MAX9754 [MAXIM]
2.2W, Low-EMI, Stereo, Class D Power Amplifiers with DirectDrive Headphone Amplifiers;
| 型号： | MAX9754 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | 2.2W, Low-EMI, Stereo, Class D Power Amplifiers with DirectDrive Headphone Amplifiers |
| 文件： | 总29页 (文件大小：593K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-3666; Rev 0; 9/05
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
General Description
Features
The MAX9752/MAX9753/MAX9754 combine a high-effi-
ciency, filterless, stereo Class D audio power amplifier
with a DirectDrive™ headphone amplifier in a single
device. The Class D amplifier operates from a single
4.5V to 5.5V supply and provides 2.2W per channel into
a 4Ω load. The headphone amplifier operates from a
single 3V to 5.5V supply, and uses Maxim’s DirectDrive
architecture to produce a ground-referenced output
from a single supply.
♦ PC2001 Compliant
♦ 2.2W Class D Stereo Speaker Amplifier
♦ Pin-for-Pin Compatible with Class AB
MAX9750/MAX9751/MAX9755
♦ 85% Efficiency (R = 8Ω, P
= 1W)
L
OUT
♦ 62mW DirectDrive Headphone Amplifier
♦ High PSRR (70dB at 1kHz)
The MAX9754 features a Class D stereo speaker ampli-
fier and headphone driver. The MAX9752 adds an ana-
log volume control and a BEEP input. The MAX9753
adds a stereo 2:1 input multiplexer. All devices feature
logic-selectable gain, and a headphone sense input
that detects the presence of a headphone.
♦ Analog Volume Control (MAX9752)
♦ Beep Input with Glitch Filter (MAX9752)
♦ 2:1 Stereo Input MUX (MAX9753)
♦
8kV ESD-Protected Headphone Outputs
The MAX9752/MAX9753/MAX9754 come in 28-pin thin
QFN (5mm x 5mm x 0.8mm) packages, and are speci-
fied over the extended -40°C to +85°C temperature
range. For a pin-for-pin-compatible Class AB version of
these devices, refer to the MAX9750/MAX9751/
MAX9755 data sheet.
♦ No Output DC-Blocking Capacitors
♦ Industry-Leading Click-and-Pop Suppression
Ordering Information
PKG
CODE
MAXIMUM
GAIN (dB)
Applications
Flat-Panel TVs
PART
PIN-PACKAGE
Notebook PCs
Tablet PCs
MAX9752AETI+
MAX9752BETI+
MAX9752CETI+
MAX9753ETI+
MAX9754ETI+
28 TQFN-EP*
28 TQFN-EP*
28 TQFN-EP*
28 TQFN-EP*
28 TQFN-EP*
T2855-1
T2855-1
T2855-1
T2855-1
T2855-1
13.5
19.5
10.5
13.5
13.5
PC Displays
Portable DVDs
LCD Projectors
Note: All devices specified for -40°C to +85°C operation.
+Denotes lead-free package.
Pin Configurations appear at end of data sheet.
*EP = Exposed paddle.
Block Diagrams
MAX9752
MAX9753
MAX9754
S
CLASS
D
CLASS
D
CLASS
D
S
AMP
AMP
AMP
VOL
INPUT
MUX
HPS
HPS
HPS
SELECT
BEEP
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
ABSOLUTE MAXIMUM RATINGS
V
, PV , HPV , CPV
to GND ....................... -0.3V to +6V
Continuous Current Into/Out of PV , OUT_, PGND ...........1.7A
DD
DD
DD
DD
DD
GND to PGND or CPGND .................................... -0.3V to +0.3V
CPV or V to PGND ........................................ -6.0V to +0.3V
Continuous Current Into/Out of CPV , C1N, CPGND,
DD
C1P, CPV , V , HPV , HP_ ......................................0.85A
SS
SS
SS SS
DD
C1N to PGND.........................................(CPV - 0.3V) to +0.3V
Continuous Input Current (all other pins) ........................ 20mA
SS
C1P to PGND........................................ -0.3V to (CPV
+ 0.3V)
+ 0.3V)
Continuous Power Dissipation (T = +70°C)
DD
DD
A
HP_ to PGND......................... (HPV - 0.3V) to (HPV
28-Pin TQFN (derate 21.3mW/°C above +70°C) .......1702mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +150°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
SS
HP_ to PGND.............................................................. -3V to +3V
Any Other Pin to PGND ............................. -0.3V to (V + 0.3V)
DD
Duration of OUT_ Short Circuit to PGND or PV .........Continuous
DD
Duration of OUT_+ Short Circuit to OUT_-.................Continuous
Duration of HP_ Short Circuit to PGND ......................Continuous
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
= HPV
= CPV
= +5.0V, GND = PGND = HPGND = 0V, V
= V , CPV
= V , C
= 1µF,
BIAS
DD
DD
DD
DD
SHDN
DD
SS
SS
C
= 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
CPVSS
MAX9752: GAIN1 = GAIN2 = 0, V
= 0V; MAX9753: GAIN = 0, V
= 0V; MAX9754: GAIN = 0; T = T
to T
, unless otherwise
VOL
A/B
A
MIN
MAX
noted. Typical values are at T = +25°C.) (Notes 1, 2)
A
PARAMETER
GENERAL
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage Range,
Speaker Amplifier
V
, PV
Inferred from PSRR test
4.5
3.0
5.5
5.5
V
V
DD
DD
Supply Voltage Range,
Headphone Amplifier
HPV
Inferred from PSRR test
DD
Speaker mode, no load
14
7.2
0.2
3
18
9.5
8
Quiescent Current
I
mA
DD
Headphone mode, no load
Shutdown Supply Current
Gain Switching Time
Mux Switching Time
I
V
= 0V
SHDN
µA
µs
µs
SHDN
t
SWG
SWM
t
MAX9753 only
MAX9752
3
10
20
6.6
25
30
Input Resistance
R
kΩ
IN
MAX9753/MAX9754
3.5
10.0
Turn-On Time
t
ms
ON
CLASS D SPEAKER AMPLIFIERS (HPS = GND)
MAX9752A,
MAX9752B,
MAX9753, MAX9754
T
T
= +25°C
9.6
7
38.8
55
A
Output Offset Voltage
OUT_+ to OUT_-
= T
to T
A
MIN
MAX
V
mV
dB
OS
T
T
= +25°C
40
60
A
MAX9752C
= T
to T
A
MIN
MAX
PV
or V
= 4.5V to 5.5V, T = +25°C
50
74
70
60
DD
DD
A
Power-Supply Rejection Ratio
(Note 3)
PSRR
f = 1kHz, V
= 100mV
RIPPLE P-P
f = 10kHz, V
= 100mV
P-P
RIPPLE
2
_______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
= PV
= HPV
= CPV
= +5.0V, GND = PGND = HPGND = 0V, V
= V , CPV
= V , C
= 1µF,
BIAS
DD
DD
DD
DD
SHDN
DD
SS
SS
C
= 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
CPVSS
MAX9752: GAIN1 = GAIN2 = 0, V
= 0V; MAX9753: GAIN = 0, V
= 0V; MAX9754: GAIN = 0; T = T
to T
, unless otherwise
VOL
A/B
A
MIN
MAX
noted. Typical values are at T = +25°C.) (Notes 1, 2)
A
PARAMETER
SYMBOL
CONDITIONS
GAIN2 = 0, GAIN1 = 0
MIN
TYP
9.0
MAX
UNITS
GAIN2 = 0, GAIN1 = 1
GAIN2 = 1, GAIN1 = 0
GAIN2 = 1, GAIN1 = 1
GAIN2 = 0, GAIN1 = 0
GAIN2 = 0, GAIN1 = 1
GAIN2 = 1, GAIN1 = 0
GAIN2 = 1, GAIN1 = 1
GAIN2 = 0, GAIN1 = 0
GAIN2 = 0, GAIN1 = 1
GAIN2 = 1, GAIN1 = 0
GAIN2 = 1, GAIN1 = 1
GAIN = 1
10.5
12.0
13.5
15.0
16.5
18.0
19.5
6.0
MAX9752A
MAX9752B
MAX9752C
Speaker Amplifier Gain (Note 4)
A
dB
V_SP
7.5
9.0
10.5
9.0
MAX9753/MAX9754
f = 1kHz, THD+N
GAIN = 0
10.5
MAX9752A,
MAX9752B, MAX9753,
MAX9754
1.3
0.8
2.2
1.7
= 1%, T = +25°C,
A
R = 8Ω
L
MAX9752C
Output Power
P
W
OUT_SP
MAX9752A,
MAX9752B, MAX9753,
MAX9754
f = 1kHz, THD+N
= 1%, T = +25°C,
A
R = 4Ω
L
MAX9752C
R = 8Ω
0.023
0.03
90
L
Total Harmonic Distortion Plus
Noise
THD+N
SNR
f = 1kHz, P
= 1W
%
OUT
R = 4Ω
L
Unweighted
A-weighted
P
= 1W, f = 1kHz,
OUT
Signal-to-Noise Ratio
