MAX9766ETJ+T ,750mW Audio Amplifiers with Headphone Amp, Microphone Preamp, and Input Muxapplications that do not require♦ Headphone Sense Inputa headphone amp and includes a stereo BTL sp ..
MAX9768ETG+ ,10W Mono Class D Speaker Amplifier with Volume ControlBlock Diagram3.3V 4.5V TO 14VMAX9768 EMI WITH FERRITE BEAD FILTERS(V = 12V, 1m CABLE, 8Ω LOAD)DD40S ..
MAX9768ETG+T ,10W Mono Class D Speaker Amplifier with Volume ControlELECTRICAL CHARACTERISTICS(V = 12V, V = 3.3V, V = V = 0, V = V , V = 0; Max volume setting; speaker ..
MAX976ESA ,Single/Dual/Quad / SOT23 / Single-Supply / High-Speed / Low-Power Comparatorsfeatures a' 1nA Shutdown Supply Currentlow-power shutdown mode that places the output in ahigh-impe ..
MAX976ESA+ ,Single/Dual/Quad, SOT23, Single-Supply, High-Speed, Low-Power ComparatorsELECTRICAL CHARACTERISTICS(V = +2.7V to +5.5V, V = 0V, T = -40°C to +85°C, unless otherwise noted. ..
MAX976ESA+T ,Single/Dual/Quad, SOT23, Single-Supply, High-Speed, Low-Power Comparatorsapplications. They achieve a20ns propagation delay while consuming only 225µA ♦ 225µA Supply Curren ..
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
MAX9766ETJ+T
750mW Audio Amplifiers with Headphone Amp, Microphone Preamp, and Input Mux
General DescriptionThe MAX9765/MAX9766/MAX9767 family combines
speaker, headphone, and microphone amplifiers, all in
a small thin QFN package. The MAX9765 is targeted at
stereo speaker playback applications and includes a
stereo bridge-tied load (BTL) speaker amp, stereo
headphone amp, single-ended output mic amp, input
MUX, and I2C control. The MAX9766 is targeted at
mono speaker playback applications and includes a
mono BTL speaker amp, stereo headphone amp, differ-
ential output mic amp, input MUX, and I2C control. The
MAX9767 is targeted at applications that do not require
a headphone amp and includes a stereo BTL speaker
amp, differential output mic amp, and parallel control.
These devices operate from a single 2.7V to 5.5V supply.
A high 95dB PSRR allows these devices to operate from
noisy supplies without additional power conditioning. An
ultra-low 0.003% THD+N ensures clean, low distortion
amplification of the audio signal. Click-and-pop suppres-
sion eliminates audible transients on power and shut-
down cycles.
In speaker mode, the amplifiers can deliver up to
750mW of continuous average power into a 4Ωload. In
headphone mode, the amplifier can deliver up to 65mW
of continuous average power into a 16Ωload. The gain
of the amplifiers is externally set, allowing maximum
flexibility in optimizing output levels for a given load.
The MAX9765/MAX9766 also feature a 2:1 input multi-
plexer, allowing multiple audio sources to be selected.
The various functions are controlled by either an I2C-
compatible (MAX9765/MAX9766) or simple parallel
control interface (MAX9767).
All devices include two low-noise microphone pre-
amps, a differential amp for internal microphones, and
a single-ended amplifier for additional external micro-
phones. A microphone bias output is provided, reduc-
ing external component count.
The MAX9765/MAX9766/MAX9767 are available in a
thermally efficient 32-pin thin QFN package (5mm ✕
5mm ✕0.8mm). All devices have short-circuit and
thermal-overload protection (OVP) and are specified
over the extended -40°C to +85°C temperature range.
Features750mW BTL Stereo Speaker Amplifier65mW Stereo Headphone Amplifier2.7V to 5.5V Single-Supply OperationClick-and-Pop SuppressionLow 0.003% THD+N Low Quiescent Current: 13mALow-Power Shutdown Mode: 5µAMUTE FunctionHeadphone Sense InputStereo 2:1 Input MultiplexerOptional 2-Wire, I2C-Compatible, or Parallel
InterfaceSmall 32-Pin Thin QFN (5mm ✕5mm ✕0.8mm)
Package
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input MuxMUX
INL1
INL2
MUX
INR1
INR2
DEVICE
CONTROL
AUXIN
MICBIAS
MICIN-
MICIN+
SPKR
LEFT
SPKR
RIGHT
HEADPHONE
CONTROL
MICOUT
BIAS
MUX
MAX9765
Simplified Diagram
Ordering Information19-2862; Rev 2; 3/07
EVALUATION KIT
AVAILABLE
PARTTEMP RANGEPIN-
PACKAGE
PKG
CODE
MAX9765ETJ-40oC to +85oC32 TQFN-EP*T3255-4
MAX9766ETJ-40oC to +85oC32 TQFN-EP*T3255-4
MAX9767ETJ-40oC to +85oC32 TQFN-EP*T3255-4
*EP = Exposed paddle.
Pin Configurations and Functional Diagrams appear at end of data
sheet.PDAAudio Systems
Tablet PCs
Cell Phones
Notebooks
Digital Cameras
Applications
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
ABSOLUTE MAXIMUM RATINGSStresses 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
SVDDto GND.........................................................................+6V
SVDDto VDD.........................................................................-0.3V
PVDDto VDD.......................................................................±0.3V
PGND to GND.....................................................................±0.3V
All Other Pins to GND.................................-0.3V to (VDD+ 0.3V)
Output Short-Circuit Duration (to VDD or GND)..........Continuous
Continuous Input Current (into any pin except power-supply
and output pins)...............................................................±20mA
Continuous Power Dissipation (TA= +70°C)
32-Pin Thin QFN(derate 26.3mW/°C above +70°C)...2105.3mW
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
ELECTRICAL CHARACTERISTICS(VDD= PVDD= 3.0V, GND = 0, HPS = MUTE = GND, SHDN= 3V, CBIAS= 1µF, RIN= RF= 15kΩ, RL= ∞. TA= TMINto TMAX, unless
otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSSupply Voltage RangeVDD/PVDDInferred from PSRR test2.75.5V
MAX9765/MAX97671228Speaker modeMAX9766717Quiescent Supply Current
(IVDD + IPVDD)IDD
Headphone mode, HPS = VDD717
Shutdown CurrentISHDNSHDN = GND518µA
Switching TimetSWGain or input switching
(MAX9765/MAX9766)10µs
CBIAS = 1µF, settled to 90%250Turn-On/Turn-Off TimetON/OFFCBIAS = 0.1µF, settled to 90%25ms
Input Bias CurrentIBIAS50nA
Thermal Shutdown Threshold150oC
Thermal Shutdown Hysteresis8oC
Output Short-Circuit CurrentTo VDD or GND1.2A
STANDBY SUPPLY (SVDD)VBIAS = 1.25V, VDD = 0V230400Standby CurrentISVDDVBIAS = 1.5V, VDD = 3V5µA
OUTPUT AMPLIFIERS (SPEAKER MODE)Output Offset VoltageVOSVOUT_+ - VOUT_-, AV = 1V/V1045mV
VDD = 2.7V to 5.5V7285Power-Supply Rejection RatioPSRRf = 1kHz, VRIPPLE = 200mVP-P72dB
RL = 8Ω450Output PowerPOUTfIN = 1kHz, THD+N = 1%,
TA = +25oC (Note 2)RL = 4Ω400750mW
POUT = 200mW,
RL = 8Ω0.033
Total Harmonic Distortion Plus
NoiseTHD+NfIN = 1kHz, BW = 22Hz to
22kHzPOUT = 400mW,
RL = 4Ω0.065
Signal-to-Noise RatioSNRRL = 8Ω, VOUT_ = 1.4VRMS, BW = 22Hz to
22kHz89dB
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
ELECTRICAL CHARACTERISTICS (continued)(VDD= PVDD= 3.0V, GND = 0, HPS = MUTE = GND, SHDN= 3V, CBIAS= 1µF, RIN= RF= 15kΩ, RL= ∞. TA= TMINto TMAX, unless
otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSMaximum Capacitive Load DriveCLNo sustained oscillations400pF
Slew RateSR1.4V/µs
CrosstalkfIN = 10kHz73dB
OUTPUT AMPLIFIERS (HEADPHONE MODE)VDD = 2.7V to 5.5V95
f = 1kHz, VRIPPLE = 200mVP-P75Power-Supply Rejection RatioPSRR
f = 20kHz, VRIPPLE = 200mVP-P50
RL = 32Ω40Output PowerPOUTfIN = 1kHz, THD+N = 1%,
TA = +25oC (Note 2)RL = 16Ω3565mW
VOUT = 0.7RMS,
RL = 10kΩ0.002
POUT = 15mW,
RL = 32Ω0.005Total Harmonic Distortion Plus
NoiseTHD+NfIN = 1kHz, BW = 22Hz to
22kHz
POUT = 30mW,
RL = 16Ω0.004
Signal-to-Noise RatioSNRRL = 8Ω, VOUT_ = 1.4VRMS,
BW = 20Hz to 22kHz89dB
Slew RateSR0.7V/µs
Maximum Capacitive Load DriveCLNo sustained oscillations200pF
CrosstalkfIN = 10kHz79dB
BIAS VOLTAGE (BIAS)BIAS VoltageVBIAS1.41.51.6V
Output ResistanceRBIAS50kΩ
MICROPHONE AMPLIFIER GENERALVDD - VOH3570RL = 100kΩVOL - GND50400
VDD - VOH80150Output Voltage SwingVOUT
RL = 2kΩVOL - GND70400
Slew RateSRAV = 10dB0.6V/µs
Output Short-Circuit CurrentTo VDD or GND10mA
Maximum Capacitive Load DriveCLNo sustained oscillations50pF
DIFFERENTIAL INPUT AMPLIFIER (MICIN+, MICIN-)Input Offset VoltageVOS25mV
