Page 1
General Description
The MAX9713/MAX9714 mono/stereo class D audio
power amplifiers provide class AB amplifier performance
with class D efficiency, conserving board space and
eliminating the need for a bulky heatsink. Using a class
D architecture, these devices deliver up to 6W while
offering greater than 85% efficiency. Proprietary and
patent-protected modulation and switching schemes
render the traditional class D output filter unnecessary.
The MAX9713/MAX9714 offer two modulation schemes:
a fixed-frequency mode (FFM), and a spread-spectrum
mode (SSM) that reduces EMI-radiated emissions due
to the modulation frequency. The device utilizes a fully
differential architecture, a full bridged output, and comprehensive click-and-pop suppression.
The MAX9713/MAX9714 feature high 76dB PSRR, low
0.07% THD+N, and SNR in excess of 100dB. Short-circuit and thermal-overload protection prevent the
devices from being damaged during a fault condition.
The MAX9713 is available in a 32-pin TQFN (5mm x
5mm x 0.8mm) package. The MAX9714 is available in a
32-pin TQFN (7mm x 7mm x 0.8mm) package. Both
devices are specified over the extended -40°C to
+85°C temperature range.
Applications
Features
♦ Filterless Class D Amplifier
♦ Unique Spread-Spectrum Mode Offers 5dB
Emissions Improvement Over Conventional
Methods
♦ Up to 85% Efficient
♦ 6W Output Power into 8Ω
♦ Low 0.07% THD+N
♦ High PSRR (76dB at 1kHz)
♦ 10V to 25V Single-Supply Operation
♦ Differential Inputs Minimize Common-Mode Noise
♦ Pin-Selectable Gain Reduces Component Count
♦ Industry-Leading Integrated Click-and-Pop
Suppression
♦ Low Quiescent Current (18mA)
♦ Low-Power Shutdown Mode (0.2µA)
♦ Short-Circuit and Thermal-Overload Protection
♦ Available in Thermally Efficient, Space-Saving
Packages:
32-Pin TQFN (5mm x 5mm x 0.8mm)–MAX9713
32-Pin TQFN (7mm x 7mm x 0.8mm)–MAX9714
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
________________________________________________________________ Maxim Integrated Products 1
19-3039; Rev 0; 10/03
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.
Ordering Information
*EP = Exposed paddle.
LCD Monitors
LCD TVs
Desktop PCs
LCD Projectors
High-End Notebook
Audio
Hands-Free Car
Phone Adaptors
MAX9714
0.47µF
INL+ OUTL+
OUTL-INL-
0.47µF
H-BRIDGE
0.47µF
INR+ OUTR+
OUTR-INR-
0.47µF
H-BRIDGE
Pin Configurations appear at end of data sheet.
MAX9713
0.47µF
IN+ OUT+
OUT-
IN-
0.47µF
H-BRIDGE
Block Diagrams
PART TEMP RANGE
MAX9713ETJ -40
MAX9714ETJ -40oC to +85oC
o
C to +85oC
PIN-PACKAGE
32 TQFN-EP*
32 TQFN-EP*
AMP
Mono
Stereo
Page 2
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.
(All voltages referenced to GND.)
V
DD
to PGND, AGND .............................................................30V
OUTR_, OUTL_, C1N..................................-0.3V to (V
DD
+ 0.3V)
C1P............................................(V
DD
- 0.3V) to (CHOLD + 0.3V)
CHOLD........................................................(V
DD
- 0.3V) to +40V
All Other Pins to GND.............................................-0.3V to +12V
Duration of OUTR_/OUTL_
Short Circuit to GND, V
DD
......................................Continuous
Continuous Input Current (V
DD
, PGND, AGND) ...................1.6A
Continuous Input Current (all other pins)..........................±20mA
Continuous Power Dissipation (T
A
= +70°C)
MAX9713 32-Pin TQFN (derate 21.3mW/°C
above +70°C)..........................................................1702.1mW
MAX9714 32-Pin TQFN (derate 33.3mW/°C
above +70°C)..........................................................2666.7mW
Junction Temperature......................................................+150°C
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
ELECTRICAL CHARACTERISTICS
(VDD= 15V, GND = PGND = 0V, SHDN ≥ VIH, AV= 16dB, CSS= CIN= C
REG
= 0.47µF, C1 = 100nF, C2 = 1µF, FS1 = FS2 = GND
(f
S
= 330kHz), RLconnected between OUTL+ and OUTL- and OUTR+ and OUTR-, TA= T
MIN
to T
MAX
, unless otherwise noted.
