19-2842; Rev 3; 6/09
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
Features
The MAX4409 stereo headphone amplifier combines
Maxim’s DirectDrive ® architecture and a commonmode sense input, which allows the amplifier to reject
common-mode noise. Conventional headphone amplifiers require a bulky DC-blocking capacitor between
the headphone and the amplifier. DirectDrive produces
a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors,
which saves cost, board space, and component height.
The common-mode voltage sensing corrects for any
difference between SGND of the amplifier and the
headphone return. This feature minimizes ground-loop
noise when the HP socket is used as a line out connection to other grounded equipment, for example, a PC
connected to a home hi-fi system.
The MAX4409 draws only 5mA of supply current, delivers up to 80mW per channel into a 16Ω load, and has a
low 0.002% THD+N. A high 86dB power-supply rejection ratio allows this device to operate from noisy digital
supplies without additional power-supply conditioning.
The MAX4409 includes ±8kV ESD protection on the
headphone outputs. Comprehensive click-and-pop circuitry eliminates audible clicks and pops on startup
and shutdown. A low-power shutdown mode reduces
supply current draw to only 6µA.
The MAX4409 operates from a single 1.8V to 3.6V supply, has short-circuit and thermal overload protection,
and is specified over the extended -40°C to +85°C temperature range. The MAX4409 is available in a tiny 20pin thin QFN (4mm x 4mm x 0.8mm) package.
♦ No Bulky DC-Blocking Capacitors Required
♦ Ground-Referenced Outputs Eliminate DC-Bias
Voltages on Headphone Ground Pin
♦ Common-Mode Voltage Sensing Eliminates
Ground-Loop Noise
♦ 96dB CMRR
♦ No Degradation of Low-Frequency Response Due
to Output Capacitors
♦ 80mW per Channel into 16Ω
♦ Low 0.002% THD+N
♦ High 86dB PSRR
♦ Integrated Click-and-Pop Suppression
♦ 1.8V to 3.6V Single-Supply Operation
♦ Low Quiescent Current
♦ Low-Power Shutdown Mode
♦ Short-Circuit and Thermal-Overload Protection
♦ ±8kV ESD-Protected Amplifier Outputs
♦ Available in a Space-Saving Package
20-Pin Thin QFN (4mm x 4mm x 0.8mm)
Applications
Functional Diagram
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX4409ETP
-40°C to +85°C
20 Thin QFN-EP*
*EP = Exposed pad.
Notebooks
Desktop PCs
Cellular Phones
PDAs
DirectDrive OUTPUTS
ELIMINATE DC-BLOCKING
CAPACITORS
MAX4409
LEFT
AUDIO
INPUT
MP3 Players
Tablet PCs
SHDN
Portable Audio Equipment
DirectDrive is a registered trademark of Maxim Integrated
Products, Inc.
COM
RIGHT
AUDIO
INPUT
COMMON-MODE
SENSE INPUT ELIMINATES
GROUND-LOOP NOISE
Pin Configurations and Typical Application Circuit appear
at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com
MAX4409
General Description
MAX4409
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
ABSOLUTE MAXIMUM RATINGS
Output Short Circuit to GND or VDD ...........................Continuous
Thermal Limits (Note 1)
Continuous Power Dissipation (TA = +70°C)
20-Pin Thin QFN Multilayer (derate 25.6mW/°C
above +70°C)..........................................................2051mW
θJA ................................................................................39°C/W
θJC ...............................................................................5.7°C/W
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
PGND to SGND .....................................................-0.3V to +0.3V
PVDD to SVDD .................................................................-0.3V to +0.3V
PVSS to SVSS .........................................................-0.3V to +0.3V
PVDD and SVDD to PGND or SGND .........................-0.3V to +4V
PVSS and SVSS to PGND or SGND ..........................-4V to +0.3V
IN_ and COM to SGND.................................SVSS to (SVDD - 1V)
IN_ to COM .....................................(COM + 2V) to (COM - 0.3V)
SHDN_ to SGND........................(SGND - 0.3V) to (SVDD + 0.3V)
OUT_ to SGND ............................(SVSS - 0.3V) to (SVDD + 0.3V)
C1P to PGND.............................(PGND - 0.3V) to (PVDD + 0.3V)
C1N to PGND .............................(PVSS - 0.3V) to (PGND + 0.3V)
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a 4-layer
board. For detailed information on package thermal considerations see www.maxim-ic.com/thermal-tutorial.
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.