AV = 20dB31Input Noise-Voltage DensityeNfIN = 1kHzAV = 40dB11.6nV/√Hz
Total Harmonic Distortion Plus
NoiseTHD+NVDD = 3V, VOUT = 0.35VRMS, AV = 10dB,
fIN = 1kHz, BW = 22Hz to 22kHz0.01%
Small-Signal BandwidthBW-3dBAV = 40dB, VOUT = 100mVP-P300kHz
Input ResistanceRINMICIN_ to GND100kΩ
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
ELECTRICAL CHARACTERISTICS (continued)(VDD= PVDD= 3.0V, GND = 0, HPS = MUTE = GND, SHDN= 3V, CBIAS= 1µF, RIN= RF= 15kΩ, RL= ∞. TA= TMINto TMAX, unless
otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSInput Resistance MatchingRMATCH1%
MAX9765, AV = 4dB to 39dB24
MAX9766, AV = 10dB to 45dB24Differential Gain AccuracyAVDIFF
MAX9767, AV = 10dB, 20dB, 30dB24
Common-Mode Rejection RatioCMRRAV = 10dB, fIN = 1kHz, VCM = 200mVP-P,
RS = 2kΩ60dB
VDD = 2.7V to 5.5V6280
f = 1kHz, VRIPPLE =
200mVP-P80Power-Supply Rejection RatioPSRRAV = 10dB, output
referred
f = 20kHz, VRIPPLE =
200mVP-P68
Common-Mode Input Voltage
RangeVCM1V
SINGLE-ENDED INPUT AMPLIFIER (AUXIN)Input Offset VoltageVOS410mV
Input Noise-Voltage DensityeNAV = 20dB, fIN = 1kHz73nV/√Hz
Total Harmonic Distortion Plus
NoiseTHD+NAV = 10dB, fIN = 1kHz, BW = 22Hz to
22kHz, VOUT = 0.7VRMS0.01%
Small-Signal BandwidthBW-3dBAV = 20dB, VOUT = 100mVP-P200kHz
Input ResistanceRIN100kΩ
Voltage Gain AccuracyAV4%
VDD = 2.7V to 5.5V6580
f = 1kHz, VRIPPLE =
200mVP-P76Power-Supply Rejection RatioPSRRAV = 10dB, output
referred
f = 20kHz, VRIPPLE =
200mVP-P58
MICROPHONE BIAS OUTPUT (MICBIAS)Microphone Bias Output VoltageVMICBIASVDD = 2.7V to 5.5V, ILOAD = 500µA2.42.52.6V
Output Noise-Voltage DensityeNf = 1kHz52nV/√Hz
VDD = 2.7V to 5.5V6372Power-Supply Rejection RatioPSRRfIN = 1kHz, VRIPPLE = 200mVP-P70dB
DIGITAL INPUTS (MUTE, SHDN, INT/EXT)Input Voltage HighVIH2V
Input Voltage LowVIL0.8V
Input Leakage CurrentIIN±1µA
MAX9767 MICGAIN INPUT (TRI-STATE PIN))Input Voltage HighVIHVDDV
Input Voltage LowVILGNDV
Input Voltage MidVIZFLOATV
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
ELECTRICAL CHARACTERISTICS (continued)(VDD= PVDD= 3.0V, GND = 0, HPS = MUTE = GND, SHDN= 3V, CBIAS= 1µF, RIN= RF= 15kΩ, RL= ∞. TA= TMINto TMAX, unless
otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
HEADPHONE SENSE INPUT (HPS)Input Voltage HighVIH0.9 x
VDDV
Input Voltage LowVIL0.7 x
VDDV
Input Leakage CurrentIIN±1µA
2-WIRE SERIAL INTERFACE (SCL, SDA, ADD) (MAX9765/MAX9766)VDD > 3.6V3Input Voltage HighVIHVDD ≤ 3.6V2V
Input Voltage LowVIL0.8V
Input Hysteresis0.2V
Input High Leakage CurrentIIHVIN = 3V±1µA
Input Low Leakage CurrentIILVIN = 0V±1µA
Input CapacitanceCIN10pF
Output Voltage LowVOLIOL = 3mA0.4V
Output Current HighIOHVOH = 3V1µA
TIMING CHARACTERISTICS (MAX9765/MAX9766)Serial Clock FrequencyfSCL400kHz
Bus Free Time Between STOP
and START ConditionstBUF1.3µs
START Condition Hold TimetHD:STA0.6µs
START Condition Setup TimetSU:STA0.6µs
Clock Period LowtLOW1.3µs
Clock Period HightHIGH0.6µs
Data Setup TimetSU:DAT100ns
Data Hold TimetHD:DAT(Note 3)00.9µs
Receive SCL/SDA Rise TimetR(Note 4)20 +
0.1CB300ns
Receive SCL/SDA Fall TimetF(Note 4)20 +
0.1CB300ns
Transmit SDA Fall TimetF(Note 4)20 +
0.1CB250ns
Pulse Width of Suppressed SpiketSP(Note 5)50ns
Note 1:All devices are 100% production tested at +25°C. All temperature limits are guaranteed by design.
Note 2:POUTlimits are tested by a combination of electrical and guaranteed by design.
Note 3:A device must provide a hold time of at least 300ns for the SDA signal to bridge the undefined region of SCL’s falling edge.
Note 4:CB= total capacitance of one of the bus lines in picofarads. Device tested with CB= 400pF. 1kΩpullup resistors connected
from SDA/SCL to VDD.
Note 5:Input filters on SDA, SCL, and ADD suppress noise spikes less than 50ns.