Typical values are at T
A
= +25°C.) (Notes 1, 2)
GENERAL
Supply Voltage Range V
Quiescent Current I
Shutdown Current I
Turn-On Time t
Amplifier Output Resistance in
Shutdown
Input Impedance R
Voltage Gain A
Gain Matching Between channels (MAX9714) 0.5 %
Output Offset Voltage V
Common-Mode Rejection Ratio CMRR fIN = 1kHz, input referred 60 dB
Power-Supply Rejection Ratio
(Note 3)
Output Power P
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DD
DD
SHDN
ON
IN
V
OS
PSRR
OUT
Inferred from PSRR test 10 25 V
RL = ∞
CSS = 470nF 100
CSS = 180nF 50
SHDN = GND 150 330 kΩ
AV = 13dB 35 58 80
AV = 16dB 30 48 65
AV = 19.1dB 23 39 55
AV = 22.1dB 20 31 42
G1 = L, G2 = L 21.9 22.1 22.3
G1 = L, G2 = H 18.9 19.1 19.3
G1 = H, G2 = L 12.8 13 13.2
G1 = H, G2 = H 15.9 16 16.3
VDD = 10V to 25V 54 76
200mV
TH D + N = 10%,
f = 1kH z
P-P
ripple
MAX9713 10 17.5
MAX9714 18 23
f
RIPPLE
f
RIPPLE
RL = 16Ω 5.5 8
R
= 1kHz 76
= 20kHz 60
= 8Ω 6
L
0.2 1.5 µA
±1.6 ±1.3 mV
mA
ms
kΩ
dB
dB
W
Page 3
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VDD= 15V, GND = PGND = 0V, SHDN ≥ VIH, AV= 16dB, CSS= CIN= C
REG
= 0.47µF, C1 = 100nF, C2 = 1µF, FS1 = FS2 = GND
(f
S
= 330kHz), RLconnected between OUTL+ and OUTL- and OUTR+ and OUTR-, TA= T
MIN
to T
MAX
, unless otherwise noted.
Typical values are at T
A
= +25°C.) (Notes 1, 2)
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
= 8Ω, L = 68µH.
For R
L
= 16Ω, L = 136µH.
Note 3: PSRR is specified with the amplifier inputs connected to GND through C
IN
.
Total Harmonic Distortion Plus
Noise
Signal-to-Noise Ratio SNR
Oscillator Frequency f
Efficiency η
DIGITAL INPUTS (SHDN, FS_, G_)
Input Thresholds
Input Leakage Current ±1µA
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
THD+N
OSC
f
= 1kHz, either FFM or SSM, RL = 8Ω,
IN
P
= 4W
OUT
BW = 22Hz to
R
= 8Ω, P
L
4W, f = 1kHz
FS1 = L, FS2 = L 300 335 370
FS1 = L, FS2 = H 460
FS1 = H, FS2 = L 236
FS1 = H, FS2 = H (spread-spectrum mode) 335
P
OUT
P
OUT
V
IH
V
IL
OUT
= 5W, f
= 4W, f = 1kHz, RL = 8Ω 75
22kHz
=
A-weighted
= 1kHz, RL = 16Ω 85
IN
FFM 94
SSM 88
FFM 97
SSM 91
2.5
0.07 %
0.8
dB
kHz
%
V
Page 4
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
4 _______________________________________________________________________________________
S
S
Typical Operating Characteristics
(136µH with 16Ω, 68µH with 8Ω, part in SSM mode, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
10
VDD = +15V
= 13dB
A
V
= 8Ω
R
L
1
THD+N (%)
0.1
0.01
10 100k
P
OUT
P
= 4W
OUT
= 100mW
10k1k100
FREQUENCY (Hz)
MAX9713 toc01
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
10
VDD = +20V
= 13dB
A
V
= 16Ω
R
L
1
P
= 7.5W
THD+N (%)
0.1
0.01
OUT
P
= 120mW
OUT
10 100k
FREQUENCY (Hz)
10k1k100
MAX9713 toc04
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
100
VDD = 20V
= 13dB
A
V
= 8Ω
R
L
10
MAX9713 toc07
TOTAL HARMONIC DISTORTION PLU
NOISE vs. FREQUENCY
10
VDD = +20V
= 13dB
A
V
= 8Ω
R
L
1
THD+N (%)
0.1
0.01
10 100k
P
OUT
P
= 4W
OUT
= 100mW
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
