MAX9770ETI+T ,1.2W, Low-EMI, Filterless, Mono Class D Amplifier with Stereo DirectDrive Headphone Amplifiersfeatures THD+N as low as 0.025%, high 70dB PackagesPSRR, and SNR in excess of 90dB.The headphone am ..
MAX9776ETJ+ ,2 x 1.5W, Stereo Class D Audio Subsystem with DirectDrive Headphone AmplifierELECTRICAL CHARACTERISTICS2(V = PV = CPV = 3.3V, V = V = V = 0V, SHDN = V , I C settings (INA gain ..
MAX977EEE ,Single/Dual / +3V/+5V Dual-Speed Comparators with Auto-StandbyELECTRICAL CHARACTERISTICS(V = +2.7V to +5.25V, specifications are for high-speed mode, T = -40°C t ..
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MAX9788ETI+ ,14VP-P, Class G Ceramic Speaker Driverfeatures a mono Class G power amplifier♦ Integrated Charge-Pump Power Supply—Nowith an integrated i ..
MAX9788EWP+TG45 ,14VP-P, Class G Ceramic Speaker DriverBlock Diagram2.7V TO 5.5VV CPVCC DDFB+MAX9788RFB+CINRIN+IN+ OUT+CLASS G+OUTPUTIN- OUT-STAGE-RC IN-I ..
MB89475 ,F2MC-8L/Low Power/Low Voltage Microcontrollersapplications forconsumer product.2* : F MC stands for FUJITSU Flexible Microcontroller.n
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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
MAX9770ETI+-MAX9770ETI+T
1.2W, Low-EMI, Filterless, Mono Class D Amplifier with Stereo DirectDrive Headphone Amplifiers
General DescriptionThe MAX9770 combines a mono, filterless, Class D
speaker amplifier and stereo DirectDrive® headphone
amplifier in a single device. The MAX9770 operates
from a single 2.5V to 5.5V supply and includes features
that reduce external component count, system cost,
board space, and offer improved audio reproduction.
The speaker amplifier makes use of Maxim’s Class D
architecture, providing Class AB performance with Class
D efficiency, conserving board space, and extending
battery life. The speaker amplifier delivers 1.2W into anload while offering efficiencies above 85%. A spread-
spectrum modulation scheme reduces radiated emis-
sions caused by the modulation frequency. Furthermore,
the MAX9770 oscillator can be synchronized to an exter-
nal clock through the SYNC input, avoiding possible
problem frequencies inside a system. The speaker
amplifier features THD+N as low as 0.025%, high 70dB
PSRR, and SNR in excess of 90dB.
The headphone amplifiers feature Maxim’s DirectDrive
architecture that produces a ground-referenced output
from a single supply, eliminating the need for large DC-
blocking capacitors. The headphone amplifiers deliver up
to 80mW into a 16Ωload, feature low 0.015% THD+N,
high 85dB PSRR, and ±8kV ESD-protected outputs. A
headphone sense input detects the presence of a head-
phone, and automatically configures the amplifiers for
either speaker or headphone mode.
The MAX9770 includes internally set, logic-selectable
gain, and a comprehensive input multiplexer/mixer, allow-
ing multiple audio sources to be selected and for true
mono reproduction of a stereo source in speaker mode.
Industry-leading click-and-pop suppression eliminates
audible transients during power and shutdown cycles. A
low-power shutdown mode decreases supply current
consumption to 0.1µA, further extending battery life.
The MAX9770 is offered in space-saving, thermally effi-
cient 28-pin TQFN (5mm x 5mm x 0.8mm) and 28-pin
TSSOP packages. The MAX9770 features thermal-over-
load and output short-circuit protection, and is speci-
fied over the extended -40°C to +85°C temperature
range.
