MAX9752BETI+T ,2.2W, Low-EMI, Stereo, Class D Power Amplifiers with DirectDrive Headphone AmplifiersBlock DiagramsMAX9752 MAX9753 MAX9754SCLASS CLASS CLASSD D DSAMP AMP AMPVOLINPUT HPS HPS HPSMUX SEL ..
MAX9755ETI ,2.6W Stereo Audio Power Amplifiers and DirectDrive Headphone AmplifiersBlock DiagramsPIN- M A XIMU M PART TEMP RANGEPACKAGE G A I N ( d B ) †MAX9750AETI* -40°C to +85°C ..
MAX9755ETI+ ,2.6W Stereo Audio Power Amplifiers and DirectDrive® Headphone AmplifiersELECTRICAL CHARACTERISTICS(V = PV = CPV = HPV = 5V, V = V = V = 0V, SHDN = V , C = 1µF, C1 = C2 = 1 ..
MAX9755ETI+ ,2.6W Stereo Audio Power Amplifiers and DirectDrive® Headphone Amplifiersfeatures an analog volume control, and a♦ High 90dB PSRRBEEP input. The MAX9751
MAX9755ETI+T ,2.6W Stereo Audio Power Amplifiers and DirectDrive® Headphone Amplifiersfeatures a 2:1 input multiplexer,allowing multiple audio sources to be selected. All devices♦ Low-P ..
MAX9759ETE+T ,3.2W, High-Efficiency, Low-EMI, Filterless, Class D Audio AmplifierFeaturesThe MAX9759 mono Class D, audio power amplifier♦ 3.2W into 4Ω Load (THD+N = 10%)provides Cl ..
MB89475 ,F2MC-8L/Low Power/Low Voltage Microcontrollersapplications forconsumer product.2* : F MC stands for FUJITSU Flexible Microcontroller.n
MB89535A ,F2MC-8L/Low Power/Low Voltage MicrocontrollersFEATURES• Wide range of package options• Two types of QFP packages (1 mm pitch, 0.65 mm pitch) • LQ ..
MB89535A ,F2MC-8L/Low Power/Low Voltage MicrocontrollersFUJITSU SEMICONDUCTORDS07-12547-4EDATA SHEET8-bit Original Microcontroller CMOS2F MC-8L MB89530A Se ..
MB89537A , 8-bit Original Microcontroller CMOS, F-2MC-8L MB89530A Series
MB89537A , 8-bit Original Microcontroller CMOS, F-2MC-8L MB89530A Series
MB89537AC , 8-bit Original Microcontroller CMOS, F-2MC-8L MB89530A Series
MAX9752BETI+T
2.2W, Low-EMI, Stereo, Class D Power Amplifiers with DirectDrive Headphone Amplifiers
General DescriptionThe 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 versionof
these devices, refer to the MAX9750/MAX9751/
MAX9755 data sheet.
ApplicationsNotebook PCsFlat-Panel TVs
Tablet PCsPC Displays
Portable DVDsLCD Projectors
FeaturesPC2001 Compliant2.2W Class D Stereo Speaker AmplifierPin-for-Pin Compatible with Class AB
MAX9750/MAX9751/MAX975585% Efficiency (RL= 8Ω, POUT= 1W)62mW DirectDrive Headphone AmplifierHigh PSRR (70dB at 1kHz)Analog Volume Control (MAX9752)Beep Input with Glitch Filter (MAX9752)2:1 Stereo Input MUX (MAX9753)±8kV ESD-Protected Headphone OutputsNo Output DC-Blocking CapacitorsIndustry-Leading Click-and-Pop Suppression
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Ordering InformationHPS
CLASS
AMP
CLASS
AMP
HPSINPUT
MUX
SELECT
HPS
VOL
BEEP
MAX9752MAX9753MAX9754
CLASS
AMP
Block Diagrams19-3666; Rev 0; 9/05
PARTPIN-PACKAGEPKG
CODEA XIM U M A I N ( d B )
MAX9752AETI+28 TQFN-EP*T2855-113.5
MAX9752BETI+28 TQFN-EP*T2855-119.5
MAX9752CETI+28 TQFN-EP*T2855-110.5
MAX9753ETI+28 TQFN-EP*T2855-113.5
MAX9754ETI+28 TQFN-EP*T2855-113.5
Pin Configurations appear at end of data sheet.Note:All devices specified for -40°C to +85°C operation.
+Denoteslead-free package.
*EP = Exposed paddle.
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
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= TMINto 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, CPVDDto GND.......................-0.3V to +6V
GND to PGND or CPGND....................................-0.3V to +0.3V
CPVSSor VSSto 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
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
GENERALSupply Voltage Range,
Speaker AmplifierVDD, PVDDInferred from PSRR test4.55.5V
Supply Voltage Range,
Headphone AmplifierHPVDDInferred from PSRR test3.05.5V
Speaker mode, no load1418Quiescent CurrentIDDHeadphone mode, no load7.29.5mA
Shutdown Supply CurrentI SHDNV SHDN = 0V0.28µA
Gain Switching TimetSWG3µs
Mux Switching TimetSWMMAX9753 only3µs
MAX9752102030Input ResistanceRINMAX9753/MAX97543.56.610.0kΩ
Turn-On TimetON25ms
CLASS D SPEAKER AMPLIFIERS (HPS = GND)TA = +25°C±9.6±38.8MAX9752A,
MAX9752B,
MAX9753, MAX9754TA = TMIN to TMAX±55
TA = +25°C±7±40
Output Offset Voltage
OUT_+ to OUT_-VOS
MAX9752CTA = TMIN to TMAX±60
PVDD or VDD = 4.5V to 5.5V, TA = +25°C5074
f = 1kHz, VRIPPLE = 100mVP-P70Power-Supply Rejection Ratio
(Note 3)PSRR
f = 10kHz, VRIPPLE = 100mVP-P60
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
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= TMINto TMAX, unless otherwise
noted. Typical values are at TA= +25°C.) (Notes 1, 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSGAIN2 = 0, GAIN1 = 09.0
GAIN2 = 0, GAIN1 = 110.5
GAIN2 = 1, GAIN1 = 012.0MAX9752A
GAIN2 = 1, GAIN1 = 113.5
GAIN2 = 0, GAIN1 = 015.0
GAIN2 = 0, GAIN1 = 116.5
GAIN2 = 1, GAIN1 = 018.0MAX9752B
GAIN2 = 1, GAIN1 = 119.5
GAIN2 = 0, GAIN1 = 06.0
GAIN2 = 0, GAIN1 = 17.5
GAIN2 = 1, GAIN1 = 09.0MAX9752C
GAIN2 = 1, GAIN1 = 110.5
GAIN = 19.0
Speaker Amplifier Gain (Note 4)AV_SP
MAX9753/MAX9754GAIN = 010.5
MAX9752A,
MAX9752B, MAX9753,
MAX9754
1.3f = 1kHz, THD+N
= 1%, TA = +25°C,
RL = 8Ω
MAX9752C0.8
MAX9752A,
MAX9752B, MAX9753,
MAX9754
Output PowerPOUT_SP
f = 1kHz, THD+N
= 1%, TA = +25°C,
RL = 4Ω
MAX9752C1.7
RL = 8Ω0.023Total Harmonic Distortion Plus
NoiseTHD+Nf = 1kHz, POUT = 1WRL = 4Ω0.03%
Unweighted90Signal-to-Noise RatioSNRPOUT = 1W, f = 1kHz,
BW = 22Hz to 22kHzA-weighted91dB
Into shutdown-47Click-and-Pop Level (Note 5)KCPOut of shutdown-34dBV
Capacitive-Load DriveCL_MAXDifferential200pF
Switching FrequencyfSW100012001400kHz
CrosstalkChannel to channel, f = 10kHz, POUT = 1W70dB
Off-IsolationMAX9753, unselected input to any active
input, f = 10kHz70dB
EfficiencyηRL = 8Ω, POUT = 1W, f = 1kHz85%
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
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= TMINto TMAX, unless otherwise
noted. Typical values are at TA= +25°C.) (Notes 1, 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
HEADPHONE AMPLIFIER (HPS = VDD)TA = +25°C±0.5±3.5Output Offset VoltageVOSTA = TMIN to TMAX±8mV
GAIN2 = 00MAX9752,
GAIN1 = don’t careGAIN2 = 13
GAIN = 10
Maximum Headphone Amplifier
Gain (Note 6)AV_HP
MAX9753/MAX9754GAIN = 03
HPVDD or VDD = 3V to 5.5V, TA = +25°C6673
f = 1kHz, VRIPPLE = 100mVP-P80Power-Supply Rejection Ratio
(Note 3)PSRR
f = 10kHz, VRIPPLE = 100mVP-P60
RL = 32Ω31Output PowerPOUT_HPTHD+N = 1%, fIN =
1kHz, TA = +25°CRL = 16Ω62mW
RL = 32Ω,
POUT = 31mW0.005
Total Harmonic Distortion Plus
NoiseTHD+NfIN = 1kHz
RL = 16Ω,
POUT = 62mW0.005
Unweighted95
Signal-to-Noise RatioSNR
RL = 32Ω,
POUT = 31mW,
fIN = 1kHz,
BW = 22Hz to 22kHzA-weighted101
Into shutdown-33Click-and-Pop Level (Note 7)KCPOut of shutdown-37dBV
