19-2618; Rev 2; 9/06
KIT
ATION
EVALU
E
L
B
A
AVAIL
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
Features
The MAX4411 fixed-gain, stereo headphone amplifier is
designed for portable equipment where board space is
at a premium. The MAX4411 uses a unique DirectDrive
architecture to produce a ground-referenced output
from a single supply, eliminating the need for large DCblocking capacitors, saving cost, board space, and
component height. Additionally, the gain of the
amplifier is set internally (-1.5V/V, MAX4411 and
-2V/V, MAX4411B), further reducing component count.
The MAX4411 delivers up to 80mW per channel into a
16Ω load and has low 0.003% THD+N. An 86dB at
217Hz power-supply rejection ratio (PSRR) allows this
device to operate from noisy digital supplies without an
additional linear regulator. The MAX4411 includes ±8kV
ESD protection on the headphone outputs. Comprehensive click-and-pop circuitry suppresses audible
clicks and pops on startup and shutdown. Independent
left/right, low-power shutdown controls make it possible
to optimize power savings in mixed-mode, mono/stereo
applications.
The MAX4411 operates from a single 1.8V to 3.6V supply,
consumes only 5mA of supply current, has short-circuit
and thermal-overload protection, and is specified over the
extended -40°C to +85°C temperature range. The
MAX4411 is available in a tiny (2mm ✕ 2mm ✕ 0.6mm),
16-bump chip-scale package (UCSP™) and a 20-pin thin
QFN package (4mm ✕ 4mm ✕ 0.8mm).
♦ No Bulky DC-Blocking Capacitors Required
♦ Fixed -1.5V/V Gain Eliminates External Feedback
Network
MAX4411: -1.5V/V
MAX4411B: -2V/V
♦ Ground-Referenced Outputs Eliminate DC-Bias
Voltages on Headphone Ground Pin
♦ No Degradation of Low-Frequency Response Due
to Output Capacitors
♦ 80mW per Channel into 16Ω
♦ Low 0.003% THD+N
♦ High PSRR (86dB at 217Hz)
♦ Integrated Click-and-Pop Suppression
♦ 1.8V to 3.6V Single-Supply Operation
♦ Low Quiescent Current (5mA)
♦ Independent Left/Right, Low-Power
Shutdown Controls
♦ Short-Circuit and Thermal-Overload Protection
♦ ±8kV ESD-Protected Amplifier Outputs
♦ Available in Space-Saving Packages
16-Bump UCSP (2mm ✕ 2mm ✕ 0.6mm)
20-Pin Thin QFN (4mm ✕ 4mm ✕ 0.8mm)
Applications
Notebook PCs
Cellular Phones
PDAs
MP3 Players
Smart Phones
Portable Audio Equipment
UCSP is a trademark of Maxim Integrated Products, Inc.
Ordering Information
PART
MAX4411EBE-T
MAX4411EBE+T
MAX4411ETP
TEMP RANGE
PIN/BUMPPACKAGE
GAIN
(V/V)
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
16 UCSP-16
16 UCSP-16
20 Thin QFN
-1.5
-1.5
-1.5
Ordering Information continued at end of data sheet.
+Denotes lead-free package.
Functional Diagram
DirectDrive OUTPUTS
ELIMINATE DC-BLOCKING
CAPACITORS
LEFT
AUDIO
INPUT
SHDNL
SHDNR
MAX4411
RIGHT
AUDIO
INPUT
FIXED GAIN ELIMINATES
EXTERNAL RESISTOR
NETWORK
Pin Configurations and Typical Application Circuit appear at end of data sheet.
