MAX9789A [MAXIM]
Windows Vista-Compliant, Stereo Class AB Speaker Amplifiers and DirectDrive Headphone Amplifiers; 兼容Windows Vista的立体声，AB类扬声器放大器及DirectDrive耳机放大器
| 型号： | MAX9789A |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Windows Vista-Compliant, Stereo Class AB Speaker Amplifiers and DirectDrive Headphone Amplifiers |
| 文件： | 总26页 (文件大小：1028K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-0606; Rev 0; 9/06
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
8/MX790A
General Description
Features
The MAX9789A/MAX9790A combine a stereo, 2W Class
AB speaker power amplifier with a stereo 100mW
DirectDrive™ headphone amplifier in a single device.
The MAX9789A/MAX9790A are designed for use with the
Microsoft Windows Vista™ operating system and are fully
compliant with Microsoft’s Windows Vista specifications.
o Microsoft Windows Vista Compliant
o Class AB 2W Stereo BTL Speaker Amplifier
o 100mW DirectDrive Headphone Amplifier
Eliminates Costly, Bulky DC-Blocking Capacitors
o Excellent RF Immunity
†
The headphone amplifier features Maxim’s patented
o Integrated 120mA LDO (MAX9789A)
o High +90dB PSRR, Low 0.002% THD+N
o Low-Power Shutdown Mode
o Click-and-Pop Suppression
o Short-Circuit and Thermal-Overload Protection
DirectDrive architecture that produces a ground-refer-
enced output from a single supply to eliminate the need
for large DC-blocking capacitors, as well as save cost,
board space, and component height. A high +90dB
PSRR and low 0.002% THD+N ensures clean, low-distor-
tion amplification of the audio signal.
o
8kV ESD-Protected Headphone Driver Outputs
Separate speaker and headphone amplifier control
inputs provide independent shutdown of the speaker
and headphone amplifiers, allowing speaker and head-
phone amplifiers to be active simultaneously, if
required. The industry-leading click-and-pop suppres-
sion circuitry reduces audible transients during startup
and shutdown cycles.
o Available in 32-Pin Thin QFN (5mm x 5mm x
0.8mm) Package
Ordering Information
INTERNAL
LDO
PKG
CODE
PART
PIN-PACKAGE
MAX9789AETJ+
MAX9790AETJ+
32 Thin QFN-EP*
32 Thin QFN-EP*
Yes
No
T3255N-1
T3255N-1
The MAX9789A features an internal LDO that can be
used as a clean power supply for a CODEC or other cir-
cuits. The LDO output voltage is set internally at 4.75V or
can be adjusted between 1.21V and 4.75V using a sim-
ple resistive divider. The LDO is protected against ther-
mal overloads and short circuits while providing 120mA
of continuous output current and can be enabled inde-
pendently of the audio amplifiers.
Note: All devices are specified over the -40°C to +85°C extended
temperature range.
+Denotes lead-free package.
*EP = Exposed paddle.
Simplified Block Diagrams
By disabling the speaker and headphone amplifiers, and
the LDO (for MAX9789A), the MAX9789A/MAX9790A
enter low-power shutdown mode and draw only 0.3µA.
SPEAKER SUPPLY HEADPHONE SUPPLY
4.5V TO 5.5V
3.0V TO 5.5V
The MAX9789A/MAX9790A operate from a single 4.5V
to 5.5V supply and feature thermal-overload and out-
put short-circuit protection. Devices are specified over
the -40°C to +85°C extended temperature range.
SPKR_INR
MAX9789A
SPKR_INL
HP_INR
Applications
Notebook Computers
Tablet PCs
HP_INL
SPKR_EN
HP_EN
Portable Multimedia Players
MUTE
GAIN1
GAIN2
Pin Configurations appear at end of data sheet.
LDO
1.21V TO 4.75V
4.5V TO 5.5V
†
U.S. Patent # 7,061,327
Simplified Block Diagrams continued at end of data sheet.
Windows Vista is a trademark of Microsoft Corp.
________________________________________________________________ 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.
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V , PV , HPV
,
Continuous Current (CPV , C1N, C1P, CPV , PV
,
SS
DD
DD
DD
DD
SS
CPV
to GND)..................................................-0.3V to +6.0V
V
HPV , LDO_OUT, HPR, HPL) .............................850mA
DD
DD, DD
GND to PGND, CPGND...................................................... 0.3V
CPV , C1N, V to GND......................................-6.0V to +0.3V
Continuous Input Current (all other pins) ......................... 20mA
Continuous Power Dissipation (T = +70°C)
SS
SS
A
HPR, HPL to GND............................................................... 3.0V
32-Pin Thin QFN Single-Layer Board
(derate 18.6mW/°C above +70°C)..............................1489mW
32-Pin Thin QFN Multilayer Board
Any Other Pin .............................................-0.3V to (V
Duration of OUT_+, OUT_- Short Circuit
+ 0.3V)
DD
to GND or PV ......................................................Continuous
Duration of Short Circuit between OUT_+, OUT_-
and LDO_OUT.........................................................Continuous
Duration of Short Circuit between HPR, HPL and GND,
(derate 24.9 mW/°C above +70°C).............................1990mW
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
DD
V
or HPV ..........................................................Continuous
SS
DD
Continuous Current (PV , OUT_+, OUT_-, PGND).............1.7A
DD
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
= PV
= CPV
= HPV
= LDO_EN (MAX9789A only) = +5V, GND = PGND = CPGND = LDO_SET (MAX9789A only) = 0V,
DD
DD
DD
DD
I
(MAX9789A only) = 0, C1 = C2 = C
= 1µF. R = ∞, unless otherwise specified, GAIN1 = 0, GAIN2 = 5V (A = 10dB,
LDO_OUT
BIAS
L
VSP
A
VHP
= 3.5dB), T = T
to T
, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
MAX A
A
MIN
8/MX790A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
GENERAL
Guaranteed by PSRR and LDO Line
Regulation Tests
Supply Voltage
V
, PV
4.5
3.0
5.5
5.5
V
V
DD
DD
CPV
,
DD
Headphone Supply Voltage
Quiescent Current
Guaranteed by PSRR Test
HPV
DD
SPKR_EN
HP_EN
1 (MAX9789A)
0 (MAX9789A)
0.1
0.3
0.16
6
mA
µA
1 (MAX9790A)
0 (MAX9790A)
I
DD
1
0
0
1
0
1
7
13
29
40
6
mA
14
18
Shutdown Current
Bias Voltage
I
SPKR_EN = V , HP_EN = LDO_EN = GND
0.3
1.8
100
10
µA
V
SHDN
DD
V
1.7
1.9
BIAS
Shutdown to Full Operation
Gain Switching Time
t
ms
µs
SON
t
SW
Channel-to-Channel Gain
Tracking
0.1
dB
SPEAKER AMPLIFIER
R = 4Ω
2
1
L
THD+N = 1%, f = 1kHz,
= +25°C
Output Power
P
W
%
OUT
T
A
R = 8Ω
L
R = 8Ω, P
= 1W, f = 1kHz
= 1W, f = 1kHz
0.002
0.004
90
L
OUT
Total Harmonic Distortion Plus
Noise
THD+N
PSRR
R = 4Ω, P
L
OUT
V
= 4.5V to 5.5V, T = +25°C
72
DD
A
Power-Supply Rejection Ratio
f = 1kHz, 200mV
(Note 3)
70
dB
P-P
f = 10kHz, 200mV
(Note 3)
50
P-P
2
_______________________________________________________________________________________
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
8/MX790A
ELECTRICAL CHARACTERISTICS (continued)
(V
= PV
= CPV
= HPV
= LDO_EN (MAX9789A only) = +5V, GND = PGND = CPGND = LDO_SET (MAX9789A only) = 0V,
DD
DD
DD
DD
I
(MAX9789A only) = 0, C1 = C2 = C
= 1µF. R = ∞, unless otherwise specified, GAIN1 = 0, GAIN2 = 5V (A = 10dB,
LDO_OUT
BIAS
L
VSP
A
VHP
= 3.5dB), T = T
to T
, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
MAX A
A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
GAIN1
GAIN2
0
0
1
1
0
1
0
1
6
Voltage Gain
A
10
dB
V
15.6
21.6
Measured at speaker amplifier inputs
GAIN1
GAIN2
0
0
1
1
0
1
0
1
80
65
45
25
Input Impedance
R
kΩ
IN
Measured between OUT_+ and OUT_-,
= +25°C
Output Offset Voltage
Click-and-Pop Level
Signal-to-Noise Ratio
V
1
15
mV
dBV
dB
OS
T
A
R = 8Ω, peak voltage,
L
Into shutdown
-50
-50
K
A-weighted, 32 samples
CP
Out of shutdown
per second (Notes 2, 3)
A-weighted
102
99
SNR
R = 8Ω, P
= 1W
L
OUT
f = 22Hz to 22kHz
Noise
V
BW = 22Hz to 22kHz
30
µV
RMS
n
Capacitive-Load Drive
C
No sustained oscillations
200
pF
L
L to R, R to L, R = 8Ω, FS = 0.707V
,
RMS
L
V
= 70.7nV
, 20kHz AES17,
Crosstalk
Slew Rate
-70
1.4
dB
OUT
RMS
BW = 20Hz to 20kHz
SR
V/µs
HEADPHONE AMPLIFIER
R = 16Ω
100
55
L
THD+N = 1%, f =
Output Power
P
mW
OUT
1kHz, T = +25°C
A
R = 32Ω
L
R = 32Ω, FS = 0.300V
L
,
RMS
V
= 210mV
, 20kHz AES17,
-77
dB FS
%
OUT
RMS
BW = 20Hz to 20kHz
R = 32Ω, P
= 40mW, f = 1kHz
= 60mW, f = 1kHz
0.02
0.03
L
OUT
OUT
Total Harmonic Distortion Plus
Noise
THD+N
R = 16Ω, P
L
R = 10kΩ, FS = 0.707V
,
L
RMS
V
= 500mV
, 20kHz AES17,
-94
dB FS
OUT
RMS
BW = 20Hz to 20kHz
_______________________________________________________________________________________
3
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
= PV
= CPV
= HPV
= LDO_EN (MAX9789A only) = +5V, GND = PGND = CPGND = LDO_SET (MAX9789A only) = 0V,
DD
DD
DD
DD
I
(MAX9789A only) = 0, C1 = C2 = C
= 1µF. R = ∞, unless otherwise specified, GAIN1 = 0, GAIN2 = 5V (A = 10dB,
LDO_OUT
BIAS
L
VSP
A
VHP
= 3.5dB), T = T
to T
, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
MAX A
A
MIN
PARAMETER
SYMBOL
CONDITIONS
= 3V to 5.5V, T = +25°C
MIN
TYP
95
84
63
3.5
40
2
MAX
UNITS
HPV
70
DD
A
Power-Supply Rejection Ratio
(Note 5)
PSRR
f = 1kHz, V
= 200mV
(Note 3)
dB
RIPPLE
P-P
f = 10kHz, V
= 200mV
(Note 3)
RIPPLE
P-P
Voltage Gain
A
dB
kΩ
mV
V
Input Impedance
Output Offset Voltage
R
Measured at headphone amplifier inputs
T = +25°C
A
20
80
7
IN
V
OS
R = 32Ω, peak voltage,
A-weighted, 32 samples
per second (Notes 2, 3)
L
Into shutdown
-60
-60
Click-and-Pop Level
K
dBV
CP
Out of shutdown
R = 32Ω, f = 1kHz, A-weighted,
L
89
97
FS = 0.300V
, V
= 300µV
RMS OUT RMS
Dynamic Range
DR
dB FS
dB
R = 10kΩ, f = 1kHz, A-weighted,
L
FS = 0.707V
, V
= 707µV
RMS OUT RMS
22Hz to 22kHz
A-weighted
100
103
12
R = 32Ω,
8/MX790A
L
Signal-to-Noise Ratio
SNR
P
= 60mW
OUT
Noise
V
BW = 22Hz to 22kHz
No sustained oscillations
µV
RMS
n
Capacitive-Load Drive
C
200
pF
L
R = 32Ω,
FS = 0.300V
L
,
-74
-77
RMS
L to R, R to L,
V
= 30mV
RMS
OUT
20kHz AES17
Crosstalk
dB
R = 10kΩ,
L
BW = 20Hz to 20kHz
FS = 0.707V
,
RMS
V
= 70.7mV
RMS
OUT
Slew Rate
SR
0.4
8
V/µs
kV
ESD
ESD
Human Body Model (HPR, HPL)
Charge-Pump Frequency
f
500
4.5
550
600
kHz
OSC
LOW-DROPOUT LINEAR REGULATOR
Regulator Input Voltage Range
V
Inferred from line regulation
5.5
V
DD
I
I
= 0mA
0.1
-40
0.16
OUT
Ground Current
I
mA
GND
= 120mA
OUT
Output Current
I
120
mA
dB
%
OUT
Crosstalk
V
= 4.75V, f = 1kHz, speaker P
= 2W
OUT
-88
OUT
Fixed Output Voltage Accuracy
Adjustable Output Voltage Range
LDO_SET Reference Voltage
LDO_SET Dual-Mode Threshold
I
= 1mA
1.5
4.75
1.23
OUT
1.21
1.19
V
V
1.21
200
V
SET
mV
LDO_SET Input Bias Current
(Note 4)
I
20
500
nA
SET
V
= 4.75V (fixed
OUT
I
I
= 50mA
25
75
50
OUT
Dropout Voltage (Note 5)
V
output operation),
= +25°C
mV
DO
= 120mA
150
OUT
T
A
4
_______________________________________________________________________________________
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
8/MX790A
ELECTRICAL CHARACTERISTICS (continued)
(V
= PV
= CPV
= HPV
= LDO_EN (MAX9789A only) = +5V, GND = PGND = CPGND = LDO_SET (MAX9789A only) = 0V,
DD
DD
DD
DD
I
(MAX9789A only) = 0, C1 = C2 = C
= 1µF. R = ∞, unless otherwise specified, GAIN1 = 0, GAIN2 = 5V (A = 10dB,
LDO_OUT
BIAS
L
VSP
A
VHP
= 3.5dB), T = T
to T
, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
MAX A
A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
300
20
MAX
UNITS
mA
Current Limit
Startup Time
I
LIM
µs
V
= 4.5V to 5.5V, LDO_OUT = 2.5V,
IN
Line Regulation
-4.8
+0.8
0.2
+4.8
mV/V
mV/mA
dB
I
= 1mA
LDO_OUT
V
= 4.75V,
LDO_OUT
Load Regulation
Ripple Rejection
Output Voltage Noise
1mA < I
< 120mA
LDO_OUT
f = 1kHz
59
42
V
= 200mV
RIPPLE
P-P
I
= 10mA
LDO_OUT
f = 10kHz
20Hz to 22kHz, C
= 2 x 1µF,
LDO_OUT
125
µV
RMS
I
= 120mA
LDO_OUT
DIGITAL INPUTS (SPKR_EN, HP_EN, MUTE, GAIN1, GAIN2, LDO_EN (MAX9789A Only))
Input-Voltage High
Input-Voltage Low
Input Bias Current
V
2
V
V
INH
V
0.8
1
INL
µA
Note 1: All devices are 100% production tested at room temperature. All temperature limits are guaranteed by design.
Note 2: Specified at room temperature with an 8Ω resistive load connected across BTL output for speaker amplifier. Specified at
room temperature 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 control pins, respectively.
Note 3: Amplifier inputs AC-coupled to GND.
Note 4: Maximum value is due to test limitations.
Note 5: V
= V
- 2%.
LDO_OUT
LDO_OUTNOMINAL
Typical Operating Characteristics
(V = PV = CPV = HPV = LDO_EN = +5V, GND = PGND = CPGND = LDO_SET = 0V, C1 = C2 = C
= C = 1µF. R = ∞,
IN L
DD
DD
DD
DD
BIAS
unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A
= 10dB, A = 3.5dB), measurement BW = 20kHz AES17, T = +25°C,
VHP A
VSP
unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT VOLTAGE (HEADPHONE MODE)
-60
-60
10
R = 10kΩ
L
FS = 0.707V
HPV = 3V
DD
RMS
V
= -3dB FS
FS = 0.707V
OUT
RMS
R = 10kΩ
L
V
= -3dB FS
-70
-80
OUT
L
-70
-80
1
0.1
R = 10kΩ
f
= 20Hz
IN
f
= 10kHz
IN
-90
-90
0.01
0.001
-100
-110
f
= 1kHz
IN
-100
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
FREQUENCY (Hz)
10k
100k
0
0.5
1.0
1.5
2.0
OUTPUT VOLTAGE (V
)
RMS
_______________________________________________________________________________________
5
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
Typical Operating Characteristics (continued)
(V = PV = CPV = HPV = LDO_EN = +5V, GND = PGND = CPGND = LDO_SET = 0V, C1 = C2 = C
= C = 1µF. R = ∞,
IN L
DD
DD
DD
DD
BIAS
unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A
= 10dB, A = 3.5dB), measurement BW = 20kHz AES17, T = +25°C,
VHP A
VSP
unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT VOLTAGE (HEADPHONE MODE)
CROSSTALK
vs. FREQUENCY (HEADPHONE MODE)
HEADPHONE OUTPUT SPECTRUM
0
-10
-20
-30
-40
-50
-60
-70
-80
10
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
HPV = 3V
DD
FS = 0.300V
FS = 0.707V
RMS
V
R = 10kΩ
RMS
R = 10kΩ
L
V
= -60dB FS
= -20dB FS
OUT
OUT
L
R = 10kΩ
L
1
0.1
f
= 20Hz
IN
f
= 10kHz
IN
LEFT TO RIGHT
-90
-100
-110
-120
-130
-140
0.01
0.001
f
= 1kHz
IN
RIGHT TO LEFT
10k 100k
0
5k
10k
FREQUENCY (Hz)
15k
20k
0
0.5
1.0
1.5
2.0
10
100
1k
OUTPUT VOLTAGE (V
)
FREQUENCY (Hz)
RMS
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
8/MX790A
-75
-75
-75
V
= -3dB FS
V
= -3dB FS
OUT
OUT
-80
-80
-80
-85
V
= -3dB FS
OUT
-85
-85
-90
-95
-90
-90
-100
-105
-110
-95
-95
FS = 0.707V
R = 3Ω
L
FS = 0.707V
R = 8Ω
L
RMS
FS = 0.707V
R = 4Ω
L
RMS
RMS
-100
-100
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
FREQUENCY (Hz)
10k
100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)
10
10
10
R = 4Ω
L
R = 8Ω
L
R = 3Ω
L
1
0.1
1
0.1
1
0.1
f
= 10kHz
IN
f
= 10kHz
IN
f
= 10kHz
IN
f
= 20Hz
IN
f
= 1kHz
IN
0.01
0.001
0.01
0.001
0.01
0.001
f
= 1kHz
IN
f
= 20Hz
0.5
IN
f
= 20Hz
0.5
f
= 1kHz
IN
IN
0
1.0
1.5
2.0
2.5
3.0
0
1.0
1.5
2.0
2.5
0
0.5
1.0
1.5
OUTPUT POWER (W)
OUTPUT POWER (W)
OUTPUT POWER (W)
6
_______________________________________________________________________________________
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
8/MX790A
Typical Operating Characteristics (continued)
(V = PV = CPV = HPV = LDO_EN = +5V, GND = PGND = CPGND = LDO_SET = 0V, C1 = C2 = C
= C = 1µF. R = ∞,
IN L
DD
DD
DD
DD
BIAS
unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A
= 10dB, A = 3.5dB), measurement BW = 20kHz AES17, T = +25°C,
VHP A
VSP
unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)
CROSSTALK
vs. FREQUENCY (SPEAKER MODE)
OUTPUT POWER vs. LOAD RESISTANCE
(SPEAKER MODE)
SPEAKER OUTPUT SPECTRUM
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
0
-10
-20
-30
-40
-50
-60
-70
-80
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
f
= 1kHz
IN
FS = 0.707V
RMS
FS = 0.707V
RMS
V
= -20dB FS
V
= -60dB FS
OUT
OUT
R = 8Ω
L
R = 8Ω
L
THD+N = 10%
LEFT TO RIGHT
RIGHT TO LEFT
-90
-100
-110
-120
-130
-140
THD+N = 1%
10
100
1k
FREQUENCY (Hz)
10k
100k
0
5k
10k
FREQUENCY (Hz)
15k
20k
1
10
R (Ω)
100
L
POWER DISSIPATION PER CHANNEL
vs. OUTPUT POWER (SPEAKER MODE)
POWER-SUPPLY REJECTION RATIO
(SPEAKER MODE)
1.50
0
-10
-20
f
= 1kHz
V
= 200mV
IN
RIPPLE
P-P
OUTPUT REFERRED
1.25
1.00
0.75
0.50
0.25
0
-30
-40
R = 4Ω
L
-50
-60
-70
-80
-90
R = 8Ω
L
100
0
0.5
1.0
1.5
2.0
10
100
1k
FREQUENCY (Hz)
10k
100k
OUTPUT POWER PER CHANNEL (W)
SPEAKER STARTUP WAVEFORM
SPEAKER SHUTDOWN WAVEFORM
MAX9789A toc19
MAX9789A toc18
SPKR_EN
5V/div
SPKR_EN
5V/div
OUT_+ AND OUT_-
2V/div
OUT_+ AND OUT_-
2V/div
OUT_+ - OUT_-
100mV/div
OUT_+ - OUT_-
100mV/div
20ms/div
20ms/div
_______________________________________________________________________________________
7
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
Typical Operating Characteristics (continued)
(V = PV = CPV = HPV = LDO_EN = +5V, GND = PGND = CPGND = LDO_SET = 0V, C1 = C2 = C
= C = 1µF. R = ∞,
IN L
DD
DD
DD
DD
BIAS
unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A
= 10dB, A = 3.5dB), measurement BW = 20kHz AES17, T = +25°C,
VHP A
VSP
unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
-65
-65
-65
-70
-75
-70
-75
-70
-75
V
= -3dB FS
OUT
V
= -3dB FS
OUT
-80
-80
-80
V
= -3dB FS
OUT
-85
-85
-85
-90
-90
-90
-95
-95
-95
-100
-105
-110
-100
-105
-110
-100
-105
-110
HPV = 3V
DD
FS = 0.300V
R = 32Ω
L
FS = 0.300V
R = 32Ω
L
FS = 0.300V
R = 16Ω
L
RMS
RMS
RMS
10
100
1k
10k
100k
10
100
1k
10k
100k
10
100
1k
10k
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
8/MX790A
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
-65
10
10
-70
-75
V
= -3dB FS
OUT
f = 10kHz
f = 10kHz
-80
1
0.1
1
0.1
f = 1kHz
-85
f = 20Hz
f = 1kHz
-90
-95
f = 20Hz
-100
-105
-110
HPV = 3V
DD
FS = 0.300V
R = 16Ω
L
RMS
R = 32Ω
L
R = 16Ω
L
0.01
0.01
10
100
1k
10k
100k
0
50
100
150
200
0
20
40
60
80
100
FREQUENCY (Hz)
OUTPUT POWER (mW)
OUTPUT POWER (mW)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
CROSSTALK
vs. FREQUENCY (HEADPHONE MODE)
10
10
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
FS = 0.300V
RMS
V
= -20dB FS
OUT
R = 32Ω
L
f = 10kHz
f = 10kHz
1
0.1
1
0.1
f = 20Hz
f = 1kHz
f = 20Hz
LEFT TO RIGHT
f = 1kHz
HPV = 3V
HPV = 3V
DD
R = 32Ω
L
DD
R = 16Ω
L
RIGHT TO LEFT
1k
FREQUENCY (Hz)
0.01
0.01
0
50
100
150
0
20
40
60
80
100
10
100
10k
100k
OUTPUT POWER (mW)
OUTPUT POWER (mW)
8
_______________________________________________________________________________________
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
8/MX790A
Typical Operating Characteristics (continued)
(V = PV = CPV = HPV = LDO_EN = +5V, GND = PGND = CPGND = LDO_SET = 0V, C1 = C2 = C
= C = 1µF. R = ∞,
IN L
DD
DD
DD
DD
BIAS
unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A
= 10dB, A = 3.5dB), measurement BW = 20kHz AES17, T = +25°C,
VHP A
VSP
unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)
OUTPUT POWER vs. LOAD RESISTANCE
(HEADPHONE MODE)
OUTPUT POWER vs. LOAD RESISTANCE
(HEADPHONE MODE)
HEADPHONE OUTPUT SPECTRUM
150
100
50
100
50
0
0
-10
-20
-30
-40
-50
-60
-70
-80
HPV = 3V
f
= 1kHz
DD
IN
FS = 0.707V
RMS
f
= 1kHz
IN
V
= -60dB FS
OUT
R = 32Ω
L
THD+N = 10%
THD+N = 10%
-90
-100
-110
-120
-130
-140
THD+N = 1%
THD+N = 1%
0
10
100
R (Ω)
1000
10
100
1000
0
5
10
FREQUENCY (kHz)
15
20
R (Ω)
L
L
POWER DISSIPATION vs. OUTPUT POWER
(HEADPHONE MODE)
POWER DISSIPATION PER CHANNEL
vs. OUTPUT POWER (HEADPHONE MODE)
HEADPHONE OUTPUT POWER vs. HPV
DD
125
100
75
50
25
0
125
100
75
50
25
0
300
275
250
225
200
175
150
125
100
75
HPV = 3V
DD
R = 16Ω
L
R = 16Ω
L
R = 16Ω
L
R = 32Ω
L
R = 32Ω
L
R = 32Ω
L
50
THD+N = 1%
25
f
= 1kHz
IN
0
0
20
40
60
80
3.0
3.5
4.0
HPV (V)
4.5
5.0
0
25
50
75
100
125
OUTPUT POWER PER CHANNEL (mW)
OUTPUT POWER PER CHANNEL (mW)
DD
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (HEADPHONE MODE)
HEADPHONE STARTUP WAVEFORM
HEADPHONE SHUTDOWN WAVEFORM
MAX9789A toc36
MAX9789A toc37
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
V
= 200mV
P-P
RIPPLE
OUTPUT REFERRED
HP_EN
5V/div
HP_EN
5V/div
HP_
500mV/div
HP_
500mV/div
20ms/div
20ms/div
10
100
1k
FREQUENCY (Hz)
10k
100k
_______________________________________________________________________________________
9
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
Typical Operating Characteristics (continued)
(V = PV = CPV = HPV = LDO_EN = +5V, GND = PGND = CPGND = LDO_SET = 0V, C1 = C2 = C
= C = 1µF. R = ∞,
IN L
DD
DD
DD
DD
BIAS
unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A
= 10dB, A = 3.5dB), measurement BW = 20kHz AES17, T = +25°C,
VHP A
VSP
unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
SHUTDOWN CURRENT vs. SUPPLY VOLTAGE
20
15
10
5
0.3
0.2
0.1
0
SPKR_EN = 5V
HP_EN = 0
LDO_EN = 0 (MAX9789A)
SPKR_EN = 0
SPKR_EN = 0
HP_EN = 1
HP_EN = 0
SPKR_EN = 1
HP_EN = 0
SPKR_EN = 1
HP_EN = 1
0
-5
4.50
4.75
5.00
5.25
5.50
4.50
4.75
5.00
5.25
5.50
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
8/MX790A
LDO OUTPUT VOLTAGE ACCURACY
LDO OUTPUT VOLTAGE ACCURACY
vs. AMPLIFIER OUTPUT POWER
vs. I
LOAD
2.0
1.5
1.0
0.5
0
0.10
0.05
0
V
= 4.75V
LDO_OUT
V
= 4.75V
= 0A
LDO_OUT
I
LDO_OUT
-0.5
-1.0
-1.5
-2.0
-0.05
-0.10
0
25
50
75
(mA)
100
125
150
0
0.5
1.0
1.5
2.0
2.5
3.0
I
AMPLIFIER OUTPUT POWER (W)
LOAD
LDO OUTPUT VOLTAGE ACCURACY
vs. TEMPERATURE
DROPOUT VOLTAGE vs. I
LOAD
100
90
80
70
60
50
40
30
20
10
0
2.0
1.5
1.0
0.5
0
I
= 1mA
LDO_OUT
V
= 4.75V
LDO_OUT
V
= 3.3V
LDO_OUT
-0.5
-1.0
-1.5
-2.0
0
25
50
75
(mA)
100
125
150
-40
-15
10
35
60
85
I
TEMPERATURE (°C)
LOAD
10 ______________________________________________________________________________________
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
8/MX790A
Typical Operating Characteristics (continued)
(V = PV = CPV = HPV = LDO_EN = +5V, GND = PGND = CPGND = LDO_SET = 0V, C1 = C2 = C
= C = 1µF. R = ∞,
IN L
DD
DD
DD
DD
BIAS
unless otherwise specified, GAIN1 = 0, GAIN2 = 1 (A
= 10dB, A = 3.5dB), measurement BW = 20kHz AES17, T = +25°C,
VHP A
VSP
unless otherwise noted. Headphone mode: SPKR_EN = 1, HP_EN = 0. Speaker mode: SPKR_EN = 0, HP_EN = 1.)
RIPPLE REJECTION vs. FREQUENCY OUTPUT NOISE vs. FREQUENCY
0
-10
-20
10
1
V
= 200mV
P-P
= 10mA
RIPPLE
I
OUT
OUTPUT REFERRED
-30
-40
-50
-60
V
= 4.75V
LDO_OUT
0.1
0.01
-70
-80
-90
V
= 3.3V
10k
LDO_OUT
10
100
1k
100k
10
100
1k
10k
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
LINE-TRANSIENT RESPONSE
LDO LOAD-TRANSIENT RESPONSE
MAX9789A toc46
MAX9789A toc47
V
DD
1V/div
5.5V
I
LDO_OUT
15mA/div
4.5V
LDO_OUT
(AC-COUPLED)
20mV/div
AC-COUPLED
V
LDO_OUT
10mV/div
1ms/div
20ms/div
LDO SHUTDOWN RESPONSE
LDO CROSSTALK vs. FREQUENCY
MAX9789A toc48
-20
-30
I
= 0mA
LOAD
V
P
= 4.75V
LDO_OUT
= 2W
OUT
R = 4Ω
LDO_EN
2V/div
L
-40
I
= 0mA
LOAD
-50
-60
-70
RIGHT SPEAKER TO LDO
-80
-90
V
LDO_OUT
2V/div
-100
-110
-120
LEFT SPEAKER TO LDO
200ms/div
10
100
1k
10k
100k
FREQUENCY (Hz)
______________________________________________________________________________________ 11
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
Pin Description
PIN
NAME
FUNCTION
MAX9789A MAX9790A
Regulator Feedback Input. Connect to GND for 4.75V fixed output. Connect to a resistor-
divider for adjustable output. See Figure 1.
1
—
LDO_SET
2
2
3
SPKR_INR Right-Channel Speaker Amplifier Input
SPKR_INL Left-Channel Speaker Amplifier Input
3
4
—
LDO_EN LDO Enable. Connect LDO_EN to V
to enable the LDO.
DD
5, 21
6
5, 21
6
PGND
OUTL+
OUTL-
Power Ground. Star-connect to GND.
Left-Channel Speaker Amplifier Output, Positive Phase
7
7
Left-Channel Speaker Amplifier Output, Negative Phase
8, 18
9
8, 18
9
PV
Speaker Amplifier Power-Supply Input. Bypass with a 0.1µF capacitor to PGND.