10
VDD = +15V
= 13dB
A
V
= 4W
P
OUT
= 8Ω
R
L
1
THD+N (%)
0.1
0.01
10 100k
SSM
FFM
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
100
VDD = 15V
= 13dB
A
V
= 16Ω
R
L
10
10k1k100
10k1k100
MAX9713 toc02
MAX9713 toc05
MAX9713 toc08
TOTAL HARMONIC DISTORTION PLU
NOISE vs. FREQUENCY
10
VDD = +15V
= 13dB
A
V
= 16Ω
R
L
1
P
= 5W
THD+N (%)
0.1
0.01
OUT
P
= 55mW
OUT
10 100k
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
100
VDD = 15V
= 13dB
A
V
= 8Ω
R
L
10
1
THD+N (%)
0.1
0.01
0.001
0765
f = 1kHz
f = 100Hz
4321
OUTPUT POWER (W)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
100
VDD = 20V
= 13dB
A
V
= 16Ω
R
L
10
MAX9713 toc03
10k1k100
MAX9713 toc06
f = 10kHz
MAX9713 toc09
1
THD+N (%)
0.1
0.01
0.001
07
f = 1kHz
f = 100Hz
123456
OUTPUT POWER (W)
f = 10kHz
f = 10kHz
1
THD+N (%)
0.1
0.01
0.001
08
f = 1kHz
f = 100Hz
OUTPUT POWER (W)
f = 10kHz
642
1
THD+N (%)
0.1
0.01
0.001
015
f = 1kHz
f = 100Hz
OUTPUT POWER (W)
f = 10kHz
105
Page 5
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
_______________________________________________________________________________________ 5
Typical Operating Characteristics (continued)
(136µH with 16Ω, 68µH with 8Ω, part in SSM mode, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS
100
VDD = 15V
= 13dB
A
V
f = 1kHz
10
= 8Ω
R
L
1
THD+N (%)
0.1
0.01
0.001
08
SSM
FFM
642
OUTPUT POWER (W)
MAX9713 toc10
EFFICIENCY (%)
OUTPUT POWER
vs. SUPPLY VOLTAGE
NOISE vs. OUTPUT POWER
8
7
6
5
4
3
OUTPUT POWER (W)
2
AV = 13dB
1
THD+N = 10%
= 8Ω
R
L
0
10 25
SUPPLY VOLTAGE (V)
22191613
MAX9713 toc13
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
0
-10
-20
-30
PSRR (dB)
-40
-50
-60
-70
10 100k
VDD = 15V
A
V
V
RIPPLE
RL = 16Ω
FREQUENCY (Hz)
= 13dB
= 200mV
10k1k100
MAX9713 toc16
P-P
CROSSTALK (dB)
EFFICIENCY vs. OUTPUT POWER
100
RL = 16Ω
90
80
70
60
50
40
30
20
10
0
010
RL = 8Ω
OUTPUT POWER (W)
OUTPUT POWER
vs. LOAD RESISTANCE
10
VDD = 15V
9
= 13dB
A
V
8
7
6
5
4
OUTPUT POWER (W)
3
2
1
0
1 10 100
THD+N = 1%
LOAD RESISTANCE (Ω)
CROSSTALK vs. FREQUENCY
0
OUTPUT REFERRED
= 13dB
A
V
-20
-40
-60
-80
-100
-120
LEFT TO RIGHT
RIGHT TO LEFT
0.01 100
FREQUENCY (Hz)
VDD = 15V
= 13dB
A
V
8642
THD+N = 10%
1010.1
100
90
MAX9713 toc11
80
70
60
50
40
EFFICIENCY (%)
30
20
10
0
0
-10
MAX9713 toc14
-20
-30
-40
-50
CMRR (dB)
-60
-70
-80
-90
20
MAX9713 toc17
0
-20
-40
-60
-80
OUTPUT MAGNITUDE (dB)
-100
-120
-140
EFFICIENCY vs. OUTPUT POWER
RL = 16Ω
MAX9713 toc12
= 8Ω
R
L
VDD = 20V
= 13dB
A
V
012
OUTPUT POWER (W)
COMMON-MODE REJECTION RATIO
vs. FREQUENCY
10 100k
FREQUENCY (Hz)
OUTPUT FREQUENCY SPECTRUM
020
FREQUENCY (Hz)
963
VDD = 15V
= 13dB
A
V
= 8Ω
R
L
10k1k100
FFM MODE
= 5W
P
OUT
f =1kHz
= 8Ω
R
L
UNWEIGHTED
15105
MAX9713 toc15
MAX9713 toc18
Page 6
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
6 _______________________________________________________________________________________
MAX9713 toc24
Typical Operating Characteristics (continued)
(136µH with 16Ω, 68µH with 8Ω, part in SSM mode, unless otherwise noted.)
