MAX9706ETX+ ,3-Channel, 2.3W, Filterless Class D Amplifiers with Active CrossoverBlock DiagramMAX9706MAX9707FULL-RANGEAUDIO INTRANSDUCERSFULL-RANGEAUDIO INTRANSDUCERSLOW-FREQUENCYT ..
MAX9708ETN ,20W/40W, Filterless, Spread-Spectrum, Mono/Stereo, Class D AmplifierBlock Diagram22MAX9708SYNCOUT SYNCOUTFS1, FS2 MAX9708FS1, FS2SYNCSYNCRIGHTCHANNELAUDIOCLASS DCLASS ..
MAX9708ETN+ ,20W/40W, Filterless, Spread-Spectrum, Mono/Stereo, Class D AmplifierBlock DiagramMAX9708MAX97082 2SYNCOUT SYNCOUTFS1, FS2 FS1, FS2SYNCSYNCRIGHTCHANNELAUDIOCLASS DCLASS ..
MAX9709ETN , 25W/50W, Filterless, Spread-Spectrum, Stereo/Mono, Class D Amplifier
MAX9709ETN+ ,25W/50W, Filterless, Spread-Spectrum, Stereo/Mono, Class D AmplifierBlock DiagramMAX9709MAX97092 2SYNCOUTSYNCOUTFS1, FS2 FS1, FS2SYNC SYNCRIGHTCHANNELAUDIOCLASS D CLAS ..
MAX970EEE ,Single/Dual/Quad / Micropower / Ultra-Low-Voltage / Rail-to-Rail I/O ComparatorsApplicationsMAX966EUA -40°C to +85°C 8 µMAXMAX967ESA -40°C to +85°C 8 SO_Selector GuideMAX967EUA -4 ..
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 ..
MB89191A ,8-bit Proprietary MicrocontrollerFEATURES • Minimum execution time: 0.95 m s at 4.2 MHz (VCC = 2.7 V) 2•F MC-8L family CPU core•Two ..
MB89191PF ,8-bit Proprietary MicrocontrollerFUJITSU SEMICONDUCTORDS07-12512-7EDATA SHEET8-bit Proprietary MicrocontrollerCMOS2F MC-8L MB89190/1 ..
MB89193 ,8-bit Proprietary MicrocontrollerFUJITSU SEMICONDUCTORDS07-12512-7EDATA SHEET8-bit Proprietary MicrocontrollerCMOS2F MC-8L MB89190/1 ..
MAX9706ETX+
3-Channel, 2.3W, Filterless Class D Amplifiers with Active Crossover
General DescriptionThe MAX9706/MAX9707 combine three high-efficiency
Class D amplifiers with an active crossover to provide
stereo highpass outputs, and a mono lowpass output.
All three channels deliver up to 2.3W at 1% THD+N per
channel into 4Ωwhen operating from a 5V supply.
An internal active filter processes the stereo inputs (left
and right) into stereo highpass and mono lowpass out-
puts. The crossover frequency is pin-selectable to four
different frequencies to accommodate a variety of
speaker configurations. The internal Class D amplifiers
feature low-EMI, spread-spectrum outputs. No output
filters are required.
The MAX9706 features Maxim’s DirectDrive™ headphone
amplifier, providing ground-referenced headphone out-
puts without the need for bulky DC-coupling capacitors.
The headphone outputs are capable of delivering
95mW per channel into 16Ωfrom a 3.3V supply, and
are protected against ESD up to ±8kV.
The MAX9706/MAX9707 feature pin-programmable
gain, synchronization inputs and outputs, and a shut-
down mode that reduces supply current to less than
1µA. All amplifiers feature click-and-pop suppression
circuitry. Both devices are fully specified over the -40°C
to +85°C extended temperature range and are avail-
able in the thermally enhanced 36-pin (6mm x 6mm x
0.8mm) thin QFN package.