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)MAX9765 toc01
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
VDD = 5V
RL = 4Ω
AV = 2V/V
POUT = 500mW
POUT = 100mWPOUT = 250mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)MAX9765 toc02
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
VDD = 5V
RL = 4Ω
AV = 4V/V
POUT = 100mWPOUT = 250mW
POUT = 500mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)MAX9765 toc03
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
VDD = 3V
RL = 4Ω
AV = 2V/V
POUT = 250mWPOUT = 100mW
POUT = 500mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)MAX9765 toc04
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
VDD = 3V
RL = 4Ω
AV = 4V/V
POUT = 250mW
POUT = 500mW
POUT = 100mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)MAX9765 toc05
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
VDD = 5V
RL = 8Ω
AV = 2V/V
POUT = 300mWPOUT = 50mW
POUT = 150mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)MAX9765 toc06
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
POUT = 300mWPOUT = 50mW
POUT = 150mW
VDD = 5V
RL = 8Ω
AV = 4V/V
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)MAX9765 toc07
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
POUT = 300mWPOUT = 50mW
POUT = 150mW
VDD = 3V
RL = 8Ω
AV = 4V/V
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)MAX9765 toc08
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
POUT = 150mWPOUT = 50mW
POUT = 300mW
VDD = 3V
RL = 8Ω
AV = 4V/V
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)MAX9765 toc09
OUTPUT POWER (W)
THD+N (%)
VDD = 5V
RL = 4Ω
AV = 2V/Vf = 1kHz
f = 20Hz
f = 10kHz
Typical Operating Characteristics(VDD= PVDD= 5V, BW = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
Typical Operating Characteristics (continued)(VDD= PVDD= 5V, BW = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)MAX9765 toc10
OUTPUT POWER (W)
THD+N (%)
VDD = 5V
RL =4Ω
AV = 4V/V
f = 20Hz
f = 1kHz
f = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)MAX9765 toc11
OUTPUT POWER (W)
THD+N (%)
VDD = 3V
RL = 4Ω
AV = 2V/V
f = 20Hz
f = 1kHz
f = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)MAX9765 toc12
OUTPUT POWER (W)
THD+N (%)
VDD = 3V
RL = 4Ω
AV = 4V/V
f = 20Hz
f = 1kHz
f = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)MAX9765 toc13
OUTPUT POWER (W)
THD+N (%)
VDD = 5V
RL = 8Ω
AV = 2V/V
f = 20Hz
f = 1kHz
f = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)MAX9765 toc14
OUTPUT POWER (W)
THD+N (%)
VDD = 5V
RL = 8Ω
AV = 4V/V
f = 20Hz
f = 1kHz
f = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)MAX9765 toc15
OUTPUT POWER (W)
THD+N (%)
VDD = 3V
RL = 8Ω
AV = 2V/V
f = 20Hz
f = 1kHz
f = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)MAX9765 toc16
OUTPUT POWER (W)
THD+N (%)
VDD = 3V
RL = 8Ω
AV = 4V/V
f = 20Hz
f = 1kHz
f = 10kHz
OUTPUT POWER vs. LOAD RESISTANCE
(SPEAKER MODE)MAX9765 toc17
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)10010
010k
VCC = 5V
THD+N = 10%
THD+N = 1%
OUTPUT POWER vs. LOAD RESISTANCE
(SPEAKER MODE)MAX9765 toc18
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)10010
010k
VCC = 3V
THD+N = 10%
THD+N = 1%
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
Typical Operating Characteristics (continued)(VDD= PVDD= 5V, BW = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
POWER DISSIPATION vs. OUTPUT POWER
(SPEAKER MODE)MAX9765 toc19
OUTPUT POWER (W)
POWER DISSIPATION (W)
VDD = 5V
RL = 4Ω
f = 1kHz
POWER DISSIPATION vs. OUTPUT POWER
(SPEAKER MODE)MAX9765 toc20
OUTPUT POWER (W)
POWER DISSIPATION (W)
VDD = 5V
RL = 8Ω
f = 1kHz
POWER DISSIPATION vs. OUTPUT POWER
(SPEAKER MODE)MAX9765 toc21
OUTPUT POWER (W)
POWER DISSIPATION (W)
VDD = 3V
RL = 4Ω
f = 1kHz
POWER DISSIPATION vs. OUTPUT POWER
(SPEAKER MODE)MAX9765 toc22
OUTPUT POWER (W)
POWER DISSIPATION (W)
VDD = 3V
RL = 8Ω
f = 1kHz
OUTPUT POWER vs. TEMPERATURE
(SPEAKER MODE)MAX9765 toc23
TEMPERATURE (°C)
OUTPUT POWER (mW)6010-15
THD+N = 10%
THD+N = 1%
f = 1kHz
RL = 4Ω
OUTPUT POWER vs. TEMPERATURE
(SPEAKER MODE)MAX9765 toc24
TEMPERATURE (°C)
OUTPUT POWER (mW)6010-15
THD+N = 10%
THD+N = 1%
f = 1kHz
RL = 8Ω
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (SPEAKER MODE)MAX9765 toc25
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-100100k
VDD = 5V
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (SPEAKER MODE)MAX9765 toc26
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-100100k
VDD = 3V
ENTERING SHUTDOWN (SPEAKER MODE)MAX9765 toc27
200ms/div
OUT_+ AND
OUT_-
OUT_+ -
OUT_-
100mV/div
500mV/div
2V/div
SHDN
RL = 8Ω
INPUT AC-COUPLED TO GND
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
POWER-UP
(SPEAKER MODE)MAX9765 toc30
200ms/div
OUT_+ AND
OUT
OUT_+ - OUT100mV/div
500mV/div
2V/div
VCC
RL = 8Ω
INPUT AC-COUPLED TO GND
CBIAS = 1µF
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)MAX9765 toc31
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.1100k
VDD = 5V
RL = 16Ω
AV = 1V/V
POUT = 10mWPOUT = 25mW
POUT = 50mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)MAX9765 toc32
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.1100k
VDD = 5V
RL = 16Ω
AV = 2V/V
POUT = 50mW
POUT = 25mW
POUT = 10mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)MAX9765 toc33
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.1100k
VDD = 3V
RL = 16Ω
AV = 1V/V
POUT = 25mWPOUT = 50mW
POUT = 10mW
Typical Operating Characteristics (continued)(VDD= PVDD= 5V, BW = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
EXITING SHUTDOWN (SPEAKER MODE)MAX9765 toc28
200ms/div
OUT_+ AND
OUT
OUT_+ - OUT100mV/div
500mV/div
2V/divSHDN
RL = 8Ω
INPUT AC-COUPLED TO GND
CBIAS = 1µF
ENTERING POWER-DOWN
(SPEAKER MODE)MAX9765 toc29
200ms/div
OUT_+ AND
OUT_-
OUT_+ -
OUT_-
100mV/div
500mV/div
2V/div
VCC
RL = 8Ω
INPUT AC-COUPLED TO GND
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)MAX9765 toc34
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.1100k
VDD = 3V
RL = 16Ω
AV = 2V/V
POUT = 25mWPOUT = 10mW
POUT = 50mW
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
Typical Operating Characteristics (continued)(VDD= PVDD= 5V, BW = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)MAX9765 toc35
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.1100k
VDD = 5V
RL = 32Ω
AV = 1V/V
POUT = 10mWPOUT = 5mW
POUT = 20mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)MAX9765 toc36
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.1100k
VDD = 5V
RL = 32Ω
AV = 2V/V
POUT = 10mWPOUT = 5mW
POUT = 20mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)MAX9765 toc37
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.1100k
VDD = 3V
RL = 32Ω
AV = 1V/V
POUT = 10mWPOUT = 5mW
POUT = 20mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (HEADPHONE MODE)MAX9765 toc38
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.1100k
VDD = 3V
RL = 32Ω
AV = 2V/V
POUT = 10mWPOUT = 5mW
POUT = 20mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)MAX9765 toc39
OUTPUT POWER (mW)
THD+N (%)
VDD = 5V
RL = 16Ω
AV = 1V/Vf = 1kHz
f = 20Hz
f = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)
MAX9765 toc40
OUTPUT POWER (mW)
THD+N (%)
VDD = 5V
RL = 16Ω
AV = 2V/V
f = 1kHz
f = 20Hzf = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)MAX9765 toc41
OUTPUT POWER (mW)
THD+N (%)
VDD = 3V
RL = 16Ω
AV = 1V/V
f = 1kHz
f = 20Hzf = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (HEADPHONE MODE)MAX9765 toc42
OUTPUT POWER (mW)
THD+N (%)
VDD = 3V
RL = 16Ω
AV = 2V/V
f = 1kHz
f = 20Hzf = 10kHz
OUTPUT POWER vs. LOAD RESISTANCE
(HEADPHONE MODE)MAX9765 toc43
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)10010
16010k
VCC = 5V
THD+N = 10%
THD+N = 1%
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
OUTPUT POWER vs. LOAD RESISTANCE
(HEADPHONE MODE)MAX9765 toc44
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)10010
110k
VCC = 3V
THD+ N = 10%
THD+N = 1%
POWER DISSIPATION vs. OUTPUT POWER
(HEADPHONE MODE)MAX9765 toc45
OUTPUT POWER (mW)
POWER DISSIPATION (mW)5075100
VDD = 5V
f = 1kHz
RL = 16Ω
RL = 32Ω
POWER DISSIPATION vs. OUTPUT POWER
(HEADPHONE MODE)MAX9765 toc46
OUTPUT POWER (mW)
POWER DISSIPATION (mW)15456075
VDD = 3V
f = 1kHz
RL = 16Ω
RL = 32Ω
OUTPUT POWER vs. TEMPERATURE
(HEADPHONE MODE)MAX9765 toc47
TEMPERATURE (°C)
OUTPUT POWER (mW)3510-15
THD+N = 10%
THD+N = 1%
f = 1kHz
RL = 16Ω
OUTPUT POWER vs. TEMPERATURE
(HEADPHONE MODE)MAX9765 toc48
TEMPERATURE (°C)
OUTPUT POWER (mW)3510-15
THD+N = 10%
THD+N = 1%
f = 1kHz
RL = 32Ω
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (HEADPHONE MODE)MAX9765 toc49
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-100100k
VDD = 5V
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (HEADPHONE MODE)MAX9765 toc50
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-100100k
VDD = 3V
ENTERING SHUTDOWN (HEADPHONE MODE)MAX9765 toc51
200ms/div
OUT_+
HP JACK
100mV/div
500mV/div
2V/div
SHDN
RL = 16Ω
