General Description
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 4Ωload. 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 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.
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.
Applications
Notebook PCs Flat-Panel TVs
Tablet PCs PC Displays
Portable DVDs LCD Projectors
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
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
HPS
CLASS
D
AMP
CLASS
D
AMP
HPS
INPUT
MUX
SELECT
HPS
VOL
BEEP
S
S
MAX9752 MAX9753 MAX9754
CLASS
D
AMP
Block Diagrams
19-3666; Rev 0; 9/05
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.
PART
PIN-PACKAGE
PKG
CODE
M A XIM U M
G A I N ( d B )
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
Pin Configurations appear at end of data sheet. Note: All devices specified for -40°C to +85°C operation.
+Denotes lead-free package.
*EP = Exposed paddle.
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VDD = PVDD = HPVDD = CPVDD = +5.0V, GND = PGND = HPGND = 0V, VSHDN = VDD, CPVSS = VSS, CBIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ωconnected 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)
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.
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
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
GENERAL
Supply Voltage Range,
Speaker Amplifier
VDD, PVDD
Inferred from PSRR test 4.5 5.5 V
Supply Voltage Range,
Headphone Amplifier HPVDD Inferred from PSRR test 3.0 5.5 V
Speaker mode, no load 14 18
Quiescent Current IDD Headphone mode, no load 7.2 9.5 mA
Shutdown Supply Current I SHDN V SHDN = 0V 0.2 8 µA
Gain Switching Time tSWG 3µs
Mux Switching Time tSWM MAX9753 only 3 µs
MAX9752 10 20 30
Input Resistance RIN MAX9753/MAX9754 3.5 6.6
10.0
kΩ
Turn-On Time tON 25 ms
CLASS D SPEAKER AMPLIFIERS (HPS = GND)
TA = +25°C
±9.6 ±38.8
MAX9752A,
MAX9752B,
MAX9753, MAX9754
TA = TMIN to TMAX
±55
TA = +25°C ±7
±40
Output Offset Voltage
OUT_+ to OUT_- VOS
MAX9752C TA = TMIN to TMAX
±60
mV
PVDD or VDD = 4.5V to 5.5V, TA = +25°C 50 74
f = 1kHz, VRIPPLE = 100mVP-P 70
Power-Supply Rejection Ratio
(Note 3) PSRR
f = 10kHz, VRIPPLE = 100mVP-P 60
dB
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VDD = PVDD = HPVDD = CPVDD = +5.0V, GND = PGND = HPGND = 0V, VSHDN = VDD, CPVSS = VSS, CBIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ωconnected 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
CONDITIONS
MIN
TYP
MAX
UNITS
GAIN2 = 0, GAIN1 = 0
9.0
GAIN2 = 0, GAIN1 = 1 10.5
GAIN2 = 1, GAIN1 = 0 12.0
MAX9752A
GAIN2 = 1, GAIN1 = 1 13.5
GAIN2 = 0, GAIN1 = 0 15.0
GAIN2 = 0, GAIN1 = 1 16.5
GAIN2 = 1, GAIN1 = 0 18.0
MAX9752B
GAIN2 = 1, GAIN1 = 1 19.5
GAIN2 = 0, GAIN1 = 0
6.0
GAIN2 = 0, GAIN1 = 1
7.5
GAIN2 = 1, GAIN1 = 0
9.0
MAX9752C
GAIN2 = 1, GAIN1 = 1 10.5
GAIN = 1 9.0
Speaker Amplifier Gain (Note 4) AV_SP
MAX9753/MAX9754
GAIN = 0
10.5
dB
MAX9752A,
MAX9752B, MAX9753,
MAX9754
1.3
f = 1kHz, THD+N
= 1%, TA = +25°C,
RL = 8Ω
MAX9752C 0.8
MAX9752A,
MAX9752B, MAX9753,
MAX9754
2.2
