MAX9724C [MAXIM]
Low RF Susceptibility DirectDrive Stereo Headphone Amplifier with 1.8V Compatible Shutdown;
| 型号： | MAX9724C |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Low RF Susceptibility DirectDrive Stereo Headphone Amplifier with 1.8V Compatible Shutdown |
| 文件： | 总19页 (文件大小：350K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-4130; Rev 0; 5/08
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
C/MAX9724D
General Description
Features
♦ Improved RF Noise Rejection (Up to 67dB Over
The MAX9724C/MAX9724D stereo headphone ampli-
fiers are designed for portable equipment where board
space is at a premium. These devices use a unique,
DirectDrive® architecture to produce a ground-refer-
enced output from a single supply, eliminating the need
for large DC-blocking capacitors, saving cost, board
space, and component height. The MAX9724 sup-
presses RF radiation received by input and supply
traces acting as antennas and prevents the amplifier
from demodulating the coupled noise. The MAX9724C
offers an externally adjustable gain while the
MAX9724D has an internally preset gain of -1.5V/V. The
MAX9724C/MAX9724D deliver up to 60mW per channel
into a 32Ω load and have low 0.02% THD+N. An 80dB
at 1kHz power-supply rejection ratio (PSRR) allows
these devices to operate from noisy digital supplies
without an additional linear regulator. Comprehensive
click-and-pop circuitry suppresses audible clicks and
pops on startup and shutdown.
Typical Amplifiers)
♦ No Bulky DC-Blocking Capacitors Required
♦ Low-Power Shutdown Mode, < 0.1µA
♦ Adjustable Gain (MAX9724C) or Fixed -1.5V/V
Gain (MAX9724D)
♦ Low 0.02% THD+N
♦ High PSRR (80dB at 1kHz) Eliminates LDO
♦ Integrated Click-and-Pop Suppression
♦ 2.5V to 5.5V Single-Supply Operation
♦ Low Quiescent Current (3.5mA)
♦ Available in Space-Saving Packages
12-Bump UCSP (1.5mm x 2mm)
12-Pin Thin QFN (3mm x 3mm x 0.8mm)
Ordering Information
TOP
MARK
PART
GAIN (V/V) PIN-PACKAGE
The MAX9724C/MAX9724D operate from a single 2.5V
to 5.5V supply, consume only 3.5mA of supply current,
feature short-circuit and thermal-overload protection,
and are specified over the extended -40°C to +85°C
temperature range. The devices are available in tiny
12-bump UCSP™ (1.5mm x 2mm) and 12-pin thin QFN
(3mm x 3mm x 0.8mm) packages.
MAX9724CEBC+T
MAX9724CETC+
MAX9724DEBC+T
MAX9724DETC+
Adj.
Adj.
-1.5
-1.5
12 UCSP
+AGE
+ABJ
+AEH
+ABK
12 TQFN-EP*
12 UCSP
12 TQFN-EP*
Note: All devices specified over the -40°C to +85°C operating
range.
+Denotes a lead-free package.
T = Tape and reel.
*EP = Exposed pad.
Applications
DVD Players
Smart Phones
PDAs
Cellular Phones
MP3 Players
Notebook PCs
DirectDrive is a registered trademark of
Maxim Integrated Products, Inc.
Handheld Gaming Consoles
UCSP is a trademark of Maxim Integrated Products, Inc.
Pin Configurations appear at end of data sheet.
Block Diagrams
MAX9724D
MAX9724C
DirectDrive OUTPUTS
ELIMINATE DC-BLOCKING
CAPACITORS
DirectDrive OUTPUTS
ELIMINATE DC-BLOCKING
LEFT
AUDIO
INPUT
LEFT
AUDIO
CAPACITORS
INPUT
SHDN
SHDN
RIGHT
RIGHT
AUDIO
INPUT
FIXED GAIN ELIMINATES
AUDIO
EXTERNAL RESISTOR
INPUT
NETWORK
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND..............................................................-0.3V to +6V
Continuous Input Current into PVSS .................................260mA
Continuous Input Current (any other pin)......................... 20mA
PVSS to SVSS........................................................-0.3V to +0.3V
PGND to SGND .....................................................-0.3V to +0.3V
Continuous Power Dissipation (T = +70°C, multilayer board)
12-Bump UCSP (derate 6.5mW/°C above +70°C) ........519mW
A
C1P to PGND..............................................-0.3V to (V
+ 0.3V)
DD
C1N to PGND...........................................(PVSS - 0.3V) to +0.3V
PVSS and SVSS to PGND.........................................-6V to +0.3V
θ
................................................................................154 C/W
12-Pin TQFN (derate 16.7mW/°C above +70°C) .........1333mW
JA
IN_ to SGND (MAX9724C) .........................-0.3V to (V
IN_ to SGND (MAX9724D) ............(SVSS - 0.3V) to (V
+ 0.3V)
+ 0.3V)
θ
JC
..................................................................................60°C/W
..................................................................................11°C/W
JA
θ
DD
DD
OUT_ to SVSS (Note 1) ...-0.3V to Min (V
- SVSS + 0.3V, +9V)
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +150°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
Bump Temperature (soldering) Reflow............................+235°C
DD
OUT_ to V
(Note 2) .....+0.3V to Max (SVSS - V
- 0.3V, -9V)
DD
DD
SHDN to _GND.........................................................-0.3V to +6V
OUT_ Short Circuit to GND ........................................Continuous
Short Circuit between OUTL and OUTR ....................Continuous
Note 1: OUTR and OUTL should be limited to no more than 9V above SVSS, or above V
+ 0.3V, whichever limits first.
DD
Note 2: OUTR and OUTL should be limited to no more than 9V below V , or below SVSS - 0.3V, whichever limits first.