DD
CPV
Charge-Pump Power Supply. Connect a 1µF capacitor between CPV and PGND.
DD
DD
Charge-Pump Flying Capacitor Positive Terminal. Connect a 1µF capacitor between C1P
to C1N.
10
11
12
13
14
10
11
12
13
14
C1P
CPGND
C1N
Charge-Pump Ground. Connect directly to PGND plane.
8/MX790A
Charge-Pump Flying Capacitor Negative Terminal. Connect a 1µF capacitor between C1P
to C1N.
CPV
Charge-Pump Output. Connect to PV
.
SS
SS
Headphone Amplifier Negative Power Supply. Connect a 1µF capacitor between PV and
SS
PGND.
PV
SS
15
16
15
16
HPR
HPL
Right-Channel Headphone Amplifier Output
Left-Channel Headphone Amplifier Output
Headphone Amplifier Positive Power Supply. Connect a 10µF capacitor between HPV
and PGND.
DD
17
17
HPV
DD
19
20
22
23
24
25
26
27
28
29
19
20
OUTR-
OUTR+
HP_EN
Right-Channel Speaker Amplifier Output, Negative Phase
Right-Channel Speaker Amplifier Output, Positive Phase
Active-High Headphone Amplifier Enable
22
23
SPKR_EN Active-Low Speaker Amplifier Enable
24
BIAS
MUTE
HP_INR
HP_INL
GND
Common-Mode Bias Voltage. Bypass with a 1µF capacitor to GND.
Active-Low Mute Enable. Mutes speaker and headphone amplifiers.
Right-Channel Headphone Amplifier Input
25
26
27
Left-Channel Headphone Amplifier Input
4, 28
—
Signal Ground. Star-connect to PGND.
LDO_OUT LDO Output. Bypass with two 1µF capacitors to GND.
Positive Power Supply and LDO Input (MAX9789A). Bypass with one 0.1µF capacitor and
two 1µF capacitors to GND (MAX9789A). Bypass with one 0.1µF capacitor and one 1µF
capacitor to GND (MAX9790A).
30
30
V
DD
31
32
—
31
32
GAIN1
GAIN2
N.C.
Speaker Amplifier Gain Select 1
Speaker Amplifier Gain Select 2
No Connection. Not internally connected.
Exposed Paddle. Connect to GND.
1, 29
EP
EP
EP
12 ______________________________________________________________________________________
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
8/MX790A
conserve board space and system cost, as well as
improve low-frequency response.
Detailed Description
The MAX9789A/MAX9790A combine a 2W BTL speaker
The MAX9789A/MAX9790A feature programmable
speaker amplifier gain, allowing the speaker gain to be
set by the logic voltages applied to GAIN1 and GAIN2,
while the headphone amplifiers feature a fixed 3.5dB
gain. Both amplifiers feature an undervoltage lockout
that prevents operation from an insufficient power sup-
ply and click-and-pop suppression that eliminates
audible transients on startup and shutdown. The ampli-
fiers include thermal overload and short-circuit protec-
tion, while the headphone amplifier outputs (IEC Air
Discharge) can withstand 8kV ESD strikes. An addi-
tional feature of the speaker amplifiers is that there is
no phase inversion from input to output.
amplifier with an 100mW DirectDrive headphone amplifi-
er. These devices feature comprehensive click-and-pop
suppression and programmable four-level speaker ampli-
fier gain control. The MAX9789A/MAX9790A feature high
+90dB PSRR, low 0.002% THD+N, industry-leading click-
and-pop performance, low-power shutdown mode, and
excellent RF immunity. The MAX9789A incorporates an
integrated LDO that serves as a clean power supply for a
CODEC or other circuits.
The MAX9789A/MAX9790A is Microsoft Windows Vista
compliant. See Table 1 for a comparison of the Microsoft
Windows Vista premium mobile specifications and
MAX9789A/MAX9790A specifications.
Low-Dropout Linear Regulator
(MAX9789A Only)
The speaker amplifiers use BTL architecture, doubling the
voltage drive to the speakers and eliminating the need for
DC-blocking capacitors. The output consists of two sig-
nals, identical in magnitude, but 180° out of phase.
The MAX9789A’s low-dropout (LDO) linear 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 =
The headphone amplifiers use Maxim’s patented
DirectDrive architecture to eliminate the bulky output
DC-blocking capacitors required by traditional head-
phone amplifiers. A charge pump inverts a positive
V
DD
to enable the LDO or set LDO_EN = GND to dis-
able the LDO. The LDO is capable of providing up to
120mA continuous current and features Maxim’s Dual
Mode™ feedback, easily enabling a fixed 4.75V output
or a user-adjustable output. When LDO_SET is con-
nected to GND, the output is internally set to 4.75V. The
output voltage can be adjusted from 1.21V to 4.75V by
connecting two external resistors as a voltage divider,
at LDO_SET (Figure 1).
supply (CPV ) to create a negative supply (CPV ).
DD
SS
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 V
/ 2). This
DD
feature eliminates the large DC-blocking capacitors
required with conventional headphone amplifiers to
Table 1. Windows Premium Mobile Vista Specifications vs. MAX9789A/MAX9790A
Specifications
WINDOWS PREMIUM MOBILE Vista
SPECIFICATIONS
MAX9789A/MAX9790A
TYPICAL PERFORMANCE
DEVICE TYPE
REQUIREMENT
≤ -65dB FS
[20Hz, 20kHz]
-94dB FS
[20Hz, 20kHz]
THD+N
Analog Line Output
Dynamic range with
signal present
≤ -80dB FS,
A-weighted
-97dB FS,
A-weighted
Jack (R = 10kΩ,
L
FS = 0.707V
)
RMS
≤ -50dB
[20Hz, 20kHz]
-77dB
[20Hz, 20kHz]
Line output crosstalk
THD+N
≤ -45dB FS
[20Hz, 20kHz]
-77dB FS
[20Hz, 20kHz]
Analog Headphone
Out Jack (R = 32Ω,
Dynamic range with
signal present
≤ -60dB FS,
A-weighted
-89dB FS,
A-weighted
L
FS = 0.300V
)
RMS
Headphone output
crosstalk
≤ -50dB
[20Hz, 20kHz]
-74dB
[20Hz, 20kHz]
Note: THD+N, DR, FREQUENCY ACCURACY, and CROSSTALK should be measured in accordance with AES-17 audio measure-
ments standards.
Dual Mode is a trademark of Maxim Integrated Products, Inc.
______________________________________________________________________________________ 13
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
The output voltage is set by the following equation:
capacitors. Instead of two large capacitors (330µF typi-
cally required to meet Vista magnitude response speci-
fications), the MAX9789A/MAX9790A charge pump
requires only two small 1µF ceramic capacitors, con-
serving board space, reducing cost, and improving the
low-frequency response of the headphone amplifier.
R1
R2
⎛
⎞
V
= V
1+
⎜
⎝
⎟
⎠
LDO_OUT
LDO_SET
where V
= 1.21V.
LDO_SET
Previous attempts to eliminate the output coupling
capacitors involved biasing the headphone return
(sleeve) to the DC bias voltage of the headphone
amplifiers. This method raised some issues:
To simplify resistor selection:
V
⎛
⎞
LDO_OUT
R1=R2
−1
⎜
⎟
⎝
⎠
1.21
• The sleeve is typically grounded to the chassis.
Using this biasing approach, the sleeve must be iso-
lated from system ground, complicating product
design.
Since the input bias current at LDO_SET is typically
less than 500nA (max), large resistance values can be
used for R1 and R2 to minimize power consumption
without compromising accuracy. The parallel combina-
tion of R1 and R2 should be less than 1MΩ.
• During an ESD strike, the amplifier’s ESD structures
are the only path to system ground. The amplifier
must be able to withstand the full ESD strike.
DirectDrive
Conventional single-supply headphone amplifiers have
their outputs biased about a nominal DC voltage
• When using the headphone jack as a line out to
other equipment, the bias voltage on the sleeve may
conflict with the ground potential from other equip-
ment, resulting in large ground loop current and
possible damage to the amplifiers.
