19-3666; Rev 0; 9/05
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
The MAX9752/MAX9753/MAX9754 combine a high-efficiency, 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.
The MAX9754 features a Class D stereo speaker amplifier and headphone driver. The MAX9752 adds an analog 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.
The MAX9752/MAX9753/MAX9754 come in 28-pin thin
QFN (5mm x 5mm x 0.8mm) packages, and are specified 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.
Features
♦ PC2001 Compliant
♦ 2.2W Class D Stereo Speaker Amplifier
♦ Pin-for-Pin Compatible with Class AB
MAX9750/MAX9751/MAX9755
♦ 85% Efficiency (RL = 8Ω, POUT = 1W)
♦ 62mW DirectDrive Headphone Amplifier
♦ High PSRR (70dB at 1kHz)
♦ Analog Volume Control (MAX9752)
♦ Beep Input with Glitch Filter (MAX9752)
♦ 2:1 Stereo Input MUX (MAX9753)
♦ ±8kV ESD-Protected Headphone Outputs
♦ No Output DC-Blocking Capacitors
♦ Industry-Leading Click-and-Pop Suppression
Ordering Information
Applications
Notebook PCs
Flat-Panel TVs
Tablet PCs
PC Displays
Portable DVDs
LCD Projectors
PART
PIN-PACKAGE
PKG
CODE
MAXIMUM
GAIN (dB)
MAX9752AETI+
28 TQFN-EP*
T2855-1
13.5
MAX9752BETI+
28 TQFN-EP*
T2855-1
19.5
MAX9752CETI+
28 TQFN-EP*
T2855-1
10.5
MAX9753ETI+
28 TQFN-EP*
T2855-1
13.5
MAX9754ETI+
28 TQFN-EP*
T2855-1
13.5
Note: All devices specified for -40°C to +85°C operation.
+Denotes lead-free package.
*EP = Exposed paddle.
Pin Configurations appear at end of data sheet.
Block Diagrams
MAX9752
MAX9753
MAX9754
S
S
CLASS
D
AMP
CLASS
D
AMP
VOL
HPS
BEEP
INPUT
MUX
SELECT
CLASS
D
AMP
HPS
HPS
________________________________________________________________ Maxim Integrated Products
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.
1
MAX9752/MAX9753/MAX9754
General Description
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
ABSOLUTE MAXIMUM RATINGS
VDD, PVDD, HPVDD, CPVDD to GND ....................... -0.3V to +6V
GND to PGND or CPGND .................................... -0.3V to +0.3V
CPVSS or VSS to PGND ........................................ -6.0V to +0.3V
C1N to PGND .........................................(CPVSS - 0.3V) to +0.3V
C1P to PGND........................................ -0.3V to (CPVDD + 0.3V)
HP_ to PGND......................... (HPVSS - 0.3V) to (HPVDD + 0.3V)
HP_ to PGND.............................................................. -3V to +3V
Any Other Pin to PGND ............................. -0.3V to (VDD + 0.3V)
Duration of OUT_ Short Circuit to PGND or PVDD .........Continuous
Duration of OUT_+ Short Circuit to OUT_- .................Continuous
Duration of HP_ Short Circuit to PGND ......................Continuous
Continuous Current Into/Out of PVDD, OUT_, PGND ...........1.7A
Continuous Current Into/Out of CPVDD, C1N, CPGND,
C1P, CPVSS, VSS, HPVDD, HP_ ......................................0.85A
Continuous Input Current (all other pins) ........................ ±20mA
Continuous Power Dissipation (TA = +70°C)
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
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V DD = PV DD = HPV DD = CPV DD = +5.0V, GND = PGND = HPGND = 0V, V SHDN = V DD , CPV SS = V SS , C BIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
MAX9752: GAIN1 = GAIN2 = 0, VVOL = 0V; MAX9753: GAIN = 0, VA/B = 0V; MAX9754: GAIN = 0; TA = TMIN to TMAX, unless otherwise
noted. Typical values are at TA = +25°C.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
GENERAL
Supply Voltage Range,
Speaker Amplifier
Supply Voltage Range,
Headphone Amplifier
Quiescent Current
VDD, PVDD Inferred from PSRR test
4.5
5.5
V
Inferred from PSRR test
3.0
5.5
V
HPVDD
IDD
Shutdown Supply Current
I SHDN
Gain Switching Time
tSWG
Mux Switching Time
tSWM
Input Resistance
RIN
Turn-On Time
tON
Speaker mode, no load
14
18
Headphone mode, no load
7.2
9.5
V SHDN = 0V
0.2
8
MAX9753 only
mA
µA
3
µs
3
µs
MAX9752
10
20
30
MAX9753/MAX9754
3.5
6.6
10.0
25
kΩ
ms
CLASS D SPEAKER AMPLIFIERS (HPS = GND)
Output Offset Voltage
OUT_+ to OUT_-
VOS
MAX9752A,
MAX9752B,
MAX9753, MAX9754
MAX9752C
Power-Supply Rejection Ratio
(Note 3)
2
TA = +25°C
TA = TMIN to TMAX
±38.8
±55
TA = +25°C
±7
TA = TMIN to TMAX
PVDD or VDD = 4.5V to 5.5V, TA = +25°C
PSRR
±9.6
mV
±40
±60
50
74
f = 1kHz, VRIPPLE = 100mVP-P
70
f = 10kHz, VRIPPLE = 100mVP-P
60
_______________________________________________________________________________________
dB
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
(V DD = PV DD = HPV DD = CPV DD = +5.0V, GND = PGND = HPGND = 0V, V SHDN = V DD , CPV SS = V SS , C BIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
MAX9752: GAIN1 = GAIN2 = 0, VVOL = 0V; MAX9753: GAIN = 0, VA/B = 0V; MAX9754: GAIN = 0; TA = TMIN to TMAX, unless otherwise
noted. Typical values are at TA = +25°C.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MAX9752A
MAX9752B
Speaker Amplifier Gain (Note 4)
AV_SP
MAX9752C
MAX9753/MAX9754
f = 1kHz, THD+N
= 1%, TA = +25°C,
RL = 8Ω
Output Power
POUT_SP
f = 1kHz, THD+N
= 1%, TA = +25°C,
RL = 4Ω
MIN
GAIN2 = 0, GAIN1 = 0
9.0
GAIN2 = 0, GAIN1 = 1
10.5
GAIN2 = 1, GAIN1 = 0
12.0
GAIN2 = 1, GAIN1 = 1
13.5
GAIN2 = 0, GAIN1 = 0
15.0
GAIN2 = 0, GAIN1 = 1
16.5
GAIN2 = 1, GAIN1 = 0
18.0
GAIN2 = 1, GAIN1 = 1
19.5
GAIN2 = 0, GAIN1 = 0
6.0
GAIN2 = 0, GAIN1 = 1
7.5
GAIN2 = 1, GAIN1 = 0
9.0
GAIN2 = 1, GAIN1 = 1
10.5
GAIN = 1
9.0
GAIN = 0
10.5
MAX9752A,
MAX9752B, MAX9753,
MAX9754
1.3
MAX9752C
0.8
MAX9752A,
MAX9752B, MAX9753,
MAX9754
2.2
MAX9752C
Total Harmonic Distortion Plus
Noise
THD+N
f = 1kHz, POUT = 1W
Signal-to-Noise Ratio
SNR
POUT = 1W, f = 1kHz,
BW = 22Hz to 22kHz
Click-and-Pop Level (Note 5)
KCP
Capacitive-Load Drive
Switching Frequency
CL_MAX
TYP
UNITS
dB
W
1.7
RL = 8Ω
0.023
RL = 4Ω
0.03
Unweighted
90
A-weighted
91
Into shutdown
-47
Out of shutdown
-34
Differential
200
fSW
MAX
1000
1200
%
dB
dBV
pF
1400
kHz
Crosstalk
Channel to channel, f = 10kHz, POUT = 1W
70
dB
Off-Isolation
MAX9753, unselected input to any active
input, f = 10kHz
70
dB
RL = 8Ω, POUT = 1W, f = 1kHz
85
%
Efficiency
η
_______________________________________________________________________________________
3
MAX9752/MAX9753/MAX9754
ELECTRICAL CHARACTERISTICS (continued)
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V DD = PV DD = HPV DD = CPV DD = +5.0V, GND = PGND = HPGND = 0V, V SHDN = V DD , CPV SS = V SS , C BIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
MAX9752: GAIN1 = GAIN2 = 0, VVOL = 0V; MAX9753: GAIN = 0, VA/B = 0V; MAX9754: GAIN = 0; TA = TMIN to TMAX, unless otherwise
noted. Typical values are at TA = +25°C.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
±0.5
±3.5
UNITS
HEADPHONE AMPLIFIER (HPS = VDD)
Output Offset Voltage
Maximum Headphone Amplifier
Gain (Note 6)
VOS
TA = +25°C
TA = TMIN to TMAX
MAX9752,
GAIN1 = don’t care
AV_HP
MAX9753/MAX9754
Power-Supply Rejection Ratio
(Note 3)
Output Power
Total Harmonic Distortion Plus
Noise
GAIN2 = 0
PSRR
POUT_HP
3
GAIN = 1
0
GAIN = 0
THD+N
SNR
Click-and-Pop Level (Note 7)
KCP
CL_MAX
73
80
f = 10kHz, VRIPPLE = 100mVP-P
60
fIN = 1kHz
RL = 32Ω,
POUT = 31mW,
fIN = 1kHz,
BW = 22Hz to 22kHz
dB
3
66
f = 1kHz, VRIPPLE = 100mVP-P
THD+N = 1%, fIN =
1kHz, TA = +25°C
mV
0
GAIN2 = 1
HPVDD or VDD = 3V to 5.5V, TA = +25°C
Signal-to-Noise Ratio
Capacitive-Load Drive
±8
RL = 32Ω
31
RL = 16Ω
62
RL = 32Ω,
POUT = 31mW
0.005
RL = 16Ω,
POUT = 62mW
0.005
dB
mW
%
Unweighted
95
A-weighted
101
dB
Into shutdown
-33
Out of shutdown
-37
dBV
No sustained oscillations
300
pF
Crosstalk
f = 10kHz, POUT = 62mW, RL = 16Ω
60
dB
Off-Isolation
MAX9753, unselected input to any active
input, f = 10kHz
60
dB
0.8
V/µs
1
kΩ
Slew Rate
SR
Output Impedance
HPS = GND (disabled)
CHARGE PUMP
Charge-Pump Frequency
fCP
540
600
660
kHz
VOLUME CONTROL (MAX9752 Only)
VOL Input Impedance
RVOL
VOL Input Hysteresis
HYSTVOL
Full Mute Input Voltage
Full Mute Attenuation
4
VVOL falling
VVOL_MUTE
AV_MUTE
fIN = 1kHz
100
MΩ
50
mV
0.858 x
VDD
V
-85
dB
_______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
(V DD = PV DD = HPV DD = CPV DD = +5.0V, GND = PGND = HPGND = 0V, V SHDN = V DD , CPV SS = V SS , C BIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
MAX9752: GAIN1 = GAIN2 = 0, VVOL = 0V; MAX9753: GAIN = 0, VA/B = 0V; MAX9754: GAIN = 0; TA = TMIN to TMAX, unless otherwise
noted. Typical values are at TA = +25°C.) (Notes 1, 2)
PARAMETER
SYMBOL
Channel Matching
CONDITIONS
MIN
TYP
Gain 10.5dB to 13.5dB
±0.2
Gain 6.0dB to 10.0dB
±0.2
Gain -26dB to +4.0dB
±0.3
Gain -62dB to +30dB
±1.0
MAX
UNITS
dB
BEEP INPUT (MAX9752 Only)
Beep Signal Minimum Amplitude
(Note 8)
VBEEP
Beep Signal Minimum Frequency
fBEEP
RBEEP = 47kΩ
400
mV
300
Hz
2.0
V
LOGIC INPUTS (GAIN_, IN1//2, SHDN, HPS)
Input High Voltage
VIH
Input Low Voltage
VIL
Input Leakage Current
ILEAK
0.8
GAIN_, SHDN
-1
+1
IN1/2
-2
+2
HPS
-20
+1
V
µA
Note 1: All devices are 100% production tested at TA = +25°C. All temperature limits are guaranteed by design.
Note 2: Speaker amplifier testing performed with a resistive load in series with an inductor to simulate an actual speaker load. For
RL = 4Ω, L = 33µH. For RL = 8Ω, L = 68µH.
Note 3: Measured with the amplifier input connected to GND through CIN.
Note 4: Speaker amplifier gain is defined as A = (VOUT_+ - VOUT_-) / VIN_.
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. KCP level is calculated as:
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 = VHP_ / VIN_.
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. KCP level is calculated as:
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 RBEEP dictates the minimum beep signal amplitude that is detected (see the Beep Input (MAX9752) section).
_______________________________________________________________________________________
5
MAX9752/MAX9753/MAX9754
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(V DD = PV DD = HPV DD = CPV DD = 5.0V, GND = PGND = HPGND = 0V, V SHDN = V DD , CPV SS = V SS , C BIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
MAX9752: GAIN1 = GAIN2 = 0, VVOL = 0V; MAX9753: GAIN = 0, VA/B = 0V; MAX9754: GAIN = 0; TA = +25°C, unless otherwise noted.)
RL = 3Ω
1
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
10
MAX9752/53/54 toc02
10
MAX9752/53/54 toc01
10
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
RL = 4Ω
1
MAX9752/53/54 toc03
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
RL = 8Ω
1
POUT = 1W
0.1
THD+N (%)
THD+N (%)
THD+N (%)
POUT = 1.5W
0.1
0.01
POUT = 750mW
0.01
POUT = 1W
0.1
0.01
POUT = 500mW
POUT = 500mW
0.001
0.001
10
100
1k
10k
100k
1k
10k
10
10k
100k
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
10
THD+N (%)
1
fIN = 10kHz
0.1
0.01
2.0
2.5
3.0
3.5
0.1
fIN = 20Hz
fIN = 1kHz
RL = 4Ω
MAX9752C
RL = 3Ω
0.001
1.5
fIN = 10kHz
fIN = 1kHz AND 20Hz
0.001
1.0
1
0.01
RL = 3Ω
MAX9752C
0.5
MAX9752 toc06
10
fIN = 1kHz
0.01
100
MAX9752 toc05
100
MAX9752 toc04
0.1
4.0
0.001
0
0.5
1.0
1.5
2.0
2.5
3.0
0
0.5
1.0
1.5
2.0
2.5
OUTPUT POWER (W)
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
1
fIN = 10kHz
0.1
0.01
1
fIN = 10kHz
0.1
fIN = 20Hz
0.01
fIN = 1kHz
fIN = 1kHz AND 20Hz
0.001
1.0
1.5
2.0
MAX9752 toc09
fIN = 10kHz
0.1
0.01
0.001
OUTPUT POWER (W)
2.5
fIN = 1kHz AND 20Hz
RL = 8Ω
0.001
0
0.5
1.0
OUTPUT POWER (W)
3.0
1
RL = 8Ω
MAX9752C
RL = 4Ω
0.5
10
THD+N (%)
10
THD+N (%)
10
100
MAX9752 toc08
100
MAX9752 toc07
100
0
1k
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
fIN = 10kHz
0
100
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
fIN = 20Hz
6
100k
FREQUENCY (Hz)
THD+N (%)
THD+N (%)
100
FREQUENCY (Hz)
10
1
0.001
10
FREQUENCY (Hz)
100
THD+N (%)
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
1.5
0
0.5
1.0
OUTPUT POWER (W)
_______________________________________________________________________________________
1.5
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
OUTPUT POWER vs. LOAD RESISTANCE
(SPEAKER MODE)
OUTPUT POWER vs. LOAD RESISTANCE
(SPEAKER MODE)
OUTPUT POWER (W)
3
THD+N = 1%
2
MAX9752 toc11
THD+N = 10%
4
4
OUTPUT POWER (W)
MAX9752/53/54 toc10
5
3
THD+N = 10%
2
1
1
THD+N = 1%
0
0
1
100
10
POWER DISSIPATION vs. OUTPUT POWER
(SPEAKER MODE)
EFFICIENCY vs. OUTPUT POWER
100
MAX9752 toc12
2.0
80
1.5
1.0
RL = 4Ω
RL = 8Ω||68μH
90
EFFICIENCY (%)
POWER DISSIPATION (W)
100
10
LOAD RESISTANCE (Ω)
LOAD RESISTANCE (Ω)
MAX9752 toc13
1
70
RL = 4Ω||33μH
60
50
40
30
0.5
20
10
RL = 8Ω
0
0
0
1
2
3
0
4
2
6
4
OUTPUT POWER (W)
OUTPUT POWER (W)
TURN-ON RESPONSE
(SPEAKER MODE)
TURN-OFF RESPONSE
(SPEAKER MODE)
MAX9752/53/54 toc15
MAX9752/53/54 toc14
5V/div
5V/div
SHDN
SHDN
OUT
(NO AUDIO)
100mV/div
OUT
(NO AUDIO)
100mV/div
OUT
(1kHz, 2VP-P)
500mV/div
OUT
(1kHz, 2VP-P)
500mV/div
4ms/div
2ms/div
_______________________________________________________________________________________
7
MAX9752/MAX9753/MAX9754
Typical Operating Characteristics (continued)
(V DD = PV DD = HPV DD = CPV DD = 5.0V, GND = PGND = HPGND = 0V, V SHDN = V DD , CPV SS = V SS , C BIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
MAX9752: GAIN1 = GAIN2 = 0, VVOL = 0V; MAX9753: GAIN = 0, VA/B = 0V; MAX9754: GAIN = 0; TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(V DD = PV DD = HPV DD = CPV DD = 5.0V, GND = PGND = HPGND = 0V, V SHDN = V DD , CPV SS = V SS , C BIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
MAX9752: GAIN1 = GAIN2 = 0, VVOL = 0V; MAX9753: GAIN = 0, VA/B = 0V; MAX9754: GAIN = 0; TA = +25°C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
OUTPUT POWER = 45mW
0.01
OUTPUT POWER = 30mW
OUTPUT POWER = 30mW
0.01
10
100
1k
10k
OUTPUT POWER = 10mW
0.0001
10
100k
0.01
0.001
0.0001
0.0001
0.1
OUTPUT POWER = 10mW
0.001
0.001
100
1k
10k
100k
10
100
1k
10k
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
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)
0.01
1
fIN = 10kHz
0.01
0.001
0.0001
0.001
25
0
50
75
125
150
FREQUENCY (Hz)
100
OUTPUT POWER (mW)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
1k
10k
100k
VDD = 3.3V
RL = 16Ω
AV = 3dB
100
1000
MAX9752/53/54 toc22
1000
VDD = 3.3V
RL = 32Ω
AV = 3dB
100
10
THD+N (%)
10
fIN = 1kHz
1
fIN = 20Hz
fIN = 10kHz
0.1
fIN = 1kHz
1
fIN = 20Hz
0
20
40
60
80
100
OUTPUT POWER (mW)
MAX9752/53/54 toc23
100
fIN = 20Hz
0.01
fIN = 1kHz
fIN = 20Hz
10
fIN = 10kHz
0.1
fIN = 10kHz
0.1
OUTPUT POWER vs. LOAD RESISTANCE
(HEADPHONE MODE)
180
160
THD+N = 10%
140
OUTPUT POWER (mW)
0.001
fIN = 1kHz
1
0.1
OUTPUT POWER = 10mW
MAX9752/53/54 toc21
10
THD+N (%)
THD+N (%)
10
0.1
VDD = 5V
RL = 32Ω
AV = 3dB
100
MAX9752/53/54 toc24
OUTPUT POWER = 45mW
VDD = 5V
RL = 16Ω
AV = 3dB
100
1000
MAX9752/53/54 toc20
VDD = 3.3V
RL = 32Ω
AV = 3dB
1
1000
MAX9752/53/54 toc19
10
THD+N (%)
0.1
VDD = 3.3V
RL = 16Ω
AV = 3dB
1
THD+N (%)
0.1
VDD = 5V
RL = 32Ω
AV = 3dB
1
THD+N (%)
THD+N (%)
OUTPUT POWER = 90mW
10
MAX9752/53/54 toc17
VDD = 5V
RL = 16Ω
AV = 3dB
1
10
MAX9752/53/54 toc16
10
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
MAX9752/53/54 toc18
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
THD+N (%)
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
120
100
80
60
40
0.01
0.01
THD+N = 1%
20
0.001
0.001
0
10
20
30
40
OUTPUT POWER (mW)
8
50
60
0
0
10
20
30
40
50
60 70
OUTPUT POWER (mW)
80
90
10
100
LOAD RESISTANCE (Ω)
_______________________________________________________________________________________
1000
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
125
100
RL = 32Ω
75
VDD = 5V
f = 1kHz
POUT = POUTL + POUTR
50
25
-20
-30
75
RL = 32Ω
50
-60
-90
f = 1kHz
25 50 75 100 125 150 175 200 225 250
-100
3.0
3.5
OUTPUT POWER (mW)
4.0
4.5
5.5
5.0
10
100
SUPPLY VOLTAGE (V)
10k
100k
OUTPUT POWER vs. CHARGE-PUMP
CAPACITANCE AND LOAD RESISTANCE
-40
-60
-80
RIGHT TO LEFT
200
VDD = 5V
f = 1kHz
THD+N = 1%
180
160
OUTPUT POWER (mW)
MAX9752/53/54 toc28
VCC = 5V
VRIPPLE = 200mVP-P
RL = 32Ω
1k
FREQUENCY (Hz)
CROSSTALK vs. FREQUENCY
(HEADPHONE MODE)
-20
-50
-80
0
0
-40
-70
25
0
0
MAX9752/53/54 toc27
100
VRIPPLE = 200mVP-P
AV = 10.5dB
OUTPUT REFERRED
-10
140
120
C1 = C2 = 2.2μF
100
80
60
C1 = C2 = 1μF
40
-100
MAX9752/53/54 toc29
150
RL = 16Ω
PSRR (dB)
175
0
MAX9752/53/54 toc26
RL = 16Ω
200
CROSSTALK (dB)
POWER DISSIPATION (mW)
225
125
OUTPUT POWER (mW)
MAX9752/53/54 toc25
250
20
LEFT TO RIGHT
-120
0
10
100
1k
FREQUENCY (Hz)
10k
100k
10
20
30
40
50
LOAD RESISTANCE (Ω)
_______________________________________________________________________________________
9
MAX9752/MAX9753/MAX9754
Typical Operating Characteristics (continued)
(V DD = PV DD = HPV DD = CPV DD = 5.0V, GND = PGND = HPGND = 0V, V SHDN = V DD , CPV SS = V SS , C BIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
MAX9752: GAIN1 = GAIN2 = 0, VVOL = 0V; MAX9753: GAIN = 0, VA/B = 0V; MAX9754: GAIN = 0; TA = +25°C, unless otherwise noted.)
