MAX9702ETI+T ,1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone AmplifierApplicationsRIGHT MODULATORCellular PhonesAND H-BRIDGEINR∑Notebook PCsGAININMPDAsCONTROLINLHandheld ..
MAX9703ETJ ,15W, Filterless, Spread-Spectrum Mono/Stereo Class D AmplifiersFeaturesThe MAX9703/MAX9704 mono/stereo class D audio ♦ Filterless Class D Amplifierpower amplifier ..
MAX9703ETJ+ ,10W Stereo/15W Mono, Filterless, Spread-Spectrum, Class D AmplifiersFeatures● Filterless Class D AmplifierThe MAX9703/MAX9704 mono/stereo Class D audio ● Unique Spread ..
MAX9704ETJ ,15W / Filterless / Spread-Spectrum Mono/Stereo Class D AmplifiersFeaturesThe MAX9703/MAX9704 mono/stereo class D audio ♦ Filterless Class D Amplifierpower amplifier ..
MAX9704ETJ+ ,10W Stereo/15W Mono, Filterless, Spread-Spectrum, Class D AmplifiersElectrical Characteristics(V = 15V, AGND = PGND = 0V, SHDN ≥ V , A = 16dB, C = C = 0.47μF, C = 0.01 ..
MAX9704ETJ+T ,10W Stereo/15W Mono, Filterless, Spread-Spectrum, Class D AmplifiersBlock Diagrams0.47µFMAX9704INL+ OUTL+MAX9703H-BRIDGE0.47µFINL- OUTL-0.47µFIN+ OUT+H-BRIDGE0.47µF0.4 ..
MB89163PFV ,8-bit Proprietary MicrocontrollerFUJITSU SEMICONDUCTORDS07-12405-2EDATA SHEET8-bit Proprietary MicrocontrollerCMOS2F MC-8L MB89160/1 ..
MB89165 ,8-bit Proprietary MicrocontrollerFUJITSU SEMICONDUCTORDS07-12405-2EDATA SHEET8-bit Proprietary MicrocontrollerCMOS2F MC-8L MB89160/1 ..
MB89165A ,8-bit Proprietary MicrocontrollerFUJITSU SEMICONDUCTORDS07-12405-2EDATA SHEET8-bit Proprietary MicrocontrollerCMOS2F MC-8L MB89160/1 ..
MB89185 ,F2MC-8L/Low Power/Low Voltage MicrocontrollersFUJITSU SEMICONDUCTORDS07-12404-2EDATA SHEET8-bit Proprietary MicrocontrollerCMOS2F MC-8L MB89180 S ..
MB89191A ,8-bit Proprietary MicrocontrollerFUJITSU SEMICONDUCTORDS07-12512-7EDATA SHEET8-bit Proprietary MicrocontrollerCMOS2F MC-8L MB89190/1 ..
MB89191A ,8-bit Proprietary MicrocontrollerFUJITSU SEMICONDUCTORDS07-12512-7EDATA SHEET8-bit Proprietary MicrocontrollerCMOS2F MC-8L MB89190/1 ..
MAX9702ETI+T
1.8W, Filterless, Stereo, Class D Audio Power Amplifier and DirectDrive Stereo Headphone Amplifier
General DescriptionThe MAX9702 combines a highly efficient Class D
speaker amplifier with a high-linearity Class AB head-
phone amplifier. This ensures maximum battery life in
speaker mode and maximum performance in head-
phone mode. The MAX9702 delivers up to 1.1W per
channel into an 8Ωload and 1.8W into a 4Ωload from a
5V power supply. Maxim’s 2nd-generation, spread-
spectrum modulation scheme renders the traditional
Class D output filter unnecessary.
The MAX9702 speaker amplifier offers two modulation
schemes: a fixed-frequency (FFM) mode and a spread-
spectrum (SSM) mode that reduces EMI-radiated emis-
sions. The MAX9702 speaker amplifier features a fully
differential architecture, full-bridged (BTL) output, and
comprehensive click-and-pop suppression. The
MAX9702 speaker amplifier features high 75dB PSRR,
low 0.07% THD+N, and SNR in excess of 97dB. Short-
circuit and thermal-overload protection prevent the
device from being damaged during a fault condition.
The headphone amplifier uses Maxim’s DirectDriveTM
architecture that produces a ground-referenced output
from a single supply, eliminating the need for large DC-
blocking capacitors, saving cost, board space, and
component height. A high 80dB PSRR and low 0.02%
THD+N ensures clean, low-distortion amplification of
the audio signal.
An I2C interface sets the speaker and headphone gain,
mono, stereo, and mute functions.
The MAX9702 is available in a 28-pin thin QFN-EP (5mm
x 5mm x 0.8mm) package. The MAX9702 is specified
over the extended -40°C to +85°C temperature range.