(V
DD
/ 2) for maximum dynamic range. Large coupling
8/MX790A
capacitors are needed to block this DC bias from the
headphones. Without these capacitors, a significant
amount of DC current flows to the headphone, resulting
in unnecessary power dissipation and possible dam-
age to both headphone and headphone amplifier.
Low-Frequency Response
In addition to the cost and size disadvantages, the DC-
blocking capacitors limit the low-frequency response of
the amplifier and distort the audio signal:
Maxim’s patented DirectDrive architecture uses a
charge pump to create an internal negative supply volt-
age. It allows the MAX9789A/MAX9790A headphone
amplifier output to be biased about GND. With no DC
component, there is no need for the large DC-blocking
• The impedance of the headphone load and the DC-
blocking capacitor form a highpass filter with the
-3dB point determined by:
1
f −
=
3dB
2πR C
L
OUT
where R is the impedance of the headphone and
OUT
L
LDO_OUT
C
is the value of the DC-blocking capacitor.
• The highpass filter is required by conventional single-
ended, single-supply headphone amplifier to block
the midrail DC component of the audio signal from the
headphones. Depending on the -3dB point, the filter
can attenuate low-frequency signals within the audio
1μF
1μF
R1
R2
MAX9789A
LDO_SET
band. Larger values of C
reduce the attenuation,
OUT
but are physically larger, more expensive capacitors.
Figure 2 shows the relationship between the size of
C
and the resulting low-frequency attenuation.
OUT
GND
Note the Vista’s magnitude response specification
calls for a -3dB point at 20Hz at the headphone jack.
The -3dB point at 20Hz for a 32Ω headphone requires
a 330µF blocking capacitor (Table 2).
Figure 1. Adjustable Output Using External Feedback
Resistors.
14 ______________________________________________________________________________________
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
8/MX790A
ADDITIONAL THD+N DUE TO
DC-BLOCKING CAPACITORS
LOW-FREQUENCY ROLLOFF
(R = 16Ω)
L
10
1
0
C
= 100μF
OUT
-3
R = 16Ω
L
DirectDrive
-6
-9
330μF
220μF
-12
0.1
TANTALUM
-15
-18
100μF
0.01
0.001
0.0001
-21
-24
33μF
ALUM/ELEC
100
-27
-30
10
1k
FREQUENCY (Hz)
10k
100k
1
10
100
1k
10k
100k
FREQUENCY (Hz)
Figure 3. Distortion Contributed by DC-Blocking Capacitors
Figure 2. Low-Frequency Attenuation of Common DC-Blocking
Capacitor Values
• The voltage coefficient of the capacitor, the change
in capacitance due to a change in the voltage
across the capacitor, distorts the audio signal. At
frequencies around the -3dB point, this effect is
maximized and the voltage coefficient appears as
frequency-dependent distortion. Figure 3 shows the
THD+N introduced by two different capacitor
dielectrics. Note that around the -3dB point, THD+N
increases dramatically.
speed that minimizes noise generated by switching
transients. Limiting the switching speed of the charge
pump minimizes the di/dt noise caused by the parasitic
bond wire and trace inductance.
BIAS
The MAX9789A/MAX9790A feature an internally gener-
ated, power-supply independent, common-mode bias
voltage of 1.8V referenced to GND. BIAS provides both
click-and-pop suppression and sets the DC bias level
for the amplifiers. The BIAS pin should be bypassed to
GND with a 1µF capacitor. No external load should be
applied to BIAS. Any load lowers the BIAS voltage,
affecting the overall performance of the device.
• The combination of low-frequency attenuation and fre-
quency-dependent distortion compromises audio
reproduction. DirectDrive improves low-frequency
reproduction in portable audio equipment that empha-
sizes low-frequency effects, such as multimedia lap-
tops, MP3, CD, and DVD players (See Table 2).
Headphone and Speaker Amplifier Gain
The MAX9789A/MAX9790A feature programmable
speaker amplifier gain, set by the logic voltages
applied to pins GAIN1 and GAIN2. Table 3 shows the
logic combinations that can be applied to pins GAIN1
and GAIN2 and their affects on the speaker amplifier
gain. The headphone amplifier gain is fixed at 3.5dB.
Table 2. Low-Frequency Rolloff
f
(Hz)
-3dB
C
(µF)
OUT
R = 16Ω
L
R = 32Ω
L
22
452
301
99
226
151
50
33
100
220
330*
470
Table 3. MAX9789A/MAX9790A
Programmable Gain Settings
45
23
30
15
MAX9789A/MAX9790A
21
11
SPEAKER MODE
GAIN (dB)
HEADPHONE
MODE GAIN (dB)
GAIN1
GAIN2
*Vista requirement for 32Ω load.
Charge Pump
0
0
1
1
0
1
0
1
6
3.5
3.5
3.5
3.5
The MAX9789A/MAX9790A feature a low-noise charge
pump. The 550kHz switching frequency is well beyond
the audio range, and does not interfere with the audio
signals. The switch drivers feature a controlled switching
10
15.6
21.6
______________________________________________________________________________________ 15
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
Headphone Amplifier
Speaker and Headphone
Amplifier Enable
In conventional single-supply headphone amplifiers, the
output-coupling capacitor is a major contributor of audi-
ble clicks and pops. Upon startup, the amplifier charges
the coupling capacitor to its bias voltage, typically
The MAX9789A/MAX9790A 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 time,
SPKR_EN and HP_EN can be tied together allowing a
single logic voltage to enable either the speaker or the
headphone amplifier as shown in Figure 4.
V
DD
/ 2. Likewise, during shutdown, the capacitor is dis-
charged to GND. A DC shift across the capacitor results,
which in turn, appears as an audible transient at the
headphone. Since the MAX9789A/MAX9790A do not
require output-coupling capacitors, no audible transient
occurs.
Additionally, the MAX9789A/MAX9790A features exten-
sive click-and-pop suppression that eliminates any
audible transient sources internal to the device. The
startup/shutdown waveform in the Typical Operating
Characteristics shows that there are minimal spectral
components in the audible range at the output.
MUTE
The MAX9789A/MAX9790A allow for the speaker and
headphone amplifiers to be muted. By driving MUTE
low, both the speaker and headphone amplifiers are
muted. When muted, the speaker outputs remain
biased at V
/ 2.
DD
Applications Information
Shutdown
BTL Speaker Amplifiers
The MAX9789A/MAX9790A feature speaker amplifiers
designed to drive a load differentially, a configuration
referred to as bridge-tied load (BTL). The BTL configu-
ration (Figure 5) offers advantages over the single-
ended configuration, where one side of the load is
connected to ground. Driving the load differentially
doubles the output voltage compared to a single-
ended amplifier operating under similar conditions. The
doubling of the output voltage yields four times the out-
put power at the load.
The MAX9789A/MAX9790A feature a low-power shut-
down mode, drawing 0.3µA of supply current. By dis-
abling the speaker, headphone amplifiers and the LDO
(for MAX9789A), the MAX9789A/MAX9790A enter low-
8/MX790A
power shutdown mode. Set SPKR_EN to V
and
DD
HP_EN and LDO_EN to GND to disable the speaker
amplifiers, headphone amplifiers, and LDO, respectively.
Click-and-Pop Suppression
Speaker Amplifier
The MAX9789A/MAX9790A speaker amplifiers feature
Maxim’s comprehensive, industry-leading click-and-
pop suppression. During startup, the click-and-pop
suppression circuitry eliminates any audible transient
sources internal to the device. When entering shut-
down, the differential speaker outputs ramp to GND
quickly and simultaneously.
Since the differential outputs are biased at mid-supply,
there is no net DC voltage across the load. This elimi-
nates the need for DC-blocking capacitors required for
single-ended amplifiers. These capacitors can be
large, expensive, consume board space, and degrade
low-frequency performance.