ELECTRICAL CHARACTERISTICS
(VPVDD = VSVDD = 3V, VPGND = VSGND = 0, SHDN = SVDD, C1 = C2 = 2.2µF, RIN = RF = R1 = R2 = 10kΩ, RL = ∞, TA = TMIN to
TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
Supply Voltage Range
VDD
Quiescent Supply Current
IDD
Shutdown Supply Current
I SHDN
CONDITIONS
Guaranteed by PSRR test
MIN
TYP
1.8
SHDN = GND
VIH
UNITS
3.6
V
5
8.4
mA
6
10
µA
0.7 x
SVDD
SHDN Thresholds
V
0.3 x
SVDD
VIL
SHDN Input Leakage Current
SHDN to Full Operation
MAX
-1
tSON
+1
175
µA
µs
CHARGE PUMP
Oscillator Frequency
fOSC
272
320
368
kHz
0.5
2.4
mV
-700
-100
0
nA
-1400
-200
0
AMPLIFIERS
Input Offset Voltage
VOS
Input Bias Current
IBIAS
COM Bias Current
ICOM
Equivalent Input Offset Current
IOS
RL = 32Ω
IOS = (IBIAS(INR) + IBIAS(INL) - ICOM) / 2
±2
COM Input Range
VCOM
Inferred from CMRR test
Common-Mode Rejection Ratio
CMRR
-500mV ≤ VCOM ≤ +500mV, RSOURCE ≤ 10Ω
75
96
1.8V ≤ VDD ≤ 3.6V
DC (Note 3)
75
86
VDD = 3.0V,
200mVP-P ripple (Note 4)
fRIPPLE = 1kHz
76
fRIPPLE = 20kHz
48
RL = 32Ω
65
Power-Supply Rejection Ratio
Output Power
2
PSRR
POUT
THD+N = 1%, TA = +25°C
-500
RL = 16Ω
55
+500
80
_______________________________________________________________________________________
nA
nA
mV
dB
dB
mW
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
(VPVDD = VSVDD = 3V, VPGND = VSGND = 0, SHDN = SVDD, C1 = C2 = 2.2µF, RIN = RF = R1 = R2 = 10kΩ, RL = ∞, TA = TMIN to
TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
Total Harmonic Distortion
Plus Noise
THD+N
Signal-to-Noise Ratio (Note 4)
SNR
Slew Rate
SR
Maximum Capacitive Load
CL
CONDITIONS
fIN = 1kHz
MIN
TYP
RL = 32Ω,
POUT = 50mW
0.002
RL = 16Ω,
POUT = 60mW
0.005
95
dB
0.8
V/µs
No sustained oscillations
150
pF
RL = 16Ω, POUT = 1.6mW, fIN = 10kHz
55
dB
140
°C
15
°C
±8
kV
Thermal Shutdown Threshold
Thermal Shutdown Hysteresis
ESD Protection
UNITS
%
RL = 32Ω, POUT = 20mW, fIN = 1kHz
Crosstalk
MAX
Human Body Model (OUTR, OUTL)
Note 2: All specifications are 100% tested at TA = +25°C; temperature limits are guaranteed by design.
Note 3: Inputs are connected to ground and COM.
Note 4: Inputs are AC-coupled to ground. COM is connected to ground.
Typical Operating Characteristics
(C1 = C2 = 2.2µF, RIN = RF = R1 = R2 = 10kΩ, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
VDD = 3V
RL = 16Ω
1
MAX4409 toc02
1
MAX4409 toc01
1
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
VDD = 3V
RL = 32Ω
VDD = 1.8V
RL = 16Ω
0.1
THD+N (%)
THD+N (%)
POUT = 60mW
POUT = 10mW
0.01
THD+N (%)
0.1
0.1
MAX4409 toc03
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
POUT = 50mW
0.01
POUT = 15mW
POUT = 5mW
0.01
POUT = 10mW
0.001
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
10k
100k
FREQUENCY (Hz)
_______________________________________________________________________________________
3
MAX4409
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics (continued)
(C1 = C2 = 2.2µF, RIN = RF = R1 = R2 = 10kΩ, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
10
THD+N (%)
POUT = 15mW
POUT = 5mW
0.01
OUTPUTS
IN PHASE
1
0.1
0.01
0.001
100
1k
10k
60
90
150
120
30
60
90
120
150
180
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
OUTPUTS
OUT OF
PHASE
0.01
10
THD+N (%)
OUTPUTS IN
PHASE
0.1
OUTPUTS
OUT OF
PHASE
0.001
0.001
90
120
150
180
1
OUTPUTS IN
PHASE
0.1
0.01
OUTPUTS
OUT OF
PHASE
0.001
0.0001
60
VDD = 3V
f = 1kHz
RL = 32Ω
1
0.1
30
MAX4409 toc09
VDD = 3V
f = 20Hz
RL = 32Ω
10
100
MAX4409 toc08
MAX4409 toc07
100
0.01
0
20
40
60
80
100
0
120
20
40
60
80
100
120
OUTPUT POWER (W)
OUTPUT POWER (W)
OUTPUT POWER (W)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
OUTPUTS
OUT OF
PHASE
0.01
OUTPUTS IN
PHASE
1
0.1
OUTPUTS
OUT OF
PHASE
0.01
20
40
60
80
OUTPUT POWER (W)
100
120
1
OUTPUTS IN
PHASE
0.1
OUTPUTS
OUT OF
PHASE
0.01
0.001
0.001
VDD = 1.8V
f = 1kHz
RL = 16Ω
10
THD+N (%)
0.1
THD+N (%)
OUTPUTS IN
PHASE
VDD = 1.8V
f = 20Hz
RL = 16Ω
10
100
MAX4409 toc11
VDD = 3V
f = 10kHz
RL = 32Ω
1
100
MAX4409 toc10
100
4
0
180
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
THD+N (%)
THD+N (%)
30
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