OUTPUT FREQUENCY SPECTRUM
20
0
-20
-40
-60
-80
OUTPUT MAGNITUDE (dB)
-100
-120
-140
0 20k
FREQUENCY (Hz)
SSM MODE
= 5W
P
OUT
f = 1kHz
= 8Ω
R
L
UNWEIGHTED
15k10k5k
MAX9713 toc19
OUTPUT MAGNITUDE (dB)
WIDEBAND OUTPUT SPECTRUM
(SSM MODE)
0
-10
-20
-30
-40
-50
-60
-70
OUTPUT AMPLITUDE (dB)
-80
-90
-100
1M 10M 100M
FREQUENCY (Hz)
OUTPUT FREQUENCY SPECTRUM
20
0
-20
-40
-60
-80
-100
-120
0 20k
FREQUENCY (Hz)
MAX9713toc22
SHDN
MAX9714
OUTPUT
SSM MODE
P
OUT
f = 1kHz
= 8Ω
R
L
A-WEIGHTED
RBW = 10kHz
15k10k5k
CSS = 180pF
f = 1kHz
R
L
WIDEBAND OUTPUT SPECTRUM
0
= 5W
TURN-ON/TURN-OFF RESPONSE
= 8Ω
-10
MAX9713 toc20
-20
-30
-40
-50
-60
-70
OUTPUT AMPLITUDE (dB)
-80
-90
-100
20ms/div
MAX9713 toc23
(FFM MODE)
RBW = 10kHz
MAX1973toc21
1M 10M 100M
FREQUENCY (Hz)
5V/div
1V/div
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
25
20
15
10
SUPPLY CURRENT (mA)
5
0
10 20
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (µA)
18161412
SHUTDOWN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
10 20
SUPPLY VOLTAGE (V)
18161412
MAX9713 toc25
Page 7
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
_______________________________________________________________________________________ 7
Pin Description
PIN
MAX9713 MAX9714
1, 2, 23, 24 1, 2, 23, 24 PGND Power Ground
3, 4, 21, 22 3, 4, 21, 22 V
5 5 C1N Charge-Pump Flying Capacitor Negative Terminal
6 6 C1P Charge-Pump Flying Capacitor Positive Terminal
7 7 CHOLD Charge-Pump Hold Capacitor. Connect a 1µF capacitor from CHOLD to VDD.
8, 17, 20, 25,
26, 31, 32
9 14 REG Internal Regulator Output. Bypass with a 0.47µF capacitor to PGND.
10 13 AGND Analog Ground
11 — IN- Negative Input
12 — IN+ Positive Input
13 12 SS Soft-Start. Connect a 0.47µF capacitor from SS to GND to enable soft-start feature.
14 11 SHDN
15 17 G1 Gain-Select Input 1
16 18 G2 Gain-Select Input 2
8 N.C. No Connection. Not internally connected.
NAME FUNCTION
DD
Power-Supply Input
Active-Low Shutdown. Connect SHDN to GND to disable the device. Connect to
V
for normal operation.
DD
18 19 FS1 Frequency-Select Input 1
19 20 FS2 Frequency-Select Input 2
27, 28 — OUT- Negative Audio Output
29, 30 — OUT+ Positive Audio Output
— 9 INL- Left-Channel Negative Input
— 10 INL+ Left-Channel Positive Input
— 15 INR- Right-Channel Negative Input
— 16 INR+ Right-Channel Positive Input
— 25, 26 OUTR- Right-Channel Negative Audio Output
— 27, 28 OUTR+ Right-Channel Positive Audio Output
— 29, 30 OUTL- Left-Channel Negative Audio Output
— 31, 32 OUTL+ Left-Channel Positive Audio Output
——EP Exposed Paddle. Connect to GND.
Page 8
MAX9713/MAX9714
Detailed Description
The MAX9713/MAX9714 filterless, class D audio power
amplifiers feature several improvements to switchmode amplifier technology. The MAX9713 is a mono
amplifier, the MAX9714 is a stereo amplifier. These
devices offer class AB performance with class D efficiency, while occupying minimal board space. A
unique filterless modulation scheme and spread-spectrum switching mode create a compact, flexible, lownoise, efficient audio power amplifier. The differential
input architecture reduces common-mode noise pickup, and can be used without input-coupling capacitors.
The devices can also be configured as a single-ended
input amplifier.
Comparators monitor the device inputs and compare
the complementary input voltages to the triangle waveform. The comparators trip when the input magnitude of
the triangle exceeds their corresponding input voltage.