Applications
FeaturesTriple Class D Amplifiers Deliver 3 x 2.3W into 4ΩInternal Active Crossover Filter with Adjustable
Crossover FrequencyLow-EMI, Spread-Spectrum ModulationLow 0.02% THD+NHigh PSRR (71dB)DirectDrive Headphone Amplifier (MAX9706)Enhanced Click-and-Pop SuppressionInput and Output Modulator SynchronizationLow-Power Shutdown ModeUp To 90% EfficiencySpace-Saving (6mm x 6mm x 0.8mm) 36-Pin Thin
QFN Package
MAX9706/MAX9707
3-Channel, 2.3W, Filterless Class D Amplifiers
with Active Crossover
Ordering Information19-3681; Rev 0; 12/05
Note:These devices operate over the -40°C to +85°C temper-
ature range.
+Denotes lead-free package.
EVALUATION KIT
AVAILABLE
PARTHP AMPPIN-PACKAGEPKG CODE
MAX9706ETX+Yes36 Thin QFNT3666N-1
MAX9707ETX+No36 Thin QFNT3666N-1
Functional Diagrams and Pin Configurations appear at end
of data sheet.
Block DiagramMAX9706
AUDIO IN
SHDN
FREQUENCY
SELECT
FULL-RANGE
TRANSDUCERS
LOW-FREQUENCY
TRANSDUCER
HEADPHONE
MAX9707
AUDIO IN
SHDN
FREQUENCY
SELECT
FULL-RANGE
TRANSDUCERS
LOW-FREQUENCY
TRANSDUCER
Notebook Audio Solutions
2.1 Speaker Solutions
Desktop PCs
Multimedia Monitors
Portable DVD Players
Table-Top LCD TVs
MAX9706/MAX9707
3-Channel, 2.3W, Filterless Class D Amplifiers
with Active Crossover
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VDD= PVDD= HPVDD= 5V, GND = PGND = CPGND = 0V, SHDN= VDD, GAIN1 = GAIN2 = GND (SPKR = +9dB, HP = 0dB), HPS =
GND, FS0 = FS1 = GND (800Hz), MGAIN = float (-6dB), SYNC_IN = VDD(SSM), speaker load RLconnected between OUT_+ and
OUT_-,unless otherwise noted, RL= ∞. Headphone load RLHconnected between HPR/HPL to GND, RLH= ∞. CBIAS= 1µF to GND,
C1 = 1µF, C2 = 1µF. TA= TMINto TMAX, unless otherwise noted. Typical values at TA= +25°C.) (Note 1)
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, CPGND.........................................-0.3V to +0.3V
CPVSS, VSSto GND..................................................-6V to +0.3V
C1N to GND...........................................(CPVSS- 0.3V) to +0.3V
C1P to GND...........................................-0.3V to (CPVDD+ 0.3V)
HPL, HPR.....................................................................-3V to +3V
All Other Pins to GND.................................-0.3V to (VDD+ 0.3V)
OUT_+, OUT_ -, Short Circuit to GND or PVDD...........Continuous
OUT_+ Short Circuit to OUT_-....................................Continuous
HPR, HPL Short Circuit to GND..................................Continuous
MONO_OUT Short Circuit to GND or VDD....................Continuous
Continuous Current (PVDD, OUT_+, OUT_-, PGND).............1.7A
Continuous Current (MONO_OUT, CPVDD, C1N, C1P,
CPGND, CPVSS, VSS, HPVDD, HPR, HPL)......................0.85A
Continuous Current (all other pins).....................................20mA
Continuous Power Dissipation (TA= +70°C)
Single-Layer Board
36-Pin TQFN (derate 26.3mW/°C above +70°C).......2105mW
Multilayer Board
36-Pin TQFN (derate 35.7mW/°C above +70°C).......2857mW