Capacitive-Load DriveCL_MAXNo sustained oscillations300pF
Crosstalkf = 10kHz, POUT = 62mW, RL = 16Ω60dB
Off-IsolationMAX9753, unselected input to any active
input, f = 10kHz60dB
Slew RateSR0.8V/µs
Output ImpedanceHPS = GND (disabled)1kΩ
CHARGE PUMPCharge-Pump FrequencyfCP540600660kHz
VOLUME CONTROL (MAX9752 Only)VOL Input ImpedanceRVOL100MΩ
VOL Input HysteresisHYSTVOLVVOL falling50mV
Full Mute Input VoltageVVOL_MUTE0.858 x
VDDV
Full Mute AttenuationAV_MUTEfIN = 1kHz-85dB
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
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= TMINto TMAX, unless otherwise
noted. Typical values are at TA= +25°C.) (Notes 1, 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSGain 10.5dB to 13.5dB±0.2
Gain 6.0dB to 10.0dB±0.2
Gain -26dB to +4.0dB±0.3Channel Matching
Gain -62dB to +30dB±1.0
BEEP INPUT (MAX9752 Only)Beep Signal Minimum Amplitude
(Note 8)VBEEPRBEEP = 47kΩ400mV
Beep Signal Minimum FrequencyfBEEP300Hz
LOGIC INPUTS (GAIN_, IN1////2222, SHDN, HPS)
Input High VoltageVIH2.0V
Input Low VoltageVIL0.8V
GAIN_, SHDN-1+1
IN1/2-2+2Input Leakage CurrentILEAK
HPS-20+1
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= 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. KCPlevel 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. KCPlevel 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 RBEEPdictates 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
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
0.001100k
RL = 3Ω
POUT = 1W
POUT = 500mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)MAX9752/53/54 toc02
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
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
0.001100k
RL = 8Ω
POUT = 1W
POUT = 500mW
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWERMAX9752 toc04
OUTPUT POWER (W)
THD+N (%)
RL = 3Ω
MAX9752C
fIN = 10kHz
fIN = 20HzfIN = 1kHz
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWERMAX9752 toc05
OUTPUT POWER (W)
THD+N (%)
RL = 3Ω
fIN = 1kHz AND 20Hz
fIN = 10kHz
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWERMAX9752 toc06
OUTPUT POWER (W)
THD+N (%)
RL = 4Ω
MAX9752C
fIN = 1kHz
fIN = 10kHz
fIN = 20Hz
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWERMAX9752 toc07
OUTPUT POWER (W)
THD+N (%)
RL = 4Ω
fIN = 1kHz AND 20Hz
fIN = 10kHz
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWERMAX9752 toc08
OUTPUT POWER (W)
THD+N (%)
RL = 8Ω
MAX9752C
fIN = 1kHz
fIN = 10kHz
fIN = 20Hz
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWERMAX9752 toc09
OUTPUT POWER (W)
THD+N (%)
RL = 8Ω
fIN = 10kHz
fIN = 1kHz AND 20Hz
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
OUTPUT POWER vs. LOAD RESISTANCE
(SPEAKER MODE)MAX9752/53/54 toc10
LOAD RESISTANCE (Ω)
OUTPUT POWER (W)100
THD+N = 10%
THD+N = 1%
OUTPUT POWER vs. LOAD RESISTANCE
(SPEAKER MODE)MAX9752 toc11
LOAD RESISTANCE (Ω)
OUTPUT POWER (W)
THD+N = 10%
THD+N = 1%
POWER DISSIPATION vs. OUTPUT POWER
(SPEAKER MODE)MAX9752 toc12
OUTPUT POWER (W)
POWER DISSIPATION (W)21
RL = 4Ω
RL = 8Ω
TURN-ON RESPONSE
(SPEAKER MODE)MAX9752/53/54 toc14
4ms/div
SHDN
5V/div
500mV/divOUT
(1kHz, 2VP-P)
OUT
(NO AUDIO)100mV/div
TURN-OFF RESPONSE
(SPEAKER MODE)MAX9752/53/54 toc15
2ms/div
SHDN
5V/div
500mV/divOUT
(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 POWERMAX9752 toc13
OUTPUT POWER (W)
EFFICIENCY (%)2
RL = 8Ω||68μH
RL = 4Ω||33μH
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
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.)
