
supply, and GND traces also improve the power dissipation of the device.
The MAX9791/MAX9792 thin QFN package features an
exposed thermal pad on its underside. This pad lowers
the package’s thermal resistance by providing a direct
heat conduction path from the die to the printed circuit
board. Connect the exposed thermal pad to GND by
using a large pad and multiple vias to the GND plane.
Chip Information
PROCESS: BiCMOS
______________________________________________________________________________________
25
MAX9791/MAX9792
Output Capacitor (C2)
Connect a 1µF capacitor between CPVSS and PGND.
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
HPVDD
C1P
15
PVDD
16
OUT-
17
OUT+
C1P
18
PGND
HPVDD
19
TOP VIEW
BEEP
PVDD
20
OUTL+
21
OUTL-
PGND
TOP VIEW
BEEP
21
20
19
18
17
16
15
14
CPGND
HP_EN 22
14
CPGND
PGND 23
13
C1N
PGND 23
13
C1N
OUTR+ 24
12
CPVSS
OUT+ 24
12
CPVSS
11
SENSE
OUT- 25
11
SENSE
10
HPL
PVDD 26
10
HPL
9
HPR
SPKR_EN 27
9
HPR
8
LDO_EN
4
HP_INL
COM
5
6
7
AVDD
3
GND
2
LDO_OUT
1
HP_INR
8
SPKR_INL
SPKR_INR 28
LDO_EN
SPKR_IN 28
+
1
2
3
4
5
6
7
AVDD
+
*EP
LDO_OUT
*EP
GND
PVDD 26
SPKR_EN 27
MAX9792A
COM
MAX9791A
MAX9791B
HP_INL
OUTR- 25
HP_INR
HP_EN 22
GND
MAX9791/MAX9792
Pin Configurations
TQFN
(4mm x 4mm x 0.75mm)
TQFN
(4mm x 4mm x 0.75mm)
*EP = EXPOSED PAD
*EP = EXPOSED PAD
Simplified Block Diagrams
(continued)
SPEAKER SUPPLY
4.5V TO 5.5V
HEADPHONE SUPPLY
2.7V TO 5.5V
CLASS D
AMP
SPKR_IN
MAX9792A
HP_INR
HP_INL
SPKR_EN
HP_EN
LDO_EN
BEEP
4.5V TO 5.5V
26
LDO
______________________________________________________________________________________
4.75V
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
4.5V TO 5.5V
0.1μF
PVDD
17, 26
CIN3
CIN1
RIN3
RIN1
CIN1
RIN1
CIN3
RIN3
MAX9791A
MAX9791B
20kΩ
SPKR_INL
SPKR_INR
1
STEREO
CLASS D
AMPLIFIER
28
19
OUTL+
18
OUTL-
24
OUTR+
25
OUTR-
10
HPL
9
HPR
20kΩ
CIN2
RIN2
HP_INL
40.2kΩ
3
TO HPVDD
CIN2
RIN2
HP_INR
2
LDO_EN
8
HP_EN
22
TO CPVSS
4.5V TO 5.5V
CONTROL
μC BEEP INPUT
BEEP 21
SPKR_EN 27
CCOM RCOM
COM
TO HPVDD
40.2kΩ
4
40.2kΩ
4.5V TO 5.5V
AVDD
1.0μF
1.0μF
11
SENSE
16
HPVDD
15
C1P
14
CPGND
13
C1N
2.7V TO 5.5V
C3
10μF
7
CHARGE
PUMP
0.1μF
C1
1.0μF
LDO BLOCK
LDO_OUT
TO CODEC
1.0μF
1.0μF
NOTE: LOGIC PINS CONFIGURED FOR:
LDO_EN = 1, LDO ENABLED
SPKR_EN = 0, SPEAKER AMPLIFIERS ENABLED
HP_EN = 1, HEADPHONE AMPLIFIER ENABLED
6
20, 23
5
GND
PGND
12
CPVSS
C2
1.0μF
______________________________________________________________________________________
27
MAX9791/MAX9792
MAX9791A/MAX9791B Block Diagram
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
MAX9791/MAX9792
MAX9792A Block Diagram
4.5V TO 5.5V
0.1μF
PVDD
17, 26
CIN3
CIN1
CIN2
MAX9792A
MAX9792B
RIN3
20kΩ
RIN1
SPKR_IN
RIN2
HP_INL
MONO
CLASS D
AMPLIFIER
28
19, 24
OUT+
18, 25
OUT-
40.2kΩ
3
TO HPVDD
CIN2
RIN2
HP_INR
2
LDO_EN
8
HP_EN
22
10
HPL
9
HPR
TO CPVSS
4.5V TO 5.5V
CONTROL
μC BEEP INPUT
BEEP 21
SPKR_EN 27
CCOM RCOM
COM
TO HPVDD
40.2kΩ
4
40.2kΩ
4.5V TO 5.5V
AVDD
1.0μF
1.0μF
11
SENSE
16
HPVDD
15
C1P
14
CPGND
13
C1N
CHARGE
PUMP
LDO BLOCK
TO CODEC
1.0μF
1.0μF
NOTE: LOGIC PINS CONFIGURED FOR:
LDO_EN = 1, LDO ENABLED
SPKR_EN = 0, SPEAKER AMPLIFIER ENABLED
HP_EN = 1, HEADPHONE AMPLIFIER ENABLED
28
C3
10μF
7
0.1μF
LDO_OUT
2.7V TO 5.5V
6
1, 5
GND
20, 23
PGND
12
CPVSS
C2
1.0μF
______________________________________________________________________________________
C1
1.0μF
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
PACKAGE CODE
DOCUMENT NO.
28 TQFN-EP
T2844-1
21-0139
24L QFN THIN.EPS
PACKAGE TYPE
______________________________________________________________________________________
29
MAX9791/MAX9792
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.
MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
Package Information (continued)
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
30 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2008 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.