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
1
MAX4411
General Description
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
ABSOLUTE MAXIMUM RATINGS
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_ to SGND ................................(SVSS - 0.3V) to (SVDD + 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)
Output Short Circuit to GND or VDD ...........................Continuous
Continuous Power Dissipation (TA = +70°C)
16-Bump UCSP (derate 7.4mW/°C above +70°C)........589mW
20-Pin Thin QFN (derate 16.9mW/°C above +70°C) ..1349mW
Junction Temperature ......................................................+150°C
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Bump Temperature (soldering)
Reflow ..........................................................................+230°C
Lead Temperature (soldering, 10s) .................................+300°C
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
(PVDD = SVDD = 3V, PGND = SGND = 0V, SHDNL = SHDNR = SVDD, C1 = C2 = 2.2µF, CIN = 1µF, RL = ∞, TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
Supply Voltage Range
SYMBOL
VDD
Quiescent Supply Current
IDD
Shutdown Supply Current
I SHDN
CONDITIONS
Guaranteed by PSRR test
MIN
TYP
1.8
UNITS
3.6
V
One channel enabled
3.2
Two channels enabled
5
8.4
6
10
SHDNL = SHDNR = GND
0.7 x
SVDD
VIH
SHDN_ Thresholds
mA
µA
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
MAX4411
-1.55
-1.5
-1.45
MAX4411B
-2.1
-2
-1.9
kHz
AMPLIFIERS
Voltage Gain
Gain Match
AV
ΔAV
Total Output Offset Voltage
VOS
Input Resistance
RIN
1
Input AC-coupled
1.8V ≤ VDD ≤ 3.6V,
MAX4411
Power-Supply Rejection Ratio
2
PSRR
VDD = 3.0V, 200mVP-P
ripple, MAX4411
(Note 3)
%
MAX4411
0.7
2.8
MAX4411B
0.75
3.0
10
14
19
72
86
DC (Note 2)
fRIPPLE = 217Hz
86
fRIPPLE = 1kHz
75
fRIPPLE = 20kHz
53
_______________________________________________________________________________________
V/V
mV
kΩ
dB
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
(PVDD = SVDD = 3V, PGND = SGND = 0V, SHDNL = SHDNR = SVDD, C1 = C2 = 2.2µF, CIN = 1µF, RL = ∞, TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
1.8V ≤ VDD ≤ 3.6V,
MAX4411B
Power-Supply Rejection Ratio
PSRR
Output Power
DC (Note 2)
VDD = 3.0V, 200mVP-P
ripple, MAX4411B
(Note 3)
THD+N ≤ 1%
TA = +25°C
POUT
MIN
TYP
69
86
fRIPPLE = 217Hz
THD+N
fRIPPLE = 1kHz
73
fRIPPLE = 20kHz
51
RL = 32Ω
Signal-to-Noise Ratio
55
Slew Rate
SR
Maximum Capacitive Load
CL
0.003
%
0.004
MAX4411
94
MAX4411B
95
dB
No sustained oscillations
Crosstalk
mW
80
RL = 16Ω, POUT =
60mW
RL = 32Ω, POUT =
20mW, fIN = 1kHz,
BW = 22Hz to 22kHz
SNR
dB
65
RL = 16Ω
fIN = 1kHz
UNITS
86
RL = 32Ω, POUT =
50mW
Total Harmonic Distortion Plus
Noise
MAX
0.8
V/µs
150
pF
90
dB
RL = 16Ω, POUT = 1.6mW, fIN = 10kHz
Thermal Shutdown Threshold
140
°C
Thermal Shutdown Hysteresis
15
°C
±8
kV
ESD Protection
Human Body Model (OUTR, OUTL)
Note 1: All specifications are 100% tested at TA = +25°C; temperature limits are guaranteed by design.
Note 2: Inputs are connected directly to GND.
Note 3: Inputs are AC-coupled to ground.
Typical Operating Characteristics
(C1 = C2 = 2.2µF, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
VDD = 3V
RL = 16Ω
VDD = 3V
RL = 32Ω
1
VDD = 1.8V
RL = 16Ω
THD+N (%)
THD+N (%)
0.1
POUT = 10mW
POUT = 25mW
POUT = 5mW
0.01
0.01
THD+N (%)
0.1
0.1
100
1k
FREQUENCY (Hz)
POUT = 10mW
POUT = 20mW
POUT = 25mW
0.001
10
POUT = 5mW
0.01
POUT = 10mW
POUT = 50mW
0.001
10k
100k
MAX4411 toc03
1
MAX4411 toc01
1
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX4411 toc02
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
10k
100k
FREQUENCY (Hz)
_______________________________________________________________________________________
3
MAX4411
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics (continued)
(C1 = C2 = 2.2µF, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
10
THD+N (%)
THD+N (%)
0.1
POUT = 5mW
POUT = 10mW
0.01
OUTPUTS IN
PHASE
VDD = 3V
RL = 16Ω
fIN = 20Hz
OUTPUTS 180°
OUT OF PHASE
1
0.1
0.01
10
100
1k
10k
ONE CHANNEL
DRIVEN
50
100
200
150
0
50
100
200
150
OUTPUT POWER (mW)
OUTPUT POWER (mW)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
10
OUTPUTS 180°
OUT OF PHASE
0.1
0.01
OUTPUTS IN
PHASE
1
0.1
0.001
OUTPUTS 180°
OUT OF PHASE
100
150
200
OUTPUTS IN
PHASE
1
0.1
OUTPUTS 180°
OUT OF PHASE
0.01
ONE CHANNEL
DRIVEN
0.001
50
VDD = 3V
RL = 32Ω
fIN = 1kHz
10
0.01
ONE CHANNEL
DRIVEN
0
100
THD+N (%)
1
VDD = 3V
RL = 32Ω
fIN = 20Hz
MAX4411 toc08
OUTPUTS IN
PHASE
THD+N (%)
10
100
MAX4411 toc07
VDD = 3V
RL = 16Ω
fIN = 10kHz
MAX4411 toc09
FREQUENCY (Hz)
100
0
25
50
75
100
ONE CHANNEL
DRIVEN
0.001
125
0
25
50
75
100
125
OUTPUT POWER (mW)
OUTPUT POWER (mW)
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 IN
PHASE
1
OUTPUTS 180°
OUT OF PHASE
0.1
OUTPUTS IN
PHASE
VDD = 1.8V
RL = 16Ω
fIN = 20Hz
10
1
OUTPUTS 180°
OUT OF PHASE
0.1
0.01
0.01
ONE CHANNEL
DRIVEN
0.001
0
25
50
75
OUTPUT POWER (mW)
100
125
100
OUTPUTS IN
PHASE
VDD = 1.8V
RL = 16Ω
fIN = 1kHz
10
THD+N (%)
10
100
THD+N (%)
VDD = 3V
RL = 32Ω
fIN = 10kHz
MAX4411 toc10
100
MAX4411 toc12
OUTPUT POWER (mW)
MAX4411 toc11
THD+N (%)
OUTPUTS 180°
OUT OF PHASE
0.1
0.001
0
100k
1
0.01
0.001
0.001
OUTPUTS IN
PHASE
VDD = 3V
RL = 16Ω
fIN = 1kHz
10
ONE CHANNEL
DRIVEN
POUT = 20mW
4
100
THD+N (%)
VDD = 1.8V
RL = 32Ω
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc06
100
MAX4411 toc04
1
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc05
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
THD+N (%)
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
1
OUTPUTS 180°
OUT OF PHASE
0.1
0.01
ONE CHANNEL
DRIVEN
0.001
0
10
20
30
40
OUTPUT POWER (mW)
50
ONE CHANNEL
DRIVEN
0.001
60
0
10
20
30
40
OUTPUT POWER (mW)
_______________________________________________________________________________________
50
60
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
(C1 = C2 = 2.2µF, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
OUTPUTS 180°
OUT OF PHASE
0.1
VDD = 1.8V
RL = 32Ω
fIN = 20Hz
10
OUTPUTS IN
PHASE
1
100
0.1
VDD = 1.8V
RL = 32Ω
fIN = 1kHz
10
THD+N (%)
1
OUTPUTS IN
PHASE
THD+N (%)
THD+N (%)
10
100
MAX4411 toc14
VDD = 1.8V
RL = 16Ω
fIN = 10kHz
MAX4411 toc13
100
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc15
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
OUTPUTS IN
PHASE
1
0.1
OUTPUTS 180°
OUT OF PHASE
OUTPUTS 180°
OUT OF PHASE
0.01
0.01
ONE CHANNEL
DRIVEN
0.001
0.001
20
30
40
50
60
0
10
OUTPUT POWER (mW)
0
OUTPUTS 180°
OUT OF PHASE
-20
0.001
10
20
30
40
-40
-60
-70
-80
-90
-90
-100
-100
10k
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX4411 toc19
0
-40
PSRR (dB)
-30
-40
-50
-60
VDD = 1.8V
RL = 32Ω
-20
-30
-60
-70
-80
-80
-90
-90
10
100
1k
FREQUENCY (Hz)
10k
100k
10k
100k
VDD = 3V
POUT = 1.6mW
RL = 16Ω
-20
-60
LEFT TO RIGHT
-80
-100
-120
-100
-100
1k
-40
-50
-70
100
CROSSTALK vs. FREQUENCY
0
CROSSTALK (dB)
-20
-10
10
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
VDD = 3V
RL = 32Ω
VDD = 1.8V
RL = 16Ω
-60
-80
1k
50
-50
-70
OUTPUT POWER (mW)
0
-10
-30
100
40
-20
-40
10
30
0
-10
-30
50
20
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX4411 toc20
0
10
OUTPUT POWER (mW)
-50
ONE CHANNEL
DRIVEN
0.01
0
50
PSRR (dB)
1
VDD = 3V
RL = 16Ω
-10
PSRR (dB)
THD+N (%)
OUTPUTS IN
PHASE
0.1
40
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX4411 toc16
100
10
30
OUTPUT POWER (mW)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
VDD = 1.8V
RL = 32Ω
fIN = 10kHz
20
MAX4411 toc17
10
0
MAX4411 toc18
0.001
PSRR (dB)
ONE CHANNEL
DRIVEN
ONE CHANNEL
DRIVEN
MAX4411 toc21
0.01
RIGHT TO LEFT
-140
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
10k
100k
FREQUENCY (Hz)
_______________________________________________________________________________________
5
MAX4411
Typical Operating Characteristics (continued)
Typical Operating Characteristics (continued)
(C1 = C2 = 2.2µF, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
OUTPUT POWER vs. SUPPLY VOLTAGE
100
80
60
INPUTS
IN PHASE
40
INPUTS 180°
OUT OF PHASE
200
150
100
INPUTS
IN PHASE
50
0
2.4
2.7
3.0
3.3
2.1
2.4
INPUTS 180°
OUT OF PHASE
120
100
80
INPUTS
IN PHASE
60
3.0
3.3
120
INPUTS 180°
OUT OF PHASE
60
0
0
2.4
2.7
3.0
2.4
3.3
3.0
3.3
250
VDD = 3V
fIN = 1kHz
THD+N = 10%
200
INPUTS 180°
OUT OF PHASE
100
50
INPUTS
IN PHASE
0
100
1k
10k
100k
10
100
1k
10k
SUPPLY VOLTAGE (V)
LOAD RESISTANCE (Ω)
LOAD RESISTANCE (Ω)
OUTPUT POWER vs. LOAD RESISTANCE
OUTPUT POWER vs. LOAD RESISTANCE
POWER DISSIPATION
vs. OUTPUT POWER
30
INPUTS IN
PHASE
25
20
15
VDD = 1.8V
fIN = 1kHz
THD+N = 10%
INPUTS 180°
OUT OF PHASE
50
40
INPUTS IN
PHASE
30
20
10
10
5
10
100
1k
10k
LOAD RESISTANCE (Ω)
100k
INPUTS
IN PHASE
fIN = 1kHz
RL = 16Ω
VDD = 3V
POUT = POUTL + POUTR
350
300
100k
250
INPUTS 180°
OUT OF PHASE
200
150
100
50
0
0
400
POWER DISSIPATION (mW)
35
60
OUTPUT POWER (mW)
INPUTS 180°
OUT OF PHASE
70
MAX4411 toc29
VDD = 1.8V
fIN = 1kHz
THD+N = 1%
MAX4411 toc28
40
3.6
150
INPUTS
IN PHASE
10
3.6
2.7
OUTPUT POWER vs. LOAD RESISTANCE
80
20
2.1
2.1
SUPPLY VOLTAGE (V)
100
20
45
6
1.8
40
40
1.8
INPUTS
IN PHASE
40
3.6
VDD = 3V
fIN = 1kHz
THD+N = 1%
140
OUTPUT POWER (mW)
OUTPUT POWER (mW)
140
2.7
160
MAX4411 toc25
fIN = 1kHz
RL = 32Ω
THD+N = 10%
60
OUTPUT POWER vs. LOAD RESISTANCE
OUTPUT POWER vs. SUPPLY VOLTAGE
160
80
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
180
INPUTS 180°
OUT OF PHASE
0
1.8
3.6
OUTPUT POWER (mW)
2.1
MAX4411 toc26
1.8
100
20
20
0
fIN = 1kHz
RL = 32Ω
THD+N = 1%
120
MAX4411 toc24
MAX4411 toc23
250
MAX4411 toc27
120
fIN = 1kHz
RL = 16Ω
THD+N = 10%
OUTPUT POWER vs. SUPPLY VOLTAGE
140
OUTPUT POWER (mW)
140
INPUTS 180°
OUT OF PHASE
OUTPUT POWER (mW)
OUTPUT POWER (mW)
160
MAX4411 toc22
fIN = 1kHz
RL = 16Ω
THD+N = 1%
180
300
MAX4411 toc30
OUTPUT POWER vs. SUPPLY VOLTAGE
200
OUTPUT POWER (mW)
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
0
10
100
1k
10k
LOAD RESISTANCE (Ω)
100k
0
40
80
120
OUTPUT POWER (mW)
_______________________________________________________________________________________
160
200
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
INPUTS 180°
OUT OF PHASE
120
100
80
fIN = 1kHz
RL = 32Ω
VDD = 3V
POUT = POUTL + POUTR
40
20
80
120
160
200
30
20
fIN = 1kHz
RL = 32Ω
VDD = 1.8V
POUT = POUTL + POUTR
10
0
10
0
20
30
40
50
60
0
10
20
30
40
50
GAIN FLATNESS vs. FREQUENCY
CHARGE-PUMP OUTPUT RESISTANCE
vs. SUPPLY VOLTAGE
OUTPUT POWER vs. CHARGE-PUMP
CAPACITANCE AND LOAD RESISTANCE
-10
-15
-20
C1 = C2 = 2.2μF
80
C1 = C2 = 1μF
70
OUTPUT POWER (mW)
OUTPUT RESISTANCE (Ω)
AV = -2V/V
VIN_ = GND
IPVSS = 10mA
NO LOAD
8
90
MAX4411 toc35
10
MAX4411 toc34
AV = -1.5V/V
-5
6
4
60
50
C1 = C2 = 0.68μF
40
C1 = C2 = 0.47μF
30
20
2
VDD = 3V
RL = 16Ω
fIN = 1kHz
THD+N = 1%
INPUTS IN PHASE
10
0
100
1k
10k
100k
0
1.8
1M
2.1
2.4
2.7
3.0
3.3
3.6
10
20
30
40
FREQUENCY (Hz)
SUPPLY VOLTAGE (V)
LOAD RESISTANCE (Ω)
OUTPUT SPECTRUM vs. FREQUENCY
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SHUTDOWN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
-40
-60
-80
6
4
2
-100
1
10
FREQUENCY (kHz)
100
10
SHDNL = SHDNR = GND
8
6
4
2
0
-120
50
MAX4411 toc39
8
SUPPLY CURRENT (mA)
-20
10
SUPPLY CURRENT (μA)
VOUT = 1VP-P
fIN = 1kHz
RL = 32Ω
MAX4411 toc37
0
0.1
60
OUTPUT POWER (mW)
0
10
INPUTS 180°
OUT OF PHASE
40
OUTPUT POWER (mW)
5
-30
50
OUTPUT POWER (mW)
10
-25
MAX4411 toc33
MAX4411 toc32
40
0
40
0
GAIN (dB)
60
20
0
OUTPUT SPECTRUM (dB)
INPUTS 180°
OUT OF PHASE
80
INPUTS
IN PHASE
60
MAX4411 toc36
60
100
70
MAX4411 toc38
POWER DISSIPATION (mW)
140
INPUTS
IN PHASE
fIN = 1kHz
RL = 16Ω
VDD = 1.8V
POUT = POUTL + POUTR
120
POWER DISSIPATION (mW)
INPUTS
IN PHASE
160
POWER DISSIPATION
vs. OUTPUT POWER
140
MAX4411 toc31
180
POWER DISSIPATION
vs. OUTPUT POWER
POWER DISSIPATION (mW)
POWER DISSIPATION
vs. OUTPUT POWER
0
0
0.9
1.8
SUPPLY VOLTAGE (V)
2.7
3.6
0
0.9
1.8
2.7
3.6
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
7
MAX4411
Typical Operating Characteristics (continued)
(C1 = C2 = 2.2µF, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
Typical Operating Characteristics (continued)
(C1 = C2 = 2.2µF, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.)
POWER-UP/DOWN WAVEFORM
EXITING SHUTDOWN
MAX4411 toc41
MAX4411 toc40
3V
2V/div
VDD
0V
SHDNR
OUT_
OUTR
10mV/div
-100dB
500mV/div
20dB/div
OUT_FFT
fIN = 1kHz
RL = 32Ω
SHDNL = GND
200μs/div
RL = 32Ω
VIN_ = GND
200ms/div
FFT: 25Hz/div
Pin Description
8
PIN
BUMP
QFN
UCSP
1
A4
C1P
2
B4
PGND
3
C4
C1N
Flying Capacitor Negative Terminal
4, 6, 8, 12,
16, 20
—
N.C.
No Connection. Not internally connected.
5
D4
PVSS
Charge-Pump Output
7
D3
SVSS
Amplifier Negative Power Supply. Connect to PVSS.
NAME
FUNCTION
Flying Capacitor Positive Terminal
Power Ground. Connect to ground (0V).
9
D2
OUTL
Left-Channel Output
10
D1
SVDD
Amplifier Positive Power Supply. Connect to positive supply (1.8V to 3.6V).
11
C2
OUTR
Right-Channel Output
13
C1
INL
14
B1
SHDNR
15
A1
INR
17
A2
SGND
Signal Ground. Connect to ground (0V).
18
B2
SHDNL
Active-Low Left-Channel Shutdown. Connect to VDD for normal operation.
19
A3
PVDD
—
—
EP
Left-Channel Audio Input
Active-Low Right-Channel Shutdown. Connect to VDD for normal operation.
Right-Channel Audio Input
Charge-Pump Power Supply. Powers charge-pump inverter, charge-pump logic, and
oscillator. Connect to positive supply (1.8V to 3.6V).
Exposed Paddle. Leave unconnected. Do not connect to any voltage including
GND or VDD.
_______________________________________________________________________________________
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
The MAX4411 fixed-gain, stereo headphone driver features Maxim’s DirectDrive architecture, eliminating the
large output-coupling capacitors required by conventional single-supply headphone drivers. The device consists of two 80mW Class AB headphone drivers, internal
feedback network, undervoltage lockout (UVLO)/shutdown control, charge pump, and comprehensive clickand-pop suppression circuitry (see Typical Application
Circuit). The charge pump inverts the positive supply
(PVDD), 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. The
large DC-blocking capacitors required with conventional headphone drivers are unnecessary, thus conserving
board space, system cost, and improving frequency
response.
Each channel has independent left/right, active-low
shutdown controls, optimizing power savings in mixedmode, mono/stereo operation. 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 MAX4411 features thermaloverload and short-circuit protection and can withstand
±8kV ESD strikes on the output pins.
Fixed Gain
The MAX4411 utilizes an internally fixed gain configuration of either -1.5V/V (MAX4411) or -2V/V (MAX4411B).
All gain-setting resistors are integrated into the device,
reducing external component count. The internally set
gain, in combination with DirectDrive, results in a headphone amplifier that requires only five tiny 1µF capacitors to complete the amplifier circuit: two for the charge
pump, two for audio input coupling, and one for powersupply bypassing (see Typical Application Circuit).
DirectDrive
Conventional 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 DirectDrive architecture uses a charge pump
to create an internal negative supply voltage.
MAX4411
Detailed Description
VDD
VDD/2
VOUT
GND
CONVENTIONAL DRIVER-BIASING SCHEME
+VDD
VOUT
GND
-VDD
DirectDrive BIASING SCHEME
Figure 1. Conventional Driver Output Waveform vs. MAX4411
Output Waveform
This allows the MAX4411 outputs 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
MAX4411 charge pump requires two small ceramic
capacitors, 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 MAX4411 is typically 0.7mV, which, when combined with a 32Ω load, results in less than 23µA 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
_______________________________________________________________________________________
9
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
MICROPHONE
BIAS
LOW-FREQUENCY ROLLOFF
(RL = 16Ω)
MICROPHONE
AMPLIFIER
MICROPHONE
AMPLIFIER
OUTPUT
0
-3
DirectDrive
ATTENUATION (dB)
-6
AUDIO
INPUT
-9
330μF
-12
220μF
-15
100μF
-18
33μF
-21
-24
AUDIO
INPUT
MAX4411
-27
-30
10
100
1k
10k
100k
FREQUENCY (Hz)
HEADPHONE DRIVER
Figure 2. Earbud Speaker/Microphone Combination Headset
Configuration
method raises some issues:
• The sleeve is typically grounded to the chassis.
Using this biasing approach, the sleeve must be
isolated from system ground, complicating product
design.
• 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.
• 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.
• When using a combination microphone and speaker
headset, the microphone typically requires a GND
reference. The driver DC bias on the sleeve conflicts
with the microphone requirements (Figure 2).
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:
1) The impedance of the headphone load and the DCblocking capacitor forms a highpass filter with the
-3dB point set by:
10
Figure 3. Low-Frequency Attenuation for Common DC-Blocking
Capacitor Values
f−3dB =
1
2πRLCOUT
where RL is the impedance of the headphone and
COUT is the value of the DC-blocking capacitor.
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 3 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.