ApplicationsCellular Phones
Compact Notebooks
PDAs
Features1.2W Filterless Class D Amplifiers Pass FCC
Class B Radiated EMI Standards with 100mm
of CableSpread-Spectrum Mode Offers 5dB EMI
Improvement over Conventional Methods80mW DirectDrive Headphone Amplifier
Eliminates Bulky DC-Blocking CapacitorsHigh 85dB PSRR at 217Hz85% EfficiencyLow 0.015% THD+NIndustry-Leading Click-and-Pop SuppressionIntegrated 3-Way Input Mixer/Multiplexer
(MAX9770)Logic-Adjustable GainShort-Circuit and Thermal ProtectionAvailable in Space-Saving, Thermally Efficient
Packages
MAX9770
1.2W, Low-EMI, Filterless, Mono Class D Amplifier
with Stereo DirectDrive Headphone AmplifiersSPKR
(MONO)
MAX9770
CLASS
VDD
DirectDrive
STEREO
HEADPHONEIN1L
IN2L
IN1R
IN2R
MONO
GAIN SEL
INPUT SEL
MUTE
SHDN
HPS
PARTPIN-PACKAGESELECTABLE INPUTSMAX9770ETI+28 TQFN-EP*2 stereo, 1 mono
MAX9770EUI28 TSSOP2 stereo, 1 mono
Ordering Information
Simplified Block Diagram19-3134; Rev 2; 4/08
Note:All devices specified over the -40°C to +85°C operating
temperature range.
*EP = Exposed pad.Denotes a lead-free package.
EVALUATION KIT
AVAILABLE
Pin Configuration appears at end of data sheet.
MAX9770
1.2W, Low-EMI, Filterless, Mono Class D Amplifier
with Stereo DirectDrive Headphone Amplifiers
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VDD= PVDD= CPVDD= 3.3V, GND = PGND = CPGND = 0V, SHDN=3.3V, C1 = C2 = 1µF, CBIAS= 0.047µF, SYNC = GND, RL= ∞,
speaker load connected between OUT+ and OUT-, headphone load connected between HPOUT_ and GND, 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.
GND to PGND to CPGND......................................-0.3V to +0.3V
VDDto PVDDto CPVDD..........................................-0.3V to +0.3V
VDDto GND...........................................................................+6V
PVDDto PGND.......................................................................+6V
CPVDDto CPGND..................................................................+6V
CPVSSto CPGND....................................................................-6V
SVSSto GND...........................................................................-6V
C1N..........................................(PVSS- 0.3V) to (CPGND + 0.3V)
HPOUT_ to GND....................................................................±3V
All Other Pins to GND.................................-0.3V to (VDD+ 0.3V)
Continuous Current Into/Out of:
PVDD, PGND, OUT_......................................................600mA
PVSS..............................................................................260mA
Duration of HPOUT_ Short Circuit to VDD, PVDD,
GND, PGND...........................................................Continuous
Duration of Short Circuit Between
HPOUTL and HPOUTR..........................................Continuous
Duration of OUT_ Short Circuit to VDD, PVDD, GND, PGND..10s
Duration of Short Circuit Between OUT+ and OUT-...............10s
Continuous Power Dissipation (TA= +70°C)
28-Pin TQFN (derate 20.8mW/°C above +70°C).......1667mW
28-Pin TSSOP (derate 12.8mW°C above +70°C)......1026mW
Junction Temperature......................................................+150°C
Operating Temperature Range...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
GENERALSupply Voltage RangeVDDInferred from PSRR test2.55.5V
Headphone mode5.510Quiescent Supply CurrentIDDNo loadSpeaker mode5.27.5mA
Shutdown Supply CurrentISHDNSHDN = HPS = GND0.110µA
Shutdown to Full OperationtON50ms
MONO710Input ImpedanceRIN(Note 3)INL_, INR_1420kΩ
