MAX97200_12 [MAXIM]
Low-Power, Low-Offset, Dual Mode, Class H DirectDrive Headphone Amplifier; 低功耗,低失调,双模H类DirectDrive耳机放大器型号: | MAX97200_12 |
厂家: | MAXIM INTEGRATED PRODUCTS |
描述: | Low-Power, Low-Offset, Dual Mode, Class H DirectDrive Headphone Amplifier |
文件: | 总13页 (文件大小:1721K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
19-4981; Rev 3; 8/12
Low-Power, Low-Offset, Dual Mode, Class H
DirectDrive Headphone Amplifier
General Description
The MAX97200 is a 45mW Class H headphone amplifier
that runs from a single low 1.8V supply voltage and employs
Maxim’s second-generation DirectDrive technology.
Features
S Second-Generation DirectDrive Technology
S Dynamic, Class H, Dual Mode Charge Pump
S Low Voltage Operation, V = 1.8V
PVIN
The MAX97200 features a Dual ModeK internal charge
pump to generate the power rails for the amplifier. The
charge-pump output can be QPVIN/2 or QPVIN depend-
ing on the amplitude of the output signal. When the out-
put voltage is low, the power-supply voltage is QPVIN/2.
When the output signal demands larger output voltage,
the charge pump switches modes so that a greater
power-supply voltage is realized and more output power
can be delivered to the load.
S Low Quiescent Current, 1.15mA (typ) at V
=
PVIN
1.8V
S Eliminates Large Output DC-Blocking Capacitors
S Industry-Leading Click-and-Pop Performance
S High-Fidelity, SNR 105dB (5.6µV Output Noise)
S Output Power 34mW into 32I (THD+N 1%)
S Output Power 45mW into 16I (THD+N 10%)
S Tiny, 12-Bump, 1.27mm x 1.65mm (0.4mm Lead
Second-generation DirectDrive technology improves
power consumption when compared to first-generation
DirectDrive amplifiers. The MAX97200 can be powered
from a regulated 1.8V and have similar power consump-
tion to a traditional DirectDrive amplifier that is powered
from 0.9V.
Pitch) WLP Package
Ordering Information/
Selector Guide
GAIN
(dB)
PIN-
PACKAGE
TOP
MARK
PART
Maxim’s DirectDrive architecture uses an inverting
charge pump to derive a negative voltage supply. The
headphone amplifier is powered between the positive
supply and the generated negative rail. This scheme
allows the audio output signal to be biased about
ground, eliminating the need for large DC-blocking
capacitors between the amplifier output and the head-
phone load.
MAX97200AEWC+
MAX97200BEWC+
3
0
12 WLP
12 WLP
ABF
ABG
Note: All devices operate over the -40°C to +85°C tempera-
ture range.
+Denotes a lead(Pb)-free and RoHS-compliant package.
Low-output offset voltage provides very good click-and-
pop performance both into and out of shutdown. High
signal-to-noise ratio maintains system fidelity.
Typical Operating Circuit
The MAX97200 is available in a tiny, 12-bump wafer
level packaging (WLP 1.27mm x 1.65mm) with a small,
0.4mm lead pitch and specified over the -40NC to +85NC
extended temperature range.
MAX97200
LEFT AUDIO
INPUT
LEFT AUDIO OUTPUT
Applications
APPLICATIONS
PROCESSOR
SHDN
Cellular Phones
Smartphones
MP3 Players
VoIP Phones
RIGHT AUDIO
INPUT
RIGHT AUDIO
OUTPUT
CHARGE
PUMP
DirectDrive is a registered trademark of Maxim Integrated
Products, Inc.
Dual Mode is a trademark of Maxim Integrated Products, Inc.
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.
1
Low-Power, Low-Offset, Dual Mode, Class H
DirectDrive Headphone Amplifier
ABSOLUTE MAXIMUM RATINGS
PVIN or PVDD to PGND .......................................-0.3V to +2.2V
GND to PGND ......................................................-0.3V to +0.3V
PVSS to PGND .....................................................-2.2V to +0.3V
OUT_ and IN_ to GND ............. (PVSS - 0.2V) to (PVDD + 0.2V)
C1P, C1N ...................................................Cap connection only
SHDN to GND .........................................................-0.3V to +4V
Output Short-Circuit Current .....................................Continuous
Thermal Limits (Note 1)
Continuous Power Dissipation (T = +70NC)
A
12-Bump WLP (derate 13.7mW/NC above +70NC)....1095mW
Junction Temperature .................................................+150NC
Operating Temperature Range.......................... -40NC to +85NC
Storage Temperature Range............................ -65NC to +150NC
Soldering Temperature (reflow) ......................................+260NC
Multiple Layer PCB
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion 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.