2) The voltage coefficient of the DC-blocking capacitor
contributes distortion to the reproduced audio signal
as the capacitance value varies as the function of
the voltage across the capacitor changes. 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 4 shows the THD+N intro-
______________________________________________________________________________________
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
MAX4411 fig04
10
THD+N (%)
1
0.1
TANTALUM
0.01
0.001
ALUM/ELEC
0.0001
10
100
1k
10k
100k
FREQUENCY (Hz)
Figure 4. Distortion Contributed by DC-Blocking Capacitors
duced 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 laptops, as
well as MP3, CD, and DVD players. By eliminating the
DC-blocking capacitors through DirectDrive technology,
these capacitor-related deficiencies are eliminated.
Charge Pump
The MAX4411 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
charge pump, 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 MAX4411 features two shutdown controls allowing
either channel to be shut down or muted independently.
SHDNL controls the left channel while SHDNR controls
the right channel. Driving either SHDN_ low disables
the respective channel, sets the driver output impedance to 1kΩ, and reduces the supply current. When
both SHDN_ inputs are driven low, the charge pump is
also disabled, further reducing supply current draw to
Click-and-Pop Suppression
In conventional 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 MAX4411 does not require
output-coupling capacitors, this does not arise.
Additionally, the MAX4411 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 MAX4411 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 MAX4411, 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 (80ms
to 100ms) based on RIN and CIN, relative to the startup
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:
PDISSPKG(MAX) =
TJ(MAX) − TA
θ JA
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, θ JA of the QFN package is
+59.3°C/W.
The MAX4411 has two power dissipation sources, the
charge pump and the 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 heatsinking to the device. Large
______________________________________________________________________________________
11
MAX4411
6µA. The charge pump is enabled once either SHDN_
input is driven high.
ADDITIONAL THD+N DUE
TO DC-BLOCKING CAPACITORS
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
fIN = 1kHz
RL = 16Ω
THD+N = 10%
OUTPUT POWER (mW)
250
INPUTS 180°
OUT OF PHASE
MAX4411 fig05
OUTPUT POWER vs. SUPPLY VOLTAGE
300
200
Component Selection
150
100
INPUTS
IN PHASE
50
0
1.8
2.1
2.4
2.7
3.0
3.3
3.6
SUPPLY VOLTAGE (V)
Figure 5. Output Power vs. Supply Voltage with Inputs In/Out of
Phase
output, supply, and ground traces improve the maximum power dissipation in the package.
Thermal-overload protection limits total power dissipation in the MAX4411. 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 thermaloverload 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 5 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 MAX4411 is the internally
generated, negative supply voltage (PVSS). This voltage provides the ground-referenced output level. PVSS
can, however, also be used to power other devices
within a design limit current drawn from PVSS to 5mA;
exceeding this affects the headphone driver operation.
A typical application is a negative supply to adjust the
contrast of LCD modules.
12
PVSS is roughly proportional to PVDD and is not a regulated voltage. The charge-pump output impedance
must be taken into account when powering other
devices from PVSS. The charge-pump output impedance plot appears in the Typical Operating
Characteristics. For best results, use 2.2µF chargepump capacitors.
Input Filtering
The input capacitor (CIN), in conjunction with the internal 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:
1
f−3dB =
2πRINCIN
RIN is the amplifier’s internal input resistance value
given in the Electrical Characteristics. Choose the CIN
such that f-3dB is well below the lowest frequency of
interest. Setting f-3dB too high affects the amplifier’s lowfrequency response. Use capacitors whose dielectrics
have low-voltage coefficients, such as tantalum or
aluminum electrolytic ones. 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 charge
pump’s load regulation and output resistance. 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.
Hold Capacitor (C2)
The hold capacitor value and ESR directly affect the
ripple at PV SS . Increasing the value of C2 reduces
______________________________________________________________________________________
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
PHONE
FAX
Taiyo Yuden
SUPPLIER
800-348-2496
847-925-0899
www.t-yuden.com
WEBSITE
TDK
847-803-6100
847-390-4405
www.component.tdk.com
Note: Please indicate you are using the MAX4411 when contacting these component suppliers.
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. Charge-Pump 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 MAX4411’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.
Adding Volume Control
The addition of a digital potentiometer provides simple
volume control. Figure 6 shows the MAX4411 with the
MAX5408 dual log taper digital potentiometer used as
an input attenuator. Connect the high terminal of the
MAX5408 to the audio input, the low terminal to
ground, and the wiper to CIN. Setting the wiper to the
top position passes the audio signal unattenuated.
Setting the wiper to the lowest position fully attenuates
the input.
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
LEFT AUDIO
INPUT
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
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.
The QFN package features an exposed paddle that
improves thermal efficiency of the package. However,
the MAX4411 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.