Output Power
POUT_SP
f = 1kHz, THD+N
= 1%, TA = +25°C,
RL = 4Ω
MAX9752C 1.7
W
RL = 8Ω
0.023
Total Harmonic Distortion Plus
Noise
THD+N
f = 1kHz, POUT = 1W RL = 4Ω
0.03
%
Unweighted 90
Signal-to-Noise Ratio SNR POUT = 1W, f = 1kHz,
BW = 22Hz to 22kHz A-weighted 91 dB
Into shutdown -47
Click-and-Pop Level (Note 5) KCP Out of shutdown -34 dBV
Capacitive-Load Drive
CL_MAX
Differential
200
pF
Switching Frequency fSW
1000 1200 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
Efficiency ηRL = 8Ω, POUT = 1W, f = 1kHz 85 %
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(VDD = PVDD = HPVDD = CPVDD = +5.0V, GND = PGND = HPGND = 0V, VSHDN = VDD, CPVSS = VSS, CBIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ωconnected 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
CONDITIONS
MIN
TYP
MAX
UNITS
HEADPHONE AMPLIFIER (HPS = VDD)
TA = +25°C
±0.5 ±3.5
Output Offset Voltage VOS TA = TMIN to TMAX ±8 mV
GAIN2 = 0 0
MAX9752,
GAIN1 = don’t care GAIN2 = 1 3
GAIN = 1 0
Maximum Headphone Amplifier
Gain (Note 6) AV_HP
MAX9753/MAX9754 GAIN = 0 3
dB
HPVDD or VDD = 3V to 5.5V, TA = +25°C 66 73
f = 1kHz, VRIPPLE = 100mVP-P 80
Power-Supply Rejection Ratio
(Note 3) PSRR
f = 10kHz, VRIPPLE = 100mVP-P 60
dB
RL = 32Ω31
Output Power
POUT_HP
THD+N = 1%, fIN =
1kHz, TA = +25°C RL = 16Ω62 mW
RL = 32Ω,
POUT = 31mW
0.005
Total Harmonic Distortion Plus
Noise
THD+N
fIN = 1kHz
RL = 16Ω,
POUT = 62mW
0.005
%
Unweighted 95
Signal-to-Noise Ratio SNR
RL = 32Ω,
POUT = 31mW,
fIN = 1kHz,
BW = 22Hz to 22kHz A-weighted
101
dB
Into shutdown -33
Click-and-Pop Level (Note 7) KCP Out of shutdown -37 dBV
Capacitive-Load Drive
CL_MAX
No sustained oscillations
300
pF
Crosstalk f = 10kHz, POUT = 62mW, RL = 16Ω60 dB
Off-Isolation MAX9753, unselected input to any active
input, f = 10kHz 60 dB
Slew Rate SR 0.8 V/µs
Output Impedance HPS = GND (disabled) 1 kΩ
CHARGE PUMP
Charge-Pump Frequency fCP
540 600 660
kHz
VOLUME CONTROL (MAX9752 Only)
VOL Input Impedance RVOL
100
MΩ
VOL Input Hysteresis
HYSTVOL
VVOL falling 50 mV
Full Mute Input Voltage
VVOL_MUTE
0.858 x
VDD
V
Full Mute Attenuation
AV_MUTE
fIN = 1kHz -85 dB
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICS (continued)
(VDD = PVDD = HPVDD = CPVDD = +5.0V, GND = PGND = HPGND = 0V, VSHDN = VDD, CPVSS = VSS, CBIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ωconnected 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
CONDITIONS
MIN
TYP
MAX
UNITS
Gain 10.5dB to 13.5dB
±0.2
Gain 6.0dB to 10.0dB
±0.2
Gain -26dB to +4.0dB
±0.3
Channel Matching
Gain -62dB to +30dB
±1.0
dB
BEEP INPUT (MAX9752 Only)
Beep Signal Minimum Amplitude
(Note 8) VBEEP RBEEP = 47kΩ
400
mV
Beep Signal Minimum Frequency
fBEEP
300
Hz
LOGIC INPUTS (GAIN_, IN1////22
22, SHDN, HPS)
Input High Voltage VIH 2.0 V
Input Low Voltage VIL 0.8 V
GAIN_, SHDN -1 +1
IN1/2-2 +2
Input Leakage Current ILEAK
HPS -20 +1
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 8Ωresistive 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 32Ωresistive 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).