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
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSSpeaker Amplifier Supply Voltage
RangeVDD, PVDDInferred from PSRR test4.55.5V
Headphone Amplifier Supply
Voltage Range
HPVDD,
CPVDDInferred from PSRR test (MAX9706)3.05.5V
Speaker mode2535Quiescent Supply CurrentIDDHeadphone mode, HPS = VDD (MAX9706)712mA
Shutdown Supply CurrentISHDNSHDN = GND0.53µA
Input ResistanceRIN152535kΩ
Speaker mode87Turn-On Time, Shutdown to Full
OperationHeadphone mode (MAX9706)87ms
SPEAKER AMPLIFIERS (OUTL_, OUTR_, OUTM_)RL = 8Ω, THD+N = 1%1.4Output Power (Note 2)POUTRL = 4Ω, THD+N = 1%2.3W
RL = 8Ω0.06Total Harmonic Distortion Plus
NoiseTHD+N
POUT = 1W,
bandwidth = 22Hz to
22kHz (Note 2)RL = 4Ω0.07
Bandwidth =
22Hz to 22kHz87Signal-to-Noise RatioSNRRL = 8Ω, POUT = 1W
(Note 2)A-weighted92
VDD = PVDD = 4.5V to 5.5V, TA = +25°C5071
f = 2kHz, OUTL_, OUTR_51Power-Supply Rejection RatioPSRR100mVP-P ripple
(Note 3)f = 100Hz, OUTM_65
MAX9706/MAX9707
3-Channel, 2.3W, Filterless Class D Amplifiers
with Active Crossover
ELECTRICAL CHARACTERISTICS (continued)(VDD= PVDD= HPVDD= 5V, GND = PGND = CPGND = 0V, SHDN= VDD, GAIN1 = GAIN2 = GND (SPKR = +9dB, HP = 0dB), HPS =
GND, FS0 = FS1 = GND (800Hz), MGAIN = float (-6dB), SYNC_IN = VDD(SSM), speaker load RLconnected between OUT_+ and
OUT_-,unless otherwise noted, RL= ∞. Headphone load RLHconnected between HPR/HPL to GND, RLH= ∞. CBIAS= 1µF to GND,
C1 = 1µF, C2 = 1µF. TA= TMINto TMAX, unless otherwise noted. Typical values at TA= +25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSGAIN2 = 0GAIN1 = 09
GAIN2 = 0GAIN1 = 110.5
GAIN2 = 1GAIN1 = 012Speaker Path Gain (Note 4)
GAIN2 = 1GAIN1 = 113.5
Channel-to-Channel Gain
Tracking0.3%
MGAIN = GND-4.5
MGAIN = float-6MONO Gain Offset (Note 5)
MGAIN = VDD-7.5
CrosstalkRight to left, left to right, fIN = 10kHz,
POUT = 1W70dB
Maximum Capacitive LoadCLNo sustained oscillations200pF
RL = 8Ω, POUT = 3 x 1W, f = 800Hz90
Efficiencyη
RL = 4Ω, POUT = 3 x 1W, f = 800Hz88
FFM, SYNC_IN = GND95511001270
FFM, SYNC_IN = float114013401540Class D Center FrequencyfOSC
SSM, SYNC_IN = VDD1150
kHz
Class D Spreading BandwidthSSM mode, SYNC_IN = VDD±50kHz
SYNC_IN Frequency Lock Range10001500kHz
Output Offset VoltageVOSOUT_+ to OUT_-14mV
Into shutdown47
Click-and-Pop LevelKCP
Peak voltage,
A-weighted, 32 samples
per second (Note 6)Out of shutdown50
dBV
CROSSOVER FILTERSCutoff Frequency Accuracy(Note 7)±15%
FS0 = 0FS1 = 0800
FS0 = 0FS1 = 11066.7
FS0 = 1FS1 = 01600Crossover FrequencyfXO
FS0 = 1FS1 = 12133.3
Left-to-Right Cutoff Frequency
Tracking±0.5%
MAX9706/MAX9707
3-Channel, 2.3W, Filterless Class D Amplifiers
with Active Crossover
ELECTRICAL CHARACTERISTICS (continued)(VDD= PVDD= HPVDD= 5V, GND = PGND = CPGND = 0V, SHDN= VDD, GAIN1 = GAIN2 = GND (SPKR = +9dB, HP = 0dB), HPS =
GND, FS0 = FS1 = GND (800Hz), MGAIN = float (-6dB), SYNC_IN = VDD(SSM), speaker load RLconnected between OUT_+ and
