MAX9716ETA+T ,Low-Cost, Mono, 1.4W BTL Audio Power AmplifiersFeaturesThe MAX9716/MAX9717 audio power amplifiers are ideal ♦ 2.7V to 5.5V Single-Supply Operation ..
MAX9716EUA ,Low-Cost, Mono, 1.4W BTL Audio Power AmplifiersFeaturesThe MAX9716/MAX9717 audio power amplifiers are ideal♦ 2.7V to 5.5V Single-Supply Operationf ..
MAX9716EUA+T ,Low-Cost, Mono, 1.4W BTL Audio Power AmplifiersELECTRICAL CHARACTERISTICS—5V Supply(V = 5V, V = 0V, SHDN = V , T = +25°C. C = 1µF, R = R = 20kΩ (M ..
MAX9717BEUA ,Low-Cost, Mono, 1.4W BTL Audio Power AmplifiersBlock DiagramsSINGLE SUPPLY SINGLE SUPPLY2.7V TO 5.5V 2.7V TO 5.5VBIAS BIASMAX9716 MAX9717B/C/DIN- ..
MAX9718AETB ,Low-Cost, Mono/Stereo,1.4W Differential Audio Power AmplifiersBlock DiagramSINGLE SUPPLY2.7V TO 5.5VSINGLE SUPPLY2.7V TO 5.5VOUTL+INL+OUT+IN+INL-OUTL-OUTR+INR+IN ..
MAX9718AETB+ ,Low-Cost, Mono/Stereo, 1.4W Differential Audio Power AmplifiersApplicationsPin Configurations appear at end of data sheet.Mobile PhonesUCSP is a trademark of Maxi ..
MB89193AP ,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 ..
MB89193PF ,8-bit Proprietary MicrocontrollerFUJITSU SEMICONDUCTORDS07-12512-7EDATA SHEET8-bit Proprietary MicrocontrollerCMOS2F MC-8L MB89190/1 ..
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
MAX9716ETA+-MAX9716ETA+T-MAX9716EUA+T
Low-Cost, Mono, 1.4W BTL Audio Power Amplifiers
General DescriptionThe MAX9716/MAX9717 audio power amplifiers are ideal
for portable audio devices with internal speakers. A
bridge-tied load (BTL) architecture minimizes external
component count, while providing high-quality audio
reproduction. Both devices deliver 1.4W continuous
power into a 4Ωload with less than 1% Total Harmonic
Distortion (THD) while operating from a single +5V sup-
ply. With an 8Ωload, both devices deliver 1W continuous
power. These devices also deliver 350mW continuous
power into an 8Ωload while operating from a single
+3.0V supply. The devices are available as adjustable
gain amplifiers (MAX9716/MAX9717A) or with internally
fixed gains of 6dB, 9dB, and 12dB (MAX9717B/
MAX9717C/MAX9717D), reducing component count.
A low-power shutdown mode disables the bias generator
and amplifiers, reducing quiescent current consumption
to less than 10nA. These devices feature Maxim’s
industry-leading, comprehensive click-and-pop sup-
pression that reduces audible clicks and pops during
startup and shutdown.
The MAX9717 features a headphone sense input (BTL/SE)
that senses when a headphone is connected to the
device, disables the BTL slave driver, muting the speaker
while driving the headphone as a single-ended load.
The MAX9716 is pin compatible with the LM4890 and is
available in 9-bump UCSP™, 8-pin TDFN (3mm x
3mm), and 8-pin µMAX®packages. The MAX9717 is
available in 9-bump UCSP, 8-pin TDFN, and 8-pin
µMAX packages. Both devices operate over the -40°C
to +85°C extended temperature range.