ApplicationsCellular Phones
Notebook PCs
PDAs
Handheld Gaming Consoles
FeaturesSpread-Spectrum Modulation Reduces EMI
EmissionsProgrammable Mono, Stereo, Mute, and Mix
Functions1.1W Stereo Output (8Ω, VDD= 5V)48mW Headphone Output (32Ω, VDD= 3.3V)1.8W Stereo Output (4Ω, VDD= 5V)94% Efficiency (RL= 8Ω, PO= 1.1W)High 73dB PSRR (f = 217Hz)I2C Programmable Gain Up to +21dBIntegrated Click-and-Pop SuppressionLow-Power Shutdown Mode (0.1µA)Short-Circuit and Thermal-Overload Protection±8kV (HBM) ESD-Protected Headphone Driver
Outputs
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
PARTPIN–PACKAGEI2C SLAVE
ADDRESS
PKG
CODEMAX9702ETI+28 TQFN-EP*1001100T2855-6
MAX9702BETI+28 TQFN-EP*1001110T2855-6
Ordering Information19-3608; Rev 1; 10/05
Note:All devices specified for -40°C to +85°C operating tem-
perature range.
*EP = Exposed paddle.
+ Denotes lead-free package.
Pin Configurations appear at end of data sheet.
EVALUATION KIT
AVAILABLE
Simplified Block DiagramMAX9702
RIGHT MODULATOR
AND H-BRIDGEINR
INM
INL
SHDN
SCL
SDA
C CONTROL
INPUT MUX
GAIN
CONTROL
SYNC_OUTSYNCOSCILLATOR
LEFT MODULATOR
AND H-BRIDGE
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS (VDD= 3.3V)(VDD= PVDD= CPVDD = SHDN= 3.3V, GND = PGND = CPGND = 0V, SYNC = VDD(SSM), speaker gain = +12dB, headphone gain
= +1dB. Speaker load RLconnected between OUT+ and OUT-, unless otherwise noted, RL= ∞. Headphone load RLHconnected
between HPR/HPL to GND. CBIAS= 1µF to GND, 1µF capacitor between C1P and C1N, CVSS= 1µF. TA= TMINto TMAX, unless oth-
erwise 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.
VDDto GND...........................................................................+6V
PVDDto PGND.......................................................................+6V
CPVDDto CPGND..................................................................+6V
CPVSSto VSS......................................................................±0.3V
CPVSSto CPGND.....................................................-6V to +0.3V
VSSto CPGND..........................................................-6V to +0.3V
C1N.......................................(CPVSS- 0.3V) to (CPGND + 0.3V)
C1P.......................................(CPGND - 0.3V) to (CPVDD+ 0.3V)
HP_ to GND............................(CPVSS- 0.3V) to (CPVDD+ 0.3V)
GND to PGND and CPGND................................................±0.3V
VDDto PVDDand CPVDD....................................................±0.3V
SDA, SCL to GND.....................................................-0.3V to +6V
All Other Pins to GND.................................-0.3V to (VDD+ 0.3V)
Continuous Current In/Out of PVDD, PGND,
CPVDD, CPGND, OUT_..............................................±600mA
Continuous Current In/Out of HP_..................................±120mA
Continuous Input Current CPVSS....................................+260mA
Continuous Input Current (all other pins).........................±20mA
Duration of OUT_ Short Circuit to GND or PVDD.........Continuous
Duration of Short Circuit Between OUT__..................Continuous
Duration of HP_ Short Circuit to GND
or PVDD..................................................................Continuous
Continuous Power Dissipation (TA= +70°C)
28-Pin Thin QFN (derate 21.3mW/°C above +70°C)....1702mW
Junction Temperature......................................................+150°C
Operating Temperature Range...........................-40oC to +85°C
Storage Temperature Range.............................-65oC to +150°C
Lead Temperature (soldering, 10s).................................+300°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
GENERALSupply Voltage RangeVDDInferred from PSRR test2.55.5V
HPS = GND, speaker mode1015mAQuiescent CurrentIDDHPS = VDD, headphone mode711mA
Hard shutdown, SHDN = GND0.110Shutdown CurrentISHDNSoft shutdown (see I2C section)2230µA
Stereo left and right16.52431.5Input ResistanceRINMono channel8.41215.6kΩ
Debounced DelaytDEBOUNCEDelay from HPS transition to
headphone/speaker turn-on65ms
HPS = GND (SP mode)85
Turn-On TimetON
Time from SHDN
transition to full
operationHPS = VDD (HP mode)85
Turn-Off TimetOFF0ms
Input Bias VoltageVBIAS1.1251.251.375V
SPEAKER AMPLIFIERS (HPS = GND)TA = +25°C±9±40Output Offset VoltageVOSTMIN to TMAX±50mV
VDD = 2.5V to 5.5V5475
fRIPPLE = 217Hz75Power-Supply Rejection Ratio
(Note 3)PSRR100mVP-P ripple,
VIN = 0V, TA = +25°CfRIPPLE = 20kHz55
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
ELECTRICAL CHARACTERISTICS (VDD= 3.3V) (continued)(VDD= PVDD= CPVDD = SHDN= 3.3V, GND = PGND = CPGND = 0V, SYNC = VDD(SSM), speaker gain = +12dB, headphone gain
= +1dB. Speaker load RLconnected between OUT+ and OUT-, unless otherwise noted, RL= ∞. Headphone load RLHconnected
between HPR/HPL to GND. CBIAS= 1µF to GND, 1µF capacitor between C1P and C1N, CVSS= 1µF. TA= TMINto TMAX, unless oth-
erwise noted. Typical values are at TA= +25°C.) (Notes 1, 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSRL = 8Ω470Output PowerPOUTTHD+N = 1%, TA = +25°C,
f = 1kHz, VDD = 3.3VRL = 4Ω700mW
RL = 8Ω (POUT = 400mW), f = 1kHz0.07Total Harmonic Distortion Plus
NoiseTHD+NRL = 4Ω (POUT = 600mW), f = 1kHz0.13%
FFM86.5BW = 22Hz
to 22kHzSSM87.5
FFM91.5Signal-to-Noise RatioSNR
VOUT =
2VRMS,
RL = 8ΩA-weightedSSM91.5
SYNC = GND100011001200
SYNC = float125013401450Oscillator FrequencyfS
SYNC = VDD1150
±50
kHz
SYNC Frequency Lock RangefSYNC10002000kHz
SYNC_OUT Capacitance DriveCSYNC_OUT100pF
Into shutdown56
Click-and-Pop LevelKCP
Peak voltage, 32
samples/second,
A-weighted (Note 3)Out of shutdown48dB
EfficiencyηPOUT = 2 x 500mW, fIN = 1kHz, RL = 8Ω,
L = 68µH94%
B2 = 0B1 = 0B0 = 00
B2 = 0B1 = 0B0 = 1+3
B2 = 0B1 = 1B0 = 0+6
B2 = 0B1 = 1B0 = 1+9
B2 = 1B1 = 0B0 = 0+12
B2 = 1B1 = 0B0 = 1+15
B2 = 1B1 = 1B0 = 0+18
Gain (see I2C Section)AV
B2 = 1B1 = 1B0 = 1+21
Channel-to-Channel Gain
Tracking±0.2%
CrosstalkL to R, R to L, f = 10kHz, RL = 8Ω,
POUT = 300mW65dB
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
ELECTRICAL CHARACTERISTICS (VDD= 3.3V) (continued)(VDD= PVDD= CPVDD = SHDN= 3.3V, GND = PGND = CPGND = 0V, SYNC = VDD(SSM), speaker gain = +12dB, headphone gain
= +1dB. Speaker load RLconnected between OUT+ and OUT-, unless otherwise noted, RL= ∞. Headphone load RLHconnected
between HPR/HPL to GND. CBIAS= 1µF to GND, 1µF capacitor between C1P and C1N, CVSS= 1µF. TA= TMINto TMAX, unless oth-
erwise noted. Typical values are at TA= +25°C.) (Notes 1, 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
HEADPHONE AMPLIFIERS (HPS = VDD)TA = +25°C±1.8±6Output Offset VoltageVOSTMIN to TMAX±8mV
VDD = 2.5V to 5.5V6675
fRIPPLE = 217Hz73Power-Supply Rejection Ratio
(Note 4)PSRR100mVP-P ripple,
VIN = 0V, TA = +25°CfRIPPLE = 20kHz53
RL = 32Ω48Output PowerPOUTTHD+N = 1%, VDD =
3.3V, TA = +25°CRL = 16Ω47mW
RL = 16Ω (POUT = 40mW, f = 1kHz)0.03Total Harmonic Distortion Plus
NoiseTHD+NRL = 32Ω (POUT = 32mW, f = 1kHz)0.015%
BW = 22Hz to 22kHz95.5Signal-to-Noise RatioSNRVOUT = 1VRMS,
RL = 32ΩA-weighted97.9dB
Charge-Pump FrequencyfCPfOSC/2kHz
Into shutdown65
Click-and-Pop LevelKCP
Peak voltage, 32
samples/second,
A-weighted (Note 3)Out of shutdown85dB
Slew RateSR±1V output step0.3V/µs
B4 = 0B3 = 0-2
B4 = 0B3 = 1+1
B4 = 1B3 = 0+4Gain (see I2C Section)AV
B4 = 1B3 = 1+7
Channel-to-Channel Gain
Tracking±0.2%
Capacitance DriveCLNo sustained oscillations300pF
CrosstalkL to R, R to L, f = 10kHz, RL = 16Ω,
POUT = 10mW70dB
HP_ Resistance to GNDIn speaker mode1kΩ
DIGITAL INPUTS (SHDN, SYNC, SDA, SCL, HPS)Input Voltage High, SHDN,
SYNC, HPSVINH2V
Input Voltage High, SCLVINH0.7 x
VDDV
Input Voltage Low, SHDN, SYNC,
HPSVINL0.8V
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
ELECTRICAL CHARACTERISTICS (VDD= 3.3V) (continued)(VDD= PVDD= CPVDD = SHDN= 3.3V, GND = PGND = CPGND = 0V, SYNC = VDD(SSM), speaker gain = +12dB, headphone gain
= +1dB. Speaker load RLconnected between OUT+ and OUT-, unless otherwise noted, RL= ∞. Headphone load RLHconnected
between HPR/HPL to GND. CBIAS= 1µF to GND, 1µF capacitor between C1P and C1N, CVSS= 1µF. TA= TMINto TMAX, unless oth-
erwise noted. Typical values are at TA= +25°C.) (Notes 1, 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSInput Voltage Low, SDA, SCLVINL0.3 x