OUT_-,unless otherwise noted, RL= ∞. Headphone load RLHconnected between HPR/HPL to GND, RLH= ∞. CBIAS= 1µF to GND,
C1 = 1µF, C2 = 1µF. TA= TMINto TMAX, unless otherwise noted. Typical values at TA= +25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
HEADPHONE AMPLIFIERS (MAX9706) (HPS = VDD)RL = 32Ω3550
Output PowerPOUT
HPVDD = 3.3V to 5V,
TA = +25°C, THD+N = 1%
(Notes 2, 7)RL = 16Ω95
RL = 32Ω0.02Total Harmonic Distortion Plus
NoiseTHD+N
VOUT = 1VRMS, f = 1kHz,
bandwidth = 22Hz to
22kHzRL = 16Ω0.04
Bandwidth =
22Hz to 22kHz96Signal-to-Noise RatioSNRVOUT = 1VRMS
A-weighted100
HPVDD = 3V to 5.5V7090
f = 1kHz, 100mVP-P ripple (Note 3)80Power-Supply Rejection RatioPSRR
f = 20kHz, 100mVP-P ripple (Note 3)65
GAIN2 = 00Headphone Path Gain (Note 8)GAIN2 = 13dB
Output Offset VoltageVOSHPHP_ to GND, TA = +25°C±0.7±3mV
CrosstalkHPL to HPR, HPR to HPL, fIN = 1kHz,
POUT = 32mW, RL = 32Ω-60dB
Slew Rate0.5V/µs
Maximum Capacitive LoadCLNo sustained oscillations300pF
HPS Pullup Impedance600kΩ
Debounce Time65ms
Output Impedance in ShutdownHPS = GND or SHDN = GND1.4kΩ
Charge-Pump Switching
FrequencyfCPfOSC / 2kHz
Into shutdown52
Click-and-Pop LevelKCP
Peak voltage,
A-weighted, 32 samples
per second (Note 6)
Out of
shutdown52dBV
LINE-LEVEL MONO OUTPUT (MONO_OUT)MONO_OUT Signal-Path Gain0dB
Output Impedance0.1Ω
Maximum Output LevelRL = 10kΩ1VRMS
Total Harmonic Distortion Plus
NoiseTHD+NVOUT = 1VRMS, fIN = 100Hz, RL = 10kΩ,
bandwidth = 22Hz to 22kHz0.01%
Maximum Capacitive LoadCLNo sustained oscillations200pF
MAX9706/MAX9707
3-Channel, 2.3W, Filterless Class D Amplifiers
with Active Crossover
ELECTRICAL CHARACTERISTICS (continued)(VDD= PVDD= HPVDD= 5V, GND = PGND = CPGND = 0V, SHDN= VDD, GAIN1 = GAIN2 = GND (SPKR = +9dB, HP = 0dB), HPS =
GND, FS0 = FS1 = GND (800Hz), MGAIN = float (-6dB), SYNC_IN = VDD(SSM), speaker load RLconnected between OUT_+ and
OUT_-,unless otherwise noted, RL= ∞. Headphone load RLHconnected between HPR/HPL to GND, RLH= ∞. CBIAS= 1µF to GND,
C1 = 1µF, C2 = 1µF. TA= TMINto TMAX, unless otherwise noted. Typical values at TA= +25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
DIGITAL INPUTS (GAIN1, GAIN2, FS0, FS1, SHDN, SYNC_IN, MGAIN)Input-Voltage HighVINH2V
Input-Voltage LowVINL0.8V
Input Leakage CurrentGAIN1, GAIN2, FS0, FS1, SHDN±1µA
Input CurrentSYNC_IN, MGAIN±50µA
Pullup ImpedanceSYNC_IN, MGAIN200kΩ
DIGITAL OUTPUT (SYNC_OUT)Output-Voltage HighVOHIOH = 1mAVDD x
0.9V
Output-Voltage LowVOLIOL = 1mAVDD x
0.1V
Note 1: All devices are 100% tested at TA= +25°C. Limits over temperature are guaranteed by design.
Note 2:Measured at 2kHz for OUTL_, OUTR_, HPL, and HPR; measured at 100Hz for OUTM_.
Note 3: PSRR is measured with the inputs AC-grounded.
Note 4:Left/right signal-path gain is defined as:
MONO signal-path gain is defined as:
Note 5:MONO gain offset is measured with respect to speaker-path gain.
Note 6: Speaker modetesting performed with an 8Ωresistive load in series with a 68µH inductive load connected across BTL output.