Applications
Features2.7V to 5.5V Single-Supply Operation1.4W into 4Ωat 1% THD+N10nA Low-Power Shutdown Mode73dB PSRR at 1kHzNo Audible Clicks or Pops at Power-Up/DownInternal Fixed Gain to Reduce Component Count
(MAX9717B/C/D)Adjustable Gain Option (MAX9716/MAX9717A)BTL/SE Input Senses when Headphones are
Connected (MAX9717)Pin Compatible with LM4890 (MAX9716)Pin Compatible with TPA711 (MAX9717A)Available in Compact, Thermally Enhanced µMAX
and TDFN (3mm x 3mm) Packages
MAX9716/MAX9717
Low-Cost, Mono, 1.4W BTL Audio
Power Amplifiers
Ordering InformationVCC
BTL/SE
BIAS
IN-
MAX9717B/C/D
SINGLE SUPPLY
2.7V TO 5.5V
BIAS
IN-
MAX9716
SINGLE SUPPLY
2.7V TO 5.5V
Simplified Block Diagrams19-3146; Rev 3; 3/12
Pin Configurations and Selector Guide appear at end of data
sheet.
EVALUATION KIT
AVAILABLE*EP = Exposed pad.
+Denotes a lead(Pb)-free/RoHS-compliant package.
G45 indicates protective die coating.
/V denotes automotive qualified part.
PARTTEMP RANGEPIN-
PACKAGE
GAIN
(dB)
MAX9716ETA+T-40°C to +85°C8 TDFN-EP*Adj.
MAX9716EBL+TG45-40°C to +85°C3 x 3 UCSPAdj.
MAX9716EUA-40°C to +85°C8 µMAX-EP*Adj.
MAX9716EUA/V+-40°C to +85°C8 µMAX-EP*Adj.
Ordering Information continued at end of data sheet.Mobile Phones
PDAs
Portable Devices
MAX9716/MAX9717
Low-Cost, Mono, 1.4W BTL Audio
Power Amplifiers
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS—5V Supply(VCC= 5V, VGND= 0V, SHDN= VCC, TA= +25°C. CBIAS= 1µF, RIN= RF= 20kΩ(MAX9716/MAX9717A), IN+ = BIAS (MAX9716),
BTL/SE = GND (MAX9717_), RL= ∞connected between OUT+ and OUT-. Typical values are at TA= +25°C.) (Note 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.
Supply Voltage (VCCto GND)..................................-0.3V to +6V
Any Other Pin to GND ...............................-0.3V to (VCC+ 0.3V)
IN_, BIAS, SHDN, BTL/SE Continuous Current...................20mA
OUT_ Short-Circuit Duration to GND or VCC(Note 1)...Continuous
Continuous Power Dissipation (TA= +70°C)
8-Pin TDFN (derate 24.4mW/°C above +70°C).........1951mW
8-Pin µMAX (derate 10.3mW/°C above +70°C)...........825mW
9-Bump UCSP (derate 5.2mW/°C above 70°C)...........412mW
Operating Temperature Range ..........................-40°C to +85°C
Maximum Junction Temperature ....................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
Soldering Temperature (reflow)
Lead(Pb)-Free Packages..............................................+260°C
Packages Containing Lead(Pb)....................................+240°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSSupply VoltageVCCInferred by PSRR test2.75.5V
Quiescent Supply CurrentICCVIN- = VIN+ = VBIAS (Note 3),
TA = -40°C to +85°C4.38mA
Shutdown Supply CurrentISHDNSHDN = GND0.011µA
VIH1.2SHDN ThresholdVIL0.4V
VIH0.9 x
VCCBTL/SE Threshold
VIL0.7 x
VCC
Common-Mode Bias VoltageVBIAS(Note 4)VCC/2
- 6%VCC/2VCC/2
+ 6%V
Output Offset VoltageVOSVIN- = VOUT+, VIN+ = VBIAS (Note 5)±7±15mV
VCC = 2.7V to 5.5VDC, VBIAS = 1.5V6080
f = 217Hz61Power-Supply Rejection RatioPSRRVIN+ = VBIAS,
VRIPPLE = 200mVP-P,
RL = 8Ω (Note 6)f = 1kHz73
RL = 8Ω, THD+N = 1%, fIN = 1kHz (Note 7)0.81.1
RL = 4Ω, THD+N = 1%, fIN = 1kHz (Note 7)1.4Output PowerPOUT
RL = 16Ω, BTL/SE = VCC (single-ended
mode), THD+N = 1%, fIN = 1kHz0.155
Total Harmonic Distortion Plus
NoiseTHD+NAV = 6dB, RL = 8Ω, fIN = 1kHz,
POUT = 0.5W (Note 8)0.024%
Output Noise DensityenfIN = 10kHz106nV/√Hz
Signal-to-Noise RatioSNRTHD+N = 1%105dB
MAX9716/MAX9717
Low-Cost, Mono, 1.4W BTL Audio
Power Amplifiers
ELECTRICAL CHARACTERISTICS—5V Supply (continued)(VCC= 5V, VGND= 0V, SHDN= VCC, TA= +25°C. CBIAS= 1µF, RIN= RF= 20kΩ(MAX9716/MAX9717A), IN+ = BIAS (MAX9716),
BTL/SE = GND (MAX9717_), RL= ∞connected between OUT+ and OUT-. Typical values are at TA= +25°C.) (Note 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSOutput Short-Circuit Current LimitISC(Note 9)1.1A
Thermal Shutdown Threshold+160°C
Thermal Shutdown Hysteresis15°C
250Power-Up/Enable from Shutdown
Time (Note 10)tPUCBIAS = 0.1µF25ms
Shutdown TimetSHDN5µs
Input ResistanceRINMAX9717B/C/D122028kΩ
ELECTRICAL CHARACTERISTICS—3V Supply(VCC= 3V, VGND= 0V, SHDN= VCC, TA= +25°C. CBIAS= 1µF, RIN= RF= 20kΩ(MAX9716/MAX9717A), IN+ = BIAS (MAX9716),
BTL/SE = GND (MAX9717_), RL= ∞connected between OUT+ and OUT-. Typical values are at TA= +25°C.) (Note 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSQuiescent Supply CurrentICCVIN- = VIN+ = VBIAS (Note 3),
TA = -40°C to +85°C48.0mA
Shutdown Supply CurrentISHDNSHDN = GND0.011µA
VIH1.2SHDN ThresholdVIL0.4V
VIH0.9 x
VCC
BTL/SE Threshold
VIL0.7 x
VCC
Common-Mode Bias VoltageVBIAS(Note 4)VCC/2
- 9%VCC/2VCC/2
+ 9%V
Output Offset VoltageVOSVIN- = VOUT+, VIN+ = VBIAS (Note 5)±7±15mV
f = 217Hz61
Power-Supply Rejection RatioPSRR
VIN+ = VBIAS,
VRIPPLE = 200mVP-P,
RL = 8Ω (Note 6)f = 1kHz73
RL = 8Ω, THD+N = 1%, fIN = 1kHz (Note 7)350Output PowerPOUTRL = 4Ω, THD+N = 1%, fIN = 1kHz (Note 7)525mW
Total Harmonic Distortion Plus
NoiseTHD+NAV = 6dB, RL = 8Ω, fIN = 1kHz,
POUT = 0.5W, VCC = 3V (Note 8)0.024%
Output-Noise DensityenfIN = 10kHz106nV/√Hz
Signal-to-Noise RatioSNRTHD+N = 1%100dB
MAX9716/MAX9717
Low-Cost, Mono, 1.4W BTL Audio
Power Amplifiers
ELECTRICAL CHARACTERISTICS—3V Supply (continued)(VCC= 3V, VGND= 0V, SHDN= VCC, TA= +25°C. CBIAS= 1µF, RIN= RF= 20kΩ(MAX9716/MAX9717A), IN+ = BIAS (MAX9716),
BTL/SE = GND (MAX9717_), RL= ∞connected between OUT+ and OUT-. Typical values are at TA= +25°C.) (Note 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSOutput Short-Circuit Current LimitISC(Note 9)1.1A
Thermal Shutdown Threshold+160°C
Thermal Shutdown Hysteresis15°C
250Power-Up/Enable from Shutdown
Time (Note 10)tPUCBIAS = 0.1µF25ms
Shutdown TimetSHDN5µs
Input ResistanceRINMAX9717B/C/D122028kΩ
Note 1:Continuous power dissipation must also be observed.