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
6 _______________________________________________________________________________________
Typical Operating Characteristics
(VDD = PVDD = HPVDD = CPVDD = 5.0V, GND = PGND = HPGND = 0V, VSHDN = VDD, CPVSS = VSS, CBIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ωconnected 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 (SPEAKER MODE)
MAX9752/53/54 toc01
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01
0.1
1
10
0.001
10 100k
RL = 3Ω
POUT = 1W
POUT = 500mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
MAX9752/53/54 toc02
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01
0.1
1
10
0.001
10 100k
RL = 4Ω
POUT = 1.5W
POUT = 750mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
MAX9752/53/54 toc03
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01
0.1
1
10
0.001
10 100k
RL = 8Ω
POUT = 1W
POUT = 500mW
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
MAX9752 toc04
OUTPUT POWER (W)
THD+N (%)
3.53.02.52.01.51.00.5
0.01
0.1
1
10
100
0.001
04.0
RL = 3Ω
MAX9752C
fIN = 10kHz
fIN = 20Hz fIN = 1kHz
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
MAX9752 toc05
OUTPUT POWER (W)
THD+N (%)
2.51.51.0 2.00.5
0.01
0.1
1
10
100
0.001
0 3.0
RL = 3Ω
fIN = 1kHz AND 20Hz
fIN = 10kHz
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
MAX9752 toc06
OUTPUT POWER (W)
THD+N (%)
2.51.51.0 2.00.5
0.01
0.1
1
10
100
0.001
03.0
RL = 4Ω
MAX9752C
fIN = 1kHz
fIN = 10kHz
fIN = 20Hz
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
MAX9752 toc07
OUTPUT POWER (W)
THD+N (%)
1.51.0 2.00.5
0.01
0.1
1
10
100
0.001
02.5
RL = 4Ω
fIN = 1kHz AND 20Hz
fIN = 10kHz
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
MAX9752 toc08
OUTPUT POWER (W)
THD+N (%)
0.5 1.0
0.01
0.1
1
10
100
0.001
0 1.5
RL = 8Ω
MAX9752C
fIN = 1kHz
fIN = 10kHz
fIN = 20Hz
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
MAX9752 toc09
OUTPUT POWER (W)
THD+N (%)
0.5 1.0
0.01
0.1
1
10
100
0.001
0 1.5
RL = 8Ω
fIN = 10kHz
fIN = 1kHz AND 20Hz
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
_______________________________________________________________________________________ 7
OUTPUT POWER vs. LOAD RESISTANCE
(SPEAKER MODE)
MAX9752/53/54 toc10
LOAD RESISTANCE (Ω)
OUTPUT POWER (W)
10
1
2
3
4
5
0
1 100
THD+N = 10%
THD+N = 1%
OUTPUT POWER vs. LOAD RESISTANCE
(SPEAKER MODE)
MAX9752 toc11
LOAD RESISTANCE (Ω)
OUTPUT POWER (W)
10
1
2
3
4
0
1100
THD+N = 10%
THD+N = 1%
POWER DISSIPATION vs. OUTPUT POWER
(SPEAKER MODE)
MAX9752 toc12
OUTPUT POWER (W)
POWER DISSIPATION (W)
321
0.5
1.0
1.5
2.0
0
04
RL = 4Ω
RL = 8Ω
TURN-ON RESPONSE
(SPEAKER MODE)
MAX9752/53/54 toc14
4ms/div
SHDN
5V/div
500mV/div
OUT
(1kHz, 2VP-P)
OUT
(NO AUDIO) 100mV/div
TURN-OFF RESPONSE
(SPEAKER MODE)
MAX9752/53/54 toc15
2ms/div
SHDN
5V/div
500mV/div
OUT
(1kHz, 2VP-P)
OUT
(NO AUDIO) 100mV/div
Typical Operating Characteristics (continued)
(VDD = PVDD = HPVDD = CPVDD = 5.0V, GND = PGND = HPGND = 0V, VSHDN = VDD, CPVSS = VSS, CBIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ωconnected 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.)
EFFICIENCY vs. OUTPUT POWER
MAX9752 toc13
OUTPUT POWER (W)
EFFICIENCY (%)
42
10
20
30
40
50
60
70
80
90
100
0
06
RL = 8Ω||68μH
RL = 4Ω||33μH
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
8 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(VDD = PVDD = HPVDD = CPVDD = 5.0V, GND = PGND = HPGND = 0V, VSHDN = VDD, CPVSS = VSS, CBIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ωconnected 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.)