Headphone mode testing performed with a 32Ωresistive load connected between HP_ and GND. Mode transitions are controlled
by SHDN.
Note 7:Headphone-path gain is defined as:
Note 8:Guaranteed by design only.
IN_
OUTMOUTM
INLINR()−()+()
OUTOUT+−()−()
MAX9706/MAX9707
3-Channel, 2.3W, Filterless Class D Amplifiers
with Active Crossoverypical Operating Characteristics—Speaker Mode(VDD= PVDD= HPVDD= 5V, GND = PGND = CPGND = 0V, SHDN= VDD, GAIN1 = GAIN2 = GND (+9dB), FS0 = FS1 = GND (800Hz),
MGAIN = float (-6dB), SYNC_IN = VDD(SSM), 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. = TMINto TMAX, unless otherwise noted. Typical values at TA= +25°C.)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCYMAX9706 toc01
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
VDD = 5V
RL = 4Ω
OUTPUT POWER = 1.5W
OUTM
OUTL AND OUTR
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCYMAX9706 toc02
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
VDD = 5V
RL = 8Ω
OUTPUT POWER = 900mW
OUTL AND OUTR
OUTM
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWERMAX9706 toc03
OUTPUT POWER (W)
THD+N (%)
VDD = 5V
RL = 4Ω
fIN = 200Hz
fIN = 10kHz
fIN = 2kHz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
MAX9706 toc04
OUTPUT POWER (W)
THD+N (%)
VDD = 5V
RL = 8Ω
fIN = 200HzfIN = 10kHz
fIN = 2kHz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
MAX9706 toc05
OUTPUT POWER (W)
THD+N (%)
VDD = 5V
RL = 8Ω
fIN = 1kHz
SYNC_IN = FLOAT
SYNC_IN = VDDSYNC_IN = GND
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWERMAX9706 toc06
OUTPUT POWER (W)
THD+N (%)
VDD = 5V
RL = 8Ω
fIN = 1kHz
SYNC_IN = 2MHz
SYNC_IN = 0.8MHz
SYNC_IN = 1.4MHz
MAX9706/MAX9707
3-Channel, 2.3W, Filterless Class D Amplifiers
with Active Crossover
Typical Operating Characteristics—Speaker Mode (continued)(VDD= PVDD= HPVDD= 5V, GND = PGND = CPGND = 0V, SHDN= VDD, GAIN1 = GAIN2 = GND (+9dB), FS0 = FS1 = GND (800Hz),
MGAIN = float (-6dB), SYNC_IN = VDD(SSM), 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. = TMINto TMAX, unless otherwise noted. Typical values at TA= +25°C.)
OUTPUT POWER
vs. LOAD RESISTANCEMAX9706 toc07
LOAD RESISTANCE (Ω)
OUTPUT POWER (W)
VDD = 5V
f = 1kHz
THD+N = 10%
THD+N = 1%
OUTPUT POWER
vs. SUPPLY VOLTAGEMAX9706 toc08
SUPPLY VOLTAGE (V)
OUTPUT POWER (W)
f = 1kHz
RL = 4ΩTHD+N = 10%
THD+N = 1%
OUTPUT POWER
vs. SUPPLY VOLTAGEMAX9706 toc09
SUPPLY VOLTAGE (V)
OUTPUT POWER (W)
f = 1kHz
RL = 8Ω
THD+N = 10%
THD+N = 1%
EFFICIENCY vs. OUTPUT POWERMAX9706 toc10
OUTPUT POWER (W)
EFFICIENCY (%)321
RL = 4ΩRL = 8Ω
POUT = POUTL + POUTR + POUTM
fIN = 800Hz
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCYMAX9706 toc11
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-120100k
VRIPPLE = 100mVP-P
RL = 8Ω
OUTM
OUTROUTL
OUTPUT FREQUENCY SPECTRUMMAX9706 toc12
FREQUENCY (kHz)
OUTPUT MAGNITUDE (dBV)105
SSM MODE
VOUT = -60dB
f = 1kHz
RL = 8Ω
UNWEIGHTED
MAX9706/MAX9707
3-Channel, 2.3W, Filterless Class D Amplifiers
with Active Crossover
Typical Operating Characteristics—Speaker Mode (continued)(VDD= PVDD= HPVDD= 5V, GND = PGND = CPGND = 0V, SHDN= VDD, GAIN1 = GAIN2 = GND (+9dB), FS0 = FS1 = GND (800Hz),
MGAIN = float (-6dB), SYNC_IN = VDD(SSM), 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. = TMINto TMAX, unless otherwise noted. Typical values at TA= +25°C.)