Operating Modes
Fixed-Frequency Modulation (FFM) Mode
The MAX9713/MAX9714 feature three FFM modes with
different switching frequencies (Table 1). In FFM mode,
the frequency spectrum of the class D output consists
of the fundamental switching frequency and its associated harmonics (see the Wideband FFT graph in the
Typical Operating Characteristics). The MAX9713/
MAX9714 allow the switching frequency to be changed
by ±35%, should the frequency of one or more of the
harmonics fall in a sensitive band. This can be done at
any time and not affect audio reproduction.
Spread-Spectrum Modulation (SSM) Mode
The MAX9713/MAX9714 feature a unique, patented
spread-spectrum mode that flattens the wideband
spectral components, improving EMI emissions that
may be radiated by the speaker and cables. This mode
is enabled by setting FS1 = FS2 = H. In SSM mode, the
switching frequency varies randomly by ±1.7%kHz
around the center frequency (335kHz). The modulation
scheme remains the same, but the period of the triangle waveform changes from cycle to cycle. Instead of a
large amount of spectral energy present at multiples of
the switching frequency, the energy is now spread over
a bandwidth that increases with frequency. Above a
few megahertz, the wideband spectrum looks like white
noise for EMI purposes (Figure 2).
Efficiency
Efficiency of a class D amplifier is attributed to the
region of operation of the output stage transistors. In a
class D amplifier, the output transistors act as currentsteering switches and consume negligible additional
power. Any power loss associated with the class D output stage is mostly due to the I*R loss of the MOSFET
on-resistance, and quiescent current overhead.
The theoretical best efficiency of a linear amplifier is
78%, however that efficiency is only exhibited at peak
output powers. Under normal operating levels (typical
music reproduction levels), efficiency falls below 30%,
whereas the MAX9714 still exhibits >80% efficiencies
under the same conditions (Figure 3).
Shutdown
The MAX9713/MAX9714 have a shutdown mode that
reduces power consumption and extends battery life.
Driving SHDN low places the device in low-power
(0.2µA) shutdown mode. Connect SHDN to a logic high
for normal operation.
Click-and-Pop Suppression
The MAX9713/MAX9714 feature comprehensive clickand-pop suppression that eliminates audible transients
on startup and shutdown. While in shutdown, the Hbridge is pulled to GND through 300kΩ. During startup,
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
8 _______________________________________________________________________________________
Table 1. Operating Modes
Figure 1. MAX9714 Outputs with No Input Signal Applied
VIN = 0V
FS1 FS2
L L 335
L H 460
H L 236
H H 335 ±7%
SWITCHING MODE
(kHz)
OUT-
OUT+
Page 9
or power-up, the input amplifiers are muted and an
internal loop sets the modulator bias voltages to the
correct levels, preventing clicks and pops when the Hbridge is subsequently enabled. Following startup, a
soft-start function gradually un-mutes the input amplifiers. The value of the soft-start capacitor has an impact
on the click/pop levels. For optimum performance, C
SS
should be at least 180nF.
Applications Information
Filterless Operation
Traditional class D amplifiers require an output filter to
recover the audio signal from the amplifier’s PWM output. The filters add cost, increase the solution size of
the amplifier, and can decrease efficiency. The traditional PWM scheme uses large differential output
swings (2
✕
VDDpeak-to-peak) and causes large ripple
currents. Any parasitic resistance in the filter components results in a loss of power, lowering the efficiency.
The MAX9713/MAX9714 do not require an output filter.
The devices rely on the inherent inductance of the
speaker coil and the natural filtering of both the speaker and the human ear to recover the audio component
of the square-wave output. Eliminating the output filter
results in a smaller, less costly, more efficient solution.
Because the frequency of the MAX9713/MAX9714 output is well beyond the bandwidth of most speakers,
voice coil movement due to the square-wave frequency
is very small. Although this movement is small, a speaker not designed to handle the additional power can be
damaged. For optimum results, use a speaker with a
series inductance > 30µH. Typical 8Ω speakers exhibit
series inductances in the range of 30µH to 100µH.
Optimum efficiency is achieved with speaker inductances > 60µH.
Gain Selection
Table 2 shows the suggested gain settings to attain a
maximum output power from a given peak input voltage
and given load.
Output Offset
Unlike a class AB amplifier, the output offset voltage of
class D amplifiers does not noticeably increase quiescent current draw when a load is applied. This is due to
the power conversion of the class D amplifier. For
example, an 8mV DC offset across an 8Ω load results
in 1mA extra current consumption in a class AB device.
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
_______________________________________________________________________________________ 9
Figure 3. MAX9714 Efficiency vs. Class AB Efficiency
Figure 2. SSM Radiated Emissