MAXIM MAX4411 Technical data

General Description
The MAX4411 fixed-gain, stereo headphone amplifier is designed for portable equipment where board space is at a premium. The MAX4411 uses a unique, patented DirectDrive architecture to produce a ground-refer­enced output from a single supply, eliminating the need for large DC-blocking 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).
Applications
Features
No Bulky DC-Blocking Capacitors RequiredFixed -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 16ΩLow 0.003% THD+NHigh PSRR (86dB at 217Hz)Integrated Click-and-Pop Suppression1.8V to 3.6V Single-Supply OperationLow Quiescent Current (5mA)Independent Left/Right, Low-Power
Shutdown Controls
Short-Circuit and Thermal-Overload Protection±8kV ESD-Protected Amplifier OutputsAvailable in Space-Saving Packages
16-Bump UCSP (2mm 2mm 0.6mm) 20-Pin Thin QFN (4mm 4mm 0.8mm)
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
________________________________________________________________ Maxim Integrated Products 1
LEFT AUDIO INPUT
DirectDrive OUTPUTS
ELIMINATE DC-BLOCKING
CAPACITORS
FIXED GAIN ELIMINATES
EXTERNAL RESISTOR
NETWORK
RIGHT AUDIO INPUT
SHDNL SHDNR
MAX4411
Functional Diagram
Ordering Information
19-2618; Rev 2; 9/06
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.
EVALUATION KIT
AVAILABLE
PART
TEMP RANGE
PIN/BUMP­PACKAGE
GAIN
(V/V)
MAX4411EBE-T
-1.5
MAX4411EBE+T
-1.5
MAX4411ETP
-1.5
Notebook PCs Cellular Phones PDAs
MP3 Players Smart Phones Portable Audio Equipment
UCSP is a trademark of Maxim Integrated Products, Inc.
Pin Configurations and Typical Application Circuit appear at end of data sheet.
Ordering Information continued at end of data sheet.
+Denotes lead-free package.
-40°C to +85°C 16 UCSP-16
-40°C to +85°C 16 UCSP-16
-40°C to +85°C 20 Thin QFN
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with Shutdown
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(PVDD= SVDD= 3V, PGND = SGND = 0V, SHDNL = SHDNR = SVDD, C1 = C2 = 2.2µF, CIN= 1µF, RL= , TA= T
MIN
to T
MAX
,
unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
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.
PGND to SGND .....................................................-0.3V to +0.3V
PV
DD
to SV
DD .................................................................
-0.3V to +0.3V
PV
SS
to SVSS.........................................................-0.3V to +0.3V
PV
DD
and SVDDto PGND or SGND .........................-0.3V to +4V
PV
SS
and SVSSto PGND or SGND ..........................-4V to +0.3V
IN_ to SGND ................................(SV
SS
- 0.3V) to (SVDD+ 0.3V)
SHDN_ to SGND........................(SGND - 0.3V) to (SV
DD
+ 0.3V)
OUT_ to SGND .............................(SV
SS
- 0.3V) to (SVDD+0.3V)
C1P to PGND.............................(PGND - 0.3V) to (PV
DD
+ 0.3V)
C1N to PGND .............................(PV
SS
- 0.3V) to (PGND + 0.3V)
Output Short Circuit to GND or V
DD
...........................Continuous
Continuous Power Dissipation (T
A
= +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
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage Range V
DD
Guaranteed by PSRR test 1.8 3.6 V
One channel enabled 3.2
Quiescent Supply Current I
DD
Two channels enabled 5 8.4
mA
Shutdown Supply Current I
SHDN
SHDNL = SHDNR = GND 6 10 µA
V
IH
0.7 x
SHDN_ Thresholds
V
IL
0.3 x
V
SHDN_ Input Leakage Current -1 +1 µA SHDN_ to Full Operation t
SON
µs
CHARGE PUMP
Oscillator Frequency f
OSC
368 kHz
AMPLIFIERS
MAX4411
Voltage Gain A
V
MAX4411B
-2
V/V
Gain Match ΔA
V
1%
MAX4411 0.7 2.8
Total Output Offset Voltage V
OS
Input AC-coupled
MAX4411B
3.0
mV
Input Resistance R
IN
10 14 19 kΩ
1.8V VDD 3.6V, MAX4411
DC (Note 2) 72 86
f
RIPPLE
= 217Hz 86
f
RIPPLE
= 1kHz 75
Power-Supply Rejection Ratio PSRR
V
DD
= 3.0V, 200mV
P-P
ripple, MAX4411 (Note 3)
f
RIPPLE
= 20kHz 53
dB
SV
DD
175
272 320
-1.55 -1.5 -1.45
-2.1
0.75
SV
DD
-1.9
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(PVDD= SVDD= 3V, PGND = SGND = 0V, SHDNL = SHDNR = SVDD, C1 = C2 = 2.2µF, CIN= 1µF, RL= , TA= T
MIN
to T
MAX
,
unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
Note 1: All specifications are 100% tested at T
A
= +25°C; temperature limits are guaranteed by design.