OUTPUT FREQUENCY SPECTRUMMAX9706 toc13
FREQUENCY (kHz)
OUTPUT MAGNITUDE (dBV)105
SSM MODE
VOUT = -60dB
f = 1kHz
RL = 8Ω
A-WEIGHTED
WIDEBAND OUTPUT SPECTRUM
(FFM MODE)MAX9706 toc14
FREQUENCY (MHz)
OUTPUT AMPLITUDE (dBV)
RBW = 10kHz
INPUT AC-GROUNDED
WIDEBAND OUTPUT SPECTRUM
(SSM MODE)
MAX9706 toc15
FREQUENCY (MHz)
OUTPUT AMPLITUDE (dBV)
RBW = 10kHz
INPUT AC-GROUNDED
TURN-ON/-OFF RESPONSE
MAX9706 toc16
2V/div
200mA/div
20ms/div
AMPLITUDEvs. FREQUENCYMAX9706 toc17
FREQUENCY (Hz)
AMPLITUDE (dBV)
10k1k100
-50100k
fXO = 800Hz
AMPLITUDEvs. FREQUENCYMAX9706 toc18
FREQUENCY (Hz)
AMPLITUDE (dBV)
10k1k100
-50100k
fXO = 2.1kHz
MAX9706/MAX9707
3-Channel, 2.3W, Filterless Class D Amplifiers
with Active Crossover
Typical Operating Characteristics—Headphone Mode(VDD= PVDD= HPVDD= 5V, GND = PGND = CPGND = 0V, SHDN= VDD, GAIN1 = GAIN2 = GND (+9dB), FS0 = FS1 = GND (800Hz),
MGAIN = float (-6dB), SYNC_IN = VDD(SSM), 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. = TMINto TMAX, unless otherwise noted. Typical values at TA= +25°C.)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCYMAX9706 toc19
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
HPVDD = 3.3V
RL = 16Ω
OUTPUT POWER = 25mW
OUTPUT POWER = 75mW
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCYMAX9706 toc20
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
HPVDD = 3.3V
RL = 32Ω
OUTPUT POWER = 10mW
OUTPUT POWER = 35mW
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCYMAX9706 toc21
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
HPVDD = 5V
RL = 16Ω
OUTPUT POWER = 20mW
OUTPUT POWER = 80mW
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCYMAX9706 toc22
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
HPVDD = 5V
RL = 32Ω
OUTPUT POWER = 10mW
OUTPUT POWER = 35mW
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWERMAX9706 toc23
OUTPUT POWER (mW)
THD+N (%)
HPVDD = 3.3V
RL = 16Ω
fIN = 1kHz
fIN = 10kHz
fIN = 200Hz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
MAX9706 toc24
OUTPUT POWER (mW)
THD+N (%)
HPVDD = 3.3V
RL = 32Ω
fIN = 1kHzfIN = 10kHz
fIN = 200Hz
0.0012010070605040
MAX9706/MAX9707
3-Channel, 2.3W, Filterless Class D Amplifiers
with Active Crossover
Typical Operating Characteristics—Headphone Mode (continued)(VDD= PVDD= HPVDD= 5V, GND = PGND = CPGND = 0V, SHDN= VDD, GAIN1 = GAIN2 = GND (+9dB), FS0 = FS1 = GND (800Hz),
MGAIN = float (-6dB), SYNC_IN = VDD(SSM), 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. = TMINto TMAX, unless otherwise noted. Typical values at TA= +25°C.)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWERMAX9706 toc25
OUTPUT POWER (mW)
THD+N (%)
HPVDD = 5V
RL = 16Ω
fIN = 1kHzfIN = 10kHz
fIN = 200Hz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
MAX9706 toc26
OUTPUT POWER (mW)
THD+N (%)
HPVDD = 5V
RL = 32Ω
fIN = 1kHzfIN = 10kHz
fIN = 200Hz
OUTPUT POWER
vs. LOAD RESISTANCE
MAX9706 toc27
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
HPVDD = 3.3V
f = 1kHz
THD+N = 10%
THD+N = 1%
OUTPUT POWER