OUTPUT POWER vs. SUPPLY VOLTAGE
POWER-SUPPLY REJECTION RATIO
POWER DISSIPATION vs. OUTPUT POWER
(HEADPHONE MODE)
vs. FREQUENCY (HEADPHONE MODE)
(HEADPHONE MODE)
Typical Operating Characteristics (continued)
(V DD = PV DD = HPV DD = CPV DD = 5.0V, GND = PGND = HPGND = 0V, V SHDN = V DD , CPV SS = V SS , C BIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ω connected between OUT_+ and OUT_-, headphone load is terminated to GND;
MAX9752: GAIN1 = GAIN2 = 0, VVOL = 0V; MAX9753: GAIN = 0, VA/B = 0V; MAX9754: GAIN = 0; TA = +25°C, unless otherwise noted.)
TURN-ON RESPONSE
(HEADPHONE MODE)
HEADPHONE OUTPUT SPECTRUM
VDD = 5V
f = 1kHz
VOUT = -60dB
RL = 32Ω
-20
-40
MAX9752/53/54 toc30
MAX9752/53/54 toc31
0
MAGNITUDE (dB)
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
5V/div
SHDN
-60
-80
20mV/div
HPOUT_
-100
-120
RL = 32Ω
-140
0
5
10
15
20
10ms/div
FREQUENCY (Hz)
TURN-OFF RESPONSE
(HEADPHONE MODE)
MAX9752/53/54 toc32
5V/div
SHDN
20mV/div
HPOUT_
RL = 32Ω
10ms/div
10
______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
PIN
MAX9752
MAX9753
MAX9754
NAME
FUNCTION
1
—
2
INL
Left-Channel Audio Input
2
—
—
BEEP
Audible Alert Beep Input
3, 19
3, 19
3, 19
PGND
Power Ground
4
4
4
OUTL+
Left-Channel Positive Speaker Output
5
5
5
OUTL-
Left-Channel Negative Speaker Output
6, 16
6, 16
6, 16
PVDD
Speaker Amplifier Power Supply
7
7
7
CPVDD
8
8
8
C1P
9
9
9
CPGND
10
10
10
C1N
11
11
11
CPVSS
Charge-Pump Power Supply
Charge-Pump Flying-Capacitor Positive Terminal
Charge-Pump Ground
Charge-Pump Flying-Capacitor Negative Terminal
Charge-Pump Output. Connect to VSS.
12
12
12
VSS
13
13
13
HPOUTR
Right-Channel Headphone Output
Headphone Amplifier Negative Power Supply
14
14
14
HPOUTL
Left-Channel Headphone Output
15
15
15
HPVDD
Headphone Positive Power Supply
17
17
17
OUTR-
Right-Channel Negative Speaker Output
18
18
18
OUTR+
Right-Channel Positive Speaker Output
20
20
20
HPS
Headphone Sense Input
21
21
21
BIAS
Common-Mode Bias Voltage. Bypass with a 1µF capacitor to GND.
22
22
22
SHDN
Shutdown. Drive SHDN low to disable the device. Connect SHDN to
VDD for normal operation.
23
—
—
GAIN2
Gain-Control Input 2
24
—
—
GAIN1
25
25
25
VDD
Power Supply
Gain-Control Input 1
26
26
23, 26
GND
Ground
27
—
28
INR
Right-Channel Audio Input
28
—
—
VOL
Analog Volume Control Input
—
1
—
INL1
Left-Channel Audio Input 1
—
2
—
INL2
Left-Channel Audio Input 2
—
23
—
IN1/2
Input Select
—
24
24
GAIN
Gain Select
—
27
—
INR1
Right-Channel Audio Input 1
—
28
—
INR2
Right-Channel Audio Input 2
—
—
1, 27
N.C.
No Connection. Not internally connected.
______________________________________________________________________________________
11
MAX9752/MAX9753/MAX9754
Pin Descriptions
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
MAX9752 ONLY
VDD
IN_
VOUT
VDD / 2
GND
OUT_+
BIAS
BIAS
CONVENTIONAL DRIVER-BIASING SCHEME
+VDD
VOL
VOLUME
CONTROL
OUT_
BIAS
GND
HPOUT_
-VDD
GND
DirectDrive BIASING SCHEME
Figure 1. MAX9752/MAX9753/MAX9754 Signal Path
Detailed Description
The MAX9752/MAX9753/MAX9754 combine a 2.2W,
Class D speaker amplifier and a 62mW DirectDrive
headphone amplifier with integrated headphone sensing 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.
The MAX9752 features an analog volume control, BEEP
input, and four-level gain control. The MAX9753 features 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.
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 (CPVDD), creating a negative supply (CPVSS). The headphone amplifiers operate from these bipolar supplies with their
outputs biased about GND (Figure 2). The amplifiers
12
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 (typically VDD / 2). This eliminates the large DC-blocking
capacitors required with conventional headphone amplifiers, 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 thermal-overload and short-circuit protection, and can withstand ±8kV ESD strikes on the headphone amplifier
outputs (IEC Air-Gap Discharge). An additional feature
of the speaker amplifiers is that there is no phase inversion from input to output.
Class D Speaker Amplifier
The MAX9752/MAX9753/MAX9754 feature a unique
spread-spectrum mode that flattens the wideband spectral components, improving EMI emissions that may be
radiated by the speaker and cables. The switching frequency varies randomly by ±90kHz around the center
frequency (1200kHz). Instead of a large amount of spectral energy present at multiples of the switching frequency, the energy is now spread over a bandwidth that
increases with frequency. Above a few megahertz, the
wideband spectrum looks like white noise for EMI purposes (Figure 3).
______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
MAX9752/MAX9753/MAX9754
50
45
AMPLITUDE (dBμV/m)
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
VIN_ = 0V
MAX9752
MAX9753
MAX9754
90
EFFICIENCY (%)
80
OUT_-
70
60
50
40
30
OUT_+
CLASS AB
20
10
RL = 8Ω
0
0
VOUT_+ - VOUT_- = 0V
0.5
1.0
1.5
2.0
OUTPUT POWER (W)
Figure 4. Second-Generation Class D Output Waveform with
No Signal
Figure 5. MAX9752/MAX9753/MAX9754 Class D Efficiency vs.
MAX9750/MAX9751/MAX9755 Class AB Efficiency
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 inphase. This lowers the high-frequency energy and spectral 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 associated with the Class D output stage is mostly due to the
I2R loss of the MOSFET on-resistance, and quiescent
current overhead.
The theoretical best efficiency of a linear amplifier is 78%,
however, that efficiency is only exhibited at peak output
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
Headphone Amplifier
DirectDrive
Conventional single-supply headphone amplifiers have
their outputs biased about a nominal DC voltage (typically half the supply) for maximum dynamic range.
Large coupling capacitors are needed to block the DC
bias from the headphones.
Maxim’s DirectDrive architecture uses a charge pump to
create an internal negative supply voltage. This allows the
MAX9752/MAX9753/MAX9754 headphone amplifier output to be biased about GND, almost doubling the dynamic 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 capacitors (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.
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:
1) The sleeve is typically grounded to the chassis. Using
this biasing approach, the sleeve must be isolated
from system ground, complicating product design.
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.
LOW-FREQUENCY ROLLOFF
(RL = 16Ω)
0
DirectDrive
-3
ATTENUATION (dB)
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
330μF
-6
220μF
100μF
-9
33μF
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.
Low-Frequency Response
In addition to the cost and size disadvantages, the DCblocking capacitors limit the low-frequency response of
the amplifier and distort the audio signal:
1) The impedance of the headphone load and the DCblocking capacitor form a highpass filter with the
-3dB point determined by:
1
f−3dB =
2πRLCOUT
where RL is the impedance of the headphone and
COUT is the value of the DC-blocking capacitor.
The highpass filter is required by conventional singleended, 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
audio band. Larger values of COUT reduce the attenuation, but are physically larger, more expensive
capacitors. Figure 6 shows the relationship between
the size of COUT and the resulting low-frequency
attenuation. Note the -3dB point for a 16Ω headphone with a 100µF blocking capacitor is 100Hz, well
within the audio band.
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 frequencies 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.
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 multimedia laptops, MP3, CD, and DVD players.
-12
-15
10
100
1k
10k
100k
FREQUENCY (Hz)
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
MAX9752/MAX9753/MAX9754
ADDITIONAL THD+N DUE
TO DC-BLOCKING CAPACITORS
VDD
10
THD+N (%)
1
MAX9752
MAX9753
MAX9754
0.1
R1
100kΩ
TANTALUM
0.01
HPS
OUTL
0.001
ALUM/ELEC
OUTR
0.0001
10
100
1k
100k
10k
FREQUENCY (Hz)
Figure 7. Distortion Contributed by DC-Blocking Capacitors
Figure 8. HPS Configuration
Table 1. MAX9752 Gain Settings
GAIN2
GAIN1
0
0
1
1
SPEAKER MODE GAIN (dB)
HEADPHONE MODE GAIN (dB)
MAX9752A
MAX9752B
MAX9752C
0
9.0
15.0
6.0
0
1
10.5
16.5
7.5
0
0
12.0
18.0
9.0
3
1
13.5
19.5
10.5
3
Charge Pump
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 turnon 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).
Headphone Sense Input (HPS)
The headphone sense input (HPS) monitors the headphone 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 voltage of greater than 2V disables the speaker amplifiers
and enables the headphone amplifiers.
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-
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
to VDD through the internal 100kΩ pullup resistor.
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.
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 headphone amplifiers (Table 1). The voltage at VOL varies
the gain of the speaker and headphone amplifiers, providing a user-adjusted volume control, see the Analog
Volume Control (VOL, MAX9752) section.
______________________________________________________________________________________
15
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Table 2. MAX9752 Speaker Amplifier Gain
Settings for Maximum Output Power
GAIN
(dB)
INPUT
(VRMS)
RL
(Ω)
POUT
(W)
9.0
1.004
4
2.0
10.5
0.844
4
2.0
12.0
0.710
4
2.0
13.5
0.598
4
2.0
MAX9752A
Table 3. MAX9753/MAX9754 Maximum
Gain Settings
GAIN
SPEAKER MODE
GAIN (dB)
HEADPHONE MODE
GAIN (dB)
0
10.5
3
1
9.0
0
Table 4. MAX9753/MAX9754 Input Voltage
and Gain Settings for Maximum Output
Power
9.0
1.099
8
1.2
10.5
0.925
8
1.2
12.0
0.778
8
1.2
GAIN
(dB)
INPUT
(VRMS)
RL
(Ω)
POUT
(W)
13.5
0.655
8
1.2
10.5
0.844
4
2.0
9.0
1.004
4
2.0
15.0
0.503
4
2.0
10.5
0.925
8
1.2
16.5
0.423
4
2.0
9.0
1.099
8
1.2
18.0
0.356
4
2.0
19.5
0.300
4
2.0
15.0
0.551
8
1.2
16.5
0.464
8
1.2
18.0
0.390
8
1.2
MAX9752B
19.5
0.328
8
1.2
6.0
1.418
4
2.0
7.5
1.193
4
2.0
9.0
1.004
4
2.0
10.5
0.844
4
2.0
6.0
1.553
8
1.2
7.5
1.307
8
1.2
9.0
1.099
8
1.2
10.5
0.925
8
1.2
MAX9752C
Table 2 shows the amplifier gain settings needed to
attain maximum speaker output power from a given
input voltage and load.
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
0.858 x HPVDD (full mute). Example step sizes are shown
in Table 5. Control VOL with either a DAC or potentiometer 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
DAC or potentiometer to HPVDD. Since the volume control is ratiometric to HPVDD, any changes in HPVDD are
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 control for HPVDD = 3.3V.
MAX9753/MAX9754
The gain of the MAX9753/MAX9754 is set by GAIN.
Drive GAIN high to set the gain of the speaker amplifiers 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
VVOL (V)
VMIN*
VMAX*
FRACTION
OF
HPVDD
SPEAKER MODE GAIN (dB)
GAIN1 = 0,
GAIN2 = 0
GAIN1 = 1,
GAIN2 = 0
HEADPHONE MODE GAIN (dB)
GAIN1 = 0,
GAIN2 = 1
GAIN1 = 1
GAIN2 = 1
GAIN1 = X,
GAIN2 = 0
GAIN1 = X,
GAIN2 = 1
0
0.4900
0.074
9
10.5
12
13.5
0
3
0.4900
0.5673
0.160
8
10
11.5
13
-1
2.5
0.5673
0.6447
0.183
7
9
11
12.5
-2
2
0.6447
0.7220
0.207
6
8
10.5
12
-3
1.5
0.7220
0.7994
0.230
4
7
10
11.5
-5
1
0.7994
0.8767
0.253
2
6
9
11
-7
0
0.8767
0.9541
0.277
0
4
8
10.5
-9
-1
0.9541
1.0314
0.300
-2
2
7
10
-11
-2
1.0314
1.1088
0.324
-4
0
6
9
-13
-3
1.1088
1.1861
0.347
-6
-2
4
8
-15
-5
1.1861
1.2635
0.371
-8
-4
2
7
-17
-7
1.2635
1.3408
0.394
-10
-6
0
6
-19
-9
1.3408
1.4182
0.418
-12
-8
-2
4
-21
-11
1.4182
1.4955
0.441
-14
-10
-4
2
-23
-13
1.4955
1.5728
0.464
-16
-12
-6
0
-25
-15
1.5728
1.6502
0.488
-18
-14
-8
-2
-27
-17
1.6502
1.7275
0.511
-20
-16
-10
-4
-29
-19
1.7275
1.8049
0.535
-22
-18
-12
-6
-31
-21
1.8094
1.8822
0.558
-24
-20
-14
-8
-33
-23
1.8822
1.9596
0.582
-26
-22
-16
-10
-35
-25
1.9596
2.0369
0.605
-28
-24
-18
-12
-37
-27
2.0369
2.1143
0.628
-30
-26
-20
-14
-39
-29
2.1143
2.1916
0.652
-32
-28
-22
-16
-41
-31
2.1916
2.2690
0.675
-34
-30
-24
-18
-43
-33
2.2690
2.3463
0.699
-38
-32
-26
-20
-47
-35
2.3463
2.4237
0.722
-42
-34
-28
-22
-51
-37
2.4237
2.5010
0.746
-46
-38
-30
-24
-55
-39
2.5010
2.5783
0.769
-50
-42
-32
-26
-59
-41
2.5783
2.6557
0.793
-54
-46
-34
-28
-63
-43
2.6557
2.7330
0.816
-58
-50
-38
-30
-67
-47
2.7330
2.8104
0.839
-62
-54
-42
-32
-71
-51
2.8104
3.3000
0.858
MUTE
MUTE
MUTE
MUTE
MUTE
MUTE
*Based on HPVDD = 3.3V.
X = Don’t care.
______________________________________________________________________________________
17
MAX9752/MAX9753/MAX9754
Table 5a. MAX9752A Volume Levels
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Table 5b. MAX9752B Volume Levels
VVOL (V)
VMIN*
VMAX*
FRACTION
OF
HPVDD
SPEAKER MODE GAIN (dB)
GAIN1 = 0,
GAIN2 = 0
GAIN1 = 1,
GAIN2 = 0
HEADPHONE MODE GAIN (dB)
GAIN1 = 0,
GAIN2 = 1
GAIN1 = 1
GAIN2 = 1
GAIN1 = X,
GAIN2 = 0
0
0.4900
0.074
15
16.5
18
19.5
0
3
0.4900
0.5673
0.160
14
16
17.5
19
-1
2.5
0.5673
0.6447
0.183
13
15
17
18.5
-2
2
0.6447
0.7220
0.207
12
14
16.5
18
-3
1.5
0.7220
0.7994
0.230
10
13
16
17.5
-5
1
0.7994
0.8767
0.253
8
12
15
17
-7
0
0.8767
0.9541
0.277
6
10
14
16.5
-9
-1
0.9541
1.0314
0.300
4
8
13
16
-11
-2
1.0314
1.1088
0.324
2
6
12
15
-13
-3
1.1088
1.1861
0.347
0
4
10
14
-15
-5
1.1861
1.2635
0.371
-2
2
8
13
-17
-7
1.2635
1.3408
0.394
-4
0
6
12
-19
-9
1.3408
1.4182
0.418
-6
-2
4
10
-21
-11
1.4182
1.4955
0.441
-8
-4
2
8
-23
-13
1.4955
1.5728
0.464
-10
-6
0
6
-25
-15
1.5728
1.6502
0.488
-12
-8
-2
4
-27
-17
1.6502
1.7275
0.511
-14
-10
-4
2
-29
-19
1.7275
1.8049
0.535
-16
-12
-6
0
-31
-21
1.8049
1.8822
0.558
-18
-14
-8
-2
-33
-23
1.8822
1.9596
0.582
-20
-16
-10
-4
-35
-25
1.9596
2.0369
0.605
-22
-18
-12
-6
-37
-27
2.0369
2.1143
0.628
-24
-20
-14
-8
-39
-29
2.1143
2.1916
0.652
-26
-22
-16
-10
-41
-31
2.1916
2.2690
0.675
-28
-24
-18
-12
-43
-33
2.2690
2.3463
0.699
-32
-26
-20
-14
-47
-35
2.3463
2.4237
0.722
-36
-28
-22
-16
-51
-37
2.4237
2.5010
0.746
-40
-32
-24
-18
-55
-39
2.5010
2.5783
0.769
-44
-36
-26
-20
-59
-41
2.5783
2.6557
0.793
-48
-40
-28
-22
-63
-43
2.6557
2.7330
0.816
-52
-44
-32
-24
-67
-47
2.7330
2.8104
0.839
-56
-48
-36
-26
-71
-51
2.8104
3.3000
0.858
MUTE
MUTE
MUTE
MUTE
MUTE
MUTE
*Based on HPVDD = 3.3V.
X = Don’t care.
18
GAIN1 = X,
GAIN2 = 1
______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
VVOL (V)
SPEAKER MODE GAIN (dB)
HEADPHONE MODE GAIN (dB)
VMIN*
VMAX*
FRACTION
OF
HPVDD
0
0.4900
0.074
0.4900
0.5673
0.160
5
7
8.5
10
-1
0.5673
0.6447
0.183
4
6
8
9.5
-2
2
0.6447
0.7220
0.207
3
5
7.5
9
-3
1.5
0.7220
0.7994
0.230
1
4
7
8.5
-5
1
0.7994
0.8767
0.253
-1
3
6
8
-7
0
0.8767
0.9541
0.277
-3
1
5
7.5
-9
-1
0.9541
1.0314
0.300
-5
-1
4
7
-11
-2
1.0314
1.1088
0.324
-7
-3
3
6
-13
-3
1.1088
1.1861
0.347
-9
-5
1
5
-15
-5
1.1861
1.2635
0.371
-11
-7
-1
4
-17
-7
1.2635
1.3408
0.394
-13
-9
-3
3
-19
-9
1.3408
1.4182
0.418
-15
-11
-5
1
-21
-11
1.4182
1.4955
0.441
-17
-13
-7
-1
-23
-13
1.4955
1.5728
0.464
-19
-15
-9
-3
-25
-15
1.5728
1.6502
0.488
-21
-17
-11
-5
-27
-17
1.6502
1.7275
0.511
-23
-19
-13
-7
-29
-19
1.7275
1.8049
0.535
-25
-21
-15
-9
-31
-21
1.8049
1.8822
0.558
-27
-23
-17
-11
-33
-23
1.8822
1.9596
0.582
-29
-25
-9
-13
-35
-25
1.9596
2.0369
0.605
-31
-27
-21
-15
-37
-27
2.0369
2.1143
0.628
-33
-29
-23
-17
-39
-29
2.1143
2.1916
0.652
-35
-31
-2
-19
-41
-31
2.1916
2.2690
0.675
-37
-3
-27
-21
-43
-33
2.2690
2.3463
0.699
-41
-35
-29
-23
-47
-35
2.3463
2.4237
0.722
-45
-37
-31
-25
-51
-37
2.4237
2.5010
0.746
-48
-41
-33
-27
-55
-39
2.5010
2.5783
0.769
-53
-45
-35
-29
-59
-41
2.5783
2.6557
0.793
-57
-49
-37
-31
-63
-43
2.6557
2.7330
0.816
-61
-53
-41
-33
-67
-47
2.7330
2.8104
0.839
-65
-57
-45
-35
-71
-51
2.8104
3.3000
0.858
MUTE
MUTE
MUTE
MUTE
MUTE
MUTE
GAIN1 = 0,
GAIN2 = 0
GAIN1 = 1,
GAIN2 = 0
GAIN1 = 0,
GAIN2 = 1
GAIN1 = 1
GAIN2 = 1
GAIN1 = X,
GAIN2 = 0
GAIN1 = X,
GAIN2 = 1
6
7.5
9
10.5
0
3
2.5
*Based on HPVDD = 3.3V.