Note 2: Inputs are connected directly to GND. Note 3: Inputs are AC-coupled to ground.
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
1.8V VDD 3.6V, MAX4411B
DC (Note 2) 69 86
f
RIPPLE
= 217Hz 86
f
RIPPLE
= 1kHz 73
Power-Supply Rejection Ratio PSRR
V
DD
= 3.0V, 200mV
P-P
ripple, MAX4411B (Note 3)
f
RIPPLE
= 20kHz 51
dB
RL = 32Ω 65
Output Power P
OUT
THD+N 1% T
A
= +25°C
R
L
= 16Ω 55 80
mW
RL = 32Ω, P
OUT
=
50mW
Total Harmonic Distortion Plus Noise
fIN = 1kHz
R
L
= 16Ω, P
OUT
=
60mW
%
MAX4411 94
Signal-to-Noise Ratio SNR
R
L
= 32Ω, P
OUT
=
20mW, f
IN
= 1kHz,
BW = 22Hz to 22kHz
MAX4411B 95
dB
Slew Rate SR 0.8 V/µs
Maximum Capacitive Load C
L
No sustained oscillations
pF
Crosstalk RL = 16Ω, P
OUT
= 1.6mW, fIN = 10kHz 90 dB
Thermal Shutdown Threshold
°C
Thermal Shutdown Hysteresis 15 °C
ESD Protection Human Body Model (OUTR, OUTL) ±8kV
Typical Operating Characteristics
(C1 = C2 = 2.2µF, THD+N measurement bandwidth = 22Hz to 22kHz, T
A
= +25°C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX4411 toc01
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01
0.1
1
0.001 10 100k
VDD = 3V R
L
= 16
Ω
P
OUT
= 10mW
P
OUT
= 25mW
P
OUT
= 50mW
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX4411 toc02
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01
0.1
1
0.001 10 100k
P
OUT
= 5mW
P
OUT
= 10mW
P
OUT
= 25mW
VDD = 3V R
L
= 32
Ω
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX4411 toc03
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01
0.1
1
0.001 10 100k
P
OUT
= 5mW
P
OUT
= 10mW
P
OUT
= 20mW
VDD = 1.8V R
L
= 16
Ω
THD+N
0.003
0.004
150
140
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with Shutdown
4 _______________________________________________________________________________________
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX4411 toc04
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.01
0.1
1
0.001
10 100k
P
OUT
= 5mW
P
OUT
= 10mW
P
OUT
= 20mW
VDD = 1.8V R
L
= 32
Ω
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc05
OUTPUT POWER (mW)
THD+N (%)
15010050
0.01
0.1
1
10
100
0.001 0 200
VDD = 3V R
L
= 16
Ω
f
IN
= 20Hz
OUTPUTS IN PHASE
OUTPUTS 180
°
OUT OF PHASE
ONE CHANNEL DRIVEN
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc06
OUTPUT POWER (mW)
THD+N (%)
15010050
0.01
0.1
1
10
100
0.001 0200
OUTPUTS IN PHASE
OUTPUTS 180
°
OUT OF PHASE
ONE CHANNEL DRIVEN
VDD = 3V R
L
= 16
Ω
f
IN
= 1kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc07
OUTPUT POWER (mW)
THD+N (%)
15010050
0.01
0.1
1
10
100
0.001 0200
OUTPUTS IN PHASE
OUTPUTS 180
°
OUT OF PHASE
ONE CHANNEL DRIVEN
VDD = 3V R
L
= 16
Ω
f