1
0
OUTPUTS
OUT OF
PHASE
0.01
OUTPUT POWER (W)
OUTPUTS IN
PHASE
10
0.1
OUTPUT POWER (W)
VDD = 3V
f = 10kHz
RL = 16Ω
0
OUTPUTS IN
PHASE
FREQUENCY (Hz)
100
10
1
0.001
0
100k
10
OUTPUTS
OUT OF
PHASE
0.001
10
VDD = 3V
f = 1kHz
RL = 16Ω
MAX4409 toc12
THD+N (%)
0.1
100
MAX4409 toc06
VDD = 3V
f = 20Hz
RL = 16Ω
THD+N (%)
VDD = 1.8V
RL = 32Ω
MAX4409 toc05
100
MAX4409 toc04
1
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
THD+N (%)
MAX4409
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
0.001
0
10
20
30
40
OUTPUT POWER (W)
50
60
0
10
20
30
40
OUTPUT POWER (W)
_______________________________________________________________________________________
50
60
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
(C1 = C2 = 2.2µF, RIN = RF = R1 = R2 = 10kΩ, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
0.1
0.01
20
30
40
50
MAX4409 toc14
OUTPUTS
OUT OF
PHASE
10
20
30
40
0
10
20
30
OUTPUT POWER (W)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
VDD = 3V
VIN = 200mVP-P
RL = 16Ω
-10
-20
0
-20
0.001
10
20
30
-20
-60
-70
-80
-80
-90
-90
40
10
100
1k
10k
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX4410 toc19
VDD = 1.8V
VIN = 200mVP-P
RL = 32Ω
-10
-20
100k
0
-40
-50
-40
-70
-70
-80
-80
-80
-90
-90
FREQUENCY (Hz)
10k
100k
RIGHT TO LEFT
-50
-70
1k
100k
-30
-60
100
10k
-20
-60
10
1k
VIN = 200mVP-P
-10
CROSSTALK (dB)
PSRR (dB)
-50
100
CROSSTALK vs. FREQUENCY
-30
-40
10
FREQUENCY (Hz)
0
-30
-50
-70
FREQUENCY (Hz)
VDD = 1.8V
VIN = 200mVP-P
RL = 16Ω
-40
-60
OUTPUT POWER (W)
0
-10
-50
MAX4410 toc20
0
-40
MAX4410 toc21
OUTPUTS
OUT OF
PHASE
0.01
-30
PSRR (dB)
PSRR (dB)
OUTPUTS IN
PHASE
0.1
VDD = 3V
VIN = 200mVP-P
RL = 16Ω
-10
40
MAX4410 toc18
0
MAX4409 toc16
VDD = 1.8V
f = 10kHz
RL = 32Ω
-30
THD+N (%)
OUTPUTS
OUT OF
PHASE
0.01
OUTPUT POWER (W)
1
PSRR (dB)
OUTPUTS IN
PHASE
0.1
0.001
0
60
1
OUTPUT POWER (W)
100
10
0.1
0.001
0.001
10
OUTPUTS IN
PHASE
0.01
OUTPUTS
OUT OF
PHASE
0
1
VDD = 1.8V
f = 1kHz
RL = 32Ω
10
THD+N (%)
OUTPUTS IN
PHASE
100
MAX4409 toc17
THD+N (%)
1
VDD = 1.8V
f = 20Hz
RL = 32Ω
10
THD+N (%)
VDD = 1.8V
f = 10kHz
RL = 16Ω
10
100
MAX4409 toc13
100
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
MAX4409 toc15
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
LEFT TO RIGHT
-60
-90
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
10k
100k
FREQUENCY (Hz)
_______________________________________________________________________________________
5
MAX4409
Typical Operating Characteristics (continued)
Typical Operating Characteristics (continued)
(C1 = C2 = 2.2µF, RIN = RF = R1 = R2 = 10kΩ, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
OUTPUT POWER vs. SUPPLY VOLTAGE
-50
-60
-70
140
120
100
80
60
-80
40
-90
20
INPUTS
IN PHASE
1k
10k
2.1
MAX4409 toc25
INPUTS 180°
OUT OF PHASE
80
60
INPUTS
IN PHASE
40
fIN = 1kHz
RL = 32Ω
THD+N = 10%
160
140
2.7
3.0
3.3
INPUTS 180°
OUT OF PHASE
120
100
80
INPUTS
IN PHASE
60
3.0
3.3
40
2.4
2.7
3.0
3.3
VDD = 1.8V
fIN = 1kHz
THD+N = 1%
INPUTS 180°
OUT OF PHASE
35
OUTPUT POWER (mW)
INPUTS 180°
OUT OF PHASE
MAX4409 toc24
INPUTS 180°
OUT OF PHASE
60
INPUTS
IN PHASE
10
3.6
INPUTS IN
PHASE
20
1k
10k
100k
OUTPUT POWER vs. LOAD RESISTANCE
30
25
100
LOAD RESISTANCE (Ω)
OUTPUT POWER vs. LOAD RESISTANCE
150
100
80
0
2.1
45
MAX4409 toc28
VDD = 3V
fIN = 1kHz
THD+N = 10%
200
100
SUPPLY VOLTAGE (V)
OUTPUT POWER vs. LOAD RESISTANCE
3.6
120
20
SUPPLY VOLTAGE (V)
250
3.3
40
1.8
3.6
3.0
VDD = 3V
fIN = 1kHz
THD+N = 1%
140
70
60
OUTPUT POWER (mW)
2.7
2.7
OUTPUT POWER vs. LOAD RESISTANCE
MAX4409 toc29
2.4
2.4
160
0
0
2.1
2.1
SUPPLY VOLTAGE (V)
20
1.8
INPUTS
IN PHASE
1.8
3.6
40
20
15
VDD = 1.8V
fIN = 1kHz
THD+N = 10%
INPUTS 180°
OUT OF PHASE
50
40
INPUTS IN
PHASE
30
20
10
50
INPUTS
IN PHASE
10
10
5
0
0
100
1k
10k
LOAD RESISTANCE (Ω)
6
2.4
180
OUTPUT POWER (mW)
OUTPUT POWER (mW)
100
100
OUTPUT POWER vs. SUPPLY VOLTAGE
OUTPUT POWER vs. SUPPLY VOLTAGE
140
fIN = 1kHz
RL = 32Ω
THD+N = 1%
150
SUPPLY VOLTAGE (V)
FREQUENCY (Hz)
120
200
0
1.8
100k
OUTPUT POWER (mW)
100
MAX4409 toc26
10
INPUTS 180°
OUT OF PHASE
50
0
-100
fIN = 1kHz
RL = 16Ω