INPUT AC-COUPLED TO GND
EXITING SHUTDOWN (HEADPHONE MODE)MAX9765 toc52
200ms/div
OUT_+
HP JACK
100mV/div
500mV/div
2V/div
SHDN
RL = 16Ω
INPUT AC-COUPLED TO GND
Typical Operating Characteristics (continued)(VDD= PVDD= 5V, BW = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
Typical Operating Characteristics (continued)(VDD= PVDD= 5V, BW = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
EXITING POWER-DOWN (HEADPHONE MODE)MAX9765 toc54
200ms/div
OUT_+
HP JACK
100mV/div
500mV/div
2V/div
VCC
RL = 16Ω
INPUT AC-COUPLED TO GND
ENTERING POWER-DOWN (HEADPHONE MODE)MAX9765 toc53
200ms/div
OUT_+
HP JACK
100mV/div
500mV/div
2V/div
VCC
RL = 16Ω
INPUT AC-COUPLED TO GND
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (DIFFERENTIAL INPUT)MAX9765 toc55
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.1100k
VDD = 5V
VOUT = 0.26VRMS
VOUT = 0.35VRMS
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (DIFFERENTIAL INPUT)MAX9765 toc56
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.1100k
VDD = 3V
VOUT = 0.35VRMS
VOUT = 0.26VRMS
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT AMPLITUDE (DIFFERENTIAL INPUT)MAX9765 toc57
OUTPUT VOLTAGE (VRMS)
THD+N (%)1
VDD = 5V
f = 100Hz
f = 1kHz
f = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT AMPLITUDE (DIFFERENTIAL INPUT)MAX9765 toc58
OUTPUT VOLTAGE (VRMS)
THD+N (%)1
VDD = 3V
f = 100Hz
f = 1kHz
f = 10kHz
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (DIFFERENTIAL INPUT)MAX9765 toc59
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-120100k
VDD = 5V
VDD = 3V
INPUT-REFERRED NOISE
(DIFFERENTIAL MICROPHONE AMPLIFIER)MAX9765 toc60
FREQUENCY (Hz)
10k1k100
1000100k
INPUT-REFERRED NOISE (nV/
AV = 20dB
AV = 40dB
DIFFERENTIAL MICROPHONE AMPLIFIER
SMALL-SIGNAL TRANSIENT RESPONSEMAX9765 toc61
200µs/div
OUT
50mV/div
50mV/div
AV = 4dB
fIN = 1kHz
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
DIFFERENTIAL MICROPHONE AMPLIFIER
LARGE-SIGNAL TRANSIENT RESPONSEMAX9765 toc62
200µs/div
OUT
1V/div
500mV/div
AV = 4dB
fIN = 1kHz
DIFFERENTIAL MICROPHONE AMPLIFIER
OVERDRIVEN OUTPUTMAX9765 toc63
200µs/div
OUT
1V/div
1V/div
AV = 4dB
fIN = 1kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SINGLE-ENDED INPUT)MAX9765 toc64
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.1100k
VDD = 5V
VOUT = 265mVRMS
VOUT = 176mVRMS
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SINGLE-ENDED INPUT)MAX9765 toc65
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.1100k
VDD = 3V
VOUT = 176mVRMS
VOUT = 265mVRMS
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT AMPLITUDE (SINGLE-ENDED INPUT)MAX9765 toc66
OUTPUT VOLTAGE (VRMS)
THD+N (%)
VDD = 5V
f = 100Hz
f = 1kHz
f = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT AMPLITUDE (SINGLE-ENDED INPUT)MAX9765 toc67
OUTPUT VOLTAGE (VRMS)
THD+N (%)
VDD = 3V
f = 100Hz
f = 1kHz
f = 10kHz
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (SINGLE-ENDED INPUT)MAX9765 toc68
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-120100k
VDD = 5V
VDD = 3V
INPUT-REFERRED NOISE
(SINGLE-ENDED INPUT
MICROPHONE AMPLIFIER)MAX9765 toc69
FREQUENCY (Hz)
10k1k100
600100k
INPUT-REFERRED NOISE (nV/
AV = 40dB
Typical Operating Characteristics (continued)(VDD= PVDD= 5V, BW = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
Typical Operating Characteristics (continued)(VDD= PVDD= 5V, BW = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
SINGLE-ENDED MICROPHONE AMPLIFIER
LARGE-SIGNAL TRANSIENT RESPONSEMAX9765 toc71
200µs/div
OUT
1V/div
500mV/div
AV = 10dB
fIN = 1kHz
SINGLE-ENDED MICROPHONE AMPLIFIER
OVERDRIVEN OUTPUTMAX9765 toc72
200µs/div
OUT
1V/div
1V/div
AV = 10dB
fIN = 1kHz
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(SPEAKER MODE)MAX9765 toc73
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +85°C
TA = +25°C
TA = -40°C
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(HEADPHONE MODE)MAX9765 toc74
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +85°CTA = +25°C
TA = -40°C
SHUTDOWN SUPPLY CURRENT
vs. SUPPLY VOLTAGEMAX9765 toc75
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (
TA = +85°C
TA = +25°C
TA = -40°C
SINGLE-ENDED MICROPHONE AMPLIFIER
SMALL-SIGNAL TRANSIENT RESPONSEMAX9765 toc70
200µs/div
OUT
100mV/div
50mV/div
AV = 10dB
fIN = 1kHz
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
Pin Description
PINA X9 7 6 5 M A X9 7 6 6 M A X9 7 6 7 NAMEFUNCTION1SHDNActive-Low Shutdown. Connect SHDN to VDD for normal operation.