dB
BW = 22Hz to 22kHz
91
Into shutdown
Out of shutdown
Differential
-47
Click-and-Pop Level (Note 5)
K
dBV
CP
-34
Capacitive-Load Drive
Switching Frequency
Crosstalk
C
200
1200
70
pF
kHz
dB
L_MAX
f
1000
1400
SW
Channel to channel, f = 10kHz, P
= 1W
OUT
MAX9753, unselected input to any active
input, f = 10kHz
Off-Isolation
Efficiency
70
85
dB
%
η
R = 8Ω, P
= 1W, f = 1kHz
L
OUT
_______________________________________________________________________________________
3
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
= PV
= HPV
= CPV
= +5.0V, GND = PGND = HPGND = 0V, V
= V , CPV
= V , C
= 1µF,
BIAS
DD
DD
DD
DD
SHDN
DD
SS
SS
C
= 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
CPVSS
MAX9752: GAIN1 = GAIN2 = 0, V
= 0V; MAX9753: GAIN = 0, V
= 0V; MAX9754: GAIN = 0; T = T
to T
, unless otherwise
VOL
A/B
A
MIN
MAX
noted. Typical values are at T = +25°C.) (Notes 1, 2)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
HEADPHONE AMPLIFIER (HPS = V
)
DD
T
T
= +25°C
0.5
3.5
8
A
Output Offset Voltage
V
mV
OS
= T
to T
MAX
A
MIN
GAIN2 = 0
GAIN2 = 1
GAIN = 1
GAIN = 0
0
3
MAX9752,
GAIN1 = don’t care
Maximum Headphone Amplifier
Gain (Note 6)
A
V_HP
dB
0
MAX9753/MAX9754
3
HPV
or V
= 3V to 5.5V, T = +25°C
66
73
80
60
31
62
DD
DD
A
Power-Supply Rejection Ratio
(Note 3)
PSRR
f = 1kHz, V
= 100mV
dB
RIPPLE
P-P
f = 10kHz, V
= 100mV
P-P
RIPPLE
R = 32Ω
L
THD+N = 1%, f
1kHz, T = +25°C
=
IN
Output Power
P
mW
OUT_HP
A
R = 16Ω
L
R = 32Ω,
L
0.005
0.005
95
P
= 31mW
OUT
Total Harmonic Distortion Plus
Noise
THD+N
SNR
f
= 1kHz
%
IN
R = 16Ω,
L
P
= 62mW
OUT
R = 32Ω,
P
L
Unweighted
A-weighted
= 31mW,
OUT
Signal-to-Noise Ratio
dB
f
IN
= 1kHz,
101
BW = 22Hz to 22kHz
Into shutdown
-33
-37
300
60
Click-and-Pop Level (Note 7)
K
dBV
CP
Out of shutdown
Capacitive-Load Drive
Crosstalk
C
No sustained oscillations
pF
dB
L_MAX
f = 10kHz, P
= 62mW, R = 16Ω
L
OUT
MAX9753, unselected input to any active
input, f = 10kHz
Off-Isolation
60
dB
Slew Rate
SR
0.8
1
V/µs
Output Impedance
CHARGE PUMP
Charge-Pump Frequency
HPS = GND (disabled)
kΩ
f
540
600
660
kHz
CP
VOLUME CONTROL (MAX9752 Only)
VOL Input Impedance
R
100
50
MΩ
VOL
VOL Input Hysteresis
Full Mute Input Voltage
Full Mute Attenuation
HYST
V
falling
VOL
mV
VOL
0.858 x
V
V
VOL_MUTE
V
DD
A
f
IN
= 1kHz
-85
dB
V_MUTE
4
_______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
= PV
= HPV
= CPV
= +5.0V, GND = PGND = HPGND = 0V, V
= V , CPV
= V , C
= 1µF,
BIAS
DD
DD
DD
DD
SHDN
DD
SS
SS
C
= 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
CPVSS
MAX9752: GAIN1 = GAIN2 = 0, V
= 0V; MAX9753: GAIN = 0, V
= 0V; MAX9754: GAIN = 0; T = T
to T
, unless otherwise
VOL
A/B
A
MIN
MAX
noted. Typical values are at T = +25°C.) (Notes 1, 2)
A
PARAMETER
SYMBOL
CONDITIONS
Gain 10.5dB to 13.5dB
MIN
TYP
0.2
0.2
0.3
1.0
MAX
UNITS
Gain 6.0dB to 10.0dB
Gain -26dB to +4.0dB
Gain -62dB to +30dB
Channel Matching
dB
BEEP INPUT (MAX9752 Only)
Beep Signal Minimum Amplitude
(Note 8)
V
R
BEEP
= 47kΩ
400
300
mV
Hz
BEEP
Beep Signal Minimum Frequency
f
BEEP
/2
LOGIC INPUTS (GAIN_, IN1 , SHDN, HPS)
Input High Voltage
Input Low Voltage
V
2.0
V
V
IH
V
0.8
+1
IL
GAIN_, SHDN
-1
Input Leakage Current
I
µA
LEAK
IN1/2
-2
+2
+1
HPS
-20
Note 1: All devices are 100% production tested at T = +25°C. All temperature limits are guaranteed by design.
A
Note 2: Speaker amplifier testing performed with a resistive load in series with an inductor to simulate an actual speaker load. For
R = 4Ω, L = 33µH. For R = 8Ω, L = 68µH.
Note 3: Measured with the amplifier input connected to GND through C
L
L
.
IN
Note 4: Speaker amplifier gain is defined as A = (V
- V
) / V
.
OUT_+
OUT_-
IN_
Note 5: Testing performed with 8Ω resistive load in series with 68µH inductive load connected across the BTL output. Mode transitions
are controlled by SHDN. Peak reading, THD+N = 1%, A-weighted, 32 samples per second. K level is calculated as:
CP
20 x log[(peak voltage under normal operation at rated power level) / (peak voltage during mode transition, no input signal)].
Note 6: Headphone amplifier gain is defined as A = V
/ V
IN_
.
HP_
Note 7: Testing performed with 32Ω resistive load connected from HP_ output to GND. Mode transitions are controlled by SHDN.
Peak reading, THD+N = 1%, A-weighted, 32 samples per second. K level is calculated as:
CP
20 x log[(peak voltage under normal operation at rated power level) / (peak voltage during mode transition, no input signal)].
Note 8: The value of R
dictates the minimum beep signal amplitude that is detected (see the Beep Input (MAX9752) section).
BEEP
_______________________________________________________________________________________
5
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Typical Operating Characteristics
(V
= PV
= HPV
= CPV
= 5.0V, GND = PGND = HPGND = 0V, V
= V , CPV
= V , C
= 1µF,
BIAS
DD
DD
DD
DD
SHDN
DD
SS
SS
C
= 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
CPVSS
MAX9752: GAIN1 = GAIN2 = 0, V
= 0V; MAX9753: GAIN = 0, V
= 0V; MAX9754: GAIN = 0; T = +25°C, unless otherwise noted.)
VOL
A/B A
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)
10
10
10
R = 3Ω
L
R = 4Ω
L
R = 8Ω
L
1
0.1
1
0.1
1
0.1
P
= 1.5W
OUT
P
= 1W
P
= 1W
OUT
OUT
P
= 750mW
OUT
0.01
0.001
0.01
0.001
0.01
0.001
P
= 500mW
OUT
P
= 500mW
10k
OUT
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
FREQUENCY (Hz)
100k
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
100
10
100
10
100
10
1
1
1
f
= 10kHz
f
= 10kHz
IN
IN
f
= 10kHz
IN
0.1
0.1
0.1
f
= 20Hz
IN
f
= 20Hz
f
= 1kHz
IN
IN
f
= 1kHz
0.01
0.001
0.01
0.001
IN
0.01
0.001
f
= 1kHz AND 20Hz
IN
R = 3Ω
L
R = 4Ω
L
MAX9752C
R = 3Ω
MAX9752C
L
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
OUTPUT POWER (W)
0
0.5
1.0
1.5
2.0
2.5
3.0
0
0.5
1.0
1.5
2.0
2.5 3.0
OUTPUT POWER (W)
OUTPUT POWER (W)
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
100
10
100
10
100
10
1
1
1
f
= 10kHz
IN
f = 10kHz
IN
f
= 10kHz
IN
0.1
0.1
0.1
f
= 20Hz
IN
f
= 1kHz
IN
0.01
0.001
0.01
0.001
0.01
0.001
f
IN
= 1kHz AND 20Hz
0.5
f
= 1kHz AND 20Hz
R = 8Ω
IN
L
R = 4Ω
L
MAX9752C
R = 8Ω
L
0
0.5
1.0
1.5
2.0
2.5
0
0.5
1.0
1.5
0
1.0
1.5
OUTPUT POWER (W)
OUTPUT POWER (W)
OUTPUT POWER (W)
6
_______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Typical Operating Characteristics (continued)
(V
= PV
= HPV
= CPV
= 5.0V, GND = PGND = HPGND = 0V, V
= V , CPV
= V , C
= 1µF,
BIAS
DD
DD
DD
DD
SHDN
DD
SS
SS
C
= 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
CPVSS
MAX9752: GAIN1 = GAIN2 = 0, V
= 0V; MAX9753: GAIN = 0, V
= 0V; MAX9754: GAIN = 0; T = +25°C, unless otherwise noted.)