0.00011k10k100100k
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
0.00011k10k100100k
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
0.00011k10k100100k
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
0.00011k10k100100k
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
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 = 1kHzfIN = 20Hz
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
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
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)
THD+N = 10%
THD+N = 1%
MAX9752/MAX9753/MAX9754
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
POWER DISSIPATION vs. OUTPUT POWER
(HEADPHONE MODE)MAX9752/53/54 toc25
OUTPUT POWER (mW)
POWER DISSIPATION (mW)
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)
RL = 16Ω
RL = 32Ω
f = 1kHz1k10k100100k
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (HEADPHONE MODE)MAX9752/53/54 toc27
FREQUENCY (Hz)
PSRR (dB)
VRIPPLE = 200mVP-P
AV = 10.5dB
OUTPUT REFERRED
-1001001k10k100k
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
OUTPUT POWER vs. CHARGE-PUMP
CAPACITANCE AND LOAD RESISTANCE
MAX9752/53/54 toc29
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)3020
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
HEADPHONE OUTPUT SPECTRUMMAX9752/53/54 toc30
FREQUENCY (Hz)
MAGNITUDE (dB)105
VDD = 5V
f = 1kHz
VOUT = -60dB
RL = 32Ω
TURN-ON RESPONSE
(HEADPHONE MODE)MAX9752/53/54 toc31
10ms/div
SHDN
5V/div
20mV/divHPOUT_
RL = 32Ω
TURN-OFF RESPONSE
(HEADPHONE MODE)MAX9752/53/54 toc32
10ms/div
SHDN
5V/div
20mV/divHPOUT_
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
Pin Descriptions
PIN
MAX9752MAX9753MAX9754NAMEFUNCTION—2INLLeft-Channel Audio Input——BEEPAudible Alert Beep Input
3, 193, 193, 19PGNDPower Ground44OUTL+Left-Channel Positive Speaker Output55OUTL-Left-Channel Negative Speaker Output
6, 166, 166, 16PVDDSpeaker Amplifier Power Supply77CPVDDCharge-Pump Power Supply88C1PCharge-Pump Flying-Capacitor Positive Terminal99CPGNDCharge-Pump Ground1010C1NCharge-Pump Flying-Capacitor Negative Terminal1111CPVSSCharge-Pump Output. Connect to VSS.1212VSSHeadphone Amplifier Negative Power Supply1313HPOUTRRight-Channel Headphone Output1414HPOUTLLeft-Channel Headphone Output1515HPVDDHeadphone Positive Power Supply1717OUTR-Right-Channel Negative Speaker Output1818OUTR+Right-Channel Positive Speaker Output2020HPSHeadphone Sense Input2121BIASCommon-Mode Bias Voltage. Bypass with a 1µF capacitor to GND.2222SHDNShutdown. Drive SHDN low to disable the device. Connect SHDN to
VDD for normal operation.——GAIN2Gain-Control Input 2——GAIN1Gain-Control Input 12525VDDPower Supply2623, 26GNDGround—28INRRight-Channel Audio Input——VOLAnalog Volume Control Input1—INL1Left-Channel Audio Input 12—INL2Left-Channel Audio Input 223—IN1/2Input Select2424GAINGain Select27—INR1Right-Channel Audio Input 128—INR2Right-Channel Audio Input 2—1, 27N.C.No Connection. Not internally connected.
MAX9752/MAX9753/MAX9754
Detailed DescriptionThe 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 AmplifierThe 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 AmplifiersOUT_+
OUT_VOLUME
CONTROLBIAS
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 IdleThe 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.
EfficiencyEfficiency 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 AmplifiersFREQUENCY (MHz)
AMPLITUDE (dB
V/m)
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
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
DirectDriveConventional 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 Characteristicsfor 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:The sleeve is typically grounded to the chassis. Using
this biasing approach, the sleeve must be isolated
from system ground, complicating product design.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.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 ResponseIn addition to the cost and size disadvantages, the DC-
blocking capacitors limit the low-frequency response of
the amplifier and distort the audio signal: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
COUTis 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 COUTreduce the atten-
uation, but are physically larger, more expensive
capacitors. Figure 6 shows the relationship between
the size of COUTand 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.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.RCdBLOUT=31 π
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers-151001k10k100k
LOW-FREQUENCY ROLLOFF
(RL = 16Ω)FREQUENCY (Hz)
ATTENUATION (dB)
DirectDrive
330μF
220μF
100μF
33μF
Figure 6. Low-Frequency Attenuation of Common DC-Blocking
Capacitor Values
Charge PumpThe 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
Figure8. 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 VDDthrough the internal 100kΩpullup resistor.
BiasThe 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 Capacitorsection.
No external load should be applied to BIAS.
Gain Selection
MAX9752The 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 (Table1). 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
ADDITIONAL THD+N DUE
TO DC-BLOCKING CAPACITORSFREQUENCY (Hz)
THD+N (%)
10k1k100
0.0001100k
TANTALUM
ALUM/ELEC
Figure 7. Distortion Contributed by DC-Blocking Capacitors
OUTR
OUTL
MAX9752
MAX9753
MAX9754
VDD
HPS
100kΩ
Figure 8. HPS Configuration
Table 1. MAX9752 Gain Settings
SPEAKER MODE GAIN (dB)GAIN2GAIN1MAX9752AMAX9752BMAX9752CHEADPHONE MODE GAIN (dB)09.015.06.00110.516.57.50012.018.09.03113.519.510.53