2, 7, 182, 7, 18
2, 7, 8,
18, 23,
24, 27, 32
N.C.No Connection. Not internally connected.36OUTL+Left-Channel Bridged Amplifier Positive Output. OUTL+ also serves as the
left-channel headphone amplifier output.
4, 214, 214, 21PVDDOutput Amplifier Power Supply. Connect PVDD to VDD.
5, 205, 205, 20PGNDPower Ground. Connect PGND to GND.63OUTL-Left-Channel Bridged Amplifier Negative Output8—INL2Left-Channel Input 29—INL1Left-Channel Input 11010MICIN+Differential Microphone Amplifier Noninverting Input1111MICIN-Differential Microphone Amplifier Inverting Input1212AUXINSingle-Ended Microphone Amplifier Input1313VDDPower Supply1414SVDD
Standby Power Supply. Connect to a standby power supply that is always on,
or connect to VDD through a Schottky diode and bypass with a 220µF
capacitor to GND. Short to VDD if clickless operation is not essential.1515MICBIASMicrophone Bias Output. Bypass MICBIAS with a 1µF capacitor to GND.——MICOUTMicrophone Amplifier Output17—GAINRRight-Channel Gain Set—22OUTR-Right-Channel Bridged Amplifier Negative Output2219OUTR+Right-Channel Bridged Amplifier Positive Output. OUTR+ also serves as the
right-channel headphone amplifier output.——ADDAddress Select. A logic high sets the address LSB to 1, a logic low sets the
address LSB to 0.24—SDABidirectional Serial Data I/O25—SCLSerial Clock Line
26, 2926, 2929GNDGround27—INR2Right-Channel Input 228—INR1Right-Channel Input 130—HPSHeadphone Sense Input3131BIASDC Bias Bypass. See BIAS Capacitor section for capacitor selection.
Connect CBIAS capacitor from BIAS to GND.32—GAINLLeft-Channel Gain Set
—1616MICOUT+Microphone Amplifier Positive Output
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Mux
Detailed DescriptionThe MAX9765/MAX9766/MAX9767 feature 750mW BTL
speaker amplifiers, 65mW headphone amplifiers, input
multiplexers, headphone sensing, differential and sin-
gle-ended input microphone amplifiers, and compre-
hensive click-and-pop suppression. The MAX9765/
MAX9766 are controlled through an I2C-compatible, 2-
wire serial interface. The MAX9767 is controlled
through three logic inputs: MUTE, SHDN, INT(see the
Selector Guide). The MAX9765 family features excep-
tional PSRR (95dB at 1kHz), allowing these devices to
operate from noisy digital supplies without the need for
a linear regulator.
The speaker amplifiers use a BTL configuration. The
MAX9765/MAX9766 main amplifiers are composed of
an input amplifier and an output amplifier. Resistor RIN
sets the input amplifier’s gain, and resistor RFsets the
output amplifier’s gain. The output of these two ampli-
fiers serves as the input to a slave amplifier configured
as an inverting unity-gain follower. This results in two
outputs, identical in magnitude, but 180°out of phase.
The overall gain of the speaker amplifiers is twice the
product of the two amplifier gains (see the Gain-Setting
Resistor section). A unique feature of this architecture
is that there is no phase inversion from input to output.
The MAX9767 does not use a two-stage input amplifier
and therefore has phase inversion from input to output.
When configured as a headphone (single-ended) ampli-
fier, the slave amplifier is disabled, muting the speaker
and the main amplifier drives the headphone. The
MAX9765/MAX9766/MAX9767 can deliver 700mW of
continuous average power into a 4Ωload with less than
1% THD+N in speaker mode. The MAX9765/MAX9766
can deliver 70mW of continuous average power into a
16Ωload with less than 1% THD+N in headphone
mode. The speaker amplifiers also feature thermal-
overload and short-circuit current protection.
All devices feature microphone amplifiers with both dif-
ferential and single-ended inputs. Differential input is
intended for use with internal microphones. Single-
ended input is intended for use with external (auxiliary)
microphones. The differential input configuration is par-
ticularly effective when layout constraints force the
microphone amplifier to be physically remote from the
ECM microphone and/or the rest of the audio circuitry.
The MAX9766/MAX9767 feature a complementary out-
put, creating an ideal interface with CODECs and other
devices with differential inputs. All devices also feature
an internal microphone bias generator.
Amplifier Common-Mode BiasThese devices feature an internally generated com-
mon-mode bias voltage of 1.5V referenced to GND.