Bias VoltageVBIAS1.11.251.4V
FeedthroughFrom any unselected input to any output,
f = 10kHz70dB
SPEAKER AMPLIFIER (GAIN1 = GAIN2 = VDD, HPS = GND)Output Offset VoltageVOS±15±70mV
VDD = 2.5V to 5.5V,
TA = +25°C5070
VRIPPLE = 200mVP-P, f = 217Hz70
VRIPPLE = 200mVP-P, f = 1kHz68
Power-Supply Rejection RatioPSRR(Note 4)
VRIPPLE = 200mVP-P, f = 20kHz50
RL = 8Ω550VDD = 3.3VRL = 4Ω900Output PowerPOUT
f = 1kHz,
THD+N = 1%,
GAIN1 = 1,
GAIN2 = 0VDD = 5VRL = 8Ω1200
MAX9770
1.2W, Low-EMI, Filterless, Mono Class D Amplifier
with Stereo DirectDrive Headphone Amplifiers
ELECTRICAL CHARACTERISTICS (continued)(VDD= PVDD= CPVDD= 3.3V, GND = PGND = CPGND = 0V, SHDN= 3.3V, C1 = C2 = 1µF, CBIAS= 0.047µF, SYNC = GND, RL= ∞,
speaker load connected between OUT+ and OUT-, headphone load connected between HPOUT_ and GND, TA= TMINto TMAX,
unless otherwise noted. Typical values are at TA= +25°C.) (Notes 1, 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSRL = 8Ω, POUT = 300mW, f = 1kHz0.025
RL = 4Ω, POUT = 300mW, f = 1kHz0.03Total Harmonic Distortion Plus
NoiseTHD+N
RL = 8Ω, POUT = 500mW,
f = 1kHz0.1
Signal-to-Noise RatioSNRRL = 8Ω, VOUT = 2VRMS, A-weighted85.9dB
SYNC = GND98011001220
SYNC = unconnected128014501620Output Switching FrequencyfS
SYNC = VDD1220
±120kHz
kHz
SYNC Frequency Lock Range8002000kHz
EfficiencyηPO = 1000mW, f = 1kHz85%
GAIN1 = 0, GAIN2 = 06
GAIN1 = 0, GAIN2 = 13
GAIN1 = 1, GAIN2 = 09Gain (MAX9770)AV
GAIN1 = 1, GAIN2 = 10
Gain Accuracy±5%
Speaker Path Off-IsolationHPS = VDD, headphone amplifier active,
f = 1kHz102dB
Into shutdown-76
Out of shutdown-55
Into mute-83Click-and-Pop LevelKCP
Peak voltage,
A-weighted, 32
samples per second
(Notes 4, 5)Out of mute-69
HEADPHONE AMPLIFIER (GAIN1 = 1, GAIN2 = 0, HPS = VDD)Output Offset VoltageVOS±5±10mV
VDD = 2.5V to 5.5V, TA = +25°C6576
VRIPPLE = 200mVP-P, f = 217Hz75
VRIPPLE = 200mVP-P, f = 1kHz82Power-Supply Rejection RatioPSRR(Note 4)
VRIPPLE = 200mVP-P, f = 20kHz56
RL = 32Ω4055VDD = 3.3VRL = 16Ω40
RL = 32Ω60Output PowerPOUT
TA = +25°C,
f = 1kHz,
THD+N = 1%
(Note 3)VDD = 5VRL = 16Ω80
RL = 32Ω, POUT = 50mW, f = 1kHz0.015Total Harmonic Distortion Plus
NoiseTHD+NRL = 16Ω, POUT = 35mW, f = 1kHz0.03%
MAX9770
1.2W, Low-EMI, Filterless, Mono Class D Amplifier
with Stereo DirectDrive Headphone Amplifiers
ELECTRICAL CHARACTERISTICS (continued)(VDD= PVDD= CPVDD= 3.3V, GND = PGND = CPGND = 0V, SHDN= 3.3V, C1 = C2 = 1µF, CBIAS= 0.047µF, SYNC = GND, RL= ∞,
speaker load connected between OUT+ and OUT-, headphone load connected between HPOUT_ and GND, TA= TMINto TMAX,
unless otherwise noted. Typical values are at TA= +25°C.) (Notes 1, 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSSignal-to-Noise RatioSNRRL = 32Ω, VOUT = 300mVRMS,
BW = 22Hz to 22kHz101dB
CrosstalkBetween channels, f = 1kHz,
VIN = 200mVP-P80dB
Headphone Off-IsolationHPS = GND, speaker amplifier active,
f = 1kHz96dB
Into shutdown-58
Out of shutdown-53
Into mute-92Click-and-Pop LevelKCP
Peak voltage, A-
weighted, 32
samples per second
(Notes 4, 5)Out of mute-73
dBV
Capacitive-Load DriveCL1000pF
GAIN1 = 0, GAIN2 = 07
GAIN1 = 0, GAIN2 = 14
GAIN1 = 1, GAIN2 = 0-2GainAV
GAIN1 = 1, GAIN2 = 11
Gain Accuracy±2.5%
ESD ProtectionHPOUTR, HPOUTL, IEC Air Discharge±8kV
DIGITAL INPUTS (SHDN, SYNC, HPS, GAIN_, SEL_)Input Voltage HighVIH2V
Input Voltage LowVIL0.8V
SYNC input±25Input Leakage Current (Note 6)All other logic inputs±1µA
HPS Input CurrentHPS = GND-10µA
Note 1:All devices are 100% production tested at +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 = 47µH. For RL= 8Ω, L = 68µH.