VOL
A/B A
OUTPUT POWER vs. LOAD RESISTANCE
(SPEAKER MODE)
OUTPUT POWER vs. LOAD RESISTANCE
(SPEAKER MODE)
4
5
4
3
2
1
0
THD+N = 10%
3
THD+N = 10%
2
THD+N = 1%
1
THD+N = 1%
0
1
10
100
1
10
100
LOAD RESISTANCE (Ω)
LOAD RESISTANCE (Ω)
POWER DISSIPATION vs. OUTPUT POWER
(SPEAKER MODE)
EFFICIENCY vs. OUTPUT POWER
100
90
80
70
60
50
40
30
20
10
0
2.0
1.5
1.0
0.5
0
R = 8Ω||68μH
L
R = 4Ω||33μH
L
R = 4Ω
L
R = 8Ω
L
0
2
4
6
0
1
2
3
4
OUTPUT POWER (W)
OUTPUT POWER (W)
TURN-OFF RESPONSE
(SPEAKER MODE)
TURN-ON RESPONSE
(SPEAKER MODE)
MAX9752/53/54 toc15
MAX9752/53/54 toc14
5V/div
5V/div
SHDN
SHDN
OUT
(NO AUDIO)
OUT
(NO AUDIO)
100mV/div
500mV/div
100mV/div
OUT
OUT
500mV/div
(1kHz, 2V
)
P-P
(1kHz, 2V
)
P-P
2ms/div
4ms/div
_______________________________________________________________________________________
7
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Typical Operating Characteristics (continued)
(V
= PV
= HPV
= CPV
= 5.0V, GND = PGND = HPGND = 0V, V
= V , CPV
= V , C
= 1µF,
BIAS
DD
DD
DD
DD
SHDN
DD
SS
SS
C
= 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
CPVSS
MAX9752: GAIN1 = GAIN2 = 0, V
= 0V; MAX9753: GAIN = 0, V
= 0V; MAX9754: GAIN = 0; T = +25°C, unless otherwise noted.)
VOL
A/B A
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)
10
1
10
1
10
1
V
= 5V
V
= 5V
V
= 3.3V
DD
DD
DD
R = 32Ω
R = 16Ω
R = 16Ω
L
L
L
A
= 3dB
A
V
= 3dB
A = 3dB
V
V
OUTPUT POWER = 30mW
OUTPUT POWER = 45mW
OUTPUT POWER = 90mW
0.1
0.01
0.1
0.01
0.1
0.01
OUTPUT POWER = 10mW
OUTPUT POWER = 30mW
OUTPUT POWER = 10mW
0.001
0.001
0.001
0.0001
0.0001
0.0001
10
100
1k
10k
100k
10
100
1k
10k
100k
10
100
1k
10k
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
1000
100
10
1000
100
10
10
1
V
= 5V
V
= 5V
DD
V
= 3.3V
DD
DD
R = 16Ω
R = 32Ω
R = 32Ω
L
L
L
A
= 3dB
A = 3dB
V
A
V
= 3dB
V
OUTPUT POWER = 45mW
0.1
0.01
f
IN
= 1kHz
1
1
f
IN
= 10kHz
f
IN
= 10kHz
0.1
0.1
OUTPUT POWER = 10mW
f
= 20Hz
IN
0.001
0.01
0.001
0.01
0.001
f
= 1kHz
100
IN
f
IN
= 20Hz
0.0001
20
0
25
50
75
125
150
0
40
60
80
100
10
100
1k
10k
100k
OUTPUT POWER (mW)
OUTPUT POWER (mW)
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
OUTPUT POWER vs. LOAD RESISTANCE
(HEADPHONE MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
1000
100
10
180
160
140
120
100
80
1000
100
10
V
= 3.3V
V
= 3.3V
DD
L
V
DD
L
V
R = 32Ω
A
R = 16Ω
A
THD+N = 10%
= 3dB
= 3dB
f
IN
= 1kHz
f
= 1kHz
IN
1
1
f
IN
= 10kHz
f
IN
= 10kHz
0.1
0.1
60
40
0.01
0.001
0.01
0.001
THD+N = 1%
20
0
40 50
OUTPUT POWER (mW)
90
0
10 20 30
60 70 80
10
100
1000
10
40
OUTPUT POWER (mW)
0
20
30
50
60
LOAD RESISTANCE (Ω)
8
_______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Typical Operating Characteristics (continued)
(V
= PV
= HPV
= CPV
= 5.0V, GND = PGND = HPGND = 0V, V
= V , CPV
= V , C
= 1µF,
BIAS
DD
DD
DD
DD
SHDN
DD
SS
SS
C
= 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
CPVSS
MAX9752: GAIN1 = GAIN2 = 0, V
= 0V; MAX9753: GAIN = 0, V
= 0V; MAX9754: GAIN = 0; T = +25°C, unless otherwise noted.)
VOL
A/B A
OUTPUT POWER vs. SUPPLY VOLTAGE
(HEADPHONE MODE)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (HEADPHONE MODE)
POWER DISSIPATION vs. OUTPUT POWER
(HEADPHONE MODE)
250
225
200
175
150
125
100
75
125
100
75
50
25
0
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
V
A
= 200mV
P-P
= 10.5dB
RIPPLE
V
R = 16Ω
L
OUTPUT REFERRED
R = 16
Ω
L
R = 32Ω
L
R = 32
Ω
L
V
= 5V
50
DD
f = 1kHz
= P
25
P
+ P
OUTR
OUT
OUTL
f = 1kHz
0
0
25 50 75 100 125 150 175 200 225 250
OUTPUT POWER (mW)
3.0
3.5
4.0
4.5
5.0
5.5
10
100
1k
FREQUENCY (Hz)
10k
100k
SUPPLY VOLTAGE (V)
CROSSTALK vs. FREQUENCY
(HEADPHONE MODE)
OUTPUT POWER vs. CHARGE-PUMP
CAPACITANCE AND LOAD RESISTANCE
0
-20
200
V
V
= 5V
CC
V
= 5V
DD
180
160
140
120
100
80
= 200mV
RIPPLE
P-P
f = 1kHz
THD+N = 1%
R = 32Ω
L
-40
C1 = C2 = 2.2μF
-60
-80
60
RIGHT TO LEFT
C1 = C2 = 1μF
40
-100
-120
20
LEFT TO RIGHT
0
10
100
1k
10k
100k
10
20
30
40
50
FREQUENCY (Hz)
LOAD RESISTANCE (Ω)
_______________________________________________________________________________________
9
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Typical Operating Characteristics (continued)
(V
= PV
= HPV
= CPV
= 5.0V, GND = PGND = HPGND = 0V, V
= V , CPV
= V , C
= 1µF,
BIAS
DD
DD
DD
DD
SHDN
DD
SS
SS
C
= 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
CPVSS
MAX9752: GAIN1 = GAIN2 = 0, V
= 0V; MAX9753: GAIN = 0, V
= 0V; MAX9754: GAIN = 0; T = +25°C, unless otherwise noted.)