vs. LOAD RESISTANCEMAX9706 toc28
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
HPVDD = 5V
f = 1kHz
THD+N = 10%
THD+N = 1%
OUTPUT POWER
vs. HEADPHONE SUPPLY VOLTAGEMAX9706 toc29
HPVDD (V)
OUTPUT POWER (mW)
RL = 16Ω
THD+N = 1%
RL = 32Ω
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCYMAX9706 toc30
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-120100k
VRIPPLE ON VDD AND HPVDD = 100mVP-P
INPUTS AC-GROUNDED
LEFT
RIGHT
MAX9706/MAX9707
3-Channel, 2.3W, Filterless Class D Amplifiers
with Active Crossover
Typical Operating Characteristics—Headphone Mode (continued)(VDD= PVDD= HPVDD= 5V, GND = PGND = CPGND = 0V, SHDN= VDD, GAIN1 = GAIN2 = GND (+9dB), FS0 = FS1 = GND (800Hz),
MGAIN = float (-6dB), SYNC_IN = VDD(SSM), 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. = TMINto TMAX, unless otherwise noted. Typical values at TA= +25°C.)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCYMAX9706 toc31
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-120100k
VRIPPLE = 100mVP-P
INPUTS AC-GROUNDED
RIGHT
LEFT
CROSSTALKvs. FREQUENCYMAX9706 toc32
FREQUENCY (Hz)
CROSSTALK (dB)
10k1k100
-80100k
RL = 32Ω
POUT = 32mW
RIGHT TO LEFT
LEFT TO RIGHT
OUTPUT POWER
vs. CHARGE-PUMP CAPACITANCEMAX9706 toc33
LOAD (Ω)
OUTPUT POWER (mW)4020253035
f = 1kHz
THD+N = 1%
C1 = C2 = 0.22μF
C1 = C2 = 0.47μF
C1 = C2 = 1μF
SUPPLY CURRENT
vs. SUPPLY VOLTAGEMAX9706 toc34
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
SUPPLY VOLTAGE = IVDD + IHPVDD
HPS = GND
HPVDD = 3.3V
HPS = VDD
VDD = 5V
OUTPUT FREQUENCY SPECTRUMMAX9706 toc35
FREQUENCY (kHz)
OUTPUT MAGNITUDE (dBV)105
VOUT = -60dBV
f = 1kHz
RL = 32Ω
TURN-ON/-OFF RESPONSEMAX9706 toc36
2V/div
1V/div
100ms/div
MAX9706/MAX9707
3-Channel, 2.3W, Filterless Class D Amplifiers
with Active Crossover
Pin Description
PIN
MAX9706MAX9707NAMEFUNCTION1BIASInternal Bias. Bypass BIAS to GND with a 1µF capacitor.2GNDGround. Star connect to PGND (see the Supply Bypassing, Layout, and Grounding section).VDDMain Power Supply. Connect VDD to a low-noise 5V source. Bypass VDD to GND with a 1µF
capacitor.4SYNC_OUT
Synchronization Clock Output. Connect SYNC_OUT to other Class D amplifiers to maintain
synchronization. SYNC_OUT is a CMOS output proportional to VDD. Float SYNC_OUT, if not
used.
5, 23, 315, 23, 31PGNDPower Ground. PGND is the ground connection for the speaker amplifiers.6OUTL-Left-Speaker Negative Terminal7OUTL+Left-Speaker Positive Terminal
8, 20, 348, 20, 34PVDDOutput Power Supply. PVDD is the power connection for the speaker amplifiers. Connect to
VDD. Bypass each PVDD to its corresponding PGND with a 1µF capacitor.—CPVDDCharge-Pump Positive Supply. Connect CPVDD to HPVDD. Bypass CPVDD to CPGND with a
1µF capacitor.—C1PCharge-Pump Flying Capacitor Positive Terminal. Connect a 1µF capacitor from C1P to C1N.—CPGNDCharge-Pump Ground. Connect to PGND.—C1NCharge-Pump Flying Capacitor Negative Terminal. Connect a 1µF capacitor from C1N to C1P.—CPVSSNegative Supply Charge-Pump Output. Bypass CPVSS to PGND with a 1µF capacitor.