Note 3:Guaranteed by design, not production tested.
Note 4:Inputs AC-coupled to GND.
Note 5:Speaker mode testing 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 to GND. Mode transitions are controlled by SHDN. KCP
level is calculated as: 20 x log [(peak voltage during mode transition, no input signal)/(peak voltage under normal operation at
rated power level)]. Units are expressed in dB. Measured with VDD= 5V.
Note 6:SYNC has a 200kΩresistor to VREF= 1.25V.
MAX9770
1.2W, Low-EMI, Filterless, Mono Class D Amplifier
with Stereo DirectDrive Headphone Amplifiers
Typical Operating Characteristics(VDD= 3.3V, BW = 22Hz to 22kHz, GAIN1 = 1, GAIN2 = 0, spread-spectrum mode, headphone outputs in phase, unless otherwise
noted.)
0.00110010k100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)MAX9770 toc01
FREQUENCY (Hz)
THD+N (%)
VDD = +5V
RL = 4Ω
POUT = 25mW
POUT = 1000mW
0.00110010k100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)MAX9770 toc02
FREQUENCY (Hz)
THD+N (%)
RL = 4Ω
POUT = 100mW
POUT = 500mW
0.00110010k100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)MAX9770 toc03
FREQUENCY (Hz)
THD+N (%)
RL = 8Ω
POUT = 40mW
POUT = 400mW
0.00110010k100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)MAX9770 toc04
FREQUENCY (Hz)
THD+N (%)
VDD = 5V
POUT = 1W
RL = 8Ω
SSM MODE
FFM MODE
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)
MAX9770 toc05
OUTPUT POWER (mW)
THD+N (%)
VDD = 5V
RL = 8Ω
f = 20Hz
f = 1kHz
f = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)
MAX9770 toc06
OUTPUT POWER (mW)
THD+N (%)f = 20Hzf = 1kHz
f = 10kHz
RL = 4Ω
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)
MAX9770 toc07
OUTPUT POWER (mW)
THD+N (%)
RL = 8Ω
f = 20Hz
f = 1kHz
f = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)
MAX9770 toc08
OUTPUT POWER (mW)
THD+N (%)
VDD = 5V
f = 1kHz
RL = 8Ω
SSM MODE
FFM MODE
OUTPUT POWER
vs. LOAD RESISTANCE (SPEAKER MODE)
MAX9770 toc09
LOAD RESISTANCE (Ω)
OUTPUT POWER (W)
VDD = 5V
f = 1kHz
THD+N = 10%
THD+N = 1%
MAX9770
1.2W, Low-EMI, Filterless, Mono Class D Amplifier
with Stereo DirectDrive Headphone Amplifiersypical Operating Characteristics (continued)(VDD= 3.3V, BW = 22Hz to 22kHz, GAIN1 = 1, GAIN2 = 0, spread-spectrum mode, headphone outputs in phase, unless otherwise
noted.)