VOL
A/B A
TURN-ON RESPONSE
(HEADPHONE MODE)
HEADPHONE OUTPUT SPECTRUM
MAX9752/53/54 toc31
0
-20
V
= 5V
DD
f = 1kHz
= -60dB
5V/div
V
OUT
R = 32Ω
L
SHDN
-40
-60
-80
20mV/div
HPOUT_
-100
-120
-140
R
= 32Ω
L
0
5
10
15
20
10ms/div
FREQUENCY (Hz)
TURN-OFF RESPONSE
(HEADPHONE MODE)
MAX9752/53/54 toc32
5V/div
SHDN
20mV/div
HPOUT_
R
= 32Ω
L
10ms/div
10 ______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Pin Descriptions
PIN
NAME
FUNCTION
MAX9752
MAX9753
MAX9754
1
2
—
—
2
—
3, 19
4
INL
Left-Channel Audio Input
Audible Alert Beep Input
Power Ground
BEEP
3, 19
4
3, 19
4
PGND
OUTL+
OUTL-
Left-Channel Positive Speaker Output
Left-Channel Negative Speaker Output
Speaker Amplifier Power Supply
5
5
5
6, 16
7
6, 16
7
6, 16
7
PV
DD
CPV
Charge-Pump Power Supply
DD
8
8
8
C1P
Charge-Pump Flying-Capacitor Positive Terminal
Charge-Pump Ground
9
9
9
CPGND
C1N
10
11
12
13
14
15
17
18
20
21
10
11
12
13
14
15
17
18
20
21
10
11
12
13
14
15
17
18
20
21
Charge-Pump Flying-Capacitor Negative Terminal
CPV
Charge-Pump Output. Connect to V
.
SS
SS
V
Headphone Amplifier Negative Power Supply
Right-Channel Headphone Output
SS
HPOUTR
HPOUTL
Left-Channel Headphone Output
HPV
Headphone Positive Power Supply
DD
OUTR-
OUTR+
HPS
Right-Channel Negative Speaker Output
Right-Channel Positive Speaker Output
Headphone Sense Input
BIAS
Common-Mode Bias Voltage. Bypass with a 1µF capacitor to GND.
Shutdown. Drive SHDN low to disable the device. Connect SHDN to
22
22
22
SHDN
V
for normal operation.
DD
23
24
25
26
27
28
—
—
—
—
—
—
—
—
—
25
26
—
—
1
—
—
GAIN2
GAIN1
Gain-Control Input 2
Gain-Control Input 1
25
V
Power Supply
DD
23, 26
28
GND
INR
Ground
Right-Channel Audio Input
Analog Volume Control Input
Left-Channel Audio Input 1
Left-Channel Audio Input 2
Input Select
—
VOL
—
INL1
INL2
IN1/2
GAIN
INR1
INR2
N.C.
2
—
23
24
27
28
—
—
24
Gain Select
—
Right-Channel Audio Input 1
Right-Channel Audio Input 2
No Connection. Not internally connected.
—
1, 27
______________________________________________________________________________________ 11
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
MAX9752 ONLY
V
DD
IN_
V
OUT
V
DD
/ 2
GND
OUT_+
BIAS
BIAS
CONVENTIONAL DRIVER-BIASING SCHEME
+V
DD
VOLUME
CONTROL
OUT_
VOL
BIAS
GND
GND
HPOUT_
-V
DD
DirectDrive BIASING SCHEME
Figure 1. MAX9752/MAX9753/MAX9754 Signal Path
Figure 2. Traditional Amplifier Output vs. DirectDrive Output
have almost twice the supply range compared to other
single-supply amplifiers, nearly quadrupling the available
output power. The benefit of the GND bias is that the
amplifier outputs no longer have a DC component (typi-
Detailed Description
The MAX9752/MAX9753/MAX9754 combine a 2.2W,
Class D speaker amplifier and a 62mW DirectDrive
headphone amplifier with integrated headphone sens-
ing and comprehensive click-and-pop suppression.
The speaker amplifiers offer Class AB performance with
Class D efficiency, while occupying minimal board
space. A unique filterless modulation scheme and
spread-spectrum switching create a compact, flexible,
low-noise, efficient audio power amplifier.
cally V
/ 2). This eliminates the large DC-blocking
DD
capacitors required with conventional headphone ampli-
fiers, removing the dominant source of click and pop,
conserving board space, system cost, and improving
frequency response.
An undervoltage lockout prevents operation from an
insufficient power supply. The amplifiers include ther-
mal-overload and short-circuit protection, and can with-
stand ±±kV ESD strikes on the headphone amplifier
outputs (IEC Air-Gap Discharge). An additional feature
of the speaker amplifiers is that there is no phase inver-
sion from input to output.
The MAX9752 features an analog volume control, BEEP
input, and four-level gain control. The MAX9753 fea-
tures a 2:1 input stereo multiplexer and two-level gain
control. The MAX9754 has only the Class D amplifiers
and the headphone amplifiers.
An input amplifier sets the gain of the signal path, and
feeds both the speaker and headphone amplifier
(Figure 1). The speaker amplifier uses a low-EMI, Class
D architecture to drive the speakers, eliminating the
need for an external filter for short speaker cables.
Class D Speaker Amplifier
The MAX9752/MAX9753/MAX9754 feature a unique
spread-spectrum mode that flattens the wideband spec-
tral components, improving EMI emissions that may be
radiated by the speaker and cables. The switching fre-
quency varies randomly by ±9ꢀkꢁH around the center
frequency (12ꢀꢀkꢁH). Instead of a large amount of spec-
tral energy present at multiples of the switching frequen-
cy, the energy is now spread over a bandwidth that
increases with frequency. Above a few megahertH, the
wideband spectrum looks like white noise for EMI pur-
poses (Figure 3).
The headphone amplifiers use Maxim’s DirectDrive
architecture eliminating the bulky output DC-blocking
capacitors required by traditional headphone amplifiers.
A charge pump inverts the positive supply (CPV ), cre-
DD
ating a negative supply (CPV ). The headphone ampli-
SS
fiers operate from these bipolar supplies with their
outputs biased about GND (Figure 2). The amplifiers
12 ______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
50
45
40
35
30
25
20
15
10
5
0
30
60
80
100
120
140
160
180
200
220
240
260
280
300
FREQUENCY (MHz)
Figure 3. MAX9752/MAX9753/MAX9754 Radiated Emissions with 76mm of Speaker Cable
EFFICIENCY vs. OUTPUT POWER
100
V
IN_
= 0V
MAX9752
90
80
70
60
50
40
30
20
10
0
MAX9753
MAX9754
OUT_-
OUT_+
CLASS AB
R = 8Ω
L
0
0.5
1.0
OUTPUT POWER (W)
1.5
2.0
V
- V = 0V
OUT_+ OUT_-
Figure 5. MAX9752/MAX9753/MAX9754 Class D Efficiency vs.
MAX9750/MAX9751/MAX9755 Class AB Efficiency
Figure 4. Second-Generation Class D Output Waveform with
No Signal
Filterless Modulation/Common-Mode Idle
The MAX9752/MAX9753/MAX9754 use Maxim’s unique
modulation scheme that eliminates the LC filter required
by traditional Class D amplifiers, improving efficiency,
reducing component count, and conserving board
space and system cost (Figure 4). With no input signal,
the outputs are two low-duty-cycle pulses that are in-
phase. This lowers the high-frequency energy and spec-
tral content. In comparison, conventional Class D
amplifiers output a 50% duty cycle when no input signal
is present. For most applications with short speaker
cables, no filtering is required.
Efficiency
Efficiency of a Class D amplifier is attributed to the
region of operation of the output stage transistors. In a
Class D amplifier, the output transistors act as switches
and consume negligible power. Any power loss associ-
ated 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
powers. Under normal operating levels (typical music
reproduction levels), efficiency falls below 30%, whereas
the MAX9752/MAX9753/MAX9754 still exhibit > 80%
efficiencies under the same conditions (Figure 5).
______________________________________________________________________________________ 13
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
3) 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
equipment, resulting in large ground-loop current
and possible damage to the amplifiers.
Headphone Amplifier
DirectDrive
Conventional single-supply headphone amplifiers have
their outputs biased about a nominal DC voltage (typi-
cally half the supply) for maximum dynamic range.
Large coupling capacitors are needed to block the DC
bias from the headphones.
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 DirectDrive architecture uses a charge pump to
create an internal negative supply voltage. This allows the
MAX9752/MAX9753/MAX9754 headphone amplifier out-
put to be biased about GND, almost doubling the dynam-
ic range, while operating from a single supply. With no DC
component, there is no need for the large DC-blocking
capacitors. Instead of two large capacitors (220µF, typ),
the charge pump requires only two small ceramic capaci-
tors (1µF typ), conserving board space, reducing cost,
and improving the frequency response of the headphone
amplifier. See the Output Power vs. Charge-Pump
Capacitance and Load Resistance graph in the Typical
Operating Characteristics for details of the possible
capacitor values.
1) 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
L
C
is the value of the DC-blocking capacitor.
OUT
The highpass filter is required by conventional single-
ended, single-supply headphone amplifiers 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
Previous attempts to eliminate the output-coupling capac-
itors involved biasing the headphone return (sleeve) to
the DC bias voltage of the headphone amplifiers. This
method raised some issues:
audio band. Larger values of C
reduce the atten-
OUT
uation, but are physically larger, more expensive
capacitors. Figure 6 shows the relationship between
the size of C
and the resulting low-frequency
OUT
1) The sleeve is typically grounded to the chassis. Using
this biasing approach, the sleeve must be isolated
from system ground, complicating product design.
attenuation. Note the -3dB point for a 16Ω head-
phone with a 100µF blocking capacitor is 100Hz, well
within the audio band.
2) 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.
2) 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 frequen-
cies around the -3dB point, the reactance of the
capacitor dominates, and the voltage coefficient
appears as frequency-dependent distortion. Figure 7
shows the THD+N introduced by two different
capacitor dielectrics. Note that around the -3dB point,
THD+N increases dramatically.
LOW-FREQUENCY ROLLOFF
(R = 16Ω)
L
0
-3
-6
DirectDrive
330μF
220μF
100μF
The combination of low-frequency attenuation and
frequency-dependent distortion compromises audio
reproduction. DirectDrive improves low-frequency
reproduction in portable audio equipment that
emphasizes low-frequency effects such as multi-
media laptops, MP3, CD, and DVD players.
-9
-12
-15
33μF
10
100
1k
FREQUENCY (Hz)
10k
100k
Figure 6. Low-Frequency Attenuation of Common DC-Blocking
Capacitor Values
14 ______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
ADDITIONAL THD+N DUE
TO DC-BLOCKING CAPACITORS
V
DD
10
1
MAX9752
MAX9753
MAX9754
0.1
R1
100kΩ
TANTALUM
0.01
0.001
0.0001
HPS
OUTL
ALUM/ELEC
OUTR
10
100
1k
10k
100k
FREQUENCY (Hz)
Figure 7. Distortion Contributed by DC-Blocking Capacitors
Figure 8. HPS Configuration
Table 1. MAX9752 Gain Settings
SPEAKER MODE GAIN (dB)
GAIN2
GAIN1
HEADPHONE MODE GAIN (dB)
MAX9752A
9.0
MAX9752B
15.0
MAX9752C
0
0
1
1
0
1
0
1
6.0
7.5
0
0
3
3
10.5
16.5
12.0
18.0
9.0
13.5
19.5
10.5
Charge Pump
ance of the headphone amplifier pulls HPS low. When a
headphone plug is inserted into the jack, the control pin
is disconnected from the tip contact and HPS is pulled
The MAX9752/MAX9753/MAX9754 feature a low-noise
charge pump. The 600kHz switching frequency is well
beyond the audio range, and does not interfere with the
audio signals. The switch drivers feature a controlled
switching speed that minimizes noise generated by turn-
on and turn-off transients. Limiting the switching speed
of the charge pump minimizes the di/dt noise caused by
the parasitic bond wire and trace inductance. Although
not typically required, additional high-frequency ripple
attenuation can be achieved by increasing the size of C2
(see the Functional Diagrams).
to V
through the internal 100kΩ pullup resistor.
DD
Bias
The MAX9752/MAX9753/MAX9754 feature an internally
generated, power-supply-independent, common-mode
bias voltage referenced to GND. BIAS provides both
click-and-pop suppression and sets the DC bias level
for the amplifiers. Choose the value of the bypass
capacitor as described in the BIAS Capacitor section.
No external load should be applied to BIAS.
Headphone Sense Input (HPS)
The headphone sense input (HPS) monitors the head-
phone jack, and automatically configures the device
based upon the voltage applied at HPS. A voltage of
less than 0.8V sets the device to speaker mode. A volt-
age of greater than 2V disables the speaker amplifiers
and enables the headphone amplifiers.
Gain Selection
MAX9752
The MAX9752 features externally controlled gain with
four pin-selectable gain ranges. GAIN1 and GAIN2 set
the maximum gain of the MAX9752 speaker and head-
phone amplifiers (Table 1). The voltage at VOL varies
the gain of the speaker and headphone amplifiers, pro-
viding a user-adjusted volume control, see the Analog
Volume Control (VOL, MAX9752) section.
For automatic headphone detection, connect HPS to the
control pin of a 3-wire headphone jack as shown in
Figure 8. With no headphone present, the output imped-
______________________________________________________________________________________ 15
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Table 2. MAX9752 Speaker Amplifier Gain
Settings for Maximum Output Power
Table 3. MAX9753/MAX9754 Maximum
Gain Settings
GAIN
(dB)
INPUT
(V
R
(Ω)
P
OUT
(W)
L
SPEAKER MODE
GAIN (dB)
HEADPHONE MODE
GAIN (dB)
GAIN
)
RMS
MAX9752A
9.0
0
1
10.5
9.0
3
0
1.004
0.844
0.710
0.598
1.099
0.925
0.778
0.655
4
4
4
4
8
8
8
8
2.0
2.0
2.0
2.0
1.2
1.2
1.2
1.2
10.5
12.0
13.5
9.0
Table 4. MAX9753/MAX9754 Input Voltage
and Gain Settings for Maximum Output
Power
10.5
12.0
13.5
MAX9752B
15.0
16.5
18.0
19.5
15.0
16.5
18.0
19.5
MAX9752C
6.0
GAIN
(dB)
INPUT
(V
R
(Ω)
P
OUT
(W)
L
)
RMS
10.5
9.0
0.844
1.004
0.925
1.099
4
4
8
8
2.0
2.0
1.2
1.2
0.503
0.423
0.356
0.300
0.551
0.464
0.390
0.328
4
4
4
4
8
8
8
8
2.0
2.0
2.0
2.0
1.2
1.2
1.2
1.2
10.5
9.0
Table 4 shows the amplifier input voltage needed to
attain maximum speaker output power from a given
gain setting and load.
Analog Volume Control (VOL, MAX9752)
The MAX9752 features an analog volume control that
varies the speaker and headphone amplifier’s gain in 31
discrete steps based upon the DC voltage applied to
VOL. The input range of VOL is from 0 (full volume) to
1.418
1.193
1.004
0.844
1.553
1.307
1.099
0.925
4
4
4
4
8
8
8
8
2.0
2.0
2.0
2.0
1.2
1.2
1.2
1.2
0.858 x HPV (full mute). Example step sizes are shown
DD
7.5
in Table 5. Control VOL with either a DAC or potentiome-
ter as shown in Figure 9. Because the VOL input is high
impedance (typically 100MΩ), it can also be driven with
an RC-filtered PWM signal. Connect the reference of the
9.0
10.5
6.0
DAC or potentiometer to HPV . Since the volume con-
DD
trol is ratiometric to HPV , any changes in HPV
7.5
are
DD
DD
9.0
negated. The gain step sizes are not constant, the step
sizes at the upper extreme are 0.5dB/step, 2.0dB/step in
the midrange, and 4.0dB/step at the lower extreme.
Figure 10 shows the transfer function of the volume con-
10.5
Table 2 shows the amplifier gain settings needed to
attain maximum speaker output power from a given
input voltage and load.
trol for HPV = 3.3V.
DD
MAX9753/MAX9754
The gain of the MAX9753/MAX9754 is set by GAIN.
Drive GAIN high to set the gain of the speaker ampli-
fiers to 9dB, and the gain of the headphone amplifiers
to 0dB. Drive GAIN low to set the gain of the speaker
amplifiers to 10.5dB, and the gain of the headphone
amplifiers to 3dB (Table 3).