X = Don’t care.
______________________________________________________________________________________
19
MAX9752/MAX9753/MAX9754
Table 5c. MAX9752C Volume Levels
MAX9752C
VOLUME-CONTROL TRANSFER FUNCTION
20
GAIN1 = GAIN2 = 0
10
0
-10
GAIN (dB)
MAX9752
HPVDD
VREF
DAC
SPEAKER MODE
AUDIO
TAPER POT
-20
-30
-40
-50
VOL
HEADPHONE MODE
-60
-70
-80
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
VVOL (V)
Figure 9. MAX9752 Volume-Control Circuit
Figure 10c. MAX9752C Volume-Control Transfer Functions
MAX9752A
VOLUME-CONTROL TRANSFER FUNCTION
20
GAIN1 = GAIN2 = 0
10
0
SPEAKER MODE
AUDIO
TAPER POT
GAIN (dB)
-10
-20
-30
-40
-50
HEADPHONE MODE
-60
-70
-80
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
VVOL (V)
Figure 10a. MAX9752A 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
BEEP. When a signal exceeding 400mVP-P with a frequency 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 voltage amplitude sensitivity.
Input Mux (MAX9753)
MAX9752B
VOLUME-CONTROL TRANSFER FUNCTION
20
GAIN1 = GAIN2 = 0
10
0
SPEAKER MODE
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.
-10
GAIN (dB)
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
AUDIO
TAPER POT
-20
-30
-40
-50
HEADPHONE MODE
-60
-70
-80
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Shutdown
The MAX9752/MAX9753/MAX9754 feature an 8µA, lowpower shutdown mode reducing quiescent current consumption and extending battery life. Driving SHDN low
disables the drive amplifiers, bias circuitry, charge
pump, and sets the headphone amplifier output impedance to 1kΩ, and drives BIAS to GND. Connect SHDN to
VDD for normal operation.
VVOL (V)
Figure 10b. MAX9752B Volume-Control Transfer Functions
20
______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
RS1
47kΩ
RINT
47kΩ
SOURCE 1
0.47μF
RS2
47kΩ
0.47μF
RS3
47kΩ
SOURCE 2
BEEP
SOURCE 3
SPEAKER/HEADPHONE
AMPLIFIER INPUTS
VOUT(BEEP)
WINDOW
DETECTOR
(0.4VP-P THRESHOLD)
BIAS
MAX9752
FREQUENCY
DETECTOR
(300Hz THRESHOLD)
Figure 11. MAX9752 Beep Summing Circuit
Click-and-Pop Suppression
Power Dissipation and Heat Sinking
The MAX9752/MAX9753/MAX9754 feature Maxim’s
comprehensive, industry-leading click-and-pop suppression 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.
Because the MAX9752/MAX9753/MAX9754 have highefficiency, Class D speaker drivers, the intrinsic package power dissipation capabilities are sufficient for
cooling. No special heatsinking is needed in normal
operating conditions.
Applications Information
Compatibility with
MAX9750/MAX9751/MAX9755
The MAX9752/MAX9753/MAX9754 provide a high-efficiency, 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.
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 current from the charge pump, leading to a slight loss in
headroom of VSS. In typical stereo audio applications, the
left and right signals have differences in both magnitude
and phase, subsequently leading to an increase in the
maximum attainable output power. Figure 12 shows the
two cases for in- and out-of-phase. In reality, the available
power lies between these extremes.
1000
Filterless Operation
VDD = 5V
RL = 16Ω
AV = 3dB
100
10
THD+N (%)
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 natural filtering of both the speaker and the human ear to
recover the audio component of the square-wave output. Eliminating the output filter results in a smaller, less
costly, more efficient solution.
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 movement 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 speaker inductances > 60µH.
OUTPUTS IN-PHASE
1
0.1
0.01
OUTPUTS 180° OUT-OF-PHASE
0.001
0
25
50
75
100
125
150
OUTPUT POWER (mW)
Figure 12. THD+N vs. POUT with Headphone Output Signals
In- and Out-of-Phase
______________________________________________________________________________________
21
MAX9752/MAX9753/MAX9754
0.47μF
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Power Supplies
Charge-Pump Capacitor Selection
The MAX9752/MAX9753/MAX9754 have different supplies for each portion of the device allowing for the optimum combination of headroom, power dissipation, and
noise immunity. The speaker amplifiers are powered from
PVDD. PVDD ranges from 4.5V to 5.5V. The headphone
amplifiers are powered from HPVDD and VSS. HPVDD is
the positive supply of the headphone amplifiers and
ranges from 3V to 5.5V. VSS is the negative supply input
for the headphone amplifiers. Connect VSS to CPVSS. The
charge pump is powered by CPVDD, which ranges from
3V to 5.5V. CPVDD should be the same potential as
HPVDD. The charge pump inverts the voltage at CPVDD,
and the resulting voltage appears at CPVSS. The remainder of the device is powered by VDD.
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 performance over the extended temperature range.
Component Selection
Input Filtering
The input capacitor (CIN), in conjunction with the amplifier input resistance (RIN), forms a highpass filter that
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:
1
f−3dB =
2πRINCIN
RIN is the amplifier’s internal input resistance value given
in the Electrical Characteristics table. Choose CIN so
f -3dB is well below the lowest frequency of interest.
Setting f-3dB too high affects the amplifier’s low-frequency
response. Use capacitors with low-voltage coefficient
dielectrics, such as tantalum or aluminum electrolytic.
Capacitors with high-voltage coefficients, such as ceramics, may result in increased distortion at low frequencies.
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 frequencies below 10MHz are of concern, or when long
leads (> 76mm) connect the amplifier to the speaker.
BIAS Capacitor
BIAS is the output of the internally generated DC bias
voltage. The BIAS bypass capacitor, CBIAS, 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 amplifiers. Bypass
BIAS with a 1µF capacitor to GND.
22
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 regulation 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 recommended range of capacitors is from 0.33µF to 3.3µF.
Output Capacitor (C2)
The output capacitor value and ESR directly affect the
ripple at CPVSS. Increasing the value of C2 reduces
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.
CPVDD Bypass Capacitor
The CPVDD bypass capacitor (C3) lowers the output
impedance of the power supply and reduces the
impact of the charge-pump switching transients on the
headphone driver outputs. Bypass CPVDD with C3, the
same value as C1, and place it physically close to
CPVDD and PGND.
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 moving 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.