THD+N = 10%
250
MAX4409 toc27
-40
INPUTS 180°
OUT OF PHASE
OUTPUT POWER (mW)
-30
CMRR (dB)
160
OUTPUT POWER (mW)
-20
fIN = 1kHz
RL = 16Ω
THD+N = 1%
180
OUTPUT POWER vs. SUPPLY VOLTAGE
300
MAX4409 toc23
VIN = 500mVP-P
-10
200
MAX4409 toc22
0
MAX4409 toc30
COMMON-MODE REJECTION RATIO
vs. FREQUENCY
OUTPUT POWER (mW)
MAX4409
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
100k
0
10
100
1k
10k
LOAD RESISTANCE (Ω)
100k
10
100
1k
10k
LOAD RESISTANCE (Ω)
_______________________________________________________________________________________
100k
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
(C1 = C2 = 2.2µF, RIN = RF = R1 = R2 = 10kΩ, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
INPUTS 180°
OUT OF PHASE
150
100
140
INPUTS 180°
OUT OF PHASE
120
100
80
60
fIN = 1kHz
RL = 32Ω
VDD = 3V
POUT = POUTL + POUTR
40
50
20
0
120
160
200
40
OUTPUT POWER (mW)
GAIN/PHASE (dB/DEGREES)
50
INPUTS 180°
OUT OF PHASE
30
fIN = 1kHz
RL = 32Ω
VDD = 1.8V
POUT = POUTL + POUTR
10
0
0
10
20
30
40
80
120
160
200
50
80
60
40
20
0
-20
-40
-60
-80
-100
-120
-140
-160
-180
60
GAIN
PHASE
10k
1k
100k
1M
10M
C1 = C2 = 2.2μF
80
C1 = C2 = 1μF
C1 = C2 = 0.68μF
40
C1 = C2 = 0.47μF
30
2.4
2.7
3.0
SUPPLY VOLTAGE (V)
3.3
3.6
fIN = 1kHz
THD+N = 1%
INPUTS IN PHASE
10
20
30
100
1k
10k
100k
1M
MAX4409 toc33
10M
0
40
LOAD RESISTANCE (Ω)
VIN = 1VP-P
fIN = 1kHz
RL = 32Ω
AV = -1V/V
-20
OUTPUT SPECTRUM (dB)
OUTPUT POWER (mW)
60
50
10
OUTPUT SPECTRUM vs. FREQUENCY
-40
-60
-80
-100
0
2.1
VDD = 3V
AV = -1V/V
RL = 16Ω
FREQUENCY (Hz)
90
10
0
-20
-40
20
2
0
-50
100
MAX4409 toc37
4
60
50
10
VDD = 3V
AV = 1000V/V
RL = 16Ω
70
6
40
-30
OUTPUT POWER vs. CHARGE-PUMP
CAPACITANCE AND LOAD RESISTANCE
VIN_ = GND
IPVSS = 10mA
NO LOAD
30
-10
CHARGE-PUMP OUTPUT RESISTANCE
vs. SUPPLY VOLTAGE
10
20
GAIN FLATNESS vs. FREQUENCY
FREQUENCY (Hz)
1.8
10
OUTPUT POWER (mW)
OUTPUT POWER (mW)
8
0
MAX4409 toc38
POWER DISSIPATION (mW)
MAX4409 toc34
INPUTS
IN PHASE
20
40
GAIN AND PHASE vs. FREQUENCY
70
40
60
OUTPUT POWER (mW)
POWER DISSIPATION
vs. OUTPUT POWER
60
INPUTS 180°
OUT OF PHASE
80
0
0
MAX4409 toc35
80
100
20
GAIN (dB)
40
INPUTS
IN PHASE
fIN = 1kHz
RL = 16Ω
VDD = 1.8V
POUT = POUTL + POUTR
120
0
0
OUTPUT RESISTANCE (Ω)
140
MAX4410 toc36
200
INPUTS
IN PHASE
160
MAX4409 toc39
250
POWER DISSIPATION
vs. OUTPUT POWER
POWER DISSIPATION (mW)
300
180
POWER DISSIPATION (mW)
POWER DISSIPATION (mW)
INPUTS
IN PHASE
fIN = 1kHz
RL = 16Ω
VDD = 3V
POUT = POUTL + POUTR
350
MAX4409 toc31
400
POWER DISSIPATION
vs. OUTPUT POWER
MAX4409 toc32
POWER DISSIPATION
vs. OUTPUT POWER
50
-120
100
1k
10k
100k
FREQUENCY (Hz)
_______________________________________________________________________________________
7
MAX4409
Typical Operating Characteristics (continued)
Typical Operating Characteristics (continued)
(C1 = C2 = 2.2µF, RIN = RF = R1 = R2 = 10kΩ, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
SHUTDOWN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
6
4
MAX4409 toc41
SHDN = GND
8
SUPPLY CURRENT (μA)
8
POWER-UP/DOWN WAVEFORM
MAX4409 toc42
10
MAX4409 toc40
10
SUPPLY CURRENT (mA)
MAX4409
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
VDD
OUT_
0
0.9
1.8
2.7
3.6
10mV/div
-100dB
4
20dB/div
OUT_FFT
RL = 32Ω, VIN_ = GND
0
0
0V
6
2
2
3V
0
0.9
1.8
2.7
3.6
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
200ms/div
FFT: 25Hz/div
Pin Description
PIN
8
NAME
FUNCTION
18
COM
Common-Mode Voltage Sense Input
19
Charge-Pump Power Supply. Powers charge-pump inverter, charge-pump logic, and oscillator.
1
PVDD
C1P
2
PGND
Power Ground. Connect to SGND.
3
C1N
Flying Capacitor Negative Terminal
5
Charge-Pump Output
7
PVSS
SVSS
9
OUTL
Left-Channel Output
10
Amplifier Positive Power Supply. Connect to PVDD.
13
SVDD
INL
11
OUTR
Right-Channel Output
14
SHDN
Active-Low Shutdown. Connect to VDD for normal operation.
15
INR
17
SGND
4, 6, 8, 12,
16, 20
N.C.
—
EP
Flying Capacitor Positive Terminal
Amplifier Negative Power Supply. Connect to PVSS.
Left-Channel Audio Input
Right-Channel Audio Input
Signal Ground. Connect to PGND.
No Connection. Not internally connected.
Exposed Pad. Leave unconnected. Do not connect to VDD or GND.
_______________________________________________________________________________________
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
The MAX4409 stereo headphone driver features Maxim’s
patented DirectDrive architecture, eliminating the large
output-coupling capacitors required by traditional singlesupply headphone drivers. The device consists of two
80mW Class AB headphone drivers, undervoltage lockout (UVLO)/shutdown control, charge-pump, and comprehensive click-and-pop suppression circuitry (see
Typical Application Circuit). The charge pump inverts the
positive supply (PV DD ), creating a negative supply
(PVSS). The headphone drivers operate from these bipolar supplies with their outputs biased about GND (Figure
1). The drivers have almost twice the supply range compared to other 3V single-supply drivers, increasing the
available output power. The benefit of this GND bias is
that the driver outputs do not have a DC component typically VDD/2. Thus, the large DC-blocking capacitors are
unnecessary, improving frequency response while conserving board space and system cost.
The MAX4409 also features a common-mode voltage
sense input that corrects for mismatch between the
SGND of the device and the potential at the headphone
jack return. A low-power shutdown mode reduces supply current to 6µA. The device features an undervoltage
lockout that prevents operation from an insufficient
power supply and click-and-pop suppression that eliminates audible transients on startup and shutdown.
Additionally, the MAX4409 features thermal overload
and short-circuit protection and can withstand ±8kV
ESD strikes on the output pins.
MAX4409
Detailed Description
VDD
VDD/2
VOUT
GND
CONVENTIONAL DRIVER-BIASING SCHEME
+VDD
VOUT
GND
-VDD
DirectDrive BIASING SCHEME
Figure 1. Traditional Driver Output Waveform vs. MAX4409
Output Waveform
Common-Mode Sense
When the headphone jack is used as a line out to interface between other equipment (notebooks, desktops,
and stereo receivers), potential differences between
the equipment grounds can create ground loops and
excessive ground current flow. The MAX4409 COM
input senses and corrects for the difference between
the headphone return and device ground. Connect
COM through a resistive voltage-divider between the
headphone jack return and SGND of the device (see
Typical Application Circuit). For optimum commonmode rejection, use the same value resistors for R2 and
RIN, and R1 and RF. Improve DC CMRR by adding a
capacitor in between with SGND and R2 (see Typical
Application Circuit). If ground sensing is not required,
connect COM directly to SGND through a 5kΩ resistor.
DirectDrive
Traditional single-supply headphone drivers have their
outputs biased about a nominal DC voltage (typically
half the supply) for maximum dynamic range. Large
coupling capacitors are needed to block this DC bias
from the headphone. Without these capacitors, a significant amount of DC current flows to the headphone,
resulting in unnecessary power dissipation and possible damage to both headphone and headphone driver.
Maxim’s patented DirectDrive architecture uses a
charge pump to create an internal negative supply voltage. This allows the outputs of the MAX4409 to be
biased about GND, almost doubling dynamic range
while operating from a single supply. With no DC component, there is no need for the large DC-blocking
capacitors. Instead of two large (220µF, typ) tantalum
capacitors, the MAX4409 charge pump requires two
small ceramic capacitors, thereby conserving board
space, reducing cost, and improving the frequency
response of the headphone driver. See the Output
Power vs. Charge-Pump Capacitance and Load
Resistance graph in the Typical Operating Characteristics for details of the possible capacitor sizes.
There is a low DC voltage on the driver outputs due to
amplifier offset. However, the offset of the MAX4409 is
_______________________________________________________________________________________
9
When using the headphone jack as a line out to other
equipment, the bias voltage on the sleeve may conflict with the ground potential from other equipment,
resulting in possible damage to the drivers.
Low-Frequency Response
In addition to the cost and size disadvantages of the DCblocking capacitors required by conventional headphone amplifiers, these capacitors limit the amplifier’s
low-frequency response and can distort the audio signal:
• The impedance of the headphone load and the DCblocking capacitor form a highpass filter with the
-3dB point set by:
f-3dB =
1
2πRLCOUT
where RL is the headphone impedance and COUT is
the DC-blocking capacitor value. The highpass filter
is required by conventional single-ended, single
power-supply headphone drivers to block the midrail
DC bias component of the audio signal from the
headphones. The drawback to the filter is that it can
attenuate low-frequency signals. Larger values of
COUT reduce this effect but result in physically larger, more expensive capacitors. Figure 2 shows the
relationship between the size of COUT and the resulting low-frequency attenuation. Note that the -3dB
point for a 16Ω headphone with a 100µF blocking
capacitor is 100Hz, well within the normal audio
band, resulting in low-frequency attenuation of the
reproduced signal.
LF ROLL OFF (16Ω LOAD)
0
-3
-5
MAX4409 fig02
•
During an ESD strike, the driver’s ESD structures
are the only path to system ground. Thus, the driver
must be able to withstand the full ESD strike.
330μF
220μF
ATTENUATION (dB)
•
• The voltage coefficient of the DC-blocking capacitor
contributes distortion to the reproduced audio signal
as the capacitance value varies as a function of the
voltage change across the capacitor. At low frequencies, the reactance of the capacitor dominates
at frequencies below the -3dB point and the voltage
coefficient appears as frequency-dependent distortion. Figure 3 shows the THD+N introduced by two
different capacitor dielectric types. Note that below
100Hz, THD+N increases rapidly.
The combination of low-frequency attenuation and frequency-dependent distortion compromises audio
reproduction in portable audio equipment that emphasizes low-frequency effects such as multimedia lap-
-10
-3dB CORNER FOR
100μF IS 100Hz
100μF
-15
33μF
-20
-25
-30
-35
10
1k
100
FREQUENCY (Hz)
Figure 2. Low-Frequency Attenuation for Common DC-Blocking
Capacitor Values
ADDITIONAL THD+N DUE
TO DC-BLOCKING CAPACITORS
10
MAX4409 fig03
typically 0.5mV, which, when combined with a 32Ω
load, results in less than 16µA of DC current flow to the
headphones.