OUTPUT POWER
vs. LOAD RESISTANCE (SPEAKER MODE)
MAX9770 toc10
LOAD RESISTANCE (Ω)
OUTPUT POWER (W)
f = 1kHz
THD+N = 10%
THD+N = 1%
OUTPUT POWER
vs. SUPPLY VOLTAGE (SPEAKER MODE)
MAX9770 toc11
SUPPLY VOLTAGE (V)
OUTPUT POWER (W)
f = 1kHz
RL = 8Ω
THD+N = 10%
THD+N = 1%
EFFICIENCY vs. OUTPUT POWER
MAX9770 toc12
OUTPUT POWER (W)
EFFICIENCY (%)
VDD = 5V
f = 1kHz
RL = 8Ω
EFFICIENCY vs. OUTPUT POWER
MAX9770 toc13
OUTPUT POWER (W)
EFFICIENCY (%)
RL = 8Ω
RL = 4Ω
f = 1kHz
-801k10k100100k
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (SPEAKER MODE)MAX9770 toc14
FREQUENCY (Hz)
PSRR (dB)
VRIPPLE = 200mVP-P
RL = 8Ω
OUTPUT SPECTRUM
(SPEAKER MODE)
MAX9770 toc15
FREQUENCY (kHz)
MAGNITUDE (dB)101520
RL = 8Ω
f = 1kHz
FFM MODE
VIN = -60dBV
OUTPUT SPECTRUM
(SPEAKER MODE)
MAX9770 toc16
MAGNITUDE (dB)101520
RL = 8Ω
f = 1kHz
SSM MODE
VIN = -60dBV
OUTPUT SPECTRUM
(SPEAKER MODE)
MAX9770 toc17
MAGNITUDE (dB)101520
RL = 8Ω
f = 1kHz
SSM MODE
A-WEIGHTED
VIN = -60dBV
-6010M100M
WIDEBAND OUTPUT SPECTRUM
(SPEAKER MODE)MAX9770 toc18
MAGNITUDE (dBV)
-50FFM MODE
RBW = 10kHz
MAX9770
1.2W, Low-EMI, Filterless, Mono Class D Amplifier
with Stereo DirectDrive Headphone Amplifiersypical Operating Characteristics (continued)(VDD= 3.3V, BW = 22Hz to 22kHz, GAIN1 = 1, GAIN2 = 0, spread-spectrum mode, headphone outputs in phase, unless otherwise
noted.)10M100M
WIDEBAND OUTPUT SPECTRUM
(SPEAKER MODE)MAX9770 toc19
FREQUENCY (Hz)
SSM MODE
RBW = 10kHz
MAGNITUDE (dBV)
STARTUP WAVEFORM
(SPEAKER MODE)
MAX9770 toc20
4ms/div
SHDN
2V/div
OUT+ - OUT-
500mV/div
RL = 8Ω
f = 1kHz
MIXER OUTPUT (SPEAKER MODE)MAX9770 toc21
400μs/div
10kHz
1V/div
4kHz
1V/div
1kHz
2V/div
IN1_
IN2_
MONO
OUT1V/div
0.00110010k100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)MAX9770 toc22
FREQUENCY (Hz)
THD+N (%)
POUT = 10mW
POUT = 50mW
VDD = 5V
RL = 16Ω
0.00110010k100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)MAX9770 toc23
FREQUENCY (Hz)
THD+N (%)
POUT = 10mW
POUT = 50mW
VDD = 5V
RL = 32Ω
0.00110010k100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)MAX9770 toc24
FREQUENCY (Hz)
THD+N (%)
POUT = 10mW
POUT = 35mW
RL = 16Ω
0.00110010k100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)MAX9770 toc25
FREQUENCY (Hz)
THD+N (%)
POUT = 10mW
POUT = 50mW
RL = 32Ω
MAX9770
1.2W, Low-EMI, Filterless, Mono Class D Amplifier
with Stereo DirectDrive Headphone Amplifiersypical Operating Characteristics (continued)(VDD= 3.3V, BW = 22Hz to 22kHz, GAIN1 = 1, GAIN2 = 0, spread-spectrum mode, headphone outputs in phase, unless otherwise
noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
MAX9770 toc28
OUTPUT POWER (mW)
THD+N (%)
RL = 16Ω
f = 1kHz
f = 10kHz
f = 20Hz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
MAX9770 toc29
OUTPUT POWER (mW)
THD+N (%)
f = 20Hz
RL = 32Ω
f = 1kHz
f = 10kHz
OUTPUT POWER
vs. LOAD RESISTANCE (HEADPHONE MODE)
MAX9770 toc30
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
VDD = 5V