VDDV
Input Hysteresis, SDA, SCLVHYS0.05 x
VDDV
Input Capacitance SDA, SCLCIN10pF
Input Leakage Current, SHDN,
SCLIIN±1µA
Input Leakage Current, HPSIIN±10µA
SYNC Input CurrentIn play mode25µA
HPS Pullup Resistance600kΩ
DIGITAL OUTPUTS (SYNC_OUT)Output Voltage HighVOHIOH = 3mA2.4V
Output Voltage LowVOLIOL = 3mA0.4V
Output Fall Time, SDAtF300ns
ELECTRICAL CHARACTERISTICS (VDD= 5V)(VDD= PVDD= CPVDD = SHDN= 5V, GND = PGND = CPGND = 0V, SYNC = VDD(SSM), speaker gain = +12dB, headphone gain =
+1dB. Speaker load RLconnected between OUT+ and OUT-, unless otherwise noted, RL= ∞. Headphone load RLHconnected
between HPR/HPL to GND. CBIAS= 1µF to GND, 1µF capacitor between C1P and C1N, CVSS= 1µF. TA= TMINto TMAX, unless oth-
erwise noted. Typical values are at TA= +25°C.) (Notes 1, 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
GENERALHPS = GND, speaker mode14Quiescent CurrentIDDHPS = VDD, headphone mode8mA
Hard shutdown, SHDN = GND0.2Shutdown CurrentISHDNSoft shutdown (see I2C section)25µA
SPEAKER AMPLIFIERS (HPS = GND)fRIPPLE = 217Hz73Power-Supply Rejection Ratio
(Note 3)PSRR
100mVP-P ripple,
VIN = 0V,
TA = +25°CfRIPPLE = 20kHz50
RL = 8Ω1100
Output PowerPOUT
THD+N = 1%,
TA = +25°C,
f = 1kHz
VDD = 5V
RL = 4Ω1800
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
ELECTRICAL CHARACTERISTICS (VDD= 5V) (continued)(VDD= PVDD= CPVDD = SHDN= 5V, GND = PGND = CPGND = 0V, SYNC = VDD(SSM), speaker gain = +12dB, headphone gain =
+1dB. Speaker load RLconnected between OUT+ and OUT-, unless otherwise noted, RL= ∞. Headphone load RLHconnected
between HPR/HPL to GND. CBIAS= 1µF to GND, 1µF capacitor between C1P and C1N, CVSS= 1µF. TA= TMINto TMAX, unless oth-
erwise noted. Typical values are at TA= +25oC.) (Notes 1, 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSRL = 8Ω (POUT = 900mW), f = 1kHz0.08Total Harmonic Distortion Plus
NoiseTHD+NRL = 4Ω (POUT = 1500mW), f = 1kHz0.18%
FFM88BW = 22Hz
to 22kHzSSM87
FFM91Signal-to-Noise RatioSNRVOUT = 2VRMS,
RL = 8Ω
A-weightedSSM89
Into shutdown61.5
Click-and-Pop LevelKCP
Peak voltage, 32
samples/second,
A-weighted (Note 4)Out of shutdown44
EfficiencyηPOUT = 1W, fIN = 1kHz, RL = 8Ω, L = 68µH95%
Channel-to-Channel Gain
Tracking±0.2%
CrosstalkL to R, R to L, f = 10kHz, RL = 8Ω,
POUT = 300mW65dB
HEADPHONE AMPLIFIERS (HPS = VDD)fRIPPLE = 217Hz78Power-Supply Rejection Ratio
(Note 4)PSRR100mVP-P ripple,
VIN = 0V, TA = +25°CfRIPPLE = 20kHz53dB
Output PowerPOUTTHD+N = 1%, TA = +25°C,
RL = 32Ω45mW
Total Harmonic Distortion Plus
NoiseTHD+NRL = 32Ω (POUT = 32mW, f = 1kHz)0.03%
BW = 22Hz to 22kHz94.7Signal-to-Noise RatioSNRVOUT = 1VRMS,
RL = 32ΩA-weighted97.4dB
Into shutdown67
Click-and-Pop LevelKCP
Peak voltage, 32
samples/second,
A-weighted
(Notes 3, 4)Out of shutdown83
Channel-to-Channel Gain
Tracking±0.2%
CrosstalkL to R, R to L, f = 10kHz, RL = 32Ω,
POUT = 10mW70dB
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier2C TIMING CHARACTERISTICS(VDD= PVDD= CPVDD= SHDN= 3.3V, GND = PGND = CPGND = 0V, SYNC = VDD(SSM), speaker gain = +12dB, headphone gain
= +1dB. Speaker load RLconnected between OUT+ and OUT-, unless otherwise noted. RL= ∞. Headphone load RLHconnected
between HPR/HPL and GND. CBIAS= 1µF to GND, 1µF capacitor between C1P and C1N, CVSS= 1µF. TA= TMINto TMAX, unless
otherwise noted. Typical values are at TA= +25oC.) (Figure9)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSSerial ClockfSCL400kHz
Bus Free Time Between a STOP
and a START ConditiontBUF1.3µs
Hold Time (Repeated) START
ConditiontHD, STA0.6µs
Repeated START Condition
Setup TimetSU, STA0.6µs
STOP Condition Setup TimetSU, STO0.6µs
Data Hold TimetHD,DAT00.9µs
Data Setup TimetSU,DAT100ns
SCL Clock Low PeriodtLOW1.3µs
SCL Clock High PeriodtHIGH0.6µs
Rise Time of SDA and SCL,
ReceivingtR(Note 5)20 +
0.1Cb300ns
Fall Time of SDA and SCL,
ReceivingtF(Note 5)20 +
0.1Cb300ns
Fall Time of SDA, TransmittingtF(Note 5)20 +
0.1Cb250ns
Pulse Width of Spike SuppressedtSP050ns
Capacitive Load for Each Bus
LineCb400pF
Note 1:All devices are 100% production tested at +25°C. All temperature limits are guaranteed by design.
Note 2:Speaker mode testing performed with a resistive load in series with an inductor to simulate an actual speaker load. For RL=
4Ω, L = 34µH, RL= 8Ω, L = 68µH.
Note 3:Amplifier inputs (STEREO/MONO) connected to GND through CIN.
Note 4:Speaker mode testing performed with an 8Ωresistive load in series with a 68µH inductive load connected across BTL out-
put. Headphone mode testing performed with 32Ωresistive load connected to GND. Mode transitions are controlled by
SHDN. KCPlevel is calculated as: 20 x log[(peak voltage under normal operation at rated power level)/(peak voltage during
mode transition, no input signal)]. Units are expressed in dB.
Note 5:Cb= total capacitance of one bus line in pF.
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
Typical Operating Characteristics(VDD= PVDD= SHDN= 3.3V, GND = PGND = 0V, SYNC = VDD(SSM), speaker gain = 12dB.)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY(SPEAKER MODE)MAX9702 toc01
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01100k
OUTPUT POWER = 1.6W
VDD = 5V
RL = 4Ω
OUTPUT POWER = 200mW
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY(SPEAKER MODE)MAX9702 toc02
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01100k
OUTPUT POWER = 800mW
VDD = 5V
RL = 8Ω
OUTPUT POWER = 200mW
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY(SPEAKER MODE)MAX9702 toc03
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01100k
OUTPUT POWER = 400mW
VCC = 3.3V
RL = 4Ω
OUTPUT POWER = 100mW
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY(SPEAKER MODE)MAX9702 toc04
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01100k
OUTPUT POWER = 400mW
VCC = 3.3V
RL = 8Ω
OUTPUT POWER = 100mW
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY(SPEAKER MODE)MAX9702 toc05
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01100k
FFM
SSM
VDD = 5V
RL = 8Ω
POUT = 800mW
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER (SPEAKER MODE)MAX9702 toc06
OUTPUT POWER (W)
THD+N (%)
VDD = 5V
RL = 4Ω
fIN = 20Hz
fIN = 1kHzfIN = 10kHz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER (SPEAKER MODE)MAX9702 toc07
OUTPUT POWER (mW)
THD+N (%)
VDD = 5V
RL = 8Ω
fIN = 20HzfIN = 1kHz
fIN = 10kHz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER (SPEAKER MODE)MAX9702 toc08
OUTPUT POWER (mW)
THD+N (%)
VDD = 3.3V
RL = 4Ω
fIN = 1kHz
fIN = 20Hz
fIN = 10kHz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER (SPEAKER MODE)MAX9702 toc09
OUTPUT POWER (mW)
THD+N (%)
VDD = 3.3V
RL = 8Ω
fIN = 10kHz
fIN = 20Hz
fIN = 1kHz
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER (SPEAKER MODE)MAX9702 toc10
OUTPUT POWER (mW)
THD+N (%)
VDD = 5V
RL = 8Ω
fIN = 1kHz
SSM
FFM
EFFICIENCY vs. OUTPUT POWER
(SPEAKER MODE)MAX9702 toc11
OUTPUT POWER (W)
EFFICIENCY (%)
VDD = 5V
fIN = 1kHz
POUT = POUTL + POUTR
RL = 8Ω
RL = 4Ω
EFFICIENCY vs. OUTPUT POWER
(SPEAKER MODE)MAX9702 toc12
OUTPUT POWER (W)
EFFICIENCY (%)
VDD = 3.3V
fIN = 1kHz
POUT = POUTL + POUTR
RL = 8Ω
RL = 4Ω
OUTPUT POWER vs. SUPPLY VOLTAGEMAX9702 toc13
SUPPLY VOLTAGE (V)
OUTPUT POWER (mW)
THD+N = 1%
RL = 4Ω
fIN = 1kHz
THD+N = 10%
OUTPUT POWER vs. SUPPLY VOLTAGEMAX9702 toc14
SUPPLY VOLTAGE (V)
OUTPUT POWER (mW)
THD+N = 1%
RL = 8Ω
fIN = 1kHz
THD+N = 10%
OUTPUT POWER
vs. LOAD RESISTANCEMAX9702 toc15
LOAD RESISTANCE (Ω)
OUTPUT POWER (W)
THD+N = 10%
VDD = 5V
f = 1kHz
THD+N = 1%
OUTPUT POWER
vs. LOAD RESISTANCEMAX9702 toc16
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
THD+N = 1%
THD+N = 10%
VDD = 3.3V
f = 1kHz
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (SPEAKER MODE)MAX9702 toc17
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-100100k
VRIPPLE = 100mVP-P
RL = 8Ω
VDD = 3.3V
VDD = 5V
CROSSTALK vs. FREQUENCY
(SPEAKER MODE)MAX9702 toc18
FREQUENCY (Hz)
CROSSTALK (dB)
10k1k100
-100100k
VOUT = -30dBV
VDD = 3.3V, 5V
RL = 8Ω
LEFT TO RIGHT
RIGHT TO LEFT
ypical Operating Characteristics (continued)(VDD= PVDD= SHDN= 3.3V, GND = PGND = 0V, SYNC = VDD(SSM), speaker gain = 12dB.)