Note 2:All specifications are tested at TA = +25°C. Specifications over temperature (TA = TMINto TMAX) are not production tested,
and guaranteed by design.
Note 3:Quiescent power-supply current is specified and tested with no load. Quiescent power-supply current depends on the off-
set voltage when a practical load is connected to the amplifier.
Note 4:Common-mode bias voltage is the voltage on BIAS and is nominally VCC/2.
Note 5:VOS= VOUT+- VOUT-.
Note 6: Theamplifier input IN- is AC-coupled to GND through CIN.
Note 7:Output power is specified by a combination of a functional output current test and characterization analysis.
Note 8:Measurement bandwidth for THD+N is 22Hz to 22kHz.
Note 9:Extended short-circuit conditions result in a pulsed output.
Note 10:Time for VOUTto rise to 50% of final DC value.
MAX9716/MAX9717
Low-Cost, Mono, 1.4W BTL Audio
Power Amplifiers
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCYMAX9716 toc01
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
VCC = 5V
RL = 8Ω
AV = 6dB
OUTPUT POWER = 800mW
OUTPUT POWER = 30mW
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCYMAX9716 toc02
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
VCC = 5V
RL = 8Ω
AV = 12dB
OUTPUT POWER = 800mW
OUTPUT POWER = 200mW
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCYFREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
VCC = 3V
RL = 8Ω
AV = 6dB
OUTPUT POWER = 250mW
OUTPUT POWER = 30mW
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCYMAX9716 toc04
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
VCC = 3V
RL = 8Ω
AV = 12dB
OUTPUT POWER = 200mW
OUTPUT POWER = 50mW
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCYMAX9716 toc05
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
VCC = 5V
RL = 4Ω
AV = 6dB
OUTPUT POWER = 1W
OUTPUT POWER = 200mW
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCYMAX9716 toc06
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001100k
VCC = 5V
RL = 4Ω
AV = 12dB
OUTPUT POWER = 250mW
OUTPUT POWER = 1W
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCYMAX9716 toc07
THD+N (%)
10k1k100
0.001100k
VCC = 3V
RL = 4Ω
AV = 6dB
OUTPUT POWER = 50mW
OUTPUT POWER = 350mW
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCYMAX9716 toc08
THD+N (%)
10k1k100
0.001100k
VCC = 3V
RL = 4Ω
AV = 12dB
OUTPUT POWER = 50mW
OUTPUT POWER = 350mW
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY (SINGLE-ENDED)MAX9716 toc09
THD+N (%)
10k1k100
0.0001100k
VCC = 5V
RL = 16Ω
AV = 12dB
OUTPUT POWER = 125mW
OUTPUT POWER = 25mW
Typical Operating Characteristics(VCC= 5V, THD+N measurement bandwidth = 22Hz to 22kHz, BTL mode, TA= +25°C, unless otherwise noted.)
MAX9716/MAX9717
Low-Cost, Mono, 1.4W BTL Audio
Power Amplifiers
Typical Operating Characteristics (continued)(VCC= 5V, THD+N measurement bandwidth = 22Hz to 22kHz, BTL mode, TA= +25°C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWERMAX9716 toc10
OUTPUT POWER (W)
THD+N (%)
VCC = 5V
RL = 8Ω
AV = 6dB
fIN = 100Hz
fIN = 1kHz
fIN = 10kHz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWERMAX9716 toc11
OUTPUT POWER (W)
THD+N (%)
VCC = 5V
RL = 8Ω
AV = 12dB
fIN = 1kHzfIN = 100Hz
fIN = 10kHz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWERMAX9716 toc12
OUTPUT POWER (mW)
THD+N (%)
VCC = 3V
RL = 8Ω
AV = 6dB
fIN = 100Hz
fIN = 1kHz
fIN = 10kHz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWERMAX9716 toc13
OUTPUT POWER (mW)
THD+N (%)
VCC = 3V
RL = 8Ω
AV = 12dB
fIN = 100HzfIN = 1kHz
fIN = 10kHz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWERMAX9716 toc14
OUTPUT POWER (W)
THD+N (%)
VCC = 5V
RL = 4Ω
AV = 6dB
fIN = 1kHz
fIN = 100HzfIN = 10kHz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWERMAX9716 toc15
OUTPUT POWER (W)
THD+N (%)
fIN = 100HzfIN = 1kHz
VCC = 5V
RL = 4Ω
AV = 12dB
fIN = 10kHz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWERMAX9716 toc16
THD+N (%)
fIN = 10kHz
fIN = 100Hz
fIN = 1kHz
VCC = 3V
RL = 4Ω
AV = 6dB
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWERMAX9716 toc17
THD+N (%)
VCC = 3V
RL = 4Ω
AV = 12dB
fIN = 1kHz
fIN = 100Hz
fIN = 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SINGLE-ENDED)MAX9716 toc18
THD+N (%)
VCC = 5V
RL = 16Ω
AV = 6dBfIN = 100Hz
fIN = 10kHz
fIN = 1kHz
MAX9716/MAX9717
Low-Cost, Mono, 1.4W BTL Audio
Power Amplifiers
OUTPUT POWER
vs. SUPPLY VOLTAGEMAX9716 toc19
SUPPLY VOLTAGE (V)
OUTPUT POWER (W)
RL = 8Ω
f = 1kHz
AV = 6dB
THD+N = 10%
THD+N = 1%
OUTPUT POWER
vs. SUPPLY VOLTAGE
MAX9716 toc20
SUPPLY VOLTAGE (V)
OUTPUT POWER (W)
THD+N = 10%
THD+N = 1%
RL = 4Ω
f = 1kHz
AV = 6dB
OUTPUT POWER
vs. LOAD RESISTANCE
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
THD+N = 1%
THD+N = 10%
VCC = 5V
f = 1kHz
AV = 6dB
OUTPUT POWER
vs. LOAD RESISTANCE
MAX9716 toc22
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)1100
VCC = 3V
f = 1kHz
AV = 6dB
THD+N = 1%
THD+N = 10%
POWER DISSIPATION
vs. OUTPUT POWERMAX9716 toc23
OUTPUT POWER (W)
POWER DISSIPATION (W)
VCC = 5V
RL = 8Ω
f = 1kHz
AV = 6dB
POWER DISSIPATION
vs. OUTPUT POWER
MAX9716 toc24
OUTPUT POWER (mW)
POWER DISSIPATION (mW)
VCC = 3V
RL = 8Ω
f = 1kHz
AV = 6dB
POWER DISSIPATION
vs. OUTPUT POWERMAX9716 toc25
POWER DISSIPATION (W)
VCC = 5V
RL = 4Ω
f = 1kHz
AV = 6dB
POWER DISSIPATION
vs. OUTPUT POWER
MAX9716 toc26
POWER DISSIPATION (mW)
VCC = 3V
RL = 4Ω
f = 1kHz
AV = 6dB
OUTPUT-NOISE DENSITY
vs. FREQUENCYMAX9716 toc27
OUTPUT-NOISE DENSITY (nV/
Hz)
10k1k
100100k
AV = 6dB
Typical Operating Characteristics (continued)(VCC= 5V, THD+N measurement bandwidth = 22Hz to 22kHz, BTL mode, TA= +25°C, unless otherwise noted.)
MAX9716/MAX9717
Low-Cost, Mono, 1.4W BTL Audio
Power Amplifiers
Typical Operating Characteristics (continued)(VCC= 5V, THD+N measurement bandwidth = 22Hz to 22kHz, BTL mode, TA= +25°C, unless otherwise noted.)
GAIN AND PHASE vs. FREQUENCYMAX9716 toc28
FREQUENCY (Hz)
GAIN AND PHASE (
/dB)100k1001k10k
-12010M
AV = 60dB
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCYMAX9716 toc29
FREQUENCY (Hz)
PSRR (dB)
10k1k100
-10100k
SUPPLY CURRENT vs. VCCMAX9716 toc30
VCC (V)
SUPPLY CURRENT (mA)
SUPPLY CURRENT
vs. TEMPERATURE
MAX9716 toc31
TEMPERATURE (°C)
SUPPLY CURRENT (mA)3510-15
VCC = 3V
VCC = 5V
COMING OUT OF SHUTDOWNMAX9716 toc32
OUT+
1V/div
OUT+ - OUT-
200mV/div
OUT-
1V/div
SHDN
2V/div
100ms/div
RL = 8Ω
GOING INTO SHUTDOWNMAX9716 toc33
OUT+
1V/div
OUT+ - OUT-
200mV/div
OUT-
1V/div
SHDN
2V/div
10μs/div
RL = 8Ω
SHUTDOWN CURRENT vs. VCCMAX9716 toc34
SHUTDOWN CURRENT (nA)
SHUTDOWN CURRENT
vs. TEMPERATURE
MAX9716 toc35
SHUTDOWN CURRENT (nA)35-1510
VCC = 5V
VCC = 3V
Detailed DescriptionThe MAX9716/MAX9717 are 1.3W BTL speaker ampli-
fiers. Both devices feature a low-power shutdown
mode, and industry-leading click-and-pop suppression.
The MAX9717 features a headphone sense input that
disables the slave BTL amplifier to drive the headphone
as a single-ended load. These devices consist of high
output-current audio amps configured as BTL ampli-
fiers (see Functional Diagrams). The closed-loop gain
of the input op amp sets the single-ended gain of the
device. Two external gain resistors set the gain of the
MAX9716 and MAX9717A (see the Gain-Setting
Resistorsection). The MAX9717B/C/D feature internally
set gains of 6dB, 9dB, and 12dB, respectively.
The output of the first amplifier serves as the input of the
second amplifier, which is configured as an inverting
unity-gain follower. This results in two outputs, identical in
amplitude, but 180°out-of-phase.
BIASThe MAX9716/MAX9717 operate from a single 2.7V to
5.5V supply and feature an internally generated, common-
mode bias voltage of VCC/2 referenced to ground. BIAS
provides both click-and-pop suppression and sets the DC
bias level for the audio outputs. The MAX9716 can be
configured as a single-ended or differential input. For sin-
gle-ended input, connect the noninverting input IN+ to
BIAS externally. The MAX9717 BIAS is internally connect-
ed to the amplifier noninverting input IN+.
single-ended input. Always bypass BIAS to ground with a
capacitor. Choose the value of the bypass capacitor as
described in the BIAS Capacitor section. Do not connect
external loads to BIAS. Any load lowers the BIAS voltage,
affecting the overall performance of the device.
BTL/SE Control InputThe MAX9717 features a headphone sense input,
BTL/SE, that enables headphone jack sensing to con-
trol the power amplifier output configuration. Driving
BTL/SE low enables the slave amplifier (OUT-). Driving
BTL/SE high disables the slave amplifier.