f = 1kHz
THD+N = 10%
THD+N = 1%1001000
OUTPUT POWER
vs. LOAD RESISTANCE (HEADPHONE MODE)MAX9770 toc31
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
f = 1kHz
THD+N = 10%
THD+N = 1%
OUTPUT POWER
vs. SUPPLY VOLTAGE (HEADPHONE MODE)
MAX9770 toc32
SUPPLY VOLTAGE (V)
OUTPUT POWER (mW)
RL = 16Ω
f = 1kHz
THD+N = 10%
THD+N = 1%
OUTPUT POWER
vs. SUPPLY VOLTAGE (HEADPHONE MODE)
MAX9770 toc33
OUTPUT POWER (mW)
RL = 32Ω
f = 1kHzTHD+N = 10%
THD+N = 1%
POWER DISSIPATION
vs. OUTPUT POWER (HEADPHONE MODE)
MAX9770 toc34
POWER DISSIPATION (mW)
f = 1kHz
POUT = POUTL + POUTR
RL = 16Ω
RL = 32Ω
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
MAX9770 toc26
OUTPUT POWER (mW)
THD+N (%)
VDD = 5V
RL = 16Ω
f = 1kHz
f = 20Hz
f = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
MAX9770 toc27
OUTPUT POWER (mW)
THD+N (%)
f = 20Hz
VDD = 5V
RL = 32Ω
f = 1kHz
f = 10kHz
MAX9770
1.2W, Low-EMI, Filterless, Mono Class D Amplifier
with Stereo DirectDrive Headphone Amplifiersypical Operating Characteristics (continued)(VDD= 3.3V, BW = 22Hz to 22kHz, GAIN1 = 1, GAIN2 = 0, spread-spectrum mode, headphone outputs in phase, unless otherwise
noted.)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (HEADPHONE MODE)MAX9770 toc35
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-100100k
VDD = 3.3V
VRIPPLE = 200mVP-P
RL = 32Ω
MAX9770
CBIAS = 0.047μF
-1001001k10k100k
CROSSTALK vs. FREQUENCY
(HEADPHONE MODE)MAX9770 toc36
FREQUENCY (Hz)
CROSSTALK (dB)-60
-10RL = 32Ω
f = 1kHz
VIN = 200mVP-P
LEFT TO RIGHT
RIGHT TO LEFT
-1001001k10k100k
FEEDTHROUGH vs. FREQUENCYMAX9770 toc37
FREQUENCY (Hz)
FEEDTHROUGH (dB)
-10SEL1 = 0
SEL2 = 1
IN1_ = GND
IN2_ = DRIVEN
VIN = 2VP-P
HEADPHONE MODE
SPEAKER MODE304050
OUTPUT POWER vs. CHARGE-PUMP CAPACITANCE
AND LOAD RESISTANCEMAX9770 toc38
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
C1 = C2 = 1μF
C1 = C2 = 0.47μF
f = 1kHz
THD+N = 1%-140
OUTPUT SPECTRUM
(HEADPHONE MODE)
MAX9770 toc39
FREQUENCY (kHz)
MAGNITUDE (dB)5101520
RL = 32Ω
f = 1kHz
VIN = -60dBV
EXITING SHUTDOWN
(HEADPHONE MODE)MAX9770 toc40
2μs/div
SHDN
2V/div
OUT_
10mV/div
RL = 32Ω
ENTERING SHUTDOWN
(HEADPHONE MODE)MAX9770 toc41
2μs/div
SHDN
2V/div
OUT_
10mV/div
RL = 32Ω
SUPPLY CURRENT
vs. SUPPLY VOLTAGEMAX9770 toc42
SUPPLY CURRENT (mA)
SPEAKER MODE
HEADPHONE MODE
SHUTDOWN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX9770 toc43
SUPPLY CURRENT (
2.54.53.55.5
MAX9770
1.2W, Low-EMI, Filterless, Mono Class D Amplifier
with Stereo DirectDrive Headphone Amplifiers
PIN
TQFN-EPTSSOPNAMEFUNCTION4BIASCommon-Mode Bias Voltage. Bypass with a 0.047µF capacitor to GND.VDDPower Supply6HPOUTRRight-Channel Headphone Output7HPOUTLLeft-Channel Headphone OutputSVSSHeadphone Amplifier Negative Power Supply9HPSHeadphone Sense Input10CPVDDPositive Charge-Pump Power Supply11CPVSSCharge-Pump Output. Connect to SVSS.12C1NCharge-Pump Flying Capacitor Negative Terminal13C1PCharge-Pump Flying Capacitor Positive Terminal14CPGNDCharge-Pump Ground15SEL1Select Stereo Channel 1 Inputs. Digital input. Drive SEL1 high to select inputs IN1L and