Connect CPVSS to VSS.14SYNC_IN
Frequency Select or External Clock Input. Connect SYNC_IN to GND, VDD, leave floating, or
drive with an externally generated clock to control the switching frequency of the Class D
amplifiers. See Table 1.—HPS
Headphone Sense. HPS is a digital input with a pullup resistor to detect the connection of a
headphone. When HPS is high, the headphone amplifier is enabled and the Class D speaker
amplifiers are disabled. See the Headphone Sense Input (HPS) section.—VSSHeadphone Amplifier Negative Supply. Connect VSS to CPVSS.—HPRRight Headphone Output—HPLLeft Headphone Output—HPVDDPositive Supply for Headphone Amplifiers. Connect HPVDD to VDD. Bypass HPVDD to PGND
with a 0.1µF capacitor.21OUTR+Right-Speaker Positive Terminal22OUTR-Right-Speaker Negative Terminal24SHDNShutdown Input. Drive SHDN low to put the MAX9706/MAX9707 in low-power shutdown mode.
Drive SHDN high or connect to VDD to enable normal operation.25FS026FS1
Crossover Frequency Select. Connect FS0 and FS1 to GND or VDD to set the crossover
frequency. See Table 4.
MAX9706/MAX9707
3-Channel, 2.3W, Filterless Class D Amplifiers
with Active Crossover
Detailed DescriptionThe MAX9706/MAX9707 combine three high-efficiency
Class D amplifiers with an active crossover to provide
stereo highpass outputs, and a mono lowpass output
(Figure 1). All three channels deliver up to 2.3W per
channel into 4Ωwhen operating from a 5V supply.
An internal active filter processes the stereo inputs (left
and right) into stereo highpass and mono lowpass out-
puts. The crossover frequency is pin-selectable to four
different frequencies to accommodate a variety of
speaker configurations.
The internal Class D amplifiers feature low-EMI, spread-
spectrum outputs. No output filters are required.
The MAX9706 features Maxim’s DirectDrive headphone
amplifier, providing ground-referenced headphone out-
puts without the need for bulky coupling capacitors.
The headphone outputs are capable of delivering
95mW per channel into 16Ωfrom a 3.3V supply, and
are protected against ESD up to ±8kV.
Pin Description (continued)
PIN
MAX9706MAX9707NAMEFUNCTION27INRRight-Channel Audio Input. Connect the right-channel audio signal to INR with a series
capacitor. INR has a 25kΩ typical input impedance.28MGAINMono Gain Control. Connect MGAIN to GND, VDD, or leave floating to set the gain of the
MONO channel with respect to the left and right channels. See Table 3.29GAIN2Amplifier Gain-Control Input. Connect GAIN1 and GAIN2 to GND or VDD to set the gain of the
left and right channels. See Tables 2 and 4.30GAIN1Amplifier Gain-Control Input. Connect GAIN1 and GAIN2 to GND or VDD to set the gain of the
left and right channels. See Tables 2 and 4.32OUTM-Mono-Speaker Negative Terminal33OUTM+Mono-Speaker Positive Terminal35MONO_OUTMono Line-Level Output. MONO_OUT is the monaural output of the summed left and right low-
frequency signals.36INLLeft-Channel Audio Input. Connect the left-channel audio signal to INL with a series capacitor.
INL has a 25kΩ typical input impedance.9–13,
16–19N.C.No Connection. Not internally connected.15I.C.Internally Connected. Connect to GND.EPEP
Exposed Pad. The external pad lowers the package’s thermal impedance by providing a
direct heat conduction path from the die to the PC board. The exposed pad is not internally
connected. Connect the exposed pad to GND.
MAX9706
MAX9707
LEFT IN
CLASS D
AMPLIFIER
CLASS D
AMPLIFIER
CLASS D
AMPLIFIER
HPF
LPF
HPF
RIGHT IN
Figure 1. Speaker Arrangement