______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
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 frequency of Class D amplifiers, nor could human ears hear
these frequencies. However, audio analyzers and oscilloscopes can detect these signals. On an oscilloscope,
100Ω
OUT_+
CLASS D
MODULATOR
AND H-BRIDGE
IN+
47nF
AUDIO
ANALYZER
RL
47nF
OUT_-
IN100Ω
Figure 13. Connecting a Class D Output to an Analog Analyzer
the switching components obscure the audio signal. On
an audio analyzer they overload the input signal, degrading 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 LC filters can provide more performance, but must be verified to ensure they do not add their own distortion
signature to the amplifier’s output.
______________________________________________________________________________________
23
MAX9752/MAX9753/MAX9754
Connect all components associated with the charge
pump (C2 and C3) to CPGND. Connect VSS and CPVSS
together at C2. Place the charge-pump capacitors (C1,
C2, and C3) as close to the device as possible. Bypass
HPVDD with 1µF to GND. Bypass PVDD with a 0.1µF
capacitor and a 100µF capacitor to PGND. Place the
bypass capacitors as close to the device as possible.
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 compared to a 0Ω trace, a 100mΩ trace reduces the power
delivered to a 4Ω load from 2.1W to 2.0W. Large output, supply, and GND traces allow more heat to move
from the MAX9752/MAX9753/MAX9754 to the air,
reducing the thermal impedance of the system.
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 multiple vias to the ground plane.
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
MAX9752/MAX9753/MAX9754
MAX9752 Functional Diagram
4.5V TO 5.5V
0.1μF
VDD
25
6, 16 PVDD
MAX9752
CIN
1μF
LEFT-CHANNEL
AUDIO INPUT
CIN
1μF
RIGHT-CHANNEL
AUDIO INPUT
INL 1
INR 27
4.5V TO 5.5V
1μF
4 OUTL+
GAIN/
VOLUME
CONTROL
CLASS D
AMPLIFIER
GAIN/
VOLUME
CONTROL
CLASS D
AMPLIFIER
5 OUTL-
18 OUTR+
17 OUTR-
BIAS 21
CBIAS
1μF
VOL 28
VDD GAIN1 24
VDD GAIN2 23
47kΩ
BEEP 2
1μF
SHDN 22
VDD
15 HPVDD
GAIN/
VOLUME
CONTROL
20 HPS
HEADPHONE
DETECTION
3V TO 5.5V
1μF
14 HPOUTL
BEEP
DETECTION
SHUTDOWN
CONTROL
13 HPOUTR
CPVDD 7
3V TO 5.5V
1μF
C1P 8
C1
1μF
10
CHARGE
PUMP
C1N
CPGND 9
11
CPVSS
24
12
26
VSS
C2
1μF
3, 19
GND
PGND
______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
4.5V TO 5.5V
0.1μF
VDD
25
6, 16 PVDD
MAX9753
CIN
1μF
LEFT-CHANNEL
AUDIO INPUT
INL1 1
LEFT-CHANNEL
AUDIO INPUT
INL2 2
4.5V TO 5.5V
1μF
4 OUTL+
INPUT
MUX
CLASS D
AMPLIFIER
INPUT
MUX
CLASS D
AMPLIFIER
5 OUTL-
CIN
1μF
CIN
1μF
RIGHT-CHANNEL
AUDIO INPUT
INR1 27
RIGHT-CHANNEL
AUDIO INPUT
INR2 28
CIN
1μF
18 OUTR+
17 OUTR-
BIAS 21
15 HPVDD
CBIAS
1μF
GAIN 24
VDD
IN1/2 23
VDD
MUX AND
GAIN
CONTROL
20 HPS
3V TO 5.5V
1μF
14 HPOUTL
HEADPHONE
DETECTION
SHDN 22
VDD
SHUTDOWN
CONTROL
13 HPOUTR
CPVDD 7
3V TO 5.5V
1μF
C1P 8
C1
1μF
10
CHARGE
PUMP
C1N
CPGND 9
11
CVSS
26
12
VSS
C2
1μF
3, 19
GND
PGND
LOGIC PINS CONFIGURED FOR:
GAIN = 1, 9dB SPEAKER GAIN/0dB HEADPHONE GAIN.
IN1/2 = 1, SELECTED INPUT LINE 1.
SHDN = 1, PART ACTIVE.
______________________________________________________________________________________
25
MAX9752/MAX9753/MAX9754
MAX9753 Functional Diagram
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
MAX9752/MAX9753/MAX9754
MAX9754 Functional Diagram
4.5V TO 5.5V
0.1μF
VDD
25
6, 16 PVDD
MAX9754
CIN
1μF
LEFT-CHANNEL
AUDIO INPUT
CIN
1μF
RIGHT-CHANNEL
AUDIO INPUT
4.5V TO 5.5V
1μF
4 OUTL+
INL 2
CLASS D
AMPLIFIER
5 OUTL-
18 OUTR+
INR 28
CLASS D
AMPLIFIER
17 OUTR-
BIAS 21
CBIAS
1μF
15 HPVDD
GAIN 24
VDD
GAIN
CONTROL
20 HPS
HEADPHONE
DETECTION
3V TO 5.5V
1μF
14 HPOUTL
SHDN 22
VDD
SHUTDOWN
CONTROL
13 HPOUTR
CPVDD 7
3V TO 5.5V
1μF
C1P 8
C1
1μF
10
CHARGE
PUMP
C1N
CPGND 9
11
CPVSS
23, 26
12
VSS
C2
1μF
GND
3, 19
PGND
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
BIAS
HPS
PGND
OUTR+
OUTR-
PVDD
HPVDD
BIAS
HPS
PGND
OUTR+
OUTR-
PVDD
HPVDD
TOP VIEW
21
20
19
18
17
16
15
21
20
19
18
17
16
15
SHDN
22
14
HPOUTL
SHDN
22
14
HPOUTL
GAIN2
23
13
HPOUTR
IN1/2
23
13
HPOUTR
GAIN1
24
12
VSS
GAIN
24
12
VSS
VDD
25
11
CPVSS
VDD
25
11
CPVSS
GND
26
10
C1N
GND
26
10
C1N
INR
27
9
CPGND
INR1
27
9
CPGND
VOL
28
8
C1P
INR2
28
8
C1P
2
PVDD
CPVDD
INL1
INL2
BIAS
HPS
PGND
OUTR+
OUTR-
PVDD
HPVDD
THIN QFN
21
20
19
18
17
16
15
3
4
5
6
7
CPVDD
1
PVDD
7
OUTL-
6
OUTL+
5
PGND
4
OUTL-
THIN QFN
SHDN
22
14
HPOUTL
GND
23
13
HPOUTR
GAIN
24
12
VSS
VDD
25
11
CPVSS
GND
26
10
C1N
N.C.
27
9
CPGND
INR
28
8
C1P
4
5
6
7
PVDD
CPVDD
INL
3
OUTL-
2
OUTL+
1
N.C.
MAX9754
PGND
BEEP
3
OUTL+
2
MAX9753
PGND
1
INL
MAX9752
THIN QFN
Chip Information
MAX9752 TRANSISTOR COUNT: 12,263
MAX9753/MAX9754 TRANSISTOR COUNT: 12,137
PROCESS: BiCMOS
______________________________________________________________________________________
27
MAX9752/MAX9753/MAX9754
Pin Configurations
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.)
QFN THIN.EPS
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
28
______________________________________________________________________________________
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
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.
MAX9752/MAX9753/MAX9754
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.)
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