10
1
0.1
0.01
0.001
0.0001
10 1k 10k100 100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
MAX9752/53/54 toc16
FREQUENCY (Hz)
THD+N (%)
VDD = 5V
RL = 16Ω
AV = 3dB
OUTPUT POWER = 90mW
OUTPUT POWER = 30mW
10
1
0.1
0.01
0.001
0.0001
10 1k 10k100 100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
MAX9752/53/54 toc17
FREQUENCY (Hz)
THD+N (%)
VDD = 5V
RL = 32Ω
AV = 3dB
OUTPUT POWER = 45mW
OUTPUT POWER = 10mW
10
1
0.1
0.01
0.001
0.0001
10 1k 10k100 100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
MAX9752/53/54 toc18
FREQUENCY (Hz)
THD+N (%)
VDD = 3.3V
RL = 16Ω
AV = 3dB
OUTPUT POWER = 30mW
OUTPUT POWER = 10mW
10
1
0.1
0.01
0.001
0.0001
10 1k 10k100 100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)
MAX9752/53/54 toc19
FREQUENCY (Hz)
THD+N (%)
VDD = 3.3V
RL = 32Ω
AV = 3dB
OUTPUT POWER = 45mW
OUTPUT POWER = 10mW
1000
100
10
1
0.1
0.01
0.001
075
100 12550
25 150
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
MAX9752/53/54 toc20
OUTPUT POWER (mW)
THD+N (%)
VDD = 5V
RL = 16Ω
AV = 3dB
fIN = 10kHz
fIN = 1kHz
fIN = 20Hz
1000
100
10
1
0.1
0.01
0.001
0608040
20 100
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
MAX9752/53/54 toc21
OUTPUT POWER (mW)
THD+N (%)
VDD = 5V
RL = 32Ω
AV = 3dB
fIN = 10kHz
fIN = 1kHz
fIN = 20Hz
1000
100
10
1
0.1
0.01
0.001
030
40 5020
10 60
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
MAX9752/53/54 toc22
OUTPUT POWER (mW)
THD+N (%)
VDD = 3.3V
RL = 16Ω
AV = 3dB
fIN = 10kHz
fIN = 1kHz
fIN = 20Hz
1000
100
10
0.1
1
0.01
0.001
070
80
20 30 40 50 60
10 90
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
MAX9752/53/54 toc23
OUTPUT POWER (mW)
THD+N (%)
VDD = 3.3V
RL = 32Ω
AV = 3dB
fIN = 10kHz
fIN = 1kHz
fIN = 20Hz
OUTPUT POWER vs. LOAD RESISTANCE
(HEADPHONE MODE)
MAX9752/53/54 toc24
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
100
20
40
60
80
100
120
140
160
180
0
10 1000
THD+N = 10%
THD+N = 1%
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
_______________________________________________________________________________________ 9
POWER DISSIPATION vs. OUTPUT POWER
(HEADPHONE MODE)
MAX9752/53/54 toc25
OUTPUT POWER (mW)
POWER DISSIPATION (mW)
225200150 17550 75 100 12525
25
50
75
100
125
150
175
200
225
250
0
0250
VDD = 5V
f = 1kHz
POUT = POUTL + POUTR
RL = 16Ω
RL = 32Ω
OUTPUT POWER vs. SUPPLY VOLTAGE
(HEADPHONE MODE)
MAX9752/53/54 toc26
SUPPLY VOLTAGE (V)
OUTPUT POWER (mW)
5.04.54.03.5
25
50
75
100
125
0
3.0 5.5
RL = 16Ω
RL = 32Ω
f = 1kHz
10 1k 10k100 100k
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (HEADPHONE MODE)
MAX9752/53/54 toc27
FREQUENCY (Hz)
PSRR (dB)
VRIPPLE = 200mVP-P
AV = 10.5dB
OUTPUT REFERRED
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
-100
10 100 1k 10k 100k
CROSSTALK vs. FREQUENCY
(HEADPHONE MODE)
MAX9752/53/54 toc28
FREQUENCY (Hz)
CROSSTALK (dB)
VCC = 5V
VRIPPLE = 200mVP-P
RL = 32Ω
LEFT TO RIGHT
RIGHT TO LEFT
-100
-80
-60
-40
-20
0
-120
OUTPUT POWER vs. CHARGE-PUMP
CAPACITANCE AND LOAD RESISTANCE
MAX9752/53/54 toc29
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
403020
20
40
60
80
100
120
140
160
180
200
0
10 50
VDD = 5V
f = 1kHz
THD+N = 1%
C1 = C2 = 2.2μF
C1 = C2 = 1μF
Typical Operating Characteristics (continued)
(VDD = PVDD = HPVDD = CPVDD = 5.0V, GND = PGND = HPGND = 0V, VSHDN = VDD, CPVSS = VSS, CBIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ωconnected 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.)