DD
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
(V
DD
= 5V, PGND = SGND, SHDN = 5V, C1 = C2 = 1µF, R = ∞, resistive load reference to ground; for MAX9724C gain = -1.5V/V
L
(R = 20kΩ, R = 30kΩ); for MAX9724D gain = -1.5V/V (internally set), T = -40°C to +85°C, unless otherwise noted. Typical values
IN
F
A
are at T = +25°C, unless otherwise noted.) (Note 3)
A
C/MAX9724D
PARAMETER
GENERAL
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage Range
Quiescent Current
V
2.5
5.5
5.5
1
V
DD
I
3.5
0.1
mA
µA
µs
CC
Shutdown Current
I
SHDN = SGND = PGND
SHDN
Shutdown to Full Operation
Input Impedance
t
180
19
SON
R
MAX9724D, measured at IN_
= +25°C (Note 4)
12
69
28
10
kΩ
mV
IN
Output Offset Voltage
V
T
1.5
OS
A
V
= 2.7V to 5.5V, T = +25°C
86
DD
A
Power-Supply Rejection Ratio
PSRR
f = 1kHz, 100mV
(Note 4)
80
dB
P-P
f = 20kHz, 100mV
(Note 4)
65
P-P
R = 32Ω, THD+N = 1%
30
25
63
L
Output Power (TQFN)
Output Power (UCSP)
P
P
mW
mW
OUT
OUT
R = 16Ω, THD+N = 1%
42
L
R = 32Ω, THD+N = 1%
45
L
R = 16Ω, THD+N = 1%
L
35
Voltage Gain
A
MAX9724D (Note 5)
MAX9724D
-1.52
-1.5
0.15
0.003
0.02
0.04
0.003
0.03
0.05
102
105
98
-1.48
V/V
%
V
Channel-to-Channel Gain Tracking
R = 1kΩ, V
= 2V
, f = 1kHz
L
OUT
OUT
OUT
OUT
OUT
OUT
RMS IN
Total Harmonic Distortion Plus
Noise (TQFN) (Note 6)
THD+N
THD+N
%
%
R = 32Ω, P
= 50mW, f = 1kHz
IN
L
R = 16Ω, P
= 35mW, f = 1kHz
IN
L
R = 1kΩ, V
= 2V
, f = 1kHz
RMS IN
L
Total Harmonic Distortion Plus
Noise (UCSP) (Note 6)
R = 32Ω, P
= 45mW, f = 1kHz
IN
L
R = 16Ω, P
L
= 32mW, f = 1kHz
IN
BW = 22Hz to 22kHz
A-weighted
R = 1kΩ,
L
V
= 2V
OUT
RMS
Signal-to-Noise Ratio
SNR
dB
BW = 22Hz to 22kHz
A-weighted
R = 32Ω,
L
P
= 50mW
101
OUT
2
_______________________________________________________________________________________
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
C/MAX9724D
ELECTRICAL CHARACTERISTICS (continued)
(V
= 5V, PGND = SGND, SHDN = 5V, C1 = C2 = 1µF, R = ∞, resistive load reference to ground; for MAX9724C gain = -1.5V/V
DD
L
(R = 20kΩ, R = 30kΩ); for MAX9724D gain = -1.5V/V (internally set), T = -40°C to +85°C, unless otherwise noted. Typical values
IN
F
A
are at T = +25°C, unless otherwise noted.) (Note 3)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
0.5
MAX
UNITS
V/µs
pF
Slew Rate
SR
Capacitive Drive
C
No sustained oscillations
L to R, R to L, f = 10kHz, R = 16Ω,
100
L
L
Crosstalk
-70
dB
P
= 15mW
OUT
Charge-Pump Oscillator
Frequency
f
190
1.4
270
400
kHz
OSC
Into shutdown
-67
-64
R = 32Ω, peak voltage,
A-weighted, 32 samples per
second (Notes 4, 7)
L
Click-and-Pop Level
K
dB
Out of
shutdown
CP
DIGITAL INPUTS (SHDN)
Input-Voltage High
Input-Voltage Low
V
V
V
V
INH
0.4
1
INL
Input Leakage Current
µA
ELECTRICAL CHARACTERISTICS
(V
DD
= 3V, PGND = SGND, SHDN = 3V, C1 = C2 = 1µF, R = ∞, resistive load reference to ground; for MAX9724C gain = -1.5V/V
L
(R = 20kΩ, R = 30kΩ); for MAX9724D gain = -1.5V/V (internally set), T = -40°C to +85°C, unless otherwise noted. Typical values
IN
F
A
are at T = +25°C, unless otherwise noted.) (Note 3)
A
PARAMETER
Quiescent Current
SYMBOL
CONDITIONS
MIN
TYP
3.0
MAX
UNITS
mA
I
CC
Shutdown Current
I
SHDN = SGND = PGND
f = 1kHz, 100mV
0.1
µA
SHDN
80
P-P
Power-Supply Rejection Ratio
(Note 4)
PSRR
dB
mW
mW
f = 20kHz, 100mV
65
P-P
R = 32Ω, THD+N = 1%
L
20
Output Power (TQFN)
Output Power (UCSP)
P
P
OUT
OUT
R = 16Ω, THD+N = 1%
L
14
R = 32Ω, THD+N = 1%
L
17
R = 16Ω, THD+N = 1%
L
12
R = 1kΩ, V
= 2V , f = 1kHz
RMS IN
0.05
0.03
0.06
0.003
0.04
0.06
L
OUT
OUT
OUT
OUT
OUT
OUT
Total Harmonic Distortion Plus
Noise (TQFN) (Note 6)
THD+N
THD+N
%
%
R = 32Ω, P
L
= 15mW, f = 1kHz
IN
R = 16Ω, P
L
= 10mW, f = 1kHz
IN
R = 1kΩ, V
L
= 2V , f = 1kHz
RMS IN
Total Harmonic Distortion Plus
Noise (UCSP) (Note 6)
R = 32Ω, P
L
= 15mW, f = 1kHz
IN
R = 16Ω, P
L
= 10mW, f = 1kHz
IN
Note 3: All specifications are 100% tested at T = +25°C; temperature limits are guaranteed by design.
A
Note 4: The amplifier inputs are AC-coupled to GND.
Note 5: Gain for the MAX9724C is adjustable.
Note 6: Measurement bandwidth is 22Hz to 22kHz.
Note 7: Test performed with a 32Ω resistive load connected to GND. Mode transitions are controlled by SHDN. K level is calculated
CP
as 20log[(peak voltage during mode transition, no input signal)/(peak voltage under normal operation at rated power level)].
Units are expressed in dB.
_______________________________________________________________________________________
3
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
Typical Operating Characteristics
(V
DD
= 5V, PGND = SGND = 0V, SHDN = V , C1 = C2 = 1µF, R = ∞, gain = -1.5V/V (R = 20kΩ, R = 30kΩ for the MAX9724C),
DD L IN F
THD+N measurement bandwidth = 22Hz to 22kHz, both outputs driven in phase, T = +25°C, unless otherwise noted.)
A
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER (TQFN)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER (UCSP)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER (TQFN)
100
10
1
10
100
10
1
V
= 3V
V
DD
= 3V
DD
V
DD
= 3V
R = 16Ω
L
R = 16Ω
L
R = 32Ω
L
1
f
= 1kHz
IN
0.1
f
IN
= 1kHz
0.1
0.1
f
= 10kHz
IN
f
IN
= 10kHz
f
= 10kHz
0.01
IN
f
IN
= 1kHz
5
0.01
0.01
f
IN
= 20Hz
15
f
IN
= 20Hz
f
= 20Hz
20
IN
0.001
0.001
0.001
0
10
20
30
40
0
10
20
25
30
0
10
30
40
50
OUTPUT POWER (mW)
OUTPUT POWER (mW)
OUTPUT POWER (mW)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER (USCP)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER (TQFN)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER (UCSP)
C/MAX9724D
10
100
10
1
10
V
= 3V
V
DD
= 5V
V
= 5V
DD
DD
R = 32Ω
L
R = 16Ω
L
R = 16Ω
L
1
1
f
IN
= 1kHz
0.1
0.1
f
IN
= 1kHz
0.1
f
IN
= 10kHz
0.01
0.01
f = 10kHz
IN
f
IN
= 10kHz
0.01
f
IN
= 1kHz
f
IN
= 20Hz
f
IN
= 20Hz
f
= 20Hz
IN
0.001
0.001
0.001
0
5
10 15 20 25 30 35 40
OUTPUT POWER (mW)
0
20
40
60
80
100
0
10 20 30 40 50 60 70
OUTPUT POWER (mW)
80
OUTPUT POWER (mW)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER (TQFN)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER (UCSP)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY (TQFN)
100
10
1
10
1
0.1
V = 3V
DD
R = 16Ω
L
V
= 5V
V
DD
= 5V
DD
R = 32Ω
L
R = 32Ω
L
1
0.1
P
= 5mW
OUT
f
= 1kHz
IN
f
IN
= 1kHz
0.1
0.01
0.001
P
= 10mW
0.01
0.001
f
IN
= 10kHz
75
OUT
0.01
f
IN
= 10kHz
100
f
= 20Hz
f
= 20Hz
IN
IN
0.001
0
20
40
60
80
120
0
25
50
100
10
100
1k
10k
100k
OUTPUT POWER (mW)
OUTPUT POWER (mW)
FREQUENCY (Hz)
4
_______________________________________________________________________________________
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
C/MAX9724D
Typical Operating Characteristics (continued)
(V
DD
= 5V, PGND = SGND = 0V, SHDN = V , C1 = C2 = 1µF, R = ∞, gain = -1.5V/V (R = 20kΩ, R = 30kΩ for the MAX9724C),
DD L IN F
THD+N measurement bandwidth = 22Hz to 22kHz, both outputs driven in phase, T = +25°C, unless otherwise noted.)
A
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY (TQFN)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY (UCSP)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY (UCSP)
1
0.1
1
0.1
1
0.1
V
= 3V
V
= 3V
V
DD
= 3V
DD
DD
R = 16Ω
L
R = 32Ω
L
R = 32Ω
L
P
= 5mW
OUT
P
OUT
= 8mW
P
OUT
= 8mW
P
= 10mW
OUT
0.01
0.001
0.01
0.001
0.01
0.001
P
= 13mW
1k
OUT
P
= 15mW
1k
OUT
10
100
10k
100k
10
100
10k
100k
10
100
1k
FREQUENCY (Hz)
10k
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY (TQFN)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY (UCSP)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY (TQFN)
1
0.1
1
0.1
1
V
DD
= 5V
V
DD
= 5V
V
= 5V
DD
R = 16Ω
L
R = 16Ω
L
R = 32Ω
L
P
= 20mW
OUT
0.1
0.01
P
OUT
= 30mW
P
= 20mW
OUT
P
OUT
= 37mW
0.01
0.001
0.01
0.001
P
OUT
= 32mW
P
OUT
= 50mW
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
FREQUENCY (Hz)
10k
100k
OUTPUT POWER vs. SUPPLY
VOLTAGE (TQFN)
OUTPUT POWER vs. SUPPLY
VOLTAGE (UCSP)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY (UCSP)
60
50
40
30
20
10
0
70
60
50
40
30
20
10
0
1
0.1
f
= 1kHz
IN
L
f
= 1kHz
V
= 5V
IN
L
DD
R = 16Ω
R = 16Ω
R = 32Ω
L
10% THD+N
10% THD+N
P
= 20mW
OUT
1% THD+N
0.01
0.001
1% THD+N
P
OUT
= 45mW
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
10
100
1k
FREQUENCY (Hz)
10k
100k
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
5
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
Typical Operating Characteristics (continued)
(V
DD
= 5V, PGND = SGND = 0V, SHDN = V , C1 = C2 = 1µF, R = ∞, gain = -1.5V/V (R = 20kΩ, R = 30kΩ for the MAX9724C),
DD L IN F
THD+N measurement bandwidth = 22Hz to 22kHz, both outputs driven in phase, T = +25°C, unless otherwise noted.)
A
OUTPUT POWER
vs. SUPPLY VOLTAGE (TQFN)
OUTPUT POWER
vs. SUPPLY VOLTAGE (UCSP)
OUTPUT POWER
vs. LOAD RESISTANCE (TQFN)
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
35
30
25
20
15
10
5
V
= 3V
DD
= 1kHz
f
= 1kHz
f
= 1kHz
IN
L
IN
L
10% THD+N
f
R = 32Ω
R = 32Ω
IN
10% THD+N
10% THD+N
1% THD+N
1% THD+N
1% THD+N
4.5
0
10
10
10
100
1000
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.5
10
0
3.0
3.5
4.0
5.0
5.5
LOAD RESISTANCE (Ω)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
OUTPUT POWER
OUTPUT POWER
OUTPUT POWER
C/MAX9724D
vs. LOAD RESISTANCE (UCSP)
vs. LOAD RESISTANCE (TQFN)
vs. LOAD RESISTANCE (UCSP)
35
30
25
20
15
10
5
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
V
= 3V
DD
THD+N = 10%
THD+N = 10%
THD+N = 10%
f
= 1kHz
IN
THD+N = 1%
THD+N = 1%
THD+N = 1%
V
= 5V
V
= 5V
DD
DD
f
= 1kHz
f = 1kHz
IN
IN
0
10
100
1000
100
100
LOAD RESISTANCE (Ω)
LOAD RESISTANCE (Ω)
LOAD RESISTANCE (Ω)
POWER DISSIPATION
vs. OUTPUT POWER (TQFN)
POWER DISSIPATION
vs. OUTPUT POWER (UCSP)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
0
-20
250
200
150
100
50
160
140
R = 32Ω
L
R = 16Ω
L
120
R = 32Ω
L
R = 16Ω
L
-40
100
80
R = 32Ω
L
-60
V
DD
= 5V
60
40
20
0
-80
V
= 3V
V
DD
= 3V
DD
f
= 1kHz
= P
f
= 1kHz
= P
IN
IN
-100
-120
V
DD
= 3V
1k
P
OUT
+ P
OUTR
P
OUT
+ P
OUTL OUTR
OUTL
OUTPUTS IN PHASE
OUTPUTS IN PHASE
0
0
20
40
60
80
5
10 15 20 25 30 35 40 45 50
OUTPUT POWER (mW)
100
10k
100k
FREQUENCY (Hz)
OUTPUT POWER (mW)
6
_______________________________________________________________________________________
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
C/MAX9724D
Typical Operating Characteristics (continued)
(V
DD
= 5V, PGND = SGND = 0V, SHDN = V , C1 = C2 = 1µF, R = ∞, gain = -1.5V/V (R = 20kΩ, R = 30kΩ for the MAX9724C),
DD L IN F
THD+N measurement bandwidth = 22Hz to 22kHz, both outputs driven in phase, T = +25°C, unless otherwise noted.)
A
OUTPUT POWER vs. LOAD RESISTANCE AND
CHARGE-PUMP CAPACITOR SIZE (TQFN)
CROSSTALK vs. FREQUENCY
0
-20
80
70
60
50
40
30
20
P
= 15mW
OUT
C1 = C2 = 2.2μF
C1 = C2 = 1μF
R = 16Ω
L
-40
-60
RIGHT TO LEFT
C1 = C2 = 0.47μF
-80
LEFT TO RIGHT
10k
V
DD
= 5V
-100
-120
f
= 1kHz
IN
THD+N = 1%
0
50
100
150
10
100
1k
FREQUENCY (Hz)
100k
LOAD RESISTANCE (Ω)
OUTPUT POWER vs. LOAD RESISTANCE AND
CHARGE-PUMP CAPACITOR SIZE (UCSP)
80
OUTPUT SPECTRUM vs. FREQUENCY
-40
R = 32Ω
DD
L
C1 = C2 = 2.2μF
-50
-60
70
V
f
= 3V
= 1kHz
IN
60
V
OUT
= -60dBV
-70
C1 = C2 = 1μF
C1 = C2 = 0.47μF
50
40
30
-80
-90
-100
-110
-120
-130
-140
20
10
V
= 5V
DD
f
= 1kHz
IN
THD+N = 1%
0
0
5
10
FREQUENCY (kHz)
15
20
0
50
100
150
LOAD RESISTANCE (Ω)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
3.5
3.4
3.3
3.2
3.1
3.0
2.9
2.8
2.7
2.6
2.5
NO LOAD
INPUT GROUNDED
2.5
3.0
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
7
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
Typical Operating Characteristics (continued)
(V
DD
= 5V, PGND = SGND = 0V, SHDN = V , C1 = C2 = 1µF, R = ∞, gain = -1.5V/V (R = 20kΩ, R = 30kΩ for the MAX9724C),
DD L IN F
THD+N measurement bandwidth = 22Hz to 22kHz, both outputs driven in phase, T = +25°C, unless otherwise noted.)
A
EXITING SHUTDOWN
ENTERING SHUTDOWN
V
SHDN
V
SHDN
5V/div
5V/div
V
IN_
V
IN_
1V/div
1V/div
V
V
OUT_
OUT_
500mV/div
500mV/div
40μs/div
20μs/div
C/MAX9724D
Pin Description
PIN
NAME
FUNCTION
TQFN
UCSP
C1
C2
C3
C4
A2
B3
A1
B2
B4
A3
A4
B1
—
1
2
C1P
PGND
C1N
Flying Capacitor Positive Terminal. Connect a 1µF ceramic capacitor from C1P to C1N.
Power Ground. Connect to SGND.
3
Flying Capacitor Negative Terminal. Connect a 1µF ceramic capacitor from C1P to C1N.
Charge-Pump Output. Connect to SVSS and bypass with a 1µF ceramic capacitor to PGND.
Active-Low Shutdown Input
4
PVSS
SHDN
INL
5
6
Left-Channel Input
7
SGND
INR
Signal Ground. Connect to PGND.
8
Right-Channel Input
9
SVSS
OUTR
OUTL
Amplifier Negative Supply. Connect to PVSS.
Right-Channel Output
10
11
12
EP
Left-Channel Output
V
Positive Power-Supply Input. Bypass with a 1µF capacitor to PGND.
Exposed Pad. Internally connected to SVSS. Connect to SVSS or leave unconnected.
DD
EP
8
_______________________________________________________________________________________
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
C/MAX9724D
Detailed Description
V
OUT
The MAX9724C/MAX9724D stereo headphone ampli-
fiers feature Maxim’s DirectDrive architecture, eliminat-
ing the large output-coupling capacitors required by
conventional single-supply headphone amplifiers. The
device consists of two 60mW Class AB headphone
amplifiers, undervoltage lockout (UVLO)/shutdown con-
trol, charge pump, and comprehensive click-and-pop
suppression circuitry (see the Functional
Diagram/Typical Operating Circuits). The charge pump
V
DD
V
DD
V
/2
DD
GND
inverts the positive supply (V ), creating a negative
DD
supply (PVSS). The headphone amplifiers operate from
these bipolar supplies with their outputs biased about
PGND (Figure 1). The benefit of this PGND bias is that
the amplifier outputs do not have a DC component. The
large DC-blocking capacitors required with convention-
al headphone amplifiers are unnecessary, conserving
board space, reducing system cost, and improving fre-
quency response. The MAX9724C/MAX9724D feature
an undervoltage lockout that prevents operation from
an insufficient power supply and click-and-pop sup-
pression that eliminates audible transients on startup
and shutdown. The MAX9724C/MAX9724D also feature
thermal-overload and short-circuit protection.
CONVENTIONAL DRIVER-BIASING SCHEME
V
OUT
V
DD
GND
2V
DD
-V
DD
DirectDrive
Conventional single-supply headphone amplifiers have
their outputs biased about a nominal DC voltage (typi-
cally 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 head-
phone, resulting in unnecessary power dissipation and
possible damage to both headphone and headphone
amplifier.
DirectDrive BIASING SCHEME
Figure 1. Conventional Driver Output Waveform vs.
MAX9724C/MAX9724D Output Waveform
Charge Pump
The MAX9724C/MAX9724D feature a low-noise charge
pump. The 270kHz switching frequency is well beyond
the audio range and does not interfere with audio sig-
nals. The switch drivers feature a controlled switching
speed that minimizes noise generated by turn-on and
turn-off transients. The di/dt noise caused by the para-
sitic bond wire and trace inductance is minimized by
limiting the switching speed of the charge pump.
Although not typically required, additional high-fre-
quency noise attenuation can be achieved by increas-
ing the value of C2 (see the Functional Diagram/Typical
Operating Circuits).
Maxim’s DirectDrive architecture uses a charge pump
to create an internal negative supply voltage, allowing
the MAX9724C/MAX9724D outputs to be biased about
GND. With no DC component, there is no need for the
large DC-blocking capacitors. The MAX9724C/
MAX9724D charge pumps require two small ceramic
capacitors, conserving board space, reducing cost,
and improving the frequency response of the head-
phone amplifier. See the Output Power vs. Load
Resistance and Charge-Pump Capacitor Size graph in
the Typical Operating Characteristics for details of the
possible capacitor sizes. There is a low DC voltage on
the amplifier outputs due to amplifier offset. However,
the offsets of the MAX9724C/MAX9724D are typically
1.5mV, which, when combined with a 32Ω load, results
in less than 47µA of DC current flow to the head-
phones.
RF Susceptibility
Modern audio systems are often subject to RF radiation
from sources like wireless networks and cellular phone
networks. Although the RF radiation is out of the audio
band, many signals, in particular GSM signals, contain
bursts or modulation at audible frequencies. Most ana-
log amplifiers demodulate the low-frequency envelope,
adding noise to the audio signal. The architecture of
_______________________________________________________________________________________
9
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
the MAX9724 addresses the problem of the RF suscep-
tibility by rejecting RF noise and preventing it from cou-
pling into the audio band.
Typically, the output of the device driving the
MAX9724C/MAX9724D has a DC bias of half the supply
voltage. At startup, the input-coupling capacitor, C , is
IN
charged to the preamplifier’s DC bias voltage through
The RF susceptibility of an amplifier can be measured
by placing the amplifier in an isolated chamber and sub-
jecting it to an electric field of known strength. If the
electric field is modulated with an audio band signal, a
percentage of the modulated signal is demodulated and
amplified by the device in the chamber. Figure 2 shows
the signal level at the outputs of an unoptimized amplifi-
er and the MAX9724. The test conditions are shown in
Table 1.
the MAX9724C/MAX9724D input resistor, R , and a
IN
series 15kΩ resistor. This DC shift across the capacitor
results in an audible click-and-pop. Delay the rise of
SHDN 4 to 5 time constants based on R x 15kΩ x C
IN
IN
to eliminate clicks-and-pops caused by the input filter.
Shutdown
The MAX9724C/MAX9724D feature a < 0.1µA, low-
power shutdown mode that reduces quiescent current
consumption and extends battery life for portable appli-
cations. Drive SHDN low to disable the amplifiers and
the charge pump. In shutdown mode, the amplifier out-
put impedance is set to 14kΩ||R (R is 30kΩ for the
Table 1. RF Susceptibility Test Conditions
TEST PARAMETER
SETTING
RF Field Strength
50V/m
F
F
MAX9724D). The amplifiers and charge pump are
enabled once SHDN is driven high.
RF Modulation Type
Sine wave
100%
RF Modulation Index
RF Modulation Frequency
Applications Information
1kHz
7
Power Dissipation
Under normal operating conditions, linear power ampli-
fiers 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:
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 MAX9724C/MAX9724D do not require output-
coupling capacitors, this problem does not arise.
Additionally, the MAX9724C/MAX9724D feature exten-
sive click-and-pop suppression that eliminates any audi-
ble transient sources internal to the device.
T
− T
A
J(MAX)
P
=
DISSPKG(MAX)
θ
JA
where T
is +150°C, T is the ambient tempera-
A
J(MAX)
ture, and θ is the reciprocal of the derating factor in
JA
40
62dB IMPROVEMENT
AT 850MHz
RF SUSCEPTIBLE
AMPLIFIER
39dB IMPROVEMENT
AT 900MHz
20
0
67dB IMPROVEMENT
AT 1800MHz
49dB IMPROVEMENT
AT 1900MHz
-20
-40
-60
-80
-100
MAX9724
100
600
1100
1600
2100
2600
RF CARRIER FREQUENCY (MHz)
Figure 2. RF Susceptibility of the MAX9724 and a Typical Headphone Amplifier
10 ______________________________________________________________________________________
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
C/MAX9724D
°C/W as specified in the Absolute Maximum Ratings
opposite supply voltage by 9V. For example, if V
=
DD
section. For example, θ of the thin QFN package is
5V, the charge pump sets PVSS = -5V. Therefore, the
peak output swing must be less than 4V to prevent
exceeding the absolute maximum ratings.
JA
+68°C/W, and 154.2°C/W for the UCSP package.
The MAX9724C/MAX9724D have two power dissipation
sources; a charge pump and the two output amplifiers.
If power dissipation for a given application exceeds the
maximum allowed for a particular package, reduce
UVLO
The MAX9724C/MAX9724D feature an undervoltage
lockout (UVLO) function that prevents the device from
operating if the supply voltage is less than 2.5V. This fea-
ture ensures proper operation during brownout condi-
tions and prevents deep battery discharge. Once the
supply voltage exceeds the UVLO threshold, the
MAX9724C/MAX9724D charge pump is turned on and
the amplifiers are powered, provided that SHDN is high.
V
, increase load impedance, decrease the ambient
DD
temperature, or add heatsinking to the device. Large
output, supply, and ground traces decrease θ , allow-
ing more heat to be transferred from the package to the
surrounding air.
JA
Thermal-overload protection limits total power dissipa-
tion in the MAX9724C/MAX9724D. When the junction
temperature exceeds +150°C, the thermal protection
circuitry disables the amplifier output stage. The ampli-
fiers are enabled once the junction temperature cools
by approximately 12°C. This results in a pulsing output
under continuous thermal-overload conditions.
Component Selection
Input-Coupling Capacitor
The input capacitor (C ), in conjunction with the input
IN
resistor (R ), forms a highpass filter that removes the
IN
DC bias from an incoming signal (see the Functional
Diagram/Typical Operating Circuits). The AC-coupling
capacitor allows the device to bias the signal to an opti-
mum DC level. Assuming zero-source impedance, the
-3dB point of the highpass filter is given by:
Output Dynamic Range
Dynamic range is the difference between the noise floor
of the system and the output level at 1% THD+N.
Determine the system’s dynamic range before setting the
maximum output gain. Output clipping occurs if the out-
put signal is greater than the dynamic range of the sys-
tem. The DirectDrive architecture of the MAX9724C/
MAX9724D has increased the dynamic range compared
to other single-supply amplifiers.
1
f
=
−3dB
2πR C
IN IN
Choose the C such that f
is well below the lowest
-3dB
IN
-3dB
frequency of interest. Setting f
too high affects the
Maximum Output Swing
device’s low-frequency response. Use capacitors
whose dielectrics have low-voltage coefficients, such
as tantalum or aluminum electrolytic. Capacitors with
high-voltage coefficients, such as ceramics, can result
in increased distortion at low frequencies.
V
DD
< 4.35V
If the output load impedance is greater than 1kΩ, the
MAX9724C/MAX9724D can swing within a few millivolts
of their supply rail. For example, with a 3.3V supply, the
output swing is 2V , or 2.83V peak while maintaining
RMS
Charge-Pump Capacitor Selection
Use ceramic capacitors with a low ESR for optimum
performance. For optimal performance over the extend-
ed temperature range, select capacitors with an X7R
dielectric. Table 2 lists suggested manufacturers.
a low 0.003% THD+N. If the supply voltage drops to
3V, the same 2.83V peak has only 0.05% THD+N.