PACKAGE THERMAL CHARACTERISTICS (Note 1)
Junction-to-Ambient Thermal Resistance (B )..............73NC/W
JA
Junction-to-Case Thermal Resistance (B ) ..................30NC/W
CA
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
ELECTRICAL CHARACTERISTICS
(V
PVIN
= 1.8V, V
= V
= 0V, V
= 1.8V, C1 = C2 = C3 = 1FF, C4 = 10FF, T = T
to T , unless otherwise noted.
MAX
PGND
GND
SHDN
A
MIN
Typical values are at T = +25NC.) (Note 2)
A
PARAMETER
SYMBOL
CONDITIONS
Guaranteed by PSRR
MIN
TYP
MAX
UNITS
POWER SUPPLY
Supply Voltage Range
UVLO Rising
PVIN
1.62
1.36
1.80
1.48
1.46
1.15
1.16
0.2
1.98
1.58
V
V
V
UVLO Falling
Inputs grounded, T = +25NC, no load
1.7
A
Quiescent Supply Current
I
mA
DD
16Iload, inputs grounded, T = +25NC
A
Shutdown Current
Turn-On Time
FA
I
V
= 0V, T = +25NC
SHDN A
SHDN
t
0.6
1
ms
ON
CHARGE PUMP
Oscillator Frequency
f
f
V
V
= 0V, T = +25NC
78
83
88
kHz
kHz
OSC1
OSC2
OUT
OUT
A
Oscillator Frequency
Oscillator Frequency
= 0.2V, R = J, f = 1kHz
665
L
IN
f
V
V
= 0.5V, R = J, f = 1kHz
500
kHz
V
OSC3
OUT
OUT
L
IN
= 0.2V, R = J
PVIN/2
L
Positive Output Voltage
Negative Output Voltage
V
PVDD
V
V
V
= 0.5V, R = J
PVIN
-PVIN/2
-PVIN
OUT
OUT
OUT
L
= 0.2V, R = J
L
V
V
PVSS
= 0.5V, R = J
L
R = J, output voltage at which the
L
QPVIN
x
0.08
charge pump switches modes, V
OUT
Output Voltage Threshold
V
TH1
V
rising, transition from 1/8 to normal
frequency
2
Low-Power, Low-Offset, Dual Mode, Class H
DirectDrive Headphone Amplifier
ELECTRICAL CHARACTERISTICS (continued)
(V
PVIN
= 1.8V, V
= V
= 0V, V
= 1.8V, C1 = C2 = C3 = 1FF, C4 = 10FF, T = T
to T , unless otherwise noted.
MAX
PGND
GND
SHDN
A
MIN
Typical values are at T = +25NC) (Note 2)
A
PARAMETER
SYMBOL
CONDITIONS
R = J, output voltage at which the
MIN
TYP
MAX
UNITS
L
QPVIN
x
0.24
charge pump switches modes, V
OUT
Output Voltage Threshold
V
TH2
V
rising, transition from high-efficiency
mode to high-power mode
Time it takes for the charge pump to
transition from high-power mode to
t
32
20
ms
HOLD
high-efficiency mode; R = J
L
Charge-Pump Mode Transition
Timeouts (Figure 2)
Time it takes for the charge pump to
transition from high-efficiency mode to high-
t
Fs
RISE
power mode (90% of its value); R = J
L
AMPLIFIER
MAX97200A
MAX97200B
2.75
2.92
0
3.09
Voltage Gain
A
V
dB
-0.17
+0.17
R = 10kI, THD+N = 1%
1.295
1.44
L
Maximum Output Voltage
V
PK
R = 10kI, THD+N = 10%
L
Channel-to-Channel Gain
Matching
Q0.1
dB
mV
kI
Total Output Offset Voltage
V
T
= +25NC
A
Q0.1
10
Q0.3
14
OS
MAX97200A
MAX97200B
6
Input Resistance
R
IN
7.2
62
12
16.8
V
= 1.62V to 1.98V, T = +25NC
83
PVDD
A
f
f
f
= 217Hz
= 1kHz
96
IN
IN
IN
Power-Supply Rejection Ratio
PSRR
dB
100mV
ripple
94
P-P
= 20kHz
61
R = 10kI
0.16
34
L
Output Power
P
THD+N = 1%
R = 10kI
R = 32I
L
mW
OUT
R = 16I
L
45
Line Output Voltage
V
1
V
RMS
LINE
L
R = 16I, P
= 0.1mW, f = 1kHz (Note 3)
0.02
0.003
0.008
5.6
4.7
105
L
OUT
IN
Total Harmonic Distortion Plus
Noise
THD+N
R = 16I, P
L
= 10mW, f = 1kHz (Note 4)
OUT IN
%
R = 10kI, V
L
= 1V, f = 1kHz (Note 4)
IN
OUT
Inputs grounded, A-weighted, MAX97200A
Inputs grounded, A-weighted, MAX97200B
A-weighted, MAX97200B
Output Noise
V
N
FV
Signal-to-Noise Ratio
SNR
dB
R = 32I, peak
L
Into shutdown
80
68
voltage, A-weighted,
32 samples/second,
MAX97200B
Click-and-Pop Level
V
CP
dBV
Out of shutdown
Crosstalk
X
TALK
R = 16I, 1kHz, P = 5mW
L OUT
100
200
dB
pF
Maximum Capacitive Load
3
Low-Power, Low-Offset, Dual Mode, Class H
DirectDrive Headphone Amplifier
ELECTRICAL CHARACTERISTICS (continued)
(V
PVIN
= 1.8V, V
= V
= 0V, V
= 1.8V, C1 = C2 = C3 = 1FF, C4 = 10FF, T = T
to T , unless otherwise noted.
MAX
PGND
GND
SHDN
A
MIN
Typical values are at T = +25NC) (Note 2)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DIGITAL INPUT (SHDN)
Input High Voltage
Input Low Voltage
V
1.4
V
V
IH
V
0.4
+1
+1
+1
IL
-1
-1
-1
V
V
V
= 4V, T = +25NC
A
SHDN
SHDN
SHDN
I
IH
Input Leakage Current
FA
= 1.8V, T = +25NC
A
I
IL
= 0V, T = +25NC
A
Note 2: All specifications are 100% tested at T = +25NC. Temperature limits are guaranteed by design.
A
Note 3: V
Note 4: V
= 0.9V, V
= 1.8V, V
= -0.9V.
= -1.8V.
PVDD
PVDD
PVSS
PVSS
Typical Operating Characteristics
(V
PVIN
= 1.8V, V
= V
= 0V, V
= 1.8V, C1 = C2 = C3 = 1FF, C4 = 10FF, both channels driven in phase, T = +25NC,
PGND
GND
SHDN A
unless otherwise noted.)
THD+N vs. OUTPUT POWER
THD+N vs. OUTPUT POWER
THD+N vs. OUTPUT VOLTAGE
100
10
100
10
100
10
R = 16I
L
R = 32I
L
R = 10kI
L
1
1
1
0.1
0.1
0.1
f
= 100Hz
f = 100Hz
IN
IN
f
= 100Hz
f = 1kHz
IN
IN
f
IN
= 1kHz
0.01
0.001
0.01
0.001
0.01
0.001
f
= 1kHz
= 6kHz
IN
f
= 6kHz
40
IN
f
= 6kHz
f
IN
IN
0
10 20 30 40 50 60 70 80
(mW)
0
10
20
30
(mW)
50
60
0
0.5
1.0
1.5
2.0
2.5
P
OUT
P
V
(V
)
OUT
OUT RMS
THD+N vs. FREQUENCY
THD+N vs. FREQUENCY
THD+N vs. FREQUENCY
10
1
10
1
10
1
R = 16I
L
R = 32I
L
R = 10kI
L
0.1
0.1
0.1
V
= 0.868V
RMS
OUT
P
= 20mW
OUT
P
= 20mW
OUT
0.1
V
OUT
= 1.12V
RMS
P
OUT
= 25mW
0.01
0.001
0.01
0.001
0.01
0.001
P
= 2mW
P
1
= 25mW
10
OUT
OUT
P
= 2mW
0.1
V
= 0.316V
0.1
OUT
OUT
RMS
0.01
1
FREQUENCY (kHz)
10
100
0.01
100
0.01
1
FREQUENCY (kHz)
10
100
FREQUENCY (kHz)
4
Low-Power, Low-Offset, Dual Mode, Class H
DirectDrive Headphone Amplifier
Typical Operating Characteristics (continued)
(V
PVIN
= 1.8V, V
= V
= 0V, V
= 1.8V, C1 = C2 = C3 = 1FF, C4 = 10FF, both channels driven in phase, T = +25NC,
SHDN A
PGND
GND
unless otherwise noted.)
