19-3457; Rev 3; 3/09
1.3W, Filterless, Stereo Class D Audio
Power Amplifier
General Description
The MAX9701 stereo Class D audio power amplifier pro-
vides Class AB amplifier audio performance with the
benefits of Class D efficiency, eliminating the need for a
heatsink while extending battery life. The MAX9701
delivers up to 1.3W per channel into an 8Ω load while
offering 87% efficiency. Maxim’s next-generation, low-
EMI modulation scheme allows the amplifier to operate
without an external LC filter while still meeting FCC EMI
emission levels.
The MAX9701 offers two modulation schemes: a fixed-fre-
quency (FFM) mode, and a spread-spectrum (SSM)
mode that reduces EMI-radiated emissions. The
MAX9701 oscillator can be synchronized to an external
clock through the SYNC input, allowing synchronization of
multiple Maxim Class D amplifiers. The sync output
(SYNC_OUT) can be used for a master-slave application
where more channels are required. The MAX9701 fea-
tures a fully differential architecture, a full bridge-tied load
(BTL) output, and comprehensive click-and-pop suppres-
sion. The device features internally set gains of 0dB, 6dB,
12dB, and 18dB selected through two gain-select inputs,
further reducing external component count.
The MAX9701 features high 80dB PSRR, less than 0.1%
THD+N, and SNR in excess of 88dB. Short-circuit and
thermal-overload protection prevent the device from
being damaged during a fault condition. The MAX9701 is
available in 24-pin thin QFN-EP (4mm x 4mm x 0.8mm)
and 20-bump UCSP™ (2mm x 2.5mm x 0.6mm) pack-
ages. The MAX9701 is specified over the extended
-40°C to +85°C temperature range.
Features
♦
Spread-Spectrum Modulation Lowers Radiated
Emissions
♦
Single-Supply Operation (2.5V to 5.5V)
♦
1.3W Stereo Output (8Ω, V
DD
= 5V, THD+N = 1%)
♦
No LC Output Filter Required
♦
87% Efficiency (R
L
= 8Ω, P
OUT
= 1000mW)
♦
Less Than 0.1% THD+N
♦
High 80dB PSRR
♦
Fully Differential Inputs
♦
Integrated Click-and-Pop Suppression
♦
Typical Low Quiescent Current (9mA)
♦
Typical Low-Power Shutdown Mode (0.1µA)
♦
Short-Circuit and Thermal-Overload Protection
♦
Available in Thermally Efficient, Space-Saving
Packages
24-Pin Thin QFN-EP (4mm x 4mm x 0.8mm)
20-Bump UCSP (2mm x 2.5mm x 0.6mm)
MAX9701
Ordering Information
PART
MAX9701EBP+TG45
MAX9701ETG+
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
20 UCSP
24 TQFN-EP*
Applications
Cellular Phones
Notebooks
Handheld Gaming Consoles
Docking Stations
MP3 Players
+Denotes
lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed pad.
Block Diagram
V
DD
MAX9701
INR+
RIGHT
MODULATOR
AND H-BRIDGE
INR-
Pin Configurations appear at end of data sheet.
GAIN1
GAIN2
GAIN
INL+
LEFT
MODULATOR
AND H-BRIDGE
INL-
OSCILLATOR
SYNC
SYNC_OUT
UCSP is a trademark of Maxim Integrated Products, Inc.
________________________________________________________________
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.
1.3W, Filterless, Stereo Class D Audio
Power Amplifier
MAX9701
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND..............................................................................6V
V
DD
to PV
DD
..........................................................-0.3V to +0.3V
PV
DD
to PGND .........................................................................6V
GND to PGND .......................................................-0.3V to +0.3V
All Other Pins to GND.................................-0.3V to (V
DD
+ 0.3V)
Continuous Current In/Out of PV
DD
, PGND, OUT_ .........±800mA
Continuous Input Current (all other pins)..........................±20mA
Duration of OUT_ Short Circuit to GND or PV
DD
........Continuous
Duration of Short Circuit Between OUT+ and OUT- ......Continuous
Continuous Power Dissipation (T
A
= +70°C)
20-Bump UCSP (derate 10mW/°C above +70°C) ...........800mW
24-Pin Thin QFN (derate 20.8mW/°C above +70°C) ..1666.7mW
Junction Temperature ......................................................+150°C
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Bump Temperature (soldering) Reflow............................+235°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
DD
= PV
DD
=
SHDN
= 3.3V, GND = PGND = 0V, SYNC = 0V (FFM), gain = 6dB (GAIN1 = 0, GAIN2 = 1), R
L
connected between
OUT+ and OUT-, R
L
=
∞,
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Notes 1, 2)
PARAMETER
GENERAL
Supply Voltage Range
Quiescent Current
Shutdown Current
Common-Mode Rejection Ratio
Input Bias Voltage
Turn-On Time
Output Offset Voltage
V
DD
I
DD
I
SHDN
CMRR
V
BIAS
t
ON
V
OS
T
A
= +25
o
C
T
MIN
< T
A
< T
MAX
V
DD
= 2.5V to 5.5V, V
IN
= 0V
Power-Supply Rejection Ratio
PSRR
100mV
P-P
ripple,
V
IN
= 0V
THD+N = 1%,
T
A
= +25
o
C
f
RIPPLE
= 217Hz
f
RIPPLE
= 20kHz
V
DD
= 3.3V
V
DD
= 5V
R
L
= 8Ω
R
L
= 4Ω
R
L
= 8Ω
R
L
= 4Ω
60
80
72
50
460
750
1300
2200
0.08
0.15
86
86
88.5
88.5
950
1200
1100
1400
1200
±60
200
1000
1600
1250
1600
kHz
dB
%
mW
dB
f
IN
= 1kHz
1.125
Inferred from PSRR test
V
DD
= 3.3V, per channel
V
DD
= 5V, per channel
2.5
4.5
6.3
0.1
66
1.25
40
±10
±30
±55
1.375
5.5
8
10
10
V
mA
μA
dB
V
ms
mV
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Output Power (Note 3)
P
OUT
Total Harmonic Distortion Plus
Noise (Note 3)
THD+N
R
L
= 8Ω (P
OUT
= 300mW), f = 1kHz
R
L
= 4Ω (P
OUT
= 400mW), f = 1kHz
BW = 22Hz
to 22kHz
FFM
SSM
FFM
SSM
Signal-to-Noise Ratio
SNR
V
OUT
= 1V
RMS
A-weighted
SYNC = GND
SYNC = unconnected
Oscillator Frequency
f
OSC
SYNC = V
DD
Minimum On-Time
SYNC Frequency Lock Range
t
MIN
f
SYNC
ns
kHz
2
_______________________________________________________________________________________
1.3W, Filterless, Stereo Class D Audio
Power Amplifier
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
=
SHDN
= 3.3V, GND = PGND = 0V, SYNC = 0V (FFM), gain = 6dB (GAIN1 = 0, GAIN2 = 1), R
L
connected between
OUT+ and OUT-, R
L
=
∞,
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Notes 1, 2)
PARAMETER
SYNC_OUT Capacitance Drive
Capacitive Drive
SYMBOL
C
SYNC_OUT
C
L
Bridge-tied capacitance
Single ended
Peak reading, THD+N = 1% Into shutdown
A-weighted, 32 samples
Out of
per second (Note 4)
shutdown
V
DD
= 3.3V, P
OUT
= 500mW per channel,
f
IN
= 1kHz, R
L
= 8Ω
V
DD
= 5V, P
OUT
= 1000mW per channel,
f
IN
= 1kHz, R
L
= 8Ω
GAIN1 = 0, GAIN2 = 0
Input Resistance
R
IN
GAIN1 = 1, GAIN2 = 0
GAIN1 = 0, GAIN2 = 1
GAIN1 = 1, GAIN2 = 1
GAIN1 = 0, GAIN2 = 0
Gain
A
V
GAIN1 = 1, GAIN2 = 0
GAIN1 = 0, GAIN2 = 1
GAIN1 = 1, GAIN2 = 1
Channel-to-Channel Gain
Tracking
Crosstalk
L to R, R to L, f = 10kHz, R
L
= 8Ω,
P
OUT
= 300mW
V
INH
V
INL
2
0.8
±1
V
IN
= GND, normal operation
V
IN
= V
DD
, normal operation
DIGITAL OUTPUTS (SYNC_OUT)
Output-Voltage High
Output-Voltage Low
V
OH
V
OL
I
OH
= 3mA, V
DD
= 3.3V
I
OL
= 3mA
2.4
0.08
V
V
-15
-7
μA
12
25
10.5
CONDITIONS
MIN
TYP
100
200
400
66.16
dB
66.26
87
%
87.4
15
25
37.4
50
18
12
6
0
1
70
%
dB
dB
19.5
kΩ
MAX
UNITS
pF
pF
MAX9701
Click-and-Pop Level
K
CP
Efficiency
η
DIGITAL INPUTS (SHDN, SYNC, GAIN1, GAIN2)
Input-Voltage High
Input-Voltage Low
Input Leakage Current
(SHDN, GAIN1, GAIN2)
Input Leakage Current (SYNC)
V
V
μA
Note 1:
All devices are 100% production tested at +25°C. All temperature limits are guaranteed by design.
Note 2:
Testing performed with a resistive load in series with an inductor to simulate an actual speaker load. For R
L
= 4Ω, L = 33μH.
For R
L
= 8Ω, L = 68μH.
Note 3:
When driving speakers below 4Ω with large signals, exercise care to avoid violating the absolute maximum rating for continuous
output current.
Note 4:
Testing performed with 8Ω resistive load in series with 68μH inductive load connected across the BTL output. Mode transi-
tions are controlled by
SHDN.
K
CP
level is calculated as: 20 x log[(peak voltage under normal operation at rated power
level) / (peak voltage during mode transition, no input signal)]. Units are expressed in dB.
_______________________________________________________________________________________
3
1.3W, Filterless, Stereo Class D Audio
Power Amplifier
MAX9701
Typical Operating Characteristics
(V
DD
= PV
DD
=
SHDN
= 3.3V, GND = PGND = 0V, SYNC = V
DD
(SSM), gain = 6dB (GAIN1 = 0, GAIN2 = 1)).
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
MAX9701 toc01
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
MAX9701 toc02
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
V
DD
= 3.3V
R
L
= 4Ω
MAX9701 toc03
10
V
DD
= 5V
R
L
= 4Ω
10
V
DD
= 5V
R
L
= 8Ω
10
1
THD+N (%)
THD+N (%)
OUTPUT POWER = 600mW
1
THD+N (%)
OUTPUT POWER = 500mW
0.1
OUTPUT POWER = 100mW
OUTPUT POWER = 300mW
1
OUTPUT POWER = 600mW
0.1
0.1
OUTPUT POWER = 100mW
OUTPUT POWER = 100mW
OUTPUT POWER = 250mW
10
100
1k
FREQUENCY (Hz)
10k
100k
OUTPUT POWER = 300mW
0.01
10
100
1k
FREQUENCY (Hz)
10k
100k
0.01
10
100
1k
FREQUENCY (Hz)
10k
100k
0.01
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
MAX9701 toc04
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
MAX9701 toc05
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
V
DD
= 5V
R
L
= 4Ω
10
MAX9701 toc06
10
V
DD
= 3.3V
R
L
= 8Ω
10
V
DD
= 5V
R
L
= 8Ω
P
OUT
= 800mW
1
THD+N (%)
100
1
THD+N (%)
OUTPUT POWER = 400mW
0.1
OUTPUT POWER = 100mW
OUTPUT POWER = 250mW
0.01
10
100
1k
FREQUENCY (Hz)
10k
100k
THD+N (%)
f
IN
= 10kHz
1
FFM
0.1
0.1
SSM
0.01
10
100
1k
FREQUENCY (Hz)
10k
100k
0.01
0
0.5
1.0
1.5
2.0
f
IN
= 20kHz
f
IN
= 1kHz
2.5
3.0
OUTPUT POWER (W)
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
MAX9701 toc07
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
MAX9701 toc08
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
V
DD
= 3.3V
R
L
= 8Ω
10
THD+N (%)
MAX9701 toc09
100
V
DD
= 5V
R
L
= 8Ω
10
f
IN
= 10kHz
THD+N (%)
1
100
V
DD
= 3.3V
R
L
= 4Ω
10
THD+N (%)
100
1
f
IN
= 10kHz
f
IN
= 1kHz
1
f
IN
= 10kHz
0.1
f
IN
= 20kHz
f
IN
= 1kHz
0.01
0.1
f
IN
= 20kHz
0.1
f
IN
= 1kHz
f
IN
= 20kHz
0.01
0.001
0
0.5
1.0
OUTPUT POWER (W)
1.5
2.0
0.01
0
0.2
0.4
0.6
0.8
1.0
1.2
OUTPUT POWER (W)
0
100
200
300
400
500
600
700
OUTPUT POWER (mW)
4
_______________________________________________________________________________________
1.3W, Filterless, Stereo Class D Audio
Power Amplifier
Typical Operating Characteristics (continued)
(V
DD
= PV
DD
=
SHDN
= 3.3V, GND = PGND = 0V, SYNC = V
DD
(SSM), gain = 6dB (GAIN1 = 0, GAIN2 = 1)).