When using the MAX4411 in a UCSP package, make
sure the traces to OUTR (bump C2) are wide enough to
handle the maximum expected current flow. Multiple
traces may be necessary.
UCSP Applications Information
For the latest application details on UCSP construction,
dimensions, tape carrier information, printed circuit
board techniques, bump-pad layout, and recommended reflow temperature profile, as well as the latest information on reliability testing results, go to Maxim’s
website at www.maxim-ic.com/ucsp and look up the
Application Note: UCSP–A Wafer-Level Chip-Scale
Package.
5 H0
CIN
W0A 7
6
13
INL
OUTL
9
L0
MAX4411
MAX5408
RIGHT AUDIO 12 H1
INPUT
CIN
W1A 10
15
INR
OUTR
11
11 L1
Figure 6. MAX4411 and MAX5408 Volume Control Circuit
______________________________________________________________________________________
13
MAX4411
Table 1. Suggested Capacitor Manufacturers
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
MAX4411
System Diagram
VDD
0.1μF
15kΩ
0.1μF 15kΩ
INR
VDD
PVDD
0.1μF
1μF
OUTR-
MAX9710
BIAS
AUX_IN
OUTR+
1μF
SHDN
OUT
OUTL-
0.1μF 15kΩ
MAX4060
BIAS
OUTL+
INL
VCC
15kΩ
CODEC
VCC
2.2kΩ
10kΩ
0.1μF
IN-
IN+
VCC
10kΩ
Q
IN0.1μF
MAX961
Q
100kΩ
100kΩ
IN+
0.1μF
SHDNL
SHDNR
1μF
INL
MAX4411 OUTL
1μF
VCC
OUTR
INR
PVSS
1μF
PVDD
SVDD
SVSS
C1P
CIN
1μF
1μF
14
______________________________________________________________________________________
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
1.8V TO 3.6V
LEFT
CHANNEL
AUDIO IN
C3
1μF
19
(A3)
10
(D1)
18
(B2)
PVDD
SVDD
SHDNL
CIN
1μF
14
(B1)
SHDNR
13
(C1)
INL
RF*
SVDD
RIN
14kΩ
9
OUTL (D2)
HEADPHONE
JACK
UVLO/
SHUTDOWN
CONTROL
1
(A4) C1P
SVSS
CHARGE
PUMP
C1
1μF
CLICK-AND-POP
SUPPRESSION
SGND
3
(C4) C1N
SVDD
SGND
OUTR
RIN
14kΩ
MAX4411
11
(C2)
SVSS
RF
PVSS
5
(D4)
SVSS PGND
2
7
(D3) (B4)
C2
1μF
SGND
17
(A2)
INR
15
(A1)
RIGHT
CHANNEL
AUDIO IN
CIN
1μF
*MAX4411: 21kΩ, MAX4411B: 28kΩ
( ) UCSP BUMPS.
______________________________________________________________________________________
15
MAX4411
Typical Application Circuit
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
INL
N.C.
OUTR
15
14
13
12
11
TOP VIEW
1
2
3
4
INR
SGND
PVDD
C1P
A
B
PGND
10
SVDD
SGND 17
9
OUTL
8
N.C.
PVDD 19
7
SVSS
N.C. 20
6
N.C.
SHDNL 18
SVDD
OUTL
C1N
SVSS
PVSS
UCSP (B16-2)
1
2
3
4
5
PVSS
OUTR
PGND
D
INL
MAX4411
C1P
C
N.C.
SHDNL
N.C. 16
C1N
SHDNR
SHDNR
MAX4411
TOP VIEW
(BUMPS SIDE
DOWN)
INR
MAX4411
Pin Configurations
TQFN
Ordering Information (continued)
PART
TEMP RANGE
PIN/BUMPPACKAGE
GAIN
(V/V)
MAX4411ETP+
MAX4411BEBE-T
MAX4411BEBE+T
MAX4411BETP
MAX4411BETP+
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
20 Thin QFN
16 UCSP-16
16 UCSP-16
20 Thin QFN
20 Thin QFN
-1.5
-2
-2
-2
-2
Chip Information
TRANSISTOR COUNT: 4295
PROCESS: BiCMOS
+Denotes lead-free package.
16
______________________________________________________________________________________
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
16L,UCSP.EPS
PACKAGE OUTLINE, 4x4 UCSP
21-0101
H
1
1
______________________________________________________________________________________
17
MAX4411
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
24L QFN THIN.EPS
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
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.
18 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2006 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
工商网监
湘ICP备2023018690号