Previous attempts to eliminate the output-coupling capacitors involved biasing the headphone return (sleeve) to
the DC-bias voltage of the headphone amplifiers. This
method raises some issues:
• When combining a microphone and headphone on
a single connector, the microphone bias scheme
typically requires a 0V reference.
• The sleeve is typically grounded to the chassis.
Using this biasing approach, the sleeve must be
isolated from system ground, complicating product
design.
1
THD+N (%)
MAX4409
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
0.1
TANTALUM
0.01
0.001
ALUM/ELEC
0.0001
10
100
1k
10k
100k
FREQUENCY (Hz)
Figure 3. Distortion Contributed by DC-Blocking Capacitors
10
______________________________________________________________________________________
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
Charge Pump
The MAX4409 features a low-noise charge pump. The
320kHz switching frequency is well beyond the audio
range, and thus does not interfere with the audio signals. The switch drivers feature a controlled switching
speed that minimizes noise generated by turn-on and
turn-off transients. By limiting the switching speed of the
switches, the di/dt noise caused by the parasitic bond
wire and trace inductance is minimized. Although not
typically required, additional high-frequency noise attenuation can be achieved by increasing the size of C2
(see Typical Application Circuit).
Shutdown
The MAX4409 features an active-low SHDN control.
Driving SHDN low disables the charge pump and
amplifiers, sets the amplifier output impedance to
approximately 1kΩ, and reduces supply current draw
to less than 6µA.
Click-and-Pop Suppression
In traditional single-supply audio drivers, the outputcoupling capacitor is a major contributor of audible
clicks and pops. Upon startup, the driver charges the
coupling capacitor to its bias voltage, typically half the
supply. Likewise, on shutdown the capacitor is discharged to GND. This results in a DC shift across the
capacitor, which in turn, appears as an audible transient
at the speaker. Since the MAX4409 does not require
output-coupling capacitors, this does not arise.
Additionally, the MAX4409 features extensive click-andpop suppression that eliminates any audible transient
sources internal to the device. The Power-Up/Down
Waveform in the Typical Operating Characteristics
shows that there are minimal spectral components in the
audible range at the output upon startup or shutdown.
In most applications, the output of the preamplifier driving the MAX4409 has a DC bias of typically half the
supply. At startup, the input-coupling capacitor is
charged to the preamplifier’s DC-bias voltage through
the RF of the MAX4409, resulting in a DC shift across
the capacitor and an audible click/pop. Delaying the
rise of the SHDN_ signals 4 to 5 time constants (40ms
to 50ms) based on RIN and CIN relative to the start of
the preamplifier eliminates this click/pop caused by the
input filter.
Applications Information
Power Dissipation
Under normal operating conditions, linear power amplifiers can 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:
TJ(MAX) − TA
PDISSPKG(MAX) =
θJA
where TJ(MAX) is +150°C, TA is the ambient temperature,
and θJA is the reciprocal of the derating factor in °C/W as
specified in the Absolute Maximum Ratings section. For
example, θJA of the TQFN package is +39°C/W.
The MAX4409 has two sources of power dissipation,
the charge pump and two drivers. If the power dissipation for a given application exceeds the maximum
allowed for a given package, either reduce V DD ,
increase load impedance, decrease the ambient temperature, or add heat sinking to the device. Large output, supply, and ground traces improve the maximum
power dissipation in the package.
Thermal overload protection limits total power dissipation in the MAX4409. When the junction temperature
exceeds +140°C, the thermal-protection circuitry disables the amplifier output stage. The amplifiers are
enabled once the junction temperature cools by 15°C.
This results in a pulsing output under continuous thermal-overload conditions.
Output Power
The device has been specified for the worst-case scenario—when both inputs are in phase. Under this condition, the drivers simultaneously draw current from the
charge pump, leading to a slight loss in headroom of
VSS. In typical stereo audio applications, the left and
right signals have differences in both magnitude and
phase, subsequently leading to an increase in the maximum attainable output power. Figure 4 shows the two
extreme cases for in and out of phase. In reality, the
available power lies between these extremes.
Powering Other Circuits from a
Negative Supply
An additional benefit of the MAX4409 is the internally
generated, negative supply voltage (PVSS). This voltage is used by the MAX4409 to provide the ground-referenced output level. It can, however, also be used to
power other devices within a design. Current draw from
this negative supply (PVSS) should be limited to 5mA;
exceeding this affects the operation of the headphone
______________________________________________________________________________________
11
MAX4409
tops, as well as MP3, CD, and DVD players. By eliminating the DC-blocking capacitors through DirectDrive
technology, these capacitor-related deficiencies are
eliminated.
Component Selection
Gain-Setting Resistors
External feedback components set the gain of the
MAX4409. Resistors RF and RIN (see Typical Application
Circuit) set the gain of each amplifier as follows:
⎛R ⎞
AV = − ⎜ F ⎟
⎝ RIN ⎠
Choose feedback resistor values of 10kΩ. Values other
than 10kΩ increase VOS due to the input bias current,
which in turn increases the amount of DC current flow
to the load. Resistors RIN, R2, RF, and R1 must be of
equal value for best results. Use high-tolerance resistors for best matching and CMRR. For example, the
worst-case CMRR attributed to a 1% resistor mismatch
is -34dB. This is the worst case, and typical resistors do
not affect CMRR as drastically. The effect of resistor
mismatch is shown in Figure 5. If all resistors match
exactly, then any voltage applied to node A should be
duplicated on OUT so no net differential voltage
appears between node A (normally the HP jack socket
GND) and OUT. For resistors with a tolerance of n%,
the worst mismatch is found when RIN and R1 are at
+n%, and RF and R2 are at -n%. If all four resistors are
nominally the same value, then 2n% of the voltage at A
appears between A and OUT.