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
10 ______________________________________________________________________________________
HEADPHONE OUTPUT SPECTRUM
MAX9752/53/54 toc30
FREQUENCY (Hz)
MAGNITUDE (dB)
15105
0
020
-120
-100
-80
-60
-40
-20
-140
VDD = 5V
f = 1kHz
VOUT = -60dB
RL = 32Ω
TURN-ON RESPONSE
(HEADPHONE MODE)
MAX9752/53/54 toc31
10ms/div
SHDN
5V/div
20mV/div
HPOUT_
RL = 32Ω
TURN-OFF RESPONSE
(HEADPHONE MODE)
MAX9752/53/54 toc32
10ms/div
SHDN
5V/div
20mV/div
HPOUT_
RL = 32Ω
Typical Operating Characteristics (continued)
(VDD = PVDD = HPVDD = CPVDD = 5.0V, GND = PGND = HPGND = 0V, VSHDN = VDD, CPVSS = VSS, CBIAS = 1µF,
CCPVSS = 1µF, C1 = 1µF, speaker impedance = 8Ωconnected 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.)
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
______________________________________________________________________________________ 11
Pin Descriptions
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 Charge-Pump Power Supply
8 8 8 C1P Charge-Pump Flying-Capacitor Positive Terminal
9 9 9 CPGND Charge-Pump Ground
10 10 10 C1N Charge-Pump Flying-Capacitor Negative Terminal
11 11 11 CPVSS Charge-Pump Output. Connect to VSS.
12 12 12 VSS Headphone Amplifier Negative Power Supply
13 13 13 HPOUTR Right-Channel Headphone Output
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 Gain-Control Input 1
25 25 25 VDD Power Supply
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 — IN1/2Input 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.
MAX9752/MAX9753/MAX9754
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.
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.
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), cre-
ating a negative supply (CPVSS). The headphone ampli-
fiers operate from these bipolar supplies with their
outputs biased about GND (Figure 2). The amplifiers
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-
cally VDD / 2). This eliminates the large DC-blocking
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 ±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 inver-
sion from input to output.
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 ±90kHz around the center
frequency (1200kHz). 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 megahertz, the
wideband spectrum looks like white noise for EMI pur-
poses (Figure 3).
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
12 ______________________________________________________________________________________
OUT_+
OUT_
VOLUME
CONTROL BIAS
IN_
VOL
BIAS
MAX9752 ONLY
BIAS
HPOUT_
GND
Figure 1. MAX9752/MAX9753/MAX9754 Signal Path
+VDD
-VDD
GND
CONVENTIONAL DRIVER-BIASING SCHEME
DirectDrive BIASING SCHEME
VDD / 2
VDD
GND
VOUT
Figure 2. Traditional Amplifier Output vs. DirectDrive Output
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).
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
______________________________________________________________________________________ 13
FREQUENCY (MHz)
AMPLITUDE (dBμV/m)
280260240200 22080 100 120 140 160 18060
5
10
15
20
25
30
35
40
45
50
0
30 300
Figure 3. MAX9752/MAX9753/MAX9754 Radiated Emissions with 76mm of Speaker Cable
VIN_ = 0V
OUT_-
OUT_+
VOUT_+ - VOUT_- = 0V
Figure 4. Second-Generation Class D Output Waveform with
No Signal
0
30
20
10
50
40
90
80
70
60
100
0 0.5 1.51.0 2.0
EFFICIENCY vs. OUTPUT POWER
OUTPUT POWER (W)
EFFICIENCY (%)
MAX9752
MAX9753
MAX9754
CLASS AB
RL = 8Ω
Figure 5. MAX9752/MAX9753/MAX9754 Class D Efficiency vs.
MAX9750/MAX9751/MAX9755 Class AB Efficiency
MAX9752/MAX9753/MAX9754
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.
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.
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:
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.
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 DC-
blocking capacitors limit the low-frequency response of
the amplifier and distort the audio signal:
1) The impedance of the headphone load and the DC-
blocking capacitor form a highpass filter with the
-3dB point determined by:
where RLis the impedance of the headphone and
COUT is the value of the DC-blocking capacitor.
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
audio band. Larger values of COUT reduce the atten-
uation, 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 16Ωhead-
phone 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 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.
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.
fRC
dB L OUT
−=
3
1
2
π
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
14 ______________________________________________________________________________________
0
-15
10 100 1k 10k 100k
LOW-FREQUENCY ROLLOFF
(RL = 16Ω)
-12
-6
-9
-3
FREQUENCY (Hz)
ATTENUATION (dB)
DirectDrive
330μF
220μF
100μF
33μF
Figure 6. Low-Frequency Attenuation of Common DC-Blocking
Capacitor Values
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 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).
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.
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 100kΩpullup 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 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.
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
______________________________________________________________________________________ 15
ADDITIONAL THD+N DUE
TO DC-BLOCKING CAPACITORS
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001
0.01
0.1
1
10
0.0001
10 100k
TANTALUM
ALUM/ELEC
Figure 7. Distortion Contributed by DC-Blocking Capacitors
OUTR
OUTL
MAX9752
MAX9753
MAX9754
VDD
HPS
R1
100kΩ
Figure 8. HPS Configuration
Table 1. MAX9752 Gain Settings
SPEAKER MODE GAIN (dB)
GAIN2
GAIN1
MAX9752A MAX9752B MAX9752C HEADPHONE MODE GAIN (dB)
00 9.0 15.0 6.0 0
01 10.5 16.5 7.5 0
10 12.0 18.0 9.0 3
11 13.5 19.5 10.5 3
MAX9752/MAX9753/MAX9754
Table 2 shows the amplifier gain settings needed to
attain maximum speaker output power from a given
input voltage and load.
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).
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 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
DAC or potentiometer to HPVDD. Since the volume con-
trol 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 con-
trol for HPVDD = 3.3V.
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
16 ______________________________________________________________________________________
Table 2. MAX9752 Speaker Amplifier Gain
Settings for Maximum Output Power
GAIN
(dB)
INPUT
(VRMS)
RL
(Ω)
POUT
(W)
MAX9752A
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
9.0 1.099 8 1.2
10.5 0.925 8 1.2
12.0 0.778 8 1.2
13.5 0.655 8 1.2
MAX9752B
15.0 0.503 4 2.0
16.5 0.423 4 2.0
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
19.5 0.328 8 1.2
MAX9752C
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
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
GAIN
(dB)
INPUT
(VRMS)
RL
(Ω)
POUT
(W)
10.5 0.844 4 2.0
9.0 1.004 4 2.0
10.5 0.925 8 1.2
9.0 1.099 8 1.2
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
______________________________________________________________________________________ 17
Table 5a. MAX9752A Volume Levels
VVOL (V) SPEAKER MODE GAIN (dB)
HEADPHONE MODE GAIN (dB)
VMIN*
VMAX*
FRACTION
OF
HPVDD
GAIN1 = 0,
GAIN2 = 0
GAIN1 = 1,
GAIN2 = 0
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.
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
18 ______________________________________________________________________________________
Table 5b. MAX9752B Volume Levels
VVOL (V) SPEAKER MODE GAIN (dB)
HEADPHONE MODE GAIN (dB)
VMIN*
VMAX*
FRACTION
OF
HPVDD
GAIN1 = 0,
GAIN2 = 0
GAIN1 = 1,
GAIN2 = 0
GAIN1 = 0,
GAIN2 = 1
GAIN1 = 1
GAIN2 = 1
GAIN1 = X,
GAIN2 = 0
GAIN1 = X,
GAIN2 = 1
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.
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
______________________________________________________________________________________ 19
Table 5c. MAX9752C Volume Levels
VVOL (V) SPEAKER MODE GAIN (dB)
HEADPHONE MODE GAIN (dB)
VMIN*
VMAX*
FRACTION
OF
HPVDD
GAIN1 = 0,
GAIN2 = 0
GAIN1 = 1,
GAIN2 = 0
GAIN1 = 0,
GAIN2 = 1
GAIN1 = 1
GAIN2 = 1
GAIN1 = X,
GAIN2 = 0
GAIN1 = X,
GAIN2 = 1
0
0.4900
0.074 6 7.5 9 10.5 0 3
0.4900
0.5673
0.160 5 7 8.5 10 -1 2.5
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
*Based on HPVDD = 3.3V.
X = Don’t care.
MAX9752/MAX9753/MAX9754
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 fre-
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.
Input Mux (MAX9753)
The MAX9753 features a 2:1 input multiplexer on each
amplifier, allowing input selection between two stereo
sources. The logic input IN1/2controls both multiplexers.
A logic-high selects input IN_1 and a logic-low selects
input IN_2. The unselected inputs are high impedance.
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
VDD for normal operation.
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
20 ______________________________________________________________________________________
MAX9752
VREF
DAC
HPVDD
VOL
Figure 9. MAX9752 Volume-Control Circuit
-80
-60
-70
-40
-50
-20
-30
-10
10
0
20
0 1.0 1.50.5 2.0 2.5 3.0 3.5 4.0
MAX9752B
VOLUME-CONTROL TRANSFER FUNCTION
VVOL (V)
GAIN (dB)
AUDIO
TAPER POT
GAIN1 = GAIN2 = 0
SPEAKER MODE
HEADPHONE MODE
Figure 10b. MAX9752B Volume-Control Transfer Functions
-80
-60
-70
-40
-50
-20
-30
-10
10
0
20
0 1.0 1.50.5 2.0 2.5 3.0 3.5 4.0
MAX9752A
VOLUME-CONTROL TRANSFER FUNCTION
VVOL (V)
GAIN (dB)
AUDIO
TAPER POT
GAIN1 = GAIN2 = 0
SPEAKER MODE
HEADPHONE MODE
Figure 10a. MAX9752A Volume-Control Transfer Functions
-80
-60
-70
-40
-50
-20
-30
-10
10
0
20
0 1.0 1.50.5 2.0 2.5 3.0 3.5 4.0
MAX9752C
VOLUME-CONTROL TRANSFER FUNCTION
VVOL (V)
GAIN (dB)
AUDIO
TAPER POT
GAIN1 = GAIN2 = 0
SPEAKER MODE
HEADPHONE MODE
Figure 10c. MAX9752C Volume-Control Transfer Functions
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.
Applications Information
Compatibility with
MAX9750/MAX9751/MAX9755
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.
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.
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
8Ωspeakers exhibit series inductances in the 30µH to
100µH range. Highest efficiency is achieved with speak-
er inductances > 60µH.
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
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.
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
______________________________________________________________________________________ 21
MAX9752
RS3
47kΩ
BEEP
0.47μF
SOURCE 3
RS2
47kΩ
0.47μF
SOURCE 2
RS1
47kΩ
0.47μF
SOURCE 1 RINT
47kΩ
BIAS
WINDOW
DETECTOR
(0.4VP-P THRESHOLD)
FREQUENCY
DETECTOR
(300Hz THRESHOLD)
SPEAKER/HEADPHONE
AMPLIFIER INPUTS
VOUT(BEEP)
Figure 11. MAX9752 Beep Summing Circuit
OUTPUT POWER (mW)
THD+N (%)
125100755025
0.01
0.1
1
10
100
1000
0.001
0150
VDD = 5V
RL = 16Ω
AV = 3dB
OUTPUTS IN-PHASE
OUTPUTS 180° OUT-OF-PHASE
Figure 12. THD+N vs. POUT with Headphone Output Signals
In- and Out-of-Phase
MAX9752/MAX9753/MAX9754
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
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 remain-
der of the device is powered by VDD.
Component Selection
Input Filtering
The input capacitor (CIN), in conjunction with the ampli-
fier 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:
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 ceram-
ics, 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 fre-
quencies 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.
Charge-Pump Capacitor Selection
Use capacitors with less than 100mΩof 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.
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.
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 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.
fRC
dB IN IN
−=
3
1
2
π
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
22 ______________________________________________________________________________________
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 com-
pared to a 0Ωtrace, a 100mΩtrace reduces the power
delivered to a 4Ωload 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.
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.
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,
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.
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
______________________________________________________________________________________ 23
47nF
47nF
RL
100Ω
100Ω
CLASS D
MODULATOR
AND H-BRIDGE
AUDIO
ANALYZER
OUT_+
OUT_-