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifierypical Operating Characteristics (continued)(VDD= PVDD= SHDN= 3.3V, GND = PGND = 0V, SYNC = VDD(SSM), speaker gain = 12dB.)
CROSSTALK vs. AMPLITUDE
(SPEAKER MODE)MAX9702 toc19
AMPLITUDE (dB)
CROSSTALK (dB)
RIGHT TO LEFT
RL = 8Ω
f = 1kHz
LEFT TO RIGHT
OUTPUT FREQUENCY SPECTRUM
(SPEAKER MODE)MAX9702 toc20
FREQUENCY (kHz)
OUTPUT MAGNITUDE (dBV)105
FFM MODE
VOUT = -60dBV
f = 1kHz
RL = 8Ω
UNWEIGHTED
OUTPUT FREQUENCY SPECTRUM
(SPEAKER MODE)MAX9702 toc21
FREQUENCY (kHz)
OUTPUT MAGNITUDE (dBV)105
FFM MODE
VOUT = -60dBV
f = 1kHz
RL = 8Ω
A-WEIGHTED
OUTPUT FREQUENCY SPECTRUM
(SPEAKER MODE)MAX9702 toc22
FREQUENCY (kHz)
OUTPUT MAGNITUDE (dBV)105
SSM MODE
VOUT = -60dBV
f = 1kHz
RL = 8Ω
UNWEIGHTED
OUTPUT FREQUENCY SPECTRUM
(SPEAKER MODE)MAX9702 toc23
FREQUENCY (kHz)
OUTPUT MAGNITUDE (dBV)105
SSM MODE
VOUT = -60dBV
f = 1kHz
RL = 8Ω
A-WEIGHTED
WIDEBAND OUTPUT SPECTRUM
(FFM MODE, SPEAKER MODE)MAX9702 toc24
FREQUENCY (MHz)
OUTPUT AMPLITUDE (dBV)
RBW = 10kHz
INPUT AC GROUNDED
WIDEBAND OUTPUT SPECTRUM
(SSM MODE, SPEAKER MODE)
MAX9702 toc25
FREQUENCY (MHz)
OUTPUT AMPLITUDE (dBV)
RBW = 10kHz
INPUT AC GROUNDED
TURN-ON/TURN-OFF RESPONSE
(SPEAKER MODE)
MAX9702 toc26
20ms/div
SHDN
MAX9702
OUTPUT
f = 1kHz
RL = 8Ω
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(SPEAKER MODE)MAX9702 toc27
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
FFM
SSM
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
SHUTDOWN CURRENT vs. SUPPLY VOLTAGE
(SPEAKER MODE)MAX9702 toc28
SUPPLY VOLTAGE (V)
SHUTDOWN CURRENT (
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY (HEADPHONE MODE)
MAX9702 toc29
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
OUTPUT POWER = 10mW
VDD = 5V
RL = 32Ω
OUTPUT POWER = 30mW
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY (HEADPHONE MODE)MAX9702 toc30
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
OUTPUT POWER = 15mW
OUTPUT POWER = 40mW
VDD = 3.3V
RL = 16Ω
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY (HEADPHONE MODE)MAX9702 toc31
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
OUTPUT POWER = 10mW
OUTPUT POWER = 30mW
VDD = 3.3V
RL = 32Ω
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)MAX9702 toc32
OUTPUT POWER (mW)
THD+N (%)40302010
VDD = 5V
RL = 32Ω
fIN = 1kHzfIN = 10kHz
fIN = 20Hz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)MAX9702 toc33
OUTPUT POWER (mW)
THD+N (%)40302010
VDD = 3.3V
RL = 16Ω
fIN = 1kHz
fIN = 10kHz
fIN = 20Hz
ypical Operating Characteristics (continued)(VDD= PVDD= SHDN= 3.3V, GND = PGND = 0V, SYNC = VDD(SSM), speaker gain = 12dB.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)MAX9702 toc34
OUTPUT POWER (mW)
THD+N (%)40302010
VDD = 3.3V
RL = 32Ω
fIN = 1kHz
fIN = 20Hz
fIN = 10kHz
POWER DISSIPATION vs. OUTPUT POWER
(HEADPHONE MODE)MAX9702 toc35
OUTPUT POWER (mW)
POWER DISSIPATION (mW)
VDD = 5V
RL = 32Ω
POUT = POUTR + POUTL
POWER DISSIPATION vs. OUTPUT POWER
(HEADPHONE MODE)MAX9702 toc36
OUTPUT POWER (mW)
POWER DISSIPATION (mW)
VDD = 3.3V
POUT = POUTR + POUTL
RL = 16Ω
RL = 32Ω
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
OUTPUT POWER vs. SUPPLY VOLTAGE
(HEADPHONE MODE)MAX9702 toc37
SUPPLY VOLTAGE (V)
OUTPUT POWER (mW)
RL = 32Ω
THD+N = 10%
THD+N = 1%
OUTPUT POWER vs. LOAD RESISTANCE
(HEADPHONE MODE)MAX9702 toc38