Packaged resistor arrays can provide well-matched
components for this type of application. Although their
absolute tolerance is not well controlled, the internal
matching of resistors can be very good. At higher frequencies, the rejection is usually limited by PC board
layout; care should be taken to make sure any stray
capacitance due to PC board traces on node N1 matches those on node N2. Ultimately, CMRR performance is
limited by the amplifier itself (see Electrical
Characteristics).
Compensation Capacitor
The stability of the MAX4409 is affected by the value of
the feedback resistor (RF). The combination of RF and
the input and parasitic trace capacitance introduces an
additional pole. Adding a capacitor in parallel with RF
compensates for this pole. Under typical conditions
with proper layout, the device is stable without the
12
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
100
MAX4409 fig04
driver. The negative supply voltage appears on the
PVSS pin. A typical application is a negative supply to
adjust the contrast of LCD modules.
When considering the use of PVSS in this manner, note
that the charge-pump voltage at PVSS is roughly proportional to -VDD and is not a regulated voltage. The
charge-pump output impedance plot appears in the
Typical Operating Characteristics.
VDD = 3V
AV = -1V/V
RL = 16Ω
fIN = 10kHz
10
THD+N (%)
MAX4409
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
1
OUTPUTS IN
PHASE
0.1
OUTPUTS
180° OUT OF
PHASE
0.01
ONE
CHANNEL
0.001
0
50
100
150
200
OUTPUT POWER (mW)
Figure 4. Output Power vs. THD+N with Inputs In/Out of Phase
RF
RIN
N1
MAX4409
R2
N2
OUT
R1
A
Figure 5. Common-Mode Sense Equivalent Circuit
additional capacitor.
Input Filtering
The input capacitor (CIN), in conjunction with RIN, forms a
highpass filter that removes the DC bias from an incoming signal (see Typical Application Circuit). The AC-coupling capacitor allows the amplifier to bias the signal to
an optimum DC level. Assuming zero-source impedance,
the -3dB point of the highpass filter is given by:
f-3dB =
1
2πRINCIN
______________________________________________________________________________________
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
SUPPLIER
PHONE
FAX
WEBSITE
Taiyo Yuden
800-348-2496
847-925-0899
www.t-yuden.com
TDK
847-803-6100
847-390-4405
www.component.tdk.com
Note: Please indicate you are using the MAX4409 when contacting these component suppliers.
Choose RIN according to the Gain-Setting Resistors section. Choose the CIN such that f-3dB is well below the
lowest frequency of interest. Setting f -3dB too high
affects the low-frequency response of the amplifier. Use
capacitors whose dielectrics have low-voltage coefficients, such as tantalum or aluminum electrolytic.
Capacitors with high-voltage coefficients, such as
ceramics, may result in increased distortion at low frequencies.
Charge-Pump Capacitor Selection
Use capacitors with an ESR less than 100mΩ for optimum performance. Low-ESR ceramic capacitors minimize the output resistance of the charge pump. For
best performance over the extended temperature
range, select capacitors with an X7R dielectric. Table 1
lists suggested manufacturers.
Flying Capacitor (C1)
The value of the flying capacitor (C1) affects the load
regulation and output resistance of the charge pump. A
C1 value that is too small degrades the device’s ability
to provide sufficient current drive, which leads to a loss
of output voltage. Increasing the value of C1 improves
load regulation and reduces the charge-pump output
resistance to an extent. See the Output Power vs.
Charge-Pump Capacitance and Load Resistance
graph in the Typical Operating Characteristics. Above
2.2µF, the on-resistance of the switches and the ESR of
C1 and C2 dominate.
Output Capacitor (C2)
The output capacitor value and ESR directly affect the
ripple at PVSS. Increasing the value of C2 reduces output ripple. Likewise, decreasing the ESR of C2 reduces
both ripple and output resistance. Lower capacitance
values can be used in systems with low maximum output power levels. See the Output Power vs. ChargePump Capacitance and Load Resistance graph in the
Typical Operating Characteristics.
Power-Supply Bypass Capacitor
The power-supply bypass capacitor (C3) lowers the output impedance of the power supply, and reduces the
impact of the MAX4409’s charge-pump switching transients. Bypass PVDD with C3, the same value as C1, and
place it physically close to the PVDD and PGND pins.
Common-Mode Noise Rejection
Figure 6 shows a theoretical connection between two
devices, for example, a notebook computer (transmitter, on the left) and an amplifier (receiver, on the right).
The application includes the headphone socket used
as a line output to a home hi-fi system, for example. In
the upper diagram, any difference between the two
GND references (represented by VNOISE) causes current to flow through the screen of cable between the
two devices. This can cause noise pickup at the receiver due to the potential divider action of the audio
screen cable impedance and the GND wiring of the
amplifier.
Introducing impedance between the jack socket and
GND of the notebook helps (as shown in the lower diagram). This has the following effect:
• Current flow (from GND potential differences) in the
cable screen is reduced, which is a safety issue.
• It allows the MAX4409 differential sensing to reduce
the GND noise seen by the receiver (amplifier).
The other side effect is the differential HP jack sensing
corrects the headphone crosstalk (from introducing the
resistance on the jack GND return). Only one channel
is depicted in Figure 6.
Figure 6 has some example numbers for resistance,
but the audio designer has control over only one series
resistance applied to the headphone jack return. Note
that this resistance can be bypassed for ESD purposes
at frequencies much higher than audio if required. The
upper limit for this added resistance is the amount of
output swing the headphone amplifier tolerates when
driving low-impedance loads. Any headphone return
current appears as a voltage across this resistor.