V
DD
> 4.35V
Internal device structures limit the maximum voltage
swing of the MAX9724C/MAX9724D when operated at
supply voltages greater than 4.35V. The output must not
be driven such that the peak output voltage exceeds the
Flying Capacitor (C1)
The value of the flying capacitor (see the Functional
Diagram/Typical Operating Circuits) affects the charge
Table 2. Suggested Capacitor Manufacturers
WEBSITE
SUPPLIER
Taiyo Yuden
PHONE
FAX
800-348-2496
847-803-6100
770-436-1300
847-925-0899
847-390-4405
770-436-3030
www.t-yuden.com
www.component.tdk.com
www.murata.com
TDK
Murata
______________________________________________________________________________________ 11
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
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 resis-
tance to an extent. See the Output Power vs. Load
Resistance and Charge-Pump Capacitor Size graph in
the Typical Operating Characteristics. Above 1µF, the
on-resistance of the switches and the ESR of C1 and C2
dominate.
Choose feedback resistor values in the tens of kΩ
range. Lower values may cause excessive power dissi-
pation and require impractically small values of R for
IN
large gain settings. The high-impedance state of the
outputs can also be degraded during shutdown mode
if an inadequate feedback resistor is used since the
equivalent output impedance during shutdown is
14kΩ||R (R is equal to 30kΩ for the MAX9724D). The
f
F
source resistance of the input device may also need to
be taken into consideration. Since the effective value of
R
is equal to the sum of the source resistance of the
IN
Hold Capacitor (C2)
The hold capacitor value (see the Functional
Diagram/Typical Operating Circuits) and ESR directly
affect the ripple at PVSS. Increasing the value of C2
reduces output ripple. Likewise, decreasing the ESR of
C2 reduces both ripple and output resistance. Lower
capacitance values can be used in systems with low
maximum output power levels. See the Output Power
vs. Load Resistance and Charge-Pump Capacitor Size
graph in the Typical Operating Characteristics.
input device and the value of the input resistor connect-
ed to the inverting terminal of the headphone amplifier
(20kΩ for the MAX9724D), the overall closed-loop gain
of the headphone amplifier can be reduced if the input
resistor is not significantly larger than the source resis-
tance of the input device.
R
F
C/MAX9724D
Power-Supply Bypass Capacitor (C3)
The power-supply bypass capacitor (see the Functional
Diagram/Typical Operating Circuits) lowers the output
impedance of the power supply and reduces the
impact of the MAX9724C/MAX9724D’s charge-pump
MAX9724C
R
IN
LEFT
AUDIO
INPUT
INL
switching transients. Bypass V
with C3, the same
DD
OUTL
value as C1, and place it physically close to the V
and PGND pins.
DD
Amplifier Gain
The gain of the MAX9724D amplifier is internally set to
-1.5V/V. All gain-setting resistors are integrated into the
device, reducing external component count. The inter-
nally set gain, in combination with DirectDrive, results in
a headphone amplifier that requires only five small
capacitors to complete the amplifier circuit: two for the
charge pump, two for audio input coupling, and one for
power-supply bypassing (see the Functional
Diagram/Typical Operating Circuits).
OUTR
R
IN
RIGHT
AUDIO
INPUT
INR
R
F
Figure 3. Gain Setting for the MAX9724C
The gain of the MAX9724C amplifier is set externally as
shown in Figure 3, the gain is:
A = -R /R (V/V)
V
F
IN
12 ______________________________________________________________________________________
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
C/MAX9724D
sinusoidal signal equates to approximately 5.7V
,
Lineout Amplifier and Filter Block
P-P
which means that the audio system designer cannot
simply run the lineout stage from a (typically common)
5V supply—the resulting output swing would be inade-
quate. A common solution to this problem is to use op
amps driven from split supplies ( 5V typically), or to
use a high-voltage supply rail (9V to 12V). This can
mean adding extra cost and complexity to the system
power supply to meet this output level requirement.
The MAX9724C can be used as an audio line driver
capable of providing 2V
gle 5V supply (see Figure 4 for the RMS Output Voltage
vs. Supply Voltage plot). 2V is a popular audio line
level, first used in CD players, but now common in DVD
and set-top box (STB) interfacing standards. A 2V
into 10kΩ loads with a sin-
RMS
RMS
RMS
RMS OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE
Having the ability to derive 2V
from a 5V supply, or
RMS
even 3.3V supply, can often simplify power-supply
design in some systems.
3.5
f
= 1kHz
IN
R = 10kΩ
L
When the MAX9724C is used as a line driver to provide
outputs that feed stereo equipment (receivers, STBs,
notebooks, and desktops) with a digital-to-analog con-
verter (DAC) used as an audio input source, it is often
desirable to eliminate any high-frequency quantization
noise produced by the DAC output before it reaches
the load. This high-frequency noise can cause the input
stages of the line-in equipment to exceed slew-rate lim-
itations or create excessive EMI emissions on the
cables between devices.
THD+N = 1%
3.0
2.5
2.0
1.5
LIMITED BY ABS.
MAXIMUM RATINGS
2.5
3.0
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
Figure 4. RMS Output Voltage vs. Supply Voltage
15kΩ
220pF
LEFT
AUDIO
INPUT
1μF
MAX9724C
7.5kΩ
7.5kΩ
INL
LINE IN DEVICE
OUTL
1.2nF
STEREO
DAC
10kΩ
1.2nF
7.5kΩ
RIGHT
AUDIO
INPUT
OUTR
1μF
7.5kΩ
INR
10kΩ
220pF
15kΩ
Figure 5. MAX9724C Line Out Amplifier and Filter Block Configuration
______________________________________________________________________________________ 13
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
To suppress this noise, and to provide a 2V
stan-
RMS
dard audio output level from a single 5V supply, the
MAX9724C can be configured as a line driver and
active lowpass filter. Figure 5 shows the MAX9724C
connected as 2-pole Rauch/multiple feedback filter with
a passband gain of 6dB and a -3dB (below passband)
cutoff frequency of approximately 27kHz (see Figure 6
for the Gain vs. Frequency plot).
MAX9724C ACTIVE FILTER GAIN
vs. FREQUENCY
10
5
R = 10kΩ
L
0
-5
-10
-15
-20
-25
-30
-35
Layout and Grounding
Proper layout and grounding are essential for optimum
performance. Connect PGND and SGND together at a
single point on the PCB. Connect PVSS to SVSS and
bypass with a 1µF capacitor. Place the power-supply
bypass capacitor and the charge-pump hold capacitor
as close to the MAX9724 as possible. Route PGND and
all traces that carry switching transients away from
SGND and the audio signal path. The thin QFN pack-
age features an exposed pad that improves thermal
efficiency. Ensure that the exposed pad is electrical-
1k
10k
100k
1M
FREQUENCY (Hz)
Figure 6. Frequency Response of Active Filter of Figure 4
ly isolated from PGND, SGND, and V . Connect the
DD
exposed paddle to SVSS only when the board lay-
out dictates that the exposed pad cannot be left
floating.
C/MAX9724D
UCSP Applications Information
For the latest application details on UCSP construction,
dimensions, tape carrier information, PCB techniques,
bump-pad layout, and recommended reflow tempera-
ture profile, as well as the latest information on reliability
testing results, refer to the Application Note UCSP—A
Wafer-Level Chip-Scale Package available on Maxim’s
website at www.maxim-ic.com/ucsp.
14 ______________________________________________________________________________________
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
C/MAX9724D
System Diagram
V
DD
0.1μF
15kΩ
1μF
15kΩ
INR
OUTR+
OUTR-
V
DD
PVDD
BIAS
1μF
MAX9710
GND
PGND
MUTE
SHDN
INL
OUTL-
OUTL+
0.1μF
15kΩ
V
DD
15kΩ
μCONTROLLER
100kΩ
100kΩ
0.1μF
STEREO
DAC
OUTL
SHDN
O.47μF
O.47μF
MAX9724D
OUTR
SGND
INL
INR
PGND
V
PVSS
SVSS
DD
V
DD
C1P
C1N
1μF
1μF
1μF
______________________________________________________________________________________ 15
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
Functional Diagram/Typical Operating Circuits
2.7V TO 5.5V
C
IN
0.47μF
R
R
IN*
F*
LEFT
AUDIO
INPUT
20kΩ
30kΩ
ON
C3
1μF
OFF
12
5
6
(B3)
(B1)
(A2)
INL
V
DD
SHDN
V
DD
11
(A4)
OUTL
HEADPHONE
JACK
1
(C1)
SVSS
C1P
UVLO/
SHUTDOWN
CONTROL
CLICK-AND-POP
SUPPRESSION
CHARGE
PUMP
SGND
C1
1μF
V
DD
C/MAX9724D
3
10
(A3)
(C3) C1N
OUTR
MAX9724C
SVSS
PVSS
SVSS
PGND
SGND
INR
4
(C4)
7
(A1)
2
(C2)
9
(B4)
8
(B2)
C
IN
R
*
R *
IN
F
C2
1μF
0.47μF
20kΩ
30kΩ
RIGHT
AUDIO
INPUT
*R AND R VALUES ARE CHOSEN FOR A GAIN -1.5V/V.
IN
F
( ) UCSP PACKAGE
16 ______________________________________________________________________________________
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
C/MAX9724D
Functional Diagram/Typical Operating Circuits (continued)
2.7V TO 5.5V
C
IN
0.47μF
LEFT
AUDIO
INPUT
ON
C3
1μF
OFF
12
5
6
(B3)
(B1)
(A2)
V
INL
DD
SHDN
R
F*
30kΩ
V
DD
R
IN*
20kΩ
11
(A4)
OUTL
HEADPHONE
JACK
1
(C1)
V
SS
C1P
UVLO/
SHUTDOWN
CONTROL
CLICK-AND-POP
SUPPRESSION
CHARGE
PUMP
SGND
C1
1μF
V
DD
3
10
(A3)
(C3) C1N
OUTR
R
IN
20kΩ
MAX9724D
SVSS
R
F
30kΩ
SVSS
9
(B4) (C2)
PVSS
INR
8
(B2)
PGND
2
SGND
4
(C4)
C2
1μF
7
(A1)
C
IN
0.47μF
RIGHT
AUDIO
INPUT
( ) UCSP PACKAGE
______________________________________________________________________________________ 17
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
Pin Configurations
TOP VIEW (BUMPS ON BOTTOM)
TOP VIEW
1
2
3
4
9
8
7
MAX9724C/MAX9724D
A
B
C
10
OUTR
6
5
INL
SGND
SHDN
INR
OUTR
INL
OUTL
SVSS
MAX9724C
MAX9724D
OUTL 11
SHDN
PVSS
V
DD
V
DD 12
4
+
C1P
PGND
C1N
PVSS
1
2
3
UCSP
TQFN
C/MAX9724D
Chip Information
TRANSISTOR COUNT: 993
PROCESS: BiCMOS
18 ______________________________________________________________________________________
Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
C/MAX9724D/MAX9724D
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 TYPE
12 UCSP
PACKAGE CODE
B12-1
DOCUMENT NO.
21-0104
12 TQFN-EP
T1233-1
21-0136
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 19
© 2008 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
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