V
+1
OUT(P-P)
MAX9789A/MAX9790A
2 x V
OUT(P-P)
SINGLE
CONTROL PIN
SPKR_EN
-1
HP_EN
V
OUT(P-P)
Figure 5. Bridge-Tied Load Configuration
Figure 4. Enabling Either the Speaker or Headphone Amplifier
with a Single Control Pin
16 ______________________________________________________________________________________
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
8/MX790A
Mono Speaker Configuration
The MAX9789A stereo BTL Class AB speaker amplifier
can be configured to drive a mono speaker. Rather
than combining the CODEC’s left- and right-input sig-
nals in a resistive network prior to one channel of the
speaker amplifier input, the transducer itself can be
connected to the BTL speaker amplifier output as
shown in Figure 6. When compared to the resistive net-
work implementation, the configuration in Figure 6 will:
Output Power (Speaker Amplifier)
The increase in power delivered by the BTL configura-
tion directly results in an increase in internal power dis-
sipation over the single-ended configuration. The
maximum power dissipation for a given V
given by the following equation:
and load is
DD
2
2V
DD
P
=
DISS(MAX)
2
π R
L
1) Eliminate noise pickup by eliminating the high-
impedance node at the CODEC’s left- and right-
signal mixing point. SNR performance will be
improved as a result.
If the power dissipation for a given application exceeds
the maximum allowed for a given package, either reduce
DD
temperature, or add heat sinking to the device. Large
output, supply, and ground PC board traces improve the
maximum power dissipation in the package.
V
, increase load impedance, decrease the ambient
2) Eliminate gain error by eliminating any resistive
mismatch between the external resistance used to
sum the left and right signals and the MAX9789A
internal resistance.
Thermal-overload protection limits total power dissipa-
tion in these devices. When the junction temperature
exceeds +150°C, the thermal-protection circuitry dis-
ables the amplifier output stage. The amplifiers are
enabled once the junction temperature cools by +15°C.
This results in a pulsing output under continuous ther-
mal-overload conditions as the device heats and cools.
Power Dissipation and Heat Sinking
Under normal operating conditions, the MAX9789A/
MAX9790A can dissipate a significant amount of
power. The maximum power dissipation for each pack-
age is given in the Absolute Maximum Ratings section
under Continuous Power Dissipation, or can be calcu-
lated by the following equation:
Power Supplies
The MAX9789A/MAX9790A have separate supply pins
for each portion of the device, allowing for the optimum
combination of headroom and power dissipation and
noise immunity. The speaker amplifiers are powered
T
− T
A
J(MAX)
P
=
DISSPKG(MAX)
θ
JA
from PV . PV
ranges from 4.5V to 5.5V. The head-
DD
DD
where T
is +150°C, T is the ambient tempera-
phone amplifiers are powered from HPV
and PV
.
SS
J(MAX)
A
DD
ture, and θ is the reciprocal of the derating factor in
HPV
is the positive supply of the headphone ampli-
JA
DD
°C/W as specified in the Absolute Maximum Ratings
fiers and ranges from 3V to 5.5V. PV is the negative
SS
section. For example, θ for the 32-pin TQFN-EP pack-
supply of the headphone amplifiers. Connect PV to
SS
JA
age is +40.2°C/W for a multilayer PC board.
CPV . The charge pump is powered by CPV
.
DD
SS
CPV
ranges from 3V to 5.5V and should be the same
DD
potential as HPV . The charge pump inverts the volt-
DD
age at CPV , and the resulting voltage appears at
DD
C
IN1
IN1
CODEC
SPKR_OUTL
CPV . The internal LDO and the remainder of the
SS
OUTL+
OUTL-
SPKR_INL
device is powered by V
.
DD
Component Selection
C
MAX9789A
SPKR_OUTR
SPKR_INR
Supply Bypassing
OUTR+
OUTR-
The MAX9789A/MAX9790A have separate supply pins
for each portion of the device, allowing for the optimum
combination of headroom and power dissipation and
noise immunity.
C
C
IN2
LINE_OUTR
LINE_OUTL
HP_INL
HP_INR
HPL
HPR
IN2
Speaker Amplifier Power-Supply Input (PV
)
DD
The speaker amplifiers are powered from PV . PV
DD
DD
ranges from 4.5V to 5.5V. Bypass PV
with a 0.1µF
DD
capacitor to PGND. Note additional bulk capacitance is
required at the device if long input traces between
Figure 6. Mono Signal Output Configuration for MAX9789A
PV
and the power source are used.
DD
______________________________________________________________________________________ 17
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
Headphone Amplifier Power-Supply
INPUT COUPLING CAPACITOR-INDUCED THD+N
vs. FREQUENCY (HEADPHONE MODE)
-50
Input (HPV and PV
)
DD
SS
The headphone amplifiers are powered from HPV
DD
and PV . HPV
is the positive supply of the head-
SS
DD
phone amplifiers and ranges from 3.0V to 5.5V. Bypass
HPV with a 10µF capacitor to PGND. PV is the
-55
-60
-65
-70
-75
-80
-85
-90
0402 6.3V X5R 10% 1μF
0603 10V X5R 10% 1μF
DD
SS
negative supply of the headphone amplifiers. Bypass
PV with a 1µF capacitor to PGND. Connect PV to
SS
SS
DD
CPV . The charge pump is powered by CPV
.
SS
DD
CPV
ranges from 3.0V to 5.5V and should be the
same potential as HPV . Bypass CPV
with a 1µF
DD
DD
capacitor to PGND. The charge pump inverts the volt-
0805 25V X7R 10% 1μF
age at CPV , and the resulting voltage appears at
DD
V
= 3dB FS
RMS
OUT
1206 25 X7R 10% 1μF
FS = 1V
R = 32Ω
CPV . A 1µF capacitor must be connected between
SS
L
C1N and C1P.
10
100
1000
Power Supply and LDO Input (V
)
DD
FREQUENCY (Hz)
The internal LDO and the remainder of the device is
powered by V . V ranges from 4.5V to 5.5V.
Figure 8. Input Coupling Capacitor-Induced THD vs.
Frequency (Headphone Mode)
DD
DD
Bypass V
with a 0.1µF capacitor to GND and two
DD
1µF capacitors in parallel to GND. Note additional bulk
capacitance is required at the device if long input
BIAS Capacitor
BIAS is the output of the internally generated DC bias
voltage. The BIAS bypass capacitor, C improves
PSRR and THD+N by reducing power supply and other
noise sources at the common-mode bias node, and
also generates the clickless/popless, startup/shutdown
DC bias waveforms for the speaker and headphone
amplifiers. Bypass BIAS with a 1µF capacitor to GND.
8/MX790A
traces between V
and the power source are used.
DD
BIAS
Input Filtering
The input capacitor (C ), in conjunction with the ampli-
IN
fier input resistance (R ), forms a highpass filter that
IN
removes the DC bias from the incoming signal. The AC-
coupling capacitor allows the amplifier to bias the sig-
nal to an optimum DC level. Assuming zero source
impedance, the -3dB point of the highpass filter is
given by:
Charge-Pump Capacitor Selection
Use capacitors with an ESR less than 100mΩ for opti-
mum performance. Low ESR ceramic capacitors mini-
mize the output resistance of the charge pump. For
best performance over the extended temperature
range, select capacitors with an X7R dielectric.
1
f −
=
3dB
2πR C
IN IN
R
is the amplifier’s internal input resistance value
IN
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.
given in the Electrical Characteristics. Choose C such
IN
that f
Setting f
is well below the lowest frequency of interest.
-3dB
-3dB
too high affects the amplifier’s low fre-
quency response. Use capacitors with adequately low
voltage coefficient dielectrics, such as 1206-sized X7R
ceramic capacitors. Capacitors with higher voltage
coefficients result in increased distortion at low fre-
quencies (see Figure 8).
18 ______________________________________________________________________________________
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
8/MX790A
Output Capacitor (C2)
Connect C2 and C3 to the PGND plane. Connect PV
SS
The output capacitor value and ESR directly affect the
and CPV
together at C2. Place the charge-pump
SS
ripple at CPV . Increasing the value of C2 reduces
SS
capacitors (C1, C2, and C3) as close as possible to
the device. Bypass PV with a 0.1µF capacitor to
output ripple. Likewise, decreasing the ESR of C2
reduces both ripple and output resistance. Lower
capacitance values can be used in systems with low
maximum output power levels.