MAX9701
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. OUTPUT POWER
MAX9701 toc10
EFFICIENCY vs. OUTPUT POWER
90
80
EFFICIENCY (%)
70
60
50
40
30
R
L
= 4Ω
R
L
= 8Ω
MAX9701 toc11
EFFICIENCY vs. OUTPUT POWER
90
80
EFFICIENCY (%)
70
60
50
40
30
20
R
L
= 4Ω
R
L
= 8Ω
MAX9701 toc12
100
V
DD
= 5V
R
L
= 8Ω
f
IN
= 1kHz
100
100
10
THD+N (%)
1
SSM
0.1
FFM
0.01
20
10
V
DD
= 5V
f
IN
= 1kHz
0
0.5
1.0
1.5
2.0
2.5
10
0
0
0.2
0.4
0.6
0.8
V
DD
= 3.3V
f
IN
= 1kHz
1.0
1.2
0.001
0
0.4
0.8
1.2
1.6
2.0
OUTPUT POWER (W)
0
OUTPUT POWER (W)
OUTPUT POWER (W)
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX9701 toc13
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX9701 toc14
OUTPUT POWER vs. LOAD RESISTANCE
V
DD
= 5V
f
IN
= 1kHz
MAX9701 toc15
3.5
3.0
OUTPUT POWER (W)
2.5
2.0
1.5
1.0
THD+N = 1%
0.5
0
2.5
3.0
3.5
4.0
4.5
5.0
THD+N = 10%
R
L
= 4Ω
A
V
= 12dB
f
IN
= 1kHz
2.0
R
L
= 8Ω
A
V
= 12dB
f
IN
= 1kHz
3.0
2.5
OUTPUT POWER (W)
2.0
1.5
1.0
0.5
0
THD+N = 1%
THD+N = 10%
1.6
OUTPUT POWER (W)
1.2
THD+N = 10%
0.8
THD+N = 1%
0.4
0
5.5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
0
20
40
60
80
100
LOAD RESISTANCE (Ω)
OUTPUT POWER vs. LOAD RESISTANCE
MAX9701 toc16
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX9701 toc17
COMMON-MODE REJECTION RATIO
vs. FREQUENCY
-10
-20
-30
CMRR (dB)
-40
-50
-60
-70
-80
-90
-100
V
DD
= 3.3V
V
DD
= 5V
V
CM
= 100mV
P-P
R
L
= 8Ω
MAX9701 toc18
2.0
f
IN
= 1kHz
1.6
OUTPUT POWER (W)
THD+N = 10%
0
-10
-20
-30
PSRR (dB)
-40
-50
-60
-70
V
RIPPLE
= 100mV
P-P
R
L
= 8Ω
0
1.2
0.8
THD+N = 1%
0.4
-80
-90
0
0
20
40
60
80
100
LOAD RESISTANCE (Ω)
-100
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
FREQUENCY (Hz)
10k
100k
_______________________________________________________________________________________
5
微控制器 MCU
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