OUTPUT POWER
vs. LOAD RESISTANCE
POWER CONSUMPTION
vs. OUTPUT POWER
OUTPUT POWER vs. LOAD RESISTANCE
AND CHARGE-PUMP CAPACITOR
80
70
60
50
40
30
20
10
0
80
70
60
50
40
30
20
10
0
160
140
120
100
80
10% THD + N
C = C = C = 1µF
1
2
3
C = C = C = .47µF
1
2
3
C = C = C = 2.2µF
1
2
3
60
1% THD + N
40
20
0
1
10
100
1000
10,000
10
100
1000
10,000
1
10
100
LOAD RESISTANCE (I)
LOAD RESISTANCE (I)
OUTPUT POWER (mW)
POWER DISSIPATION
vs. OUTPUT POWER
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SHUTDOWN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
100
90
80
70
60
50
40
30
20
10
0
1.20
1.15
1.10
1.05
1.00
0.95
0.90
0.85
0.80
0.20
0.18
0.16
0.14
0.12
0.1
RL = J
RL = J
R = 16I
L
R = 32I
L
0.08
0.06
0.04
0.02
0
1
10
OUTPUT POWER (mW)
100
1.60 1.65 1.70 1.75 1.80 1.85 1.90 1.95 2.00
SUPPLY VOLTAGE (V)
1.60 1.65 1.70 1.75 1.80 1.85 1.90 1.95 2.00
SUPPLY VOLTAGE (V)
CROSSTALK vs. FREQUENCY
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
5mW 16I
IN-BAND OUTPUT SPECTRUM
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
0
-20
0
-20
V
= 200mV
P-P
RIPPLE
f = 1kHz
OUTPUT POWER = 5mW
R = 16I
L
-40
-40
-60
-60
-80
-100
-120
-140
-160
-80
-100
-110
-120
-100
-120
0.01
0.1
1
10
100
10
100
1k
10k
100k
0.01
0.1
1
10
100
FREQUENCY (kHz)
FREQUENCY (Hz)
FREQUENCY (Hz)
5
Low-Power, Low-Offset, Dual Mode, Class H
DirectDrive Headphone Amplifier
Typical Operating Characteristics (continued)
(V
PVIN
= 1.8V, V
= V
= 0V, V
= 1.8V, C1 = C2 = C3 = 1FF, C4 = 10FF, both channels driven in phase, T = +25NC,
SHDN A
PGND
GND
unless otherwise noted.)
SUPPLY MODE SWITCHING
TURN-ON RESPONSE
MAX97200 toc16
MAX97200 toc17
R
= 16I
L
PVDD
PVSS
OUTPUT
SHDN
20ms/div
400µs/div
TURN-OFF RESPONSE
MAX97200 toc18
OUTPUT
SHDN
400µs/div
6
Low-Power, Low-Offset, Dual Mode, Class H
DirectDrive Headphone Amplifier
Pin Configuration
TOP VIEW
MAX97200
1
2
3
4
A
B
C
OUTR
PVSS
C1N
C1P
OUTL
INL
SHDN
INR
GND
PGND
PVIN
PVDD
WLP
Pin Description
BUMP
A1
NAME
OUTR
PVSS
C1N
FUNCTION
Right Amplifier Output
A2
Negative Charge-Pump Output. Connect a 1FF capacitor between PVSS and PGND.
Charge-Pump Flying Cap Negative Connection. Connect 1FF capacitor between C1N and C1P.
Charge-Pump Flying Cap Positive Connection. Connect 1FF capacitor between C1P and C1N.
Left Amplifier Output
A3
A4
C1P
B1
OUTL
B2
Active-Low Shutdown
SHDN
GND
PGND
INL
B3
Signal Ground. Connect to PGND.
B4
Power Ground. Connect to GND.
C1
C2
C3
C4
Left Audio Input
INR
Right Audio Input
PVDD
PVIN
Positive Charge-Pump Output. Bypass to PGND with 1FF.
Main Power-Supply Connection. Bypass to PGND with 10FF.
7
Low-Power, Low-Offset, Dual Mode, Class H
DirectDrive Headphone Amplifier
Maxim’s second-generation DirectDrive architecture
Detailed Description
uses a charge pump to create an internal negative sup-
The MAX97200 is a 45mW Class H headphone ampli-
ply voltage. This allows the headphone outputs of the
fier that runs from a single low 1.8V supply voltage
MAX97200 to be biased at GND while operating from a
and employs Maxim’s second-generation DirectDrive
single supply (Figure 1). Without a DC component, there
is no need for the large DC-blocking capacitors. Instead
technology.
Maxim’s DirectDrive architecture uses an inverting
charge pump to derive a negative voltage supply. The
headphone amplifier is powered between the positive
supply and the generated negative rail. This scheme
allows the audio output signal to be biased about
ground, eliminating the need for large DC blocking
capacitors between the amplifier output and the head-
phone load.
of two large (220FF typ) capacitors, the MAX97200
charge pump requires 3 small ceramic capacitors, con-
serving board space, reducing cost, and improving the
frequency response of the headphone amplifier.
V
OUT
V
DD
Second-generation DirectDrive technology improves
power consumption when compared to first-generation
DirectDrive amplifiers. The MAX97200 can be powered
from a regulated 1.8V supply and have similar power
consumption to a traditional DirectDrive amplifier that is
powered from 0.9V.
V
/ 2
V
DD
DD
GND
The MAX97200 features a dual-mode internal charge
pump to generate the power rails for the DirectDrive
amplifier. The charge-pump output can be QPVIN/2 or
QPVIN depending on the amplitude of the output signal.
When the output voltage is low the power-supply volt-
age is QPVIN/2. When the output signal demands larger
output voltage, the charge pump switches modes so
that a greater power-supply voltage is realized and more
output power can be delivered to the load.
CONVENTIONAL DRIVER BIASING SCHEME
V
OUT
+V
DD
DirectDrive Headphone Amplifier
Traditional single-supply headphone amplifiers have
outputs biased at a nominal DC voltage (typically half
the supply). 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 dis-
sipation and possible damage to both headphone and
headphone amplifier.
GND
2V
DD
-V
DD
DirectDrive BIASING SCHEME
Figure 1. Traditional Amplifier vs. MAX97200 DirectDrive
Output
8
Low-Power, Low-Offset, Dual Mode, Class H
DirectDrive Headphone Amplifier
Dual Mode Charge Pump
The MAX97200’s Dual Mode, charge pump outputs
either QPVIN/2 in high-efficiency mode or QPVIN in high-
power mode, resulting in a power-supply differential of
1.8V or 3.6V. The charge-pump mode changes based
on the level of the output signal needed. When the
output voltage is small, the voltage rails are reduced to
minimize power consumption. When the output voltage
is large, the voltage rails are increased to accommodate
the larger output need.
The switch from high-power mode to high-efficiency
mode occurs 32ms (typ) after the threshold is crossed.
Built-in hysteresis keeps the charge pump from erratic
mode switching when the output voltage is near the high
and low thresholds.
Click-and-Pop Suppression
In conventional single-supply audio amplifiers, the out-
put-coupling capacitor contributes significantly to audi-
ble clicks and pops. Upon startup, the amplifier charges
the coupling capacitor to its bias voltage, typically half
the supply. Likewise, on shutdown, the capacitor is dis-
charged. This results in a DC shift across the capacitor,
which appears as an audible transient at the speaker.
Since the MAX97200 does not require output coupling
capacitors, this problem does not arise. Additionally,
the MAX97200 features extensive click-and-pop sup-
pression that eliminates any audible transient sources
internal to the device.