Layout and Grounding
Proper layout and grounding are essential for optimum
performance. Connect PGND and SGND together at a
single point on the PC board. Connect all components
associated with the charge pump (C2 and C3) to the
PGND plane. Connect PVDD and SVDD together at the
device. Connect PV SS and SV SS together at the
device. Bypassing of both supplies is accomplished by
charge-pump capacitors C2 and C3 (see Typical
______________________________________________________________________________________
13
MAX4409
Table 1. Suggested Capacitor Manufacturers
MAX4409
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
Application Circuit). Place capacitors C2 and C3 as
close to the device as possible. Route PGND and all
traces that carry switching transients away from SGND
and the traces and components in the audio signal
path.
Ensure that the COM traces have the same trace length
and width as the amplifier input and feedback traces.
Route COM traces away from noisy signal paths. The
thin QFN package features an exposed paddle that
improves thermal efficiency of the package. However,
the MAX4409 does not require additional heatsinking.
Ensure that the exposed paddle is isolated from GND
or VDD. Do not connect the exposed paddle to GND
or VDD.
EXAMPLE CONNECTION:
VIN = VAUDIO
VAUDIO
GND NOISE COMPONENT IN
OUTPUT = VNOISE/2
0.1Ω
VNOISE
VREF_IN = VNOISE/2
0.1Ω
• 0.10Ω RESISTANCE FROM CABLE SCREEN
• 0.10Ω RESISTANCE DUE TO GND CABLING AT RECEIVER
• VNOISE REPRESENTS THE POTENTIAL DIFFERENCE BETWEEN
THE TWO GNDS
IMPROVEMENT FROM
ADDING MAX4409 WITH
SERIES RESISTANCE
MAX4409
VIN = VAUDIO + (VNOISE x 0.98)
VAUDIO
GND NOISE COMPONENT IN
OUTPUT = VNOISE /100
0.1Ω
RESISTOR IS
INSERTED
BETWEEN THE
JACK SLEEVE
AND
GND = 9.8Ω
9.8Ω
VNOISE
VREF_IN = (VNOISE x 0.99)
0.1Ω
• 9.8Ω RESISTOR ADDS TO HP CROSSTALK, BUT DIFFERENTIAL
SENSING AT THE JACK SLEEVE CORRECTS FOR THIS (ONE CHANNEL
ONLY SHOWN).
• CURRENT FLOW (IN SIGNAL CABLE SCREEN) DUE TO VNOISE
IS GREATLY REDUCED.
• NOISE COMPONENT IN THE RECEIVER OUTPUT IS REDUCED BY 34dB
OVER THE PREVIOUS EXAMPLE WITH THE VALUES SHOWN.
Figure 6. Common-Mode Noise Rejection
14
______________________________________________________________________________________
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
1.8V to 3.6V
LEFT
CHANNEL
AUDIO IN
C3
1μF
CIN
1μF
RF
10kΩ
RIN
10kΩ
19
10
14
13
PVDD
SVDD
SHDN
INL
SVDD
OUTL 9
HEADPHONE
JACK
1 C1P
UVLO/
SHUTDOWN
CONTROL
SVSS
CLICK-AND-POP
SUPPRESSION
CHARGE
PUMP
C1
1μF
COM 18
R2
10kΩ
SVDD
3 C1N
OUTR 11
MAX4409
PVSS
5
C2
1μF
SVSS
PGND
SGND
INR
7
2
17
15
RIGHT
CHANNEL
AUDIO IN
R1
10kΩ
CIN
1μF
RIN
10kΩ
SVSS
RF
10kΩ
______________________________________________________________________________________
15
MAX4409
Typical Application Circuit
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
MAX4409
System Diagram
VDD
0.1μF
15kΩ
0.1μF
15kΩ
INR
VDD
PVDD
OUTR+
OUTR-
0.1μF
AUX_IN
1μF
BIAS
OUT
MAX4060
BIAS
MAX9710
1μF
0.1μF
15kΩ
CODEC
SHDN
OUTL-
INL
OUTL+
15kΩ
2.2kΩ
VCC
0.1μF
IN+
VCC
10kΩ
ININ-
Q
0.1μF
VCC
10kΩ
MAX961
100kΩ
100kΩ
Q
IN+
0.1μF
10kΩ
VCC
1μF
1μF
SHDN
PVDD
SVDD
INL
OUTL
10kΩ
10kΩ
MAX4409 OUTR
INR
COM
PVSS
10kΩ
10kΩ
SVSS
1μF
1μF
C1P
CIN
1μF
10kΩ
16
______________________________________________________________________________________
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
N.C.
PVDD
COM
SGND
N.C.
20
19
18
17
16
TOP VIEW
C1P
1
15
INR
PGND
2
14
SHDN
CIN
3
13
INL
N.C.
4
12
N.C.
PVSS
5
11
OUTR
6
7
8
9
10
N.C.
SVSS
N.C.
OUTL
SVDD
MAX4409
THIN QFN
Chip Information
TRANSISTOR COUNT: 4295
PROCESS: BiCMOS
______________________________________________________________________________________
17
MAX4409
Pin Configuration
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
20 TQFN
T2044-3
21-0139
24L QFN THIN.EPS
MAX4409
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
18
______________________________________________________________________________________
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
______________________________________________________________________________________
19
MAX4409
Package Information (continued)
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
MAX4409
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
Revision History
REVISION
NUMBER
REVISION
DATE
0
4/03
Initial release
1
6/04
Replaced 5mm x 5mm TQFN package information with 4mm x 4mm TQFN
package information
2
11/07
Replaced Continuous Power Dissipation in Absolute Maximum Ratings
section, changed EC table notes, updated Pin Description and Package
Outlines
3
6/09
Removed TSSOP package
DESCRIPTION
PAGES
CHANGED
—
1, 18
1, 2, 3, 8, 9, 18, 19
1, 2, 8, 11, 15, 16, 17
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
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