DD
PGND. Place the bypass capacitors as close as possi-
ble to the device.
Use large, low-resistance output traces. As load imped-
ance decreases, the current drawn from the device out-
puts 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 con-
sumed in the trace. If power is delivered through a
10mΩ trace, only 5mW is consumed in the trace. Large
output, supply and GND traces also improve the power
dissipation of the device.
CPV
Bypass Capacitor (C3)
bypass capacitor (C3) lowers the output
DD
The CPV
DD
impedance of the power supply and reduces the
impact of the MAX9789A/MAX9790A’s charge-pump
switching transients. Bypass CPV
with 1µF, the same
DD
value as C1, and place it physically close to the CPV
and CPGND pins.
DD
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 per-
formance, 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 PC board. Route PGND and all traces that
carry switching transients away from GND and the
traces and components in the audio signal path.
The MAX9789A/MAX9790A thin QFN package features
an exposed thermal pad on its underside. This pad low-
ers 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.
______________________________________________________________________________________ 19
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
Block Diagrams
4.5V TO 5.5V
0.1μF
PV
DD
8, 18
MAX9789A
6
7
OUTL+
OUTL-
1.0μF
1.0μF
SPKR_INL
SPKR_INR
3
2
STEREO
BTL
AMPLIFIER
OUTR+
20
19 OUTR-
BIAS
24
8/MX790A
TO HPV
1.0μF
DD
1.0μF
1.0μF
HP_INL
HP_INR
HP_EN
27
26
22
16 HPL
TO PV
SS
3V TO 5.5V
MUTE 25
15 HPR
17 HPV
3V TO 5.5V
C3
SPKR_EN 23
CONTROL
DD
DD
32
31
GAIN2
GAIN1
9
CPV
10μF
3V TO 5.5V
10 C1P
4.5V TO 5.5V
LDO_EN
VDD
4
C1
1μF
11 CPGND
30
CHARGE
PUMP
1.0μF
1.0μF
1.0μF
0.1μF
1.0μF
LDO_SET
LDO_OUT
1
LDO BLOCK
C1N
12
29
TO CODEC
28
5, 21
14
PV
13
CPV
GND
PGND
SS
SS
C2
1.0μF
LOGIC PINS CONFIGURED FOR:
LDO_EN = 1, LDO ENABLED
SPKR_EN = 0, SPEAKER AMPLIFIERS ENABLED
HP_EN = 1, HEADPHONE AMPLIFIER ENABLED
MUTE = 1, MUTE DISABLED
GAIN1 = 0 GAIN = 0, 6dB SPEAKER GAIN
20 ______________________________________________________________________________________
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
8/MX790A
Block Diagrams (continued)
4.5V TO 5.5V
0.1μF
0.1μF
V
PV
DD
DD
30
8, 18
MAX9790A
6
7
OUTL+
OUTL-
1.0μF
1.0μF
SPKR_INL
SPKR_INR
3
2
STEREO
BTL
AMPLIFIER
OUTR+
20
19 OUTR-
BIAS
24
TO HPV
1.0μF
DD
1.0μF
1.0μF
HP_INL
HP_INR
27
26
16 HPL
TO PV
SS
3V TO 5.5V
15 HPR
17 HPV
3V TO 5.5V
C3
HP_EN
22
DD
DD
MUTE 25
9
CPV
SPKR_EN 23
CONTROL
10μF
10 C1P
32
31
GAIN2
GAIN1
C1
1μF
11 CPGND
CHARGE
PUMP
C1N
12
4, 28
GND
5, 21
14
PV
13
CPV
PGND
SS
SS
C2
1.0μF
LOGIC PINS CONFIGURED FOR:
SPKR_EN = 0, SPEAKER AMPLIFIERS ENABLED
HP_EN = 1, HEADPHONE AMPLIFIER ENABLED
MUTE = 1, MUTE DISABLED
GAIN1 = 0 GAIN = 0, 6dB SPEAKER GAIN
______________________________________________________________________________________ 21
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
System Diagrams
5.0V
5.0V
C
BULK
10μF
0.1μF
1μF
1μF
1μF
V
V
PV
DD
DD
HPV
DD
LDO_OUT
BIAS
OUTL+
OUTL-
C
IN
4Ω
4Ω
1μF
SPKR_L
SPKR_INL
SPKR_INR
HP_INR
C
IN
1μF
SPKR_R
HDA
CODEC
C
IN
OUTR+
OUTR-
1μF
HP_R
C
IN
1μF
HP_L
HP_INL
HPL
HPR
5.0V
MONO
AGND
MAX9789A
DGND
CPV
C1P
DD
8/MX790A
C
1μF
3
C
1μF
1
4.75V
LDO_SET
LDO_OUT
C1N
SPKR_EN
1μF
1μF
HP_EN
LDO_EN
GAIN1
μC
CPV
PV
SS
C
2
SS
GAIN2
1μF
CPGND
MUTE
PGND
GND
12V
100μF
1μF
V
DD
FS2
FS1
G1
OUT+
8Ω
OUT-
G2
MAX9713
SHDN
C1P
0.47μF
0.47μF
0.1μF
IN+
C1N
V
DD
IN-
SS
1μF
CHOLD
REG
0.47μF
AGND
PGND
0.01μF
22 ______________________________________________________________________________________
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
8/MX790A
System Diagrams (continued)
+5V
+3.3V
10μF
1μF
1μF
0.1μF
V
V
PV
DD
DD
HPV
DD
LDO_OUT
OUTL+
OUTL-
1μF
SPKR_L
SPKR_INL
SPKR_INR
HP_INR
1μF
1μF
1μF
SPKR_R
HDA
CODEC
HP1_R
OUTR+
OUTR-
HP1_L
HP2_R
HP2_L
HP_INL
HP1
HPL
HPR
+3.3V
MAX9789A
CPV
C1P
DD
C
1μF
3
DGND AGND
C
1
4.75V
LDO_SET
LDO_OUT
1μF
C1N
SPKR_EN
HP_EN
1μF
1μF
μC
LDO_EN
CP
P
VSS
GAIN2
GAIN1
C
1μF
2
VSS
CPGND
MUTE
PGND
GND
C1P
C1N
SHDNR
SHDNL
1μF
1μF
MAX4411
HP2
OUTL
OUTR
INR
INL
1μF
+3.3V
PV
SV
DD
PV
SV
SS
1μF
SS
DD
PGND
SGND
1μF
______________________________________________________________________________________ 23
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
Pin Configurations
TOP VIEW
24 23 22 21 20 19 18 17
24 23 22 21 20 19 18 17
16
15
MUTE 25
HPL
HPR
16
15
MUTE 25
HPL
HPR
HP_INR 26
HP_INR 26
14 PV
27
SS
14 PV
HP_INL
27
SS
HP_INL
CPV
SS
28
13
12
CPV
SS
GND
28
29
30
31
32
13
12
GND
MAX9790A
MAX9789A
29
30
31
32
N.C.
C1N
LDO_OUT
C1N
11 CPGND
V
11 CPGND
V
DD
DD
EP*
EP*
10
9
C1P
CPV
GAIN1
GAIN2
10
9
C1P
CPV
GAIN1
GAIN2
+
+
DD
DD
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
8/MX790A
TQFN
TQFN
*EP = EXPOSED PADDLE
*EP = EXPOSED PADDLE
Chip Information
Simplified Block Diagrams
(continued)
PROCESS: BiCMOS
SPEAKER SUPPLY HEADPHONE SUPPLY
4.5V TO 5.5V
3.0V TO 5.5V
MAX9790A
SPKR_INR
SPKR_INL
HP_INR
HP_INL
SPKR_EN
HP_EN
MUTE
GAIN1
GAIN2
24 ______________________________________________________________________________________
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
8/MX790A
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
______________________________________________________________________________________ 25
Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
8/MX790A
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.
26 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2006 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
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