High-power mode is similar to Maxim’s traditional
DirectDrive architecture and is best suited for loads
that require high voltage swing. High-efficiency mode
improves power consumption by reducing the power-
supply voltage across the amplifier’s output stage by
half. The reduced power-supply voltage is good for idle
conditions or low-signal level conditions into a head-
phone.
Class H Operation
The MAX97200’s internal Class H amplifier uses a class
AB output stage with multiple, discrete power supplies.
This result’s in two power-supply differentials of 1.8V and
3.6V generated from a single 1.8V external supply. The
PVIN/2 power-supply differential is used when the output
voltage requirements are low, and the output is below
Typically, the output of the device driving the MAX97200
has a DC bias of half the supply voltage. At startup, the
input-coupling capacitor, C , is charged to the pream-
IN
plifier’s DC bias voltage through the MAX97200 input
resistor, R . This DC shift across the capacitor results
IN
in an audible click-and-pop. The MAX97200 precharges
the input capacitors when power is applied to ensure
that no audible clicks or pops are heard when SHDN is
pulled high.
V
TH2
as seen in Figure 2. The higher supply differential
is used when the output voltage exceeds the high
threshold V , maximizing output power and voltage
TH2
Shutdown
The MAX97200 features a 1FA, low-power shutdown
mode that reduces quiescent current consumption and
extends battery life. Shutdown is controlled by the SHDN
input. Driving the SHDN input low disables the drive
amplifiers and charge pump and sets the headphone
amplifier output resistance to 100I.
swing. The transition time from high-efficiency mode to
high-power mode occurs when the threshold is crossed.
V
PVDD
Applications Information
Component Selection
IN_
Input-Coupling Capacitor
The input capacitor (C ), in conjunction with the ampli-
IN
V
fier input resistance (R ), forms a highpass filter that
PVSS
IN_
removes the DC bias from the incoming signal. The
AC-coupling capacitor allows the amplifier to bias the sig-
nal to an optimum DC level. Assuming zero source imped-
ance, the -3dB point of the highpass filter is given by:
10ms/div
1
f-
=
Figure 2. Inverting and Split Mode Transitions
3dB
2πR C
IN IN
9
Low-Power, Low-Offset, Dual Mode, Class H
DirectDrive Headphone Amplifier
R
is the amplifier’s input resistance value. Choose C
Additional RF immunity can also be obtained from rely-
ing on the self-resonant frequency of capacitors as
it exhibits the frequency response similar to a notch
filter. Depending on the manufacturer, 10pF to 20pF
capacitors typically exhibit self resonance at RF frequen-
cies. These capacitors when placed at the input pins
can effectively shunt the RF noise at the inputs of the
MAX97200. For these capacitors to be effective, provide
a low-impedance, low-inductance path from the capaci-
tors to the ground plane. Do not use microvias to con-
nect to the ground plane as these vias do not conduct
well at RF frequencies. Figure 3 shows headphone RF
immunity with a well laid out PCB.
IN
IN
such that f
interest. Setting f
is well below the lowest frequency of
-3dB
too high affects the amplifier’s low
-3dB
frequency. Capacitors with higher voltage coefficients,
such as ceramics, result in increased distortion at low
frequencies.
Charge-Pump Capacitor Selection
Use capacitors with an ESR less than 100mI for opti-
mum performance. Low ESR ceramic capacitors mini-
mize the output resistance of the charge pump. For best
performance over the extended temperature range,
select capacitors with an X7R dielectric.
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. Connect a 1FF capacitor between C1P
and C1N.
HEADPHONE RF IMMUNITY
vs. FREQUENCY
0
-10
-20
-30
-40
-50
Output Capacitors (C2, C3)
The output capacitor value and ESR directly affect the
ripple at PVSS. Increasing the value of C2 and C3 reduc-
es output ripple. Likewise, decreasing the ESR of C2 and
C3 reduces both ripple and output resistance. Lower
capacitance values can be used in systems with low
maximum output power levels. Connect a 1FF capaci-
tor between PVDD and PGND. Connect a 1FF capacitor
between PVSS and PGND.
-60
-70
RIGHT CHANNEL
LEFT CHANNEL
-80
-90
-100
1000
1500
2000
2500
3000
FREQUENCY (MHz)
RF Susceptibility
Improvements to both layout and component selec-
tion can decrease the MAX97200 susceptibility to RF
noise and prevent RF signals from being demodulated
into audible noise. Trace lengths should be kept below
¼ of the wavelength of the RF frequency of interest.