BIAS provides both click-and-pop suppression and
sets the DC bias level for the audio signal. BIAS is inter-
nally connected to the noninverting input of each
speaker amplifier (see the Typical Application Circuit).
Choose the value of the bypass capacitor as described
in the BIAS Capacitorsection.
Input MultiplexerThe MAX9765/MAX9766 feature a 2:1 input multiplexer
on the front end of each amplifier. The multiplexer is
controlled by bit 1 in the control register. A logic low
Pin Description (continued)
PINA X9 7 6 5 M A X9 7 6 6 M A X9 7 6 7
NAMEFUNCTION—1917MICOUT-Microphone Amplifier Negative Output23—GAINMMono Mode Gain Set—9INLLeft-Channel Input25INT/EXTInternal (Differential) or External (Single-Ended) Input Select. Drive INT/EXT
low to select internal or high to select external microphone amplifier.26MICGAINMicrophone Amplifier Gain Set. Tri-State Pin. Connect to VDD for gain = 10dB,
float for gain = 20dB, and to GND for gain = 30dB.—28INRRight-Channel Input—30MUTEMute Input——EPExposed Pad. Connect to ground plane of PC board to optimize heatsinking.
MAX9765/MAX9766/MAX9767
750mW Audio Amplifiers with Headphone Amp,
Microphone Preamp, and Input Muxselects input IN_1 and a logic high selects input IN_2.
Both right- and left-channel multiplexers are controlled
by the same input.
The input multiplexer can also be used to further
expand the number of gain options available from the
MAX9765/MAX9766. Connect the audio source to the
device through two different input resistors for multiple
gain configurations (Figure 1). Additionally, the input
multiplexer allows a speaker equalization network to be
switched into the speaker signal path. This is typically
useful in optimizing acoustic response from speakers
with small physical dimensions.
Mono ModeThe mono MAX9766 incorporates a mixer/attenuator
(see the Functional Diagram). In speaker (mono) mode,
the mixer/attenuator combines the two stereo inputs
(INL_ and INR_) and attenuates the resultant signal by
a factor of 2. This allows for full reproduction of a stereo
signal through a single speaker while maintaining opti-
mum headroom. The resistor connected between
GAINM and OUTL+ sets the device gain in speaker
mode. This allows the speaker amplifier to have a dif-
ferent gain and feedback network from the headphone
amplifier.
Headphone Sense Disable Input The headphone sensing function can be disabled by
the HPS_D bit (MAX9765/MAX9766). HPS_D bit deter-
mines whether the device is in automatic-detection
mode, or fixed-mode operation.
Headphone Sense Input (HPS)When the MAX9765/MAX9766 are in automatic head-
phone-detection mode, the state of the headphone
sense input (HPS) determines the operating mode of
the device. A voltage on HPS less than 0.7 ✕VDDsets
the device to speaker mode. A voltage greater than 0.9VDDdisables the inverting bridge amplifier (OUT_-),
which mutes the speaker amplifier and sets the device
into headphone mode.
Connect HPS to the control pin of a 3-wire headphone
jack as shown in Figure 2. With no headphone present,
the resistive voltage-divider created by R1 and R2 sets
the voltage on HPS to 44mV, setting the device to speak-
er mode. When a headphone plug is inserted into the
jack, the control pin is disconnected from the tip contact,
and HPS is pulled to VDDthrough R1, setting the device
into headphone mode. Place a resistor in series with the
control pin and HPS (R3) to prevent any audio signal
from coupling into HPS when the device is in speaker
mode.
ShutdownThe MAX9765/MAX9766/MAX9767 feature a 5µA, low-
power shutdown mode that reduces quiescent current
consumption and extends battery life. The drive and
microphone amplifiers and the bias circuitry are dis-
abled, the amplifier outputs (OUT_/MIC_) go high
impedance, and BIAS and MICBIAS are driven to GND.
The digital section of the MAX9765/MAX9766 remains
active when the device is shut down through the inter-
face. A logic high on bit 0 of the SHDN register places
the MAX9765/MAX9766 in shutdown. A logic low
enables the device. A logic low on the SHDNinput
places the devices into shutdown mode, disables the
interface, and resets the I2C registers to a default state.
A logic high on SHDNenables the device. A logic high
on SHDNenables the devices.
MUTEAll devices feature a mute mode. When the device is
muted, the input is disconnected from the amplifiers.
MUTE only affects the power amplifiers, and does not
shut down the device. The MAX9765/MAX9766 MUTE
mode is selected by writing to the MUTE register (see
Command Byte Definitions). The left and right channels
can be independently muted. The MAX9767 features
an active-high MUTE input that mutes both channels.
INT/EXTThe MAX9767 microphone amplifier input configuration
is controlled by the INT/EXT input. A logic low In
INT/EXT selects internal (differential) microphone
mode. A logic high selects external (single-ended)
mode.
Click-and-Pop SuppressionThe MAX9765/MAX9766/MAX9767 feature Maxim’s
comprehensive click-and-pop suppression. During
startup and shutdown, the common-mode bias voltage
of the amplifiers is slowly ramped to and from the DC
bias point using an S-shaped waveform. Inheadphone
MAX9765
AUDIO
INPUT
15kΩ
30kΩ
IN_1
IN_2
Figure 1. Using the Input Multiplexer for Gain Setting