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
THD+N = 10%
VDD = 5V
f = 1kHz
THD+N = 1%
OUTPUT POWER vs. LOAD RESISTANCE
(HEADPHONE MODE)MAX9702 toc39
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
THD+N = 10%
THD+N = 1%
VDD = 3.3V
f = 1kHz
OUTPUT POWER vs. CHARGE-PUMP
CAPACITANCE (HEADPHONE MODE)MAX9702 toc40
LOAD (Ω)
OUTPUT POWER (mW)402025303550
f = 1kHz
THD+N = 1%
C1 = C2 = 1μF
C1 = C2 = 0.47μF
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (HEADPHONE MODE)MAX9702 toc41
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-100100k
VRIPPLE = 100mVP-P
INPUTS AC GROUNDED
VDD = 3.3V
VDD = 5V
OUTPUT FREQUENCY SPECTRUM
(HEADPHONE MODE)MAX9702 toc42
FREQUENCY (kHz)
OUTPUT MAGNITUDE (dBV)105
VOUT = -60dBV
f = 1kHz
RL = 32Ω
CROSSTALK vs. FREQUENCY
(HEADPHONE MODE)MAX9702 toc43
FREQUENCY (Hz)
CROSSTALK (dB)
10k1k100
-110100k
RL = 32Ω
f = 1kHz
VIN = 100mVP-P
RIGHT TO LEFT
LEFT TO RIGHT
CROSSTALK vs. AMPLITUDE
(HEADPHONE MODE)MAX9702 toc44
AMPLITUDE (dBV)
CROSSTALK (dBV)-10-30-20-40-50
RL = 32Ω
f = 1kHz
LEFT TO RIGHT
RIGHT TO LEFT
TURN-ON/TURN-OFF RESPONSE
(HEADPHONE MODE)MAX9702 toc45
100ms/div
SHDN
MAX9702
OUTPUT
f = 1kHz
RL = 32Ω
Typical Operating Characteristics (continued)(VDD= PVDD= SHDN= 3.3V, GND = PGND = 0V, SYNC = VDD(SSM), speaker gain = 12dB.)
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
Pin Description
PINNAMEFUNCTION1, 22PVDDH-Bridge Power Supply. Connect to VDD and bypass each PVDD with a 0.1µF capacitor to
PGND.SYNC_OUTClock Signal Output. Float SYNC_OUT if not used.SCLI2C Serial Clock. Connect a pullup resistor to VDD (see I2C Interface section).SDAI2C Serial Data. Connect a pullup resistor to VDD (see I2C Interface section).BIASCommon-Mode Voltage. Bypass to GND with a 1µF capacitor.SYNC
Frequency Mode Select:
SYNC = GND: Fixed-frequency mode with fS = 1100kHz.
SYNC = Float: Fixed-frequency mode with fS = 1340kHz.
SYNC = VDD: Spread-spectrum mode with fS = 1150kHz ±50kHz.
SYNC = Clocked: Fixed-frequency mode with fS = external clock frequency.CPVDDCharge-Pump Power Supply. Connect to VDD and bypass to CPGND with a 1µF capacitor.C1PCharge-Pump Flying-Capacitor Positive Terminal. Connect a 1µF capacitor from C1P to C1N.CPGNDCharge-Pump Power Ground. Connect to PGND.C1NCharge-Pump Flying-Capacitor Negative Terminal. Connect a 1µF capacitor from C1N to
C1P.CPVSSCharge-Pump Negative Output. Bypass with a 1µF capacitor to CPGND.VSSHeadphone Amplifier Negative Supply. Connect to CPVSS.HPLLeft-Channel Headphone OutputHPRRight-Channel Headphone OutputVDDAnalog Power Supply. Bypass with a 1µF capacitor to GND.GNDAnalog Ground. Connect to PGND.INRRight-Channel Audio InputINLLeft-Channel Audio InputINMMono Audio InputHPS
Headphone Sense:
HPS = VDD: Headphone mode.
HPS = GND: Speaker mode.SHDNActive-Low Shutdown. Connect to VDD for normal operation.OUTR+Right-Channel Positive Amplifier OutputOUTR-Right-Channel Negative Amplifier Output
25, 26PGNDPower Ground. Connect to GND.OUTL-Left-Channel Negative Amplifier OutputOUTL+Left-Channel Positive Amplifier OutputEP
Exposed Pad. The external pad lowers the package’s thermal impedance by providing a
direct heat conduction path from the die to the printed circuit board. The exposed pad is
internally connected to VSS. Connect the exposed thermal pad to an isolated plane if
possible or to VSS.