Minimizing the trace lengths prevents the traces from
functioning as antennas and coupling RF signals into the
MAX97200. The wavelength (λ) in meters is given by:
Figure 3. Headphone RF Immunity
Layout and Grounding
Proper layout and grounding are essential for optimum
performance. Use large traces for the power-supply
inputs and amplifier outputs to minimize losses due to
parasitic trace resistance, as well as route heat away
from the device. Good grounding improves audio per-
formance, minimizes crosstalk between channels, and
prevents switching noise from coupling into the audio
signal. Connect PGND and GND together at a single
point on the PCB. Route PGND and all traces that carry
switching transients away from GND, and the traces and
components in the audio signal path.
λ = c/f
where c = 3 x 108 m/s, and f is the RF frequency of
interest.
Route audio signals to the middle layers of the PCB to
allow the ground planes above and below to shield them
from RF interference. Ideally, the top and bottom layers
of the PCB should primarily be ground planes to create
effective shielding.
Connect C2 to the PGND plane. Place the charge-pump
capacitors (C1, C2) as close as possible to the device.
Bypass PVDD with a 1FF capacitor to PGND. Place the
bypass capacitors as close as possible to the device.
10
Low-Power, Low-Offset, Dual Mode, Class H
DirectDrive Headphone Amplifier
Simplified Functional Diagram
Chip Information
PROCESS: BiCMOS
1.8V
C4
10µF
PVIN
C4
MAX97200
R
FB
PVDD
INL C1
INR C2
B1 OUTL
A1 OUTR
R
R
IN
IN
PVSS
SHDN
B2
B3
R
FB
A2 PVSS
CHARGE
PUMP
GND
C2
1µF
C3
PGND PVDD
B4
A3
C1N
A4
C1P
C3
1µF
C1
1µF
11
Low-Power, Low-Offset, Dual Mode, Class H
DirectDrive Headphone Amplifier
Package Information
For the latest package outline information and land patterns (footprints), 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.
LAND
PATTERN NO.
PACKAGE TYPE
PACKAGE CODE
OUTLINE NO.
21-0449
12 WLP
W121A1+1
Refer to Application Note 1891
COMMON DIMENSIONS
A
0.64 0.05
E
Marking
Pin 1
Indicator
A1
A2
0.03
0.19
0.45
1
REF
A3
A
A3
b
0.025 BASIC
0.03
0.27
0.80
A2
D
AAAA
TOP VIEW
A
D1
E1
BASIC
0.05
S
S
1.20 BASIC
see Note 7
SIDE VIEW
e
BASIC
BASIC
BASIC
A1
0.40
0.00
0.20
SD
SE
DEPOPULATED
BUMPS
PKG. CODE
E
D
NONE
NONE
1.680 0.070
1.625 0.015
1.300 0.070
1.235 0.015
W121A1+1
W121F1+1
E1
e
SE
NOTES:
1. Terminal pitch is defined by terminal center to center value.
2. Outer dimension is defined by center lines between scribe lines.
3. All dimensions in millimeter.
C
B
D1
SD
B
A
1
4. Marking shown is for package orientation reference only.
5. Tolerance is ± 0.02 unless specified otherwise.
6. All dimensions apply to PbFree (+) package codes only.
7. Front - side finish can be either Black or Clear.
2
3
4
b
M
S
AB
0.05
A
BOTTOM VIEW
TITLE
PACKAGE OUTLINE 12 BUMPS,
WLP PKG. 0.40mm PITCH
REV.
APPROVAL
DOCUMENT CONTROL NO.
1
- DRAWING NOT TO SCALE -
E
1
21-0449
12
Low-Power, Low-Offset, Dual Mode, Class H
DirectDrive Headphone Amplifier
Revision History
REVISION REVISION
PAGES
CHANGED
DESCRIPTION
NUMBER
DATE
1/10
3/10
3/11
8/12
0
1
2
3
Initial release
—
2
Removed shutdown current max value
Corrected crosstalk data in TOC 14
5
Updated output noise conditions and TOC 14
3, 5
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. The parametric values (min and max limits) shown in the Electrical
Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated Products, Inc. 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
13
©
2012 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
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