IN
= 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc08
OUTPUT POWER (mW)
THD+N (%)
100755025
0.01
0.1
1
10
100
0.001 0 125
OUTPUTS IN PHASE
OUTPUTS 180
°
OUT OF PHASE
ONE CHANNEL DRIVEN
VDD = 3V R
L
= 32Ω
f
IN
= 20Hz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc09
OUTPUT POWER (mW)
THD+N (%)
100755025
0.01
0.1
1
10
100
0.001 0125
OUTPUTS IN PHASE
OUTPUTS 180° OUT OF PHASE
ONE CHANNEL DRIVEN
VDD = 3V R
L
= 32Ω
f
IN
= 1kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc10
OUTPUT POWER (mW)
THD+N (%)
100755025
0.01
0.1
1
10
100
0.001 0 125
OUTPUTS IN PHASE
OUTPUTS 180° OUT OF PHASE
ONE CHANNEL DRIVEN
VDD = 3V R
L
= 32Ω
f
IN
= 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc11
OUTPUT POWER (mW)
THD+N (%)
5040302010
0.01
0.1
1
10
100
0.001 060
OUTPUTS IN PHASE
OUTPUTS 180° OUT OF PHASE
ONE CHANNEL DRIVEN
VDD = 1.8V R
L
= 16Ω
f
IN
= 20Hz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc12
OUTPUT POWER (mW)
THD+N (%)
5040302010
0.01
0.1
1
10
100
0.001 060
OUTPUTS IN PHASE
OUTPUTS 180° OUT OF PHASE
ONE CHANNEL DRIVEN
VDD = 1.8V R
L
= 16Ω
f
IN
= 1kHz
Typical Operating Characteristics (continued)
(C1 = C2 = 2.2µF, THD+N measurement bandwidth = 22Hz to 22kHz, T
A
= +25°C, unless otherwise noted.)
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
_______________________________________________________________________________________ 5
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc16
OUTPUT POWER (mW)
THD+N (%)
40302010
0.01
0.1
1
10
100
0.001 050
OUTPUTS IN PHASE
OUTPUTS 180° OUT OF PHASE
ONE CHANNEL DRIVEN
VDD = 1.8V R
L
= 32Ω
f
IN
= 10kHz
CROSSTALK vs. FREQUENCY
MAX4411 toc21
FREQUENCY (Hz)
CROSSTALK (dB)
10k1k100
-120
-100
-80
-60
-40
-20
0
-140 10 100k
VDD = 3V P
OUT
= 1.6mW
R
L
= 16Ω
LEFT TO RIGHT
RIGHT TO LEFT
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc13
OUTPUT POWER (mW)
THD+N (%)
5040302010
0.01
0.1
1
10
100
0.001 060
OUTPUTS IN PHASE
OUTPUTS 180° OUT OF PHASE
ONE CHANNEL DRIVEN
VDD = 1.8V R
L
= 16Ω
f
IN
= 10kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc14
OUTPUT POWER (mW)
THD+N (%)
40302010
0.01
0.1
1
10
100
0.001 050
OUTPUTS IN PHASE
OUTPUTS 180° OUT OF PHASE
ONE CHANNEL DRIVEN
VDD = 1.8V R
L
= 32Ω
f
IN
= 20Hz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER
MAX4411 toc15
OUTPUT POWER (mW)
THD+N (%)
40302010
0.01
0.1
1
10
100
0.001 050
OUTPUTS IN PHASE
OUTPUTS 180° OUT OF PHASE
ONE CHANNEL DRIVEN
VDD = 1.8V R
L
= 32Ω
f
IN
= 1kHz
Typical Operating Characteristics (continued)
(C1 = C2 = 2.2µF, THD+N measurement bandwidth = 22Hz to 22kHz, T
A
= +25°C, unless otherwise noted.)
0
-100 10 100 1k 10k 100k
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
-80
MAX4411 toc18
FREQUENCY (Hz)
PSRR (dB)
-60
-40
-20
-30
-50
-70
-90
-10
VDD = 1.8V
R
L
= 16Ω
0
-100 10 100 1k 10k 100k
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
-80
MAX4411 toc19
FREQUENCY (Hz)
PSRR (dB)
-60
-40
-20
-30
-50
-70
-90
-10
VDD = 3V
R
L
= 32Ω
10 100 1k 10k 100k
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX4411 toc20
FREQUENCY (Hz)
VDD = 1.8V
R
L
= 32Ω
0
-100
-80
PSRR (dB)
-60
-40
-20
-30
-50
-70
-90
-10
0
-100
10 100 1k 10k 100k
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
-80
MAX4411 toc17
FREQUENCY (Hz)
PSRR (dB)
-60
-40
-20
-30
-50
-70
-90
-10
VDD = 3V R
L
= 16Ω
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with Shutdown
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(C1 = C2 = 2.2µF, THD+N measurement bandwidth = 22Hz to 22kHz, T
A
= +25°C, unless otherwise noted.)
POWER DISSIPATION
vs. OUTPUT POWER
MAX4411 toc30
OUTPUT POWER (mW)
POWER DISSIPATION (mW)
16012040 80
50
100
150
200
250
300
350
400
0
0200
INPUTS 180°
OUT OF PHASE
fIN = 1kHz R
L
= 16Ω
V
DD
= 3V
P
OUT
= P
OUTL + POUTR
INPUTS
IN PHASE
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX4411 toc22
SUPPLY VOLTAGE (V)
OUTPUT POWER (mW)
3.33.02.72.42.1
20
40
60
80
100
120
140
160
180
200
0
1.8 3.6
fIN = 1kHz R
L
= 16Ω
THD+N = 1%
INPUTS
IN PHASE
INPUTS 180°
OUT OF PHASE
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX4411 toc23
SUPPLY VOLTAGE (V)
OUTPUT POWER (mW)
3.33.02.72.42.1
50
100
150
200
250
300
0
1.8 3.6
fIN = 1kHz R
L
= 16Ω
THD+N = 10%
INPUTS
IN PHASE
INPUTS 180°
OUT OF PHASE
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX4411 toc24
SUPPLY VOLTAGE (V)
OUTPUT POWER (mW)
3.33.02.72.42.1
20
40
60
80
100
120
140
0
1.8 3.6
fIN = 1kHz R
L
= 32Ω
THD+N = 1%
INPUTS 180°
OUT OF PHASE
INPUTS
IN PHASE
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX4411 toc25
SUPPLY VOLTAGE (V)
OUTPUT POWER (mW)
3.33.02.72.42.1
40
20
60
80
100
120
140
160
180
0
1.8 3.6
fIN = 1kHz R
L
= 32Ω
THD+N = 10%
INPUTS
IN PHASE
INPUTS 180°
OUT OF PHASE
OUTPUT POWER vs. LOAD RESISTANCE
MAX4411 toc26
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
10k1k100
40
20
60
80
100
120
140
160
0
10 100k
VDD = 3V f
IN
= 1kHz
THD+N = 1%
INPUTS 180°
OUT OF PHASE
INPUTS
IN PHASE
OUTPUT POWER vs. LOAD RESISTANCE
MAX4411 toc27
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
10k1k100
50
100
150
200
250
0
10 100k
INPUTS
IN PHASE
INPUTS 180°
OUT OF PHASE
VDD = 3V f
IN
= 1kHz
THD+N = 10%
OUTPUT POWER vs. LOAD RESISTANCE
MAX4411 toc28
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
10k1k100
5
10
15
20
25
30
35
40
45
0
10 100k
INPUTS 180° OUT OF PHASE
INPUTS IN PHASE
VDD = 1.8V f
IN
= 1kHz
THD+N = 1%
OUTPUT POWER vs. LOAD RESISTANCE
MAX4411 toc29
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
10k1k100
10
20
30
40
50
60
70
0
10 100k
INPUTS 180° OUT OF PHASE
INPUTS IN PHASE
VDD = 1.8V f
IN
= 1kHz
THD+N = 10%
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
_______________________________________________________________________________________ 7
Typical Operating Characteristics (continued)
(C1 = C2 = 2.2µF, THD+N measurement bandwidth = 22Hz to 22kHz, T
A
= +25°C, unless otherwise noted.)
GAIN FLATNESS vs. FREQUENCY
MAX4411 toc34
FREQUENCY (Hz)
GAIN (dB)
100k10k1k100
-20
-25
-15
-10
-5
0
5
10
-30 10 1M
VDD = 3V R
L
= 16Ω
AV = -1.5V/V AV = -2V/V
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX4411 toc38
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
2.71.80.9
2
4
6
8
10
0
03.6
POWER DISSIPATION
vs. OUTPUT POWER
MAX4411 toc31
OUTPUT POWER (mW)
POWER DISSIPATION (mW)
16012040 80
20
40
60
80
120
100
140
160
180
0
0 200
INPUTS 180°
OUT OF PHASE
fIN = 1kHz R
L
= 32Ω
V
DD
= 3V
P
OUT
= P
OUTL + POUTR
INPUTS
IN PHASE
POWER DISSIPATION
vs. OUTPUT POWER
MAX4411 toc32
OUTPUT POWER (mW)
POWER DISSIPATION (mW)
50403010 20
20
40
60
80
100
120
140
0
060
INPUTS 180°
OUT OF PHASE
fIN = 1kHz R
L
= 16Ω
V
DD
= 1.8V
P
OUT
= P
OUTL + POUTR
INPUTS
IN PHASE
POWER DISSIPATION
vs. OUTPUT POWER
MAX4411 toc33
OUTPUT POWER (mW)
POWER DISSIPATION (mW)
50403010 20
10
20
30
40
50
60
70
0
060
INPUTS 180°
OUT OF PHASE
fIN = 1kHz R
L
= 32Ω
V
DD
= 1.8V
P
OUT
= P
OUTL + POUTR
INPUTS
IN PHASE
CHARGE-PUMP OUTPUT RESISTANCE
vs. SUPPLY VOLTAGE
MAX4411 toc35
SUPPLY VOLTAGE (V)
OUTPUT RESISTANCE (Ω)
3.33.02.72.42.1
2
4
6
8
10
0
1.8 3.6
V
IN_
= GND
I
PVSS
= 10mA
NO LOAD
OUTPUT POWER vs. CHARGE-PUMP
CAPACITANCE AND LOAD RESISTANCE
MAX4411 toc36
LOAD RESISTANCE (Ω)
OUTPUT POWER (mW)
403020
20
10
30
40
50
60
70
80
90
0
10 50
fIN = 1kHz
THD+N = 1%
INPUTS IN PHASE
C1 = C2 = 1μF
C1 = C2 = 0.47μF
C1 = C2 = 0.68μF
C1 = C2 = 2.2μF
SHUTDOWN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX4411 toc39
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (μA)
2.71.80.9
2
4
6
8
10
0
03.6
SHDNL = SHDNR = GND
FREQUENCY (kHz)
101
0.1 100
OUTPUT SPECTRUM vs. FREQUENCY
MAX4411 toc37
OUTPUT SPECTRUM (dB)
-100
-80
-60
-40
-20
0
-120
V
OUT
= 1V
P-P
fIN = 1kHz R
L
= 32Ω
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with Shutdown
8 _______________________________________________________________________________________
Pin Description
PIN BUMP
QFN UCSP
NAME FUNCTION
1 A4 C1P Flying Capacitor Positive Terminal
2 B4 PGND Power Ground. Connect to ground (0V).
3 C4 C1N Flying Capacitor Negative Terminal
4, 6, 8, 12,
16, 20
N.C. No Connection. Not internally connected.
5D4PVSSCharge-Pump Output
7D3SVSSAmplifier Negative Power Supply. Connect to PVSS.
9 D2 OUTL Left-Channel Output
10 D1 SV
DD
Amplifier Positive Power Supply. Connect to positive supply (1.8V to 3.6V).
11 C2 OUTR Right-Channel Output
13 C1 INL Left-Channel Audio Input 14 B1 SHDNR Active-Low Right-Channel Shutdown. Connect to VDD for normal operation.
15 A1 INR Right-Channel Audio Input
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 PV
DD
Charge-Pump Power Supply. Powers charge-pump inverter, charge-pump logic, and oscillator. Connect to positive supply (1.8V to 3.6V).
—— EP
Exposed Paddle. Leave unconnected. Do not connect to any voltage including
GND or V
DD
.
Typical Operating Characteristics (continued)
(
C1 = C2 = 2.2µF, THD+N measurement bandwidth = 22Hz to 22kHz, T
A
= +25°C, unless otherwise noted.
)
EXITING SHUTDOWN
MAX4411 toc40
OUTR
SHDNR
2V/div
500mV/div
200μs/div
fIN = 1kHz RL = 32Ω SHDNL = GND
V
OUT_
OUT_FFT
POWER-UP/DOWN WAVEFORM
DD
-100dB
200ms/div
R
L
V
IN_
= 32Ω
= GND
FFT: 25Hz/div
MAX4411 toc41
3V
0V
10mV/div
20dB/div
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
_______________________________________________________________________________________ 9
Detailed Description
The MAX4411 fixed-gain, stereo headphone driver fea­tures Maxim’s patented 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 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 V
DD
/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 patented DirectDrive architecture uses a charge pump to create an internal negative supply volt-
age. 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
+V
DD
-V
DD
GND
V
OUT
CONVENTIONAL DRIVER-BIASING SCHEME
DirectDrive BIASING SCHEME
VDD/2
V
DD
GND
V
OUT
Figure 1. Conventional Driver Output Waveform vs. MAX4411 Output Waveform
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with Shutdown
10 ______________________________________________________________________________________
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 DC-
blocking capacitor forms a highpass filter with the
-3dB point set by:
where R
L
is the impedance of the headphone and
C
OUT
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 C
OUT
reduce this effect but result in physically larger, more expensive capacitors. Figure 3 shows the relationship between the size of C
OUT
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-
f
RC
dB
L OUT
−=3
1
2π
0
-30 10 100 1k 10k 100k
LOW-FREQUENCY ROLLOFF
(R
L
= 16Ω)
-24
-27
-12
-15
-18
-21
-6
-9
-3
FREQUENCY (Hz)
ATTENUATION (dB)
DirectDrive
330μF
220μF
100μF
33μF
Figure 3. Low-Frequency Attenuation for Common DC-Blocking Capacitor Values
HEADPHONE DRIVER
MICROPHONE
AMPLIFIER
MICROPHONE
AMPLIFIER
OUTPUT
AUDIO INPUT
AUDIO INPUT
MICROPHONE
BIAS
MAX4411
Figure 2. Earbud Speaker/Microphone Combination Headset Configuration
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
______________________________________________________________________________________ 11
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
6µA. The charge pump is enabled once either SHDN_ input is driven high.
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 RFof 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 RINand C
IN,
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:
where T
J(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 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 VDD, increase load impedance, decrease the ambient tem­perature, or add heatsinking to the device. Large
P
TT
DISSPKG MAX
J MAX A
()
()
=
θ
ADDITIONAL THD+N DUE
TO DC-BLOCKING CAPACITORS
MAX4411 fig04
FREQUENCY (Hz)
THD+N (%)
10k1k100
0.001
0.01
0.1
1
10
0.0001 10 100k
TANTALUM
ALUM/ELEC
Figure 4. Distortion Contributed by DC-Blocking Capacitors
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with Shutdown
12 ______________________________________________________________________________________
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. PV
SS
can, however, also be used to power other devices within a design limit current drawn from PV
SS
to 5mA; exceeding this affects the headphone driver operation. A typical application is a negative supply to adjust the contrast of LCD modules.
PVSSis roughly proportional to PVDDand 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.
Component Selection
Input Filtering
The input capacitor (C
IN
), in conjunction with the inter-
nal R
IN,
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:
R
IN
is the amplifier’s internal input resistance value
given in the Electrical Characteristics. Choose the C
IN
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
f
RC
dB
IN IN
−=3
1
2π
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX4411 fig05
SUPPLY VOLTAGE (V)
OUTPUT POWER (mW)
3.33.02.72.42.1
50
100
150
200
250
300
0
1.8 3.6
fIN = 1kHz R
L
= 16Ω
THD+N = 10%
INPUTS
IN PHASE
INPUTS 180°
OUT OF PHASE
Figure 5. Output Power vs. Supply Voltage with Inputs In/Out of Phase
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
______________________________________________________________________________________ 13
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 PV
DD
with C3, the same value as C1, and
place it physically close to the PVDDand 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 PV
DD
and SVDDtogether at the
device. Connect PVSSand SVSStogether 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 V
DD
. 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.