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone Amplifier
Detailed DescriptionThe MAX9702 is a 1.8W, filterless, stereo Class D audio
power amplifier and DirectDrivestereo headphone
amplifier. The MAX9702 SSM amplifier features signifi-
cant improvements to switch-mode amplifier technolo-
gy. The MAX9702 offers Class AB performance with
Class D efficiency and minimal board space. The
device offers mix, mute, mono and stereo input modes,
eight selectable gains, and a low-power shutdown
mode—all programmable through an I2C interface.
The MAX9702 stereo headphone amplifier features
Maxim’s DirectDrive architecture, which eliminates the
large output-coupling capacitors required by conven-
tional single-supply headphone amplifiers. A negative
supply (VSS) is created internally by inverting the posi-
tive supply (CPVDD). Powering the amplifiers from
CPVDDand CPVSSincreases the dynamic range of the
amplifiers to almost twice that of other single-supply
amplifiers, increasing the total available output power.
The DirectDrive outputs of the MAX9702 are biased at
GND (see Figure 7). The benefit of this 0V bias is that
the amplifier outputs do not have a DC component,
eliminating the need for large DC-blocking capacitors.
Eliminating the DC-blocking capacitors on the output
saves board space, system cost, and improves fre-
quency response.
The MAX9702 features extensive click-and-pop sup-
pression circuitry on both speaker and headphone
amplifiers to eliminate audible clicks-and-pops on start-
up and shutdown.
The MAX9702 features an input multiplexer/mixer that
allows three different audio sources to be selected or
mixed. An I2C-compatible interface allows serial com-
munication between the MAX9702 and a microcon-
troller. The MAX9702 is available with two different I2C
addresses allowing two MAX9702s to share the same
bus (see Table 2). The internal command register con-
trols the shutdown status of the MAX9702, sets the
maximum gain of the amplifier, and controls the
mono/stereo/mixed/mute MUX inputs (see Table 3).
Class D Speaker AmplifierSpread-spectrum modulation and synchronizable
switching frequency significantly reduce EMI emis-
sions. Comparators monitor the audio inputs and com-
pare the complementary input voltages to a sawtooth
waveform. The comparators trip when the input magni-
tude of the sawtooth exceeds their corresponding input
voltage. Both comparators reset at a fixed time after the
rising edge of the second comparator trip point, gener-
ating a minimum-width pulse (tON(MIN),100ns typ) at
the output of the second comparator (Figure 1). As the
input voltage increases or decreases, the duration of
the pulse at one output increases while the other output
pulse duration remains the same. This causes the net
voltage across the speaker (VOUT+- VOUT-) to change.
The minimum-width pulse helps the device to achieve
high levels of linearity.
Operating Modes
Fixed-Frequency (FFM) ModeThe MAX9702 features two fixed-frequency modes.
Connect SYNC to GND to select a 1.1MHz switching fre-
quency. Float SYNC to select a 1.34MHz switching fre-
quency. The frequency spectrum of the MAX9702
consists of the fundamental switching frequency and its
associated harmonics (see the Wideband FFT graph in
Typical Operating Characteristics). Program the switch-
ing frequency such that the harmonics do not fall within
a sensitive frequency band (Table 1). Audio reproduc-
tion is not affected by changing the switching frequency.
Spread-Spectrum (SSM) ModeThe MAX9702 features a unique spread-spectrum
mode that flattens the wideband spectral components,
improving EMI emissions that may be radiated by the
speaker and cables. This mode is enabled by setting
SYNC = VDD to enable SSM (Table 1). In SSM mode,
the switching frequency varies randomly by ±50kHz
around the center frequency (1.15MHz). The modula-
tion scheme remains the same, but the period of the
sawtooth waveform changes from cycle to cycle
(Figure 2). Instead of a large amount of spectral energy
present at multiples of the switching frequency, the
energy is now spread over a bandwidth that increases
with frequency. Above a few megahertz, the wideband
spectrum looks like white noise for EMI purposes
(Figure 3). A proprietary amplifier topology ensures this
does not corrupt the noise floor in the audio bandwidth.
Table 1. Operating Modes
SYNCMODEGNDFFM with fOSC = 1100kHz
FLOATFFM with fOSC = 1340kHz
VDDSSM with fOSC = 1150kHz ±50kHz
ClockedFFM with fOSC = external clock
frequency
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone AmplifierFigure1. MAX9702 Outputs with an Input Signal Applied
OUT+
OUT-
VIN-
VIN+
VOUT+ - VOUT-
tON(MIN)
tSW
MAX9702
1.8W, Filterless, Stereo, Class D Audio Power
Amplifier and DirectDrive Stereo Headphone AmplifierFigure2. MAX9702 Output with an Input Signal Applied (SSM Mode)
VOUT_+ - VOUT_-
tSWtSWtSWtSW
VIN_-
VIN_+
OUT_+
OUT_-
tON(MIN)