16 ______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Table 5a. MAX9752A Volume Levels
V
(V)
SPEAKER MODE GAIN (dB)
HEADPHONE MODE GAIN (dB)
VOL
FRACTION
OF
GAIN1 = 0,
GAIN2 = 0
GAIN1 = 1,
GAIN2 = 0
GAIN1 = 0,
GAIN2 = 1
GAIN1 = 1
GAIN2 = 1
GAIN1 = X,
GAIN2 = 0
GAIN1 = X,
GAIN2 = 1
V
*
V
MAX
*
MIN
HPV
DD
0
0.4900
0.5673
0.6447
0.7220
0.7994
0.8767
0.9541
1.0314
1.1088
1.1861
1.2635
1.3408
1.4182
1.4955
1.5728
1.6502
1.7275
1.8049
1.8822
1.9596
2.0369
2.1143
2.1916
2.2690
2.3463
2.4237
2.5010
2.5783
2.6557
2.7330
2.8104
3.3000
0.074
0.160
0.183
0.207
0.230
0.253
0.277
0.300
0.324
0.347
0.371
0.394
0.418
0.441
0.464
0.488
0.511
0.535
0.558
0.582
0.605
0.628
0.652
0.675
0.699
0.722
0.746
0.769
0.793
0.816
0.839
0.858
9
8
10.5
10
12
11.5
11
13.5
13
0
-1
3
2.5
2
0.4900
0.5673
0.6447
0.7220
0.7994
0.8767
0.9541
1.0314
1.1088
1.1861
1.2635
1.3408
1.4182
1.4955
1.5728
1.6502
1.7275
1.8094
1.8822
1.9596
2.0369
2.1143
2.1916
2.2690
2.3463
2.4237
2.5010
2.5783
2.6557
2.7330
2.8104
7
9
12.5
12
-2
6
8
10.5
10
-3
1.5
1
4
7
11.5
11
-5
2
6
9
-7
0
0
4
8
10.5
10
-9
-1
-2
2
7
-11
-13
-15
-17
-19
-21
-23
-25
-27
-29
-31
-33
-35
-37
-39
-41
-43
-47
-51
-55
-59
-63
-67
-71
MUTE
-2
-4
0
6
9
-3
-6
-2
4
8
-5
-8
-4
2
7
-7
-10
-12
-14
-16
-18
-20
-22
-24
-26
-28
-30
-32
-34
-38
-42
-46
-50
-54
-58
-62
MUTE
-6
0
6
-9
-8
-2
4
-11
-13
-15
-17
-19
-21
-23
-25
-27
-29
-31
-33
-35
-37
-39
-41
-43
-47
-51
MUTE
-10
-12
-14
-16
-18
-20
-22
-24
-26
-28
-30
-32
-34
-38
-42
-46
-50
-54
MUTE
-4
2
-6
0
-8
-2
-10
-12
-14
-16
-18
-20
-22
-24
-26
-28
-30
-32
-34
-38
-42
MUTE
-4
-6
-8
-10
-12
-14
-16
-18
-20
-22
-24
-26
-28
-30
-32
MUTE
*Based on HPV = 3.3V.
DD
X = Don’t care.
______________________________________________________________________________________ 17
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Table 5b. MAX9752B Volume Levels
V
(V)
SPEAKER MODE GAIN (dB)
HEADPHONE MODE GAIN (dB)
VOL
FRACTION
OF
GAIN1 = 0,
GAIN2 = 0
GAIN1 = 1,
GAIN2 = 0
GAIN1 = 0,
GAIN2 = 1
GAIN1 = 1
GAIN2 = 1
GAIN1 = X,
GAIN2 = 0
GAIN1 = X,
GAIN2 = 1
V
*
V
*
MAX
MIN
HPV
DD
0
0.4900
0.5673
0.6447
0.7220
0.7994
0.8767
0.9541
1.0314
1.1088
1.1861
1.2635
1.3408
1.4182
1.4955
1.5728
1.6502
1.7275
1.8049
1.8822
1.9596
2.0369
2.1143
2.1916
2.2690
2.3463
2.4237
2.5010
2.5783
2.6557
2.7330
2.8104
3.3000
0.074
0.160
0.183
0.207
0.230
0.253
0.277
0.300
0.324
0.347
0.371
0.394
0.418
0.441
0.464
0.488
0.511
0.535
0.558
0.582
0.605
0.628
0.652
0.675
0.699
0.722
0.746
0.769
0.793
0.816
0.839
0.858
15
14
16.5
16
18
17.5
17
19.5
19
0
-1
3
2.5
2
0.4900
0.5673
0.6447
0.7220
0.7994
0.8767
0.9541
1.0314
1.1088
1.1861
1.2635
1.3408
1.4182
1.4955
1.5728
1.6502
1.7275
1.8049
1.8822
1.9596
2.0369
2.1143
2.1916
2.2690
2.3463
2.4237
2.5010
2.5783
2.6557
2.7330
2.8104
13
15
18.5
18
-2
12
14
16.5
16
-3
1.5
1
10
13
17.5
17
-5
8
12
15
-7
0
6
10
14
16.5
16
-9
-1
4
8
13
-11
-13
-15
-17
-19
-21
-23
-25
-27
-29
-31
-33
-35
-37
-39
-41
-43
-47
-51
-55
-59
-63
-67
-71
MUTE
-2
2
6
12
15
-3
0
4
10
14
-5
-2
2
8
13
-7
-4
0
6
12
-9
-6
-2
4
10
-11
-13
-15
-17
-19
-21
-23
-25
-27
-29
-31
-33
-35
-37
-39
-41
-43
-47
-51
MUTE
-8
-4
2
8
-10
-12
-14
-16
-18
-20
-22
-24
-26
-28
-32
-36
-40
-44
-48
-52
-56
MUTE
-6
0
6
-8
-2
4
-10
-12
-14
-16
-18
-20
-22
-24
-26
-28
-32
-36
-40
-44
-48
MUTE
-4
2
-6
0
-8
-2
-10
-12
-14
-16
-18
-20
-22
-24
-26
-28
-32
-36
MUTE
-4
-6
-8
-10
-12
-14
-16
-18
-20
-22
-24
-26
MUTE
*Based on HPV = 3.3V.
DD
X = Don’t care.
18 ______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Table 5c. MAX9752C Volume Levels
V
(V)
SPEAKER MODE GAIN (dB)
HEADPHONE MODE GAIN (dB)
VOL
FRACTION
OF
GAIN1 = 0,
GAIN2 = 0
GAIN1 = 1,
GAIN2 = 0
GAIN1 = 0,
GAIN2 = 1
GAIN1 = 1
GAIN2 = 1
GAIN1 = X,
GAIN2 = 0
GAIN1 = X,
GAIN2 = 1
V
*
V
*
MAX
MIN
HPV
DD
0
0.4900
0.5673
0.6447
0.7220
0.7994
0.8767
0.9541
1.0314
1.1088
1.1861
1.2635
1.3408
1.4182
1.4955
1.5728
1.6502
1.7275
1.8049
1.8822
1.9596
2.0369
2.1143
2.1916
2.2690
2.3463
2.4237
2.5010
2.5783
2.6557
2.7330
2.8104
3.3000
0.074
0.160
0.183
0.207
0.230
0.253
0.277
0.300
0.324
0.347
0.371
0.394
0.418
0.441
0.464
0.488
0.511
0.535
0.558
0.582
0.605
0.628
0.652
0.675
0.699
0.722
0.746
0.769
0.793
0.816
0.839
0.858
6
5
7.5
7
9
8.5
8
10.5
10
9.5
9
0
-1
3
2.5
2
0.4900
0.5673
0.6447
0.7220
0.7994
0.8767
0.9541
1.0314
1.1088
1.1861
1.2635
1.3408
1.4182
1.4955
1.5728
1.6502
1.7275
1.8049
1.8822
1.9596
2.0369
2.1143
2.1916
2.2690
2.3463
2.4237
2.5010
2.5783
2.6557
2.7330
2.8104
4
6
-2
3
5
7.5
7
-3
1.5
1
1
4
8.5
8
-5
-1
3
6
-7
0
-3
1
5
7.5
7
-9
-1
-5
-1
4
-11
-13
-15
-17
-19
-21
-23
-25
-27
-29
-31
-33
-35
-37
-39
-41
-43
-47
-51
-55
-59
-63
-67
-71
MUTE
-2
-7
-3
3
6
-3
-9
-5
1
5
-5
-11
-13
-15
-17
-19
-21
-23
-25
-27
-29
-31
-33
-35
-37
-41
-45
-48
-53
-57
-61
-65
MUTE
-7
-1
4
-7
-9
-3
3
-9
-11
-13
-15
-17
-19
-21
-23
-25
-27
-29
-31
-3
-5
1
-11
-13
-15
-17
-19
-21
-23
-25
-27
-29
-31
-33
-35
-37
-39
-41
-43
-47
-51
MUTE
-7
-1
-9
-3
-11
-13
-15
-17
-9
-5
-7
-9
-11
-13
-15
-17
-19
-21
-23
-25
-27
-29
-31
-33
-35
MUTE
-21
-23
-2
-27
-29
-31
-33
-35
-37
-41
-45
MUTE
-35
-37
-41
-45
-49
-53
-57
MUTE
*Based on HPV = 3.3V.
DD
X = Don’t care.