IN+
IN-
Figure 13. Connecting a Class D Output to an Analog Analyzer
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
24 ______________________________________________________________________________________
MAX9752 Functional Diagram
HPVDD
HPS
INR
BIAS
VOL
GAIN1
GAIN2
BEEP
3V TO 5.5V CPVDD
C1P
C1N
CPVSS VSS GND PGND
C1
1μF
CBIAS
1μF
CIN
1μF
CIN
1μF
C2
1μF
1μF
1μF
CPGND
INL
27
21
28
24
23
2
22
7
8
10
9
11 12 26 3, 19
1
1μF
3V TO 5.5V
6, 16
4
25
5
18
17
15
20
14
13
HPOUTL
HPOUTR
MAX9752
0.1μF
1μF
4.5V TO 5.5V
GAIN/
VOLUME
CONTROL
CLASS D
AMPLIFIER
RIGHT-CHANNEL
AUDIO INPUT
OUTR+
OUTR-
CHARGE
PUMP
GAIN/
VOLUME
CONTROL
HEADPHONE
DETECTION
BEEP
DETECTION
SHUTDOWN
CONTROL
GAIN/
VOLUME
CONTROL
CLASS D
AMPLIFIER
LEFT-CHANNEL
AUDIO INPUT
OUTL+
PVDD
4.5V TO 5.5V
VDD
OUTL-
VDD
VDD
VDD SHDN
47kΩ
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
______________________________________________________________________________________ 25
MAX9753 Functional Diagram
HPVDD
HPS
INR1
BIAS
GAIN
IN1/2
SHDN
3V TO 5.5V CPVDD
VDD
VDD
VDD
C1P
C1N
CVSS VSS GND PGND
C1
1μF
CBIAS
1μF
CIN
1μF
CIN
1μF
C2
1μF
1μF
CPGND
INL1
27
21
28
24
23
2
22
7
8
10
9
11 12 26 3, 19
1
1μF
3V TO 5.5V
6, 16
4
25
5
18
17
15
20
14
13
HPOUTL
HPOUTR
MAX9753
0.1μF
1μF
4.5V TO 5.5V
CLASS D
AMPLIFIER
RIGHT-CHANNEL
AUDIO INPUT
INR2
CIN
1μF
RIGHT-CHANNEL
AUDIO INPUT
OUTR+
OUTR-
CHARGE
PUMP
MUX AND
GAIN
CONTROL
HEADPHONE
DETECTION
SHUTDOWN
CONTROL
INPUT
MUX
INPUT
MUX
CLASS D
AMPLIFIER
LEFT-CHANNEL
AUDIO INPUT
CIN
1μF
INL2
LEFT-CHANNEL
AUDIO INPUT
OUTL+
PVDD
4.5V TO 5.5V
VDD
OUTL-
LOGIC PINS CONFIGURED FOR:
GAIN = 1, 9dB SPEAKER GAIN/0dB HEADPHONE GAIN.
IN1/2 = 1, SELECTED INPUT LINE 1.
SHDN = 1, PART ACTIVE.
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
26 ______________________________________________________________________________________
MAX9754 Functional Diagram
HPVDD
HPS
BIAS
GAIN
SHDN
3V TO 5.5V CPVDD
VDD
VDD
C1P
C1N
CPVSS VSS GND PGND
C1
1μF
CBIAS
1μF
C2
1μF
1μF
CPGND
21
28
24
2
22
7
8
10
9
11 12 23, 26 3, 19
1μF
3V TO 5.5V
6, 16
4
25
5
18
17
15
20
14
13
HPOUTL
HPOUTR
MAX9754
0.1μF
1μF
4.5V TO 5.5V
CLASS D
AMPLIFIER
INR
CIN
1μF
RIGHT-CHANNEL
AUDIO INPUT
OUTR+
OUTR-
CHARGE
PUMP
GAIN
CONTROL
HEADPHONE
DETECTION
SHUTDOWN
CONTROL
CLASS D
AMPLIFIER
CIN
1μFINL
LEFT-CHANNEL
AUDIO INPUT
OUTL+
PVDD
4.5V TO 5.5V
VDD
OUTL-
LOGIC PINS CONFIGURED FOR:
GAIN = 1, 9dB SPEAKER GAIN/0dB HEADPHONE GAIN.
SHDN = 1, PART ACTIVE.
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
______________________________________________________________________________________ 27
Pin Configurations
28
27
26
25
24
23
22
VOL
INR
GND
VDD
GAIN1
GAIN2
SHDN
8
9
10
11
12
13
14
C1P
CPGND
C1N
CPVSS
VSS
HPOUTR
HPOUTL
15161718192021
HPVDD
PVDD
OUTR-
OUTR+
PGND
HPS
BIAS
7654321
CPVDD
PVDD
OUTL-
OUTL+
PGND
BEEP
INL
MAX9752
THIN QFN
TOP VIEW
28
27
26
25
24
23
22
INR
N.C.
GND
VDD
GAIN
GND
8
9
10
11
12
13
14
C1P
CPGND
C1N
CPVSS
VSS
HPOUTR
HPOUTL
15161718192021
HPVDD
PVDD
OUTR-
OUTR+
PGND
HPS
BIAS
7654321
CPVDD
PVDD
OUTL-
OUTL+
PGND
INL
N.C.
MAX9754
THIN QFN
SHDN
28
27
26
25
24
23
22
INR2
INR1
GND
VDD
GAIN
8
9
10
11
12
13
14
C1P
CPGND
C1N
CPVSS
VSS
HPOUTR
HPOUTL
15161718192021
HPVDD
PVDD
OUTR-
OUTR+
PGND
HPS
BIAS
7654321
CPVDD
PVDD
OUTL-
OUTL+
PGND
INL2
INL1
MAX9753
THIN QFN
SHDN
IN1/2
Chip Information
MAX9752 TRANSISTOR COUNT: 12,263
MAX9753/MAX9754 TRANSISTOR COUNT: 12,137
PROCESS: BiCMOS
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
28 ______________________________________________________________________________________
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
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.
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.)