Shutdown ModeThe MAX9716/MAX9717 feature a low-power shutdown
mode that reduces quiescent current consumption to
10nA. Entering shutdown disables the bias circuitry,
forces the amplifier outputs to GND through an internal
20kΩresistor. Drive SHDNlow to enter shutdown
mode; drive SHDNhigh for normal operation.
Click-and-Pop SuppressionThe MAX9716/MAX9717 feature Maxim’s industry-leading
click-and-pop suppression circuitry. During startup, the
amplifier common-mode bias voltage ramps to the DC
bias. When entering shutdown, the amplifier outputs are
pulled to GND through an internal 20kΩresistor. This
scheme minimizes the energy present in the audio band.
MAX9716/MAX9717
Low-Cost, Mono, 1.4W BTL Audio
Power Amplifiers
Pin/Bump Description
PINBUMP
TDFN/µMAXUCSP
MAX9716MAX9717MAX9716MAX9717
NAMEFUNCTION1C3C3SHDNActive-Low Shutdown2C1C1BIASDC Bias Bypass Capacitor Connection. Bypass BIAS to ground with a
1µF capacitor.—A3—IN+Noninverting Input4A1A1IN-Inverting Input5A2A2OUT+Bridge Amplifier Positive Output6B3B3VCCPower Supply. Bypass VCC with a 1µF capacitor to ground.7B1, B2B1, B2GNDGround8C2C2OUT-Bridge Amplifier Negative Output. OUT- becomes high-impedance
when BTL/SE is driven high.—A3BTL/SEBTL/Single-Ended Mode Input. Logic low sets the device in BTL mode.
Logic high sets the device in single-ended mode.———EPExposed Pad (TDFN and µMAX Only). Connect EP to GND.
MAX9716/MAX9717
Applications Information
BTL AmplifierThe MAX9716/MAX9717 are designed to drive a load
differentially, a configuration referred to as bridge-tied
load or BTL. The BTL configuration (Figure 1) offers
advantages over the single-ended configuration, where
one side of the load is connected to ground. Driving the
load differentially doubles the output voltage compared
to a single-ended amplifier under similar conditions.
Thus, the differential gain of the device is twice the
closed-loop gain of the input amplifier. The effective
gain is given by:
Substituting 2 x VOUT(P-P)for VOUT(P-P)into the following
equations yields four times the output power due to
doubling of the output voltage:
There is no net DC voltage across the load because the
differential outputs are each biased at midsupply. This
eliminates the need for DC-blocking capacitors
required for single-ended amplifiers. These capacitors
can be large and expensive, consume board space,
and degrade low-frequency performance.
Power Dissipation and Heat SinkingUnder normal operating conditions, the MAX9716/
MAX9717 dissipate a significant amount of power. The
maximum power dissipation for each package is given
in the Absolute Maximum Ratings section under
Continuous Power Dissipation or can be calculated by
the following equation:
where TJ(MAX)is +150°C, TAis the ambient temperature,
and θJAis the reciprocal of the derating factor in °C/W as
specified in the Absolute Maximum Ratings section. For
example, θJAof the TDFN package is 41°C/W.
The increase in power delivered by the BTL configuration
directly results in an increase in internal power dissipation
over the single-ended configuration. The maximum power
dissipation for a given VCCand load is given by the
following equation:
If the power dissipation for a given application exceeds
the maximum allowed for a given package, reduce
power dissipation by increasing the ground plane heat-
sinking capability and the size of the traces to the device
(see the Layout and Groundingsection). Other methods
for reducing power dissipation are to reduce VCC,
increase load impedance, decrease ambient tempera-
ture, reduce gain, or reduce input signal.
Thermal-overload protection limits total power dissipation
in the MAX9716/MAX9717. Thermal protection circuitry
disables the amplifier output stage when the junction
temperature exceeds +160°C. The amplifiers are
enabled once the junction temperature cools by 15°C. A
pulsing output under continuous thermal-overload condi-
tions results as the device heats and cools.
Fixed GainThe MAX9717B, MAX9717C, and MAX9717D feature
internally fixed gains of 6dB, 9dB, and 12dB, respec-
tively (see the Selector Guide). Fixed gain simplifies
designs, reduces pin count, decreases required foot-
print size, and eliminates external gain-setting resistors.
Resistors RINand RFshown in the MAX9717B/C/D
Typical Operating Circuitare used to achieve each
fixed gain.VDISSMAXCC =22πTT
DISSPKGMAXMAXA() =−VOUTRMS=V
RMS
OUTPP ()=−RVF =×2
Low-Cost, Mono, 1.4W BTL Audio
Power AmplifiersVOUT(P-P)
2 x VOUT(P-P)
VOUT(P-P)-1
Figure 1. Bridge-Tied Load Configuration
Adjustable Gain
Gain-Setting ResistorsExternal feedback resistors set the gain of the
MAX9716 and MAX9717A. Resistors RFand RIN(see
Figure 2)set the gain of the amplifier as follows:
Where AVis the desired voltage gain. Hence, an RINof
20kΩand an RFof 20kΩyields a gain of 2V/V, or 6dB.can be either fixed or variable, allowing the use of a
digitally controlled potentiometer to alter the gain under
software control.
The gain of the MAX9717 in a single-ended output
configuration is half the gain when configured as BTL
output. Choose RFbetween 10kΩand 50kΩfor the
MAX9716 and MAX9717A. Gains for the MAX9717B/C/D
are set internally.
Input FilterCINand RINform a highpass filter that removes the DC
bias from an incoming signal. The AC-coupling capaci-
tor allows the amplifier to bias the signal to an optimal
DC level. Assuming zero-source impedance, the -3dB
point of the highpass filter is:
Setting f-3dBtoo high affects the low-frequency
response of the amplifier. Use capacitors with
dielectrics that have low-voltage coefficients, such as
tantalum or aluminum electrolytic. Capacitors with high-
voltage coefficients, such as ceramics, can increase
distortion at low frequencies.
Output-Coupling CapacitorThe MAX9717 require output-coupling capacitors to
operate in single-ended (headphone) mode. The out-
put-coupling capacitor blocks the DC component of the
amplifier output, preventing DC current from flowing to
the load. The output capacitor and the load impedance
form a highpass filter with a -3dB point determined by:
As with the input capacitor, choose COUTsuch that
f-3dBis well below the lowest frequency of interest.
Setting f-3dBtoo high affects the amplifier’s low-fre-
quency response. Load impedance is a concern when
choosing COUT. Load impedance can vary, changing
the -3dB point of the output filter. A lower impedance
increases the corner frequency, degrading low-fre-
quency response. Select COUTsuch that the worst-
case load/COUTcombination yields an adequate
response. Select capacitors with low ESR to minimize
resistive losses and optimize power transfer to the load.
Differential InputThe MAX9716 can be configured for a differential input.
The advantage of differential inputs is that any com-
mon-mode noise is attenuated and not passed through
the amplifier. This input improves noise rejection and
provides common-mode rejection (Figure 3). External
components should be closely matched for high
CMRR. Figure 4 shows the MAX9716 configured for a
differential input.RCdBOUT−=31 πdBIN−=31πRVF=⎛⎜⎞⎟2
MAX9716/MAX9717
Low-Cost, Mono, 1.4W BTL Audio
Power AmplifiersOUT-
OUT+MAX9716
IN-
IN+
BIAS
RINCIN
AUDIO
INPUT
Figure 2. Setting the MAX9716/MAX9717A Gain
FREQUENCY (Hz)
CMRR (dB)
10k1k100
-100100k
VRIPPLE = 200mVP-P
RL = 8Ω
CBIAS = 1μF
COMMON-MODE REJECTION RATIO
vs. FREQUENCYFigure 3. CMRR with Differential Input