______________________________________________________________________________________ 19
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
MAX9752C
VOLUME-CONTROL TRANSFER FUNCTION
20
GAIN1 = GAIN2 = 0
10
0
-10
MAX9752
SPEAKER MODE
AUDIO
TAPER POT
-20
-30
-40
-50
-60
-70
-80
HPV
VOL
DD
V
REF
DAC
HEADPHONE MODE
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
(V)
V
VOL
Figure 9. MAX9752 Volume-Control Circuit
Figure 10c. MAX9752C Volume-Control Transfer Functions
Beep Input (MAX9752)
The MAX9752 features an audible alert beep input
(BEEP). BEEP serves as the alert signal detector and the
alert input to the amplifiers. AC-couple the alert output of
a µC to BEEP. The MAX9752 monitors the signal at
MAX9752A
VOLUME-CONTROL TRANSFER FUNCTION
20
10
GAIN1 = GAIN2 = 0
0
SPEAKER MODE
AUDIO
BEEP. When a signal exceeding 400mV
with a fre-
P-P
-10
-20
-30
-40
-50
-60
-70
-80
quency greater than 300Hz is detected at BEEP, the
MAX9752 connects the signal to the amplifiers after eight
periods of the input signal. In speaker mode, the alert
signal appears at both speaker outputs, mixed with any
audio that may be present. In headphone mode, the alert
signal appears at the headphone outputs, mixed with
any audio that may be present. A signal with less than
eight input periods is ignored. Multiple BEEP signals can
be summed as shown in Figure 11. Adding external
resistors in series with BEEP increase the minimum volt-
age amplitude sensitivity.
TAPER POT
HEADPHONE MODE
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
(V)
V
VOL
Figure 10a. MAX9752A Volume-Control Transfer Functions
Input Mux (MAX9753)
The MAX9753 features a 2:1 input multiplexer on each
amplifier, allowing input selection between two stereo
sources. The logic input IN1/2 controls both multiplexers.
A logic-high selects input IN_1 and a logic-low selects
input IN_2. The unselected inputs are high impedance.
MAX9752B
VOLUME-CONTROL TRANSFER FUNCTION
20
GAIN1 = GAIN2 = 0
10
0
-10
-20
-30
-40
-50
-60
-70
-80
SPEAKER MODE
AUDIO
TAPER POT
Shutdown
The MAX9752/MAX9753/MAX9754 feature an 8µA, low-
power shutdown mode reducing quiescent current con-
sumption and extending battery life. Driving SHDN low
disables the drive amplifiers, bias circuitry, charge
pump, and sets the headphone amplifier output imped-
ance to 1kΩ, and drives BIAS to GND. Connect SHDN to
HEADPHONE MODE
V
DD
for normal operation.
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
(V)
V
VOL
Figure 10b. MAX9752B Volume-Control Transfer Functions
20 ______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
R
S1
0.47μF
0.47μF
0.47μF
47kΩ
R
INT
SOURCE 1
SOURCE 2
SOURCE 3
47kΩ
R
S2
47kΩ
SPEAKER/HEADPHONE
AMPLIFIER INPUTS
BEEP
V
OUT(BEEP)
WINDOW
R
S3
47kΩ
DETECTOR
(0.4V THRESHOLD)
P-P
MAX9752
FREQUENCY
DETECTOR
BIAS
(300Hz THRESHOLD)
Figure 11. MAX9752 Beep Summing Circuit
Click-and-Pop Suppression
The MAX9752/MAX9753/MAX9754 feature Maxim’s
comprehensive, industry-leading click-and-pop sup-
pression eliminating audible transients at startup. The
Turn-On and Turn-Off Response waveforms in the
Typical Operating Characteristics show that there are
minimal spectral components in the audible range at
the output upon startup and shutdown.
Power Dissipation and Heat Sinking
Because the MAX9752/MAX9753/MAX9754 have high-
efficiency, Class D speaker drivers, the intrinsic pack-
age power dissipation capabilities are sufficient for
cooling. No special heatsinking is needed in normal
operating conditions.
Headphone Amplifier Output Power
The headphone amplifiers have been specified for the
worst-case scenario—when both inputs are in-phase.
Under this condition, the drivers simultaneously draw cur-
rent from the charge pump, leading to a slight loss in
Applications Information
Compatibility with
MAX9750/MAX9751/MAX9755
headroom of V . In typical stereo audio applications, the
SS
The MAX9752/MAX9753/MAX9754 provide a high-effi-
ciency, Class D speaker driver with very low EMI (see
the Typical Operating Characteristics). If a Class AB
output is desired, the MAX9750/MAX9751/MAX9755
can be substituted. The MAX9750, MAX9751, and
MAX9755 are pin-for-pin compatible with the MAX9752,
MAX9753, and MAX9754, respectively.
left and right signals have differences in both magnitude
and phase, subsequently leading to an increase in the
maximum attainable output power. Figure 12 shows the
two cases for in- and out-of-phase. In reality, the available
power lies between these extremes.
1000
Filterless Operation
The MAX9752/MAX9753/MAX9754 do not require an
output filter in most applications. The devices rely on
the inherent inductance of the speaker coil and the nat-
ural filtering of both the speaker and the human ear to
recover the audio component of the square-wave out-
put. Eliminating the output filter results in a smaller, less
costly, more efficient solution.
V
= 5V
DD
L
R = 16Ω
A
100
10
= 3dB
V
OUTPUTS IN-PHASE
1
0.1
Voice coil movement due to the square-wave frequency
is very small because the switching frequency is well
beyond the bandwidth of speakers. Although this move-
ment is small, a speaker not designed to handle the
additional power can be damaged. Use a speaker with a
series inductance > 30µH for optimum results. Typical
8Ω speakers exhibit series inductances in the 30µH to
100µH range. Highest efficiency is achieved with speak-
er inductances > 60µH.
0.01
0.001
OUTPUTS 180° OUT-OF-PHASE
0
25
50
75
100
125
150
OUTPUT POWER (mW)
Figure 12. THD+N vs. P
In- and Out-of-Phase
with Headphone Output Signals
OUT
______________________________________________________________________________________ 21
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Power Supplies
The MAX9752/MAX9753/MAX9754 have different sup-
plies for each portion of the device allowing for the opti-
mum combination of headroom, power dissipation, and
noise immunity. The speaker amplifiers are powered from
Charge-Pump Capacitor Selection
Use capacitors with less than 100mΩ of equivalent
series resistance (ESR). Low-ESR ceramic capacitors
minimize the output impedance of the charge pump.
Capacitors with an X7R dielectric provide the best per-
formance over the extended temperature range.
PV . PV
ranges from 4.5V to 5.5V. The headphone
DD
DD
amplifiers are powered from HPV
and V . HPV
is
DD
SS
DD
Flying Capacitor (C1)
The value of the flying capacitor (C1) affects the load
regulation and output resistance of the charge pump.
Choosing C1 too small degrades the ability to provide
sufficient current drive, which leads to a loss of output
voltage. Increasing the value of C1 improves load regu-
lation and reduces the charge-pump output resistance.
See the Output Power vs. Charge-Pump Capacitance
and Load Resistance graph in the Typical Operating
Characteristics. Above 2.2µF, the on-resistance of the
switches and the ESR of C1 and C2 dominate. The rec-
ommended range of capacitors is from 0.33µF to 3.3µF.
the positive supply of the headphone amplifiers and
ranges from 3V to 5.5V. V is the negative supply input
SS
for the headphone amplifiers. Connect V to CPV . The
SS
SS
charge pump is powered by CPV , which ranges from
DD
3V to 5.5V. CPV
should be the same potential as
DD
HPV . The charge pump inverts the voltage at CPV
,
DD
DD
and the resulting voltage appears at CPV . The remain-
SS
der of the device is powered by V
.
DD
Component Selection
Input Filtering
The input capacitor (C ), in conjunction with the ampli-
IN
fier input resistance (R ), forms a highpass filter that
IN
Output Capacitor (C2)
removes the DC bias from an incoming signal (see the
Functional Diagrams). 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:
The output capacitor value and ESR directly affect the
ripple at CPV . Increasing the value of C2 reduces
SS
output ripple. 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. See the Output Power vs. Charge-Pump
Capacitance and Load Resistance graph in the Typical
Operating Characteristics. C2 must be greater than or
equal to C1. The recommended range of capacitors is
from 0.33µF to 3.3µF.
1
f−3dB
=
2πR C
IN IN
R
is the amplifier’s internal input resistance value given
IN
in the Electrical Characteristics table. Choose C so
IN
f
is well below the lowest frequency of interest.
-3dB
Setting f
too high affects the amplifier’s low-frequency
-3dB
CPV
Bypass Capacitor
DD
response. Use capacitors with low-voltage coefficient
dielectrics, such as tantalum or aluminum electrolytic.
Capacitors with high-voltage coefficients, such as ceram-
ics, may result in increased distortion at low frequencies.
The CPV
bypass capacitor (C3) lowers the output
DD
impedance of the power supply and reduces the
impact of the charge-pump switching transients on the
headphone driver outputs. Bypass CPV
with C3, the
DD
same value as C1, and place it physically close to
CPV and PGND.
Optional Output Filtering
In most applications, the low-EMI, Class D outputs do not
require output filters. The device passes FCC emissions
standards with 76mm of unshielded speaker cables.
Output filtering can be used if lower EMI is desired. Use a
ferrite bead filter when radiated frequencies above
10MHz are of concern. Use an LC filter when radiated fre-
quencies below 10MHz are of concern, or when long
leads (> 76mm) connect the amplifier to the speaker.
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. Large traces also aid in mov-
ing heat away from the package. Proper grounding
improves audio performance, minimizes crosstalk
between channels, and prevents any switching noise
from coupling into the audio signal. Connect CPGND,
PGND, and GND together at a single point on the PC
board. Route CPGND, PGND, and all traces that carry
switching transients away from GND and the traces and
components in the audio signal path.
BIAS Capacitor
BIAS is the output of the internally generated DC bias
voltage. The BIAS bypass capacitor, C
, improves
BIAS
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 amplifiers. Bypass
BIAS with a 1µF capacitor to GND.
22 ______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Connect all components associated with the charge
pump (C2 and C3) to CPGND. Connect V and CPV
SS
SS
together at C2. Place the charge-pump capacitors (C1,
C2, and C3) as close to the device as possible. Bypass
HPV
with 1µF to GND. Bypass PV
with a 0.1µF
DD
DD
100Ω
47nF
capacitor and a 100µF capacitor to PGND. Place the
bypass capacitors as close to the device as possible.
OUT_+
CLASS D
IN+
AUDIO
ANALYZER
Use large, low-resistance output traces. Current drawn
from the outputs increases as load impedance
decreases. High-output-trace resistance decreases the
power delivered to the load. For example, when com-
pared to a 0Ω trace, a 100mΩ trace reduces the power
delivered to a 4Ω load from 2.1W to 2.0W. Large out-
put, supply, and GND traces allow more heat to move
from the MAX9752/MAX9753/MAX9754 to the air,
reducing the thermal impedance of the system.
MODULATOR
AND H-BRIDGE
R
L
47nF
OUT_-
IN-
100Ω
Figure 13. Connecting a Class D Output to an Analog Analyzer
The MAX9752/MAX9753/MAX9754 thin QFN packages
feature exposed pads on their undersides. Connect the
exposed pad to GND with a large copper pad and mul-
tiple vias to the ground plane.
the switching components obscure the audio signal. On
an audio analyzer they overload the input signal, degrad-
ing the measurement from the true audio performance of
the amplifier. A simple RC filter can be used (Figure 13)
to aid in evaluation of Class D amplifiers in the lab. This
circuit provides a single-pole response at 34kHz, with a
minimal insertion loss. More complex designs such as L-
C filters can provide more performance, but must be veri-
fied to ensure they do not add their own distortion
signature to the amplifier’s output.
Measuring Class D Outputs
with an Analog Analyzer
Filterless Class D amplifiers use the loudspeaker’s coil
inductance to filter out switching energy. Additionally, the
loudspeaker does not respond to the switching frequen-
cy of Class D amplifiers, nor could human ears hear
these frequencies. However, audio analyzers and oscil-
loscopes can detect these signals. On an oscilloscope,
______________________________________________________________________________________ 23
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
MAX9752 Functional Diagram
4.5V TO 5.5V
0.1μF
V
DD
25
6, 16 PV
DD
4.5V TO 5.5V
MAX9752
1μF
C
1μF
IN
4
5
OUTL+
OUTL-
GAIN/
VOLUME
CONTROL
INL
1
CLASS D
AMPLIFIER
LEFT-CHANNEL
AUDIO INPUT
C
1μF
IN
18 OUTR+
17 OUTR-
GAIN/
VOLUME
CONTROL
INR 27
CLASS D
AMPLIFIER
RIGHT-CHANNEL
AUDIO INPUT
BIAS 21
VOL 28
C
1μF
BIAS
15 HPV
20 HPS
DD
3V TO 5.5V
GAIN/
VOLUME
CONTROL
1μF
GAIN1 24
GAIN2 23
V
V
DD
HEADPHONE
DETECTION
DD
14 HPOUTL
1μF
47kΩ
BEEP
DETECTION
BEEP
2
SHUTDOWN
CONTROL
SHDN 22
V
DD
13 HPOUTR
CPV
7
DD
3V TO 5.5V
1μF
C1P
8
C1
1μF
CHARGE
PUMP
10
C1N
CPGND
9
11 12
26
3, 19
PGND
CPV
V
SS
GND
SS
C2
1μF
24 ______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
MAX9753 Functional Diagram
4.5V TO 5.5V
0.1μF
V
DD
25
6, 16 PV
DD
4.5V TO 5.5V
MAX9753
1μF
C
IN
1μF
INL1
INL2
1
2
4
5
OUTL+
OUTL-
LEFT-CHANNEL
AUDIO INPUT
CLASS D
AMPLIFIER
INPUT
MUX
LEFT-CHANNEL
AUDIO INPUT
C
IN
1μF
C
IN
1μF
INR1 27
INR2 28
RIGHT-CHANNEL
AUDIO INPUT
18 OUTR+
17 OUTR-
INPUT
MUX
CLASS D
AMPLIFIER
RIGHT-CHANNEL
AUDIO INPUT
C
IN
1μF
BIAS
21
15 HPV
20 HPS
DD
C
1μF
BIAS
3V TO 5.5V
MUX AND
GAIN
CONTROL
1μF
GAIN 24
V
V
DD
IN1/2 23
SHDN 22
14 HPOUTL
HEADPHONE
DETECTION
DD
V
DD
SHUTDOWN
CONTROL
13 HPOUTR
CPV
7
DD
3V TO 5.5V
1μF
C1P
8
C1
1μF
CHARGE
PUMP
10
C1N
CPGND
9
26
3, 19
PGND
11 12
CV
SS
V
SS
GND
C2
1μF
LOGIC PINS CONFIGURED FOR:
GAIN = 1, 9dB SPEAKER GAIN/0dB HEADPHONE GAIN.
IN1/2 = 1, SELECTED INPUT LINE 1.
SHDN = 1, PART ACTIVE.
______________________________________________________________________________________ 25
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
MAX9754 Functional Diagram
4.5V TO 5.5V
0.1μF
V
DD
25
6, 16 PV
DD
4.5V TO 5.5V
MAX9754
1μF
C
1μF
IN
4
5
OUTL+
OUTL-
INL
2
CLASS D
AMPLIFIER
LEFT-CHANNEL
AUDIO INPUT
C
1μF
IN
18 OUTR+
17 OUTR-
INR 28
CLASS D
AMPLIFIER
RIGHT-CHANNEL
AUDIO INPUT
BIAS 21
C
1μF
BIAS
15 HPV
20 HPS
DD
3V TO 5.5V
GAIN
CONTROL
1μF
GAIN 24
SHDN 22
V
V
DD
HEADPHONE
DETECTION
14 HPOUTL
DD
SHUTDOWN
CONTROL
13 HPOUTR
CPV
7
DD
3V TO 5.5V
1μF
C1P
8
C1
1μF
CHARGE
PUMP
10
C1N
CPGND
9
23, 26
GND
3, 19
PGND
11 12
CPV
V
SS
SS
C2
1μF
LOGIC PINS CONFIGURED FOR:
GAIN = 1, 9dB SPEAKER GAIN/0dB HEADPHONE GAIN.
SHDN = 1, PART ACTIVE.
26 ______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Pin Configurations
TOP VIEW
21 20 19 18 17 16 15
21 20 19 18 17 16 15
SHDN 22
GAIN2 23
14 HPOUTL
SHDN 22
IN1/2 23
14 HPOUTL
13 HPOUTR
13 HPOUTR
V
V
SS
24
12
11
SS
24
12
11
10
9
GAIN1
V
GAIN
V
CPV
CPV
C1N
MAX9753
MAX9752
DD 25
SS
DD 25
SS
GND
GND
INR1
10 C1N
26
INR 27
VOL 28
26
27
CPGND
C1P
CPGND
C1P
9
8
INR2 28
8
1
2
3
4
5
6
7
1
2
3
4
5
6
7
THIN QFN
THIN QFN
21 20 19 18 17 16 15
SHDN 22
GND 23
14 HPOUTL
13 HPOUTR
V
SS
24
12
11
GAIN
V
CPV
MAX9754
DD 25
SS
GND
10 C1N
26
N.C. 27
INR 28
9
8
CPGND
C1P
1
2
3
4
5
6
7
THIN QFN
Chip Information
MAX9752 TRANSISTOR COUNT: 12,263
MAX9753/MAX9754 TRANSISTOR COUNT: 12,137
PROCESS: BiCMOS
______________________________________________________________________________________ 27
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
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.)
28 ______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with 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.)
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 29
© 2005 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
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