IN1R.16SEL2Select Stereo Channel 2 Inputs. Digital input. Drive SEL2 high to select inputs IN2L and
IN2R.17SELMSelect Mono Channel Input. Digital input. Drive SELM high to select the MONO input.18SHDNShutdown. Drive SHDN low to disable the device. Connect SHDN to VDD for normal
operation.19SYNC
Frequency Select and External Clock Input:
SYNC = GND: fixed-frequency PWM mode with fS = 1100kHz.
SYNC = Unconnected: fixed-frequency PWM mode with fS = 1450kHz.
SYNC = VDD: spread-spectrum PWM mode with fS = 1220kHz ±120kHz.
SYNC = Clocked: fixed-frequency PWM mode with fS = external clock frequency.20PGNDSpeaker Amplifier Power Ground21OUT+Speaker Amplifier Positive Output22OUT-Speaker Amplifier Negative Output23PVDDSpeaker Amplifier Power Supply24GAIN2Gain Control Input 225GAIN1Gain Control Input 126MONOMono Channel Input27IN2LStereo Channel 2, Left Input28IN1LStereo Channel 1, Left Input1GNDGround2IN2RStereo Channel 2, Right Input3IN1RStereo Channel 1, Right InputEPExposed Paddle. Can be left unconnected or connected to GND. Connect to ground
plane for improved thermal performance.
Pin Description
MAX9770
1.2W, Low-EMI, Filterless, Mono Class D Amplifier
with Stereo DirectDrive Headphone AmplifiersOUT+
OUT-
VIN-
VIN+
VOUT+ - VOUT-
tON(MIN)
tSW
Figure 1. MAX9770 Outputs with an Input Signal Applied
Detailed DescriptionThe MAX9770 combines a mono 1.2W Class D speaker
amplifiers and stereo 80mW DirectDrive headphone
amplifiers with integrated headphone sensing and
comprehensive click-and-pop suppression. A
mixer/multiplexer allows for selection and mixing
between two stereo input sources and a single mono
source. The MAX9770 features PSRR as high as 85dB,
THD as low as 0.015%, industry-leading click-and-pop
suppression, and a low-power shutdown mode.
Class D Speaker AmplifierThe MAX9770 Class D amplifier features true filterless,
low-EMI, switch-mode architecture that provides Class
AB-like performance with Class D efficiency.
Comparators monitor the MAX9770 input and compare
the input voltage to a sawtooth waveform. The com-
parators trip when the input magnitude of the sawtooth
exceeds the corresponding input voltage. The com-
parator resets at a fixed time after the rising edge of the
second comparator trip point, generating a minimum-
width pulse tON(MIN)at the output of the second com-
parator (Figure 1). As the input voltage increases or
decreases, the duration of the pulse at one output
increases (the first comparator trip point) while the
other output pulse duration remains at tON(MIN). This
causes the net voltage across the speaker (VOUT+-
VOUT-) to change.
SYNC INPUTMODEGNDFFPWM with fS = 1100kHz
UnconnectedFFPWM with fS = 1450kHz
VDDSSPWM with fS = 1220kHz ±120kHz
ClockedFFPWM with fS = external clock frequency
Table 1. Operating Modes