Table 1. Suggested Capacitor Manufacturers
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 MAX4411 when contacting these component suppliers.
OUTL
MAX4411
INL
13
MAX5408
H0
L0
5
6
W0A
7
LEFT AUDIO
INPUT
15
W1A
10
C
IN
C
IN
RIGHT AUDIO
INPUT
INR
OUTR
11
9
H1
L1
12
11
Figure 6. MAX4411 and MAX5408 Volume Control Circuit
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with Shutdown
14 ______________________________________________________________________________________
MAX9710
MAX961
OUTR+
OUTR-
OUTL-
OUTL+
INR
INL
BIAS
PV
DD
V
DD
SHDN
15kΩ
15kΩ
15kΩ
15kΩ
V
DD
0.1μF
0.1μF
0.1μF
1μF
MAX4060
MAX4411
Q
Q
IN+
IN-
0.1μF
OUTL
OUTR
C1P CIN
PV
SS
PV
DD
SV
DD
SV
SS
SHDNL SHDNR
1μF
1μF
1μF
INL
INR
AUX_IN
BIAS
IN+
IN-
2.2kΩ
0.1μF
0.1μF
0.1μF
CODEC
OUT
1μF
100kΩ
100kΩ
V
CC
V
CC
10kΩ
10kΩ
1μF
V
CC
V
CC
1μF
System Diagram
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
______________________________________________________________________________________ 15
Typical Application Circuit
CHARGE
PUMP
UVLO/
SHUTDOWN
CONTROL
CLICK-AND-POP
SUPPRESSION
C1N
C1P
PV
SS
SV
SS
PGND
SGND INR
PV
DD
SV
DD
SHDNL
SHDNR
SV
SS
SV
DD
SGND
INL
R
IN
14kΩ
R
F
R
IN
14kΩ
OUTR
LEFT
CHANNEL
AUDIO IN
RIGHT
CHANNEL
AUDIO IN
HEADPHONE
JACK
18
(B2)
19
(A3)
1
(A4)
2 (B4)
3
(C4)
5
(D4)
7 (D3)
9 (D2)
10 (D1)
13 (C1)
11 (C2)
14 (B1)
17 (A2)
MAX4411
C1
1μF
C2
1μF
*MAX4411: 21kΩ, MAX4411B: 28kΩ ( ) UCSP BUMPS.
1.8V TO 3.6V
C3
1μF
C
IN
1μF
SV
SS
SV
DD
SGND
OUTL
C
IN
1μF
15 (A1)
R
F*
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with Shutdown
16 ______________________________________________________________________________________
Chip Information
TRANSISTOR COUNT: 4295
PROCESS: BiCMOS
123
C
B
A
D
UCSP (B16-2)
TOP VIEW
(BUMPS SIDE
DOWN)
4
SV
DD
OUTL SV
SS
PV
SS
INR SGND PV
DD
C1P
PGND
INL OUTR
C1N
MAX4411
SHDNR SHDNL
TOP VIEW
19
20
18
17
7
6
8
PGND
N.C.
PV
SS
9
C1P
SHDNR
N.C.
OUTR
INR
12
SHDNL
45
15 14 12 11
PV
DD
N.C.
OUTL
N.C.
SV
SS
N.C.
MAX4411
C1N
INL
3
13
SGND
16
10
SV
DD
N.C.
TQFN
Pin Configurations
Ordering Information (continued)
PART
TEMP RANGE
PIN/BUMP­PACKAGE
GAIN
(V/V)
MAX4411ETP+
-1.5
-2
-2
MAX4411BETP
-2
MAX4411BETP+
-2
+Denotes lead-free package.
MAX4411BEBE-T -40°C to +85°C 16 UCSP-16 MAX4411BEBE+T -40°C to +85°C 16 UCSP-16
-40°C to +85°C 20 Thin QFN
-40°C to +85°C 20 Thin QFN
-40°C to +85°C 20 Thin QFN
MAX4411
80mW, Fixed-Gain, DirectDrive, Stereo
Headphone Amplifier with Shutdown
______________________________________________________________________________________ 17
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
.)
16L,UCSP.EPS
PACKAGE OUTLINE, 4x4 UCSP
21-0101
1
H
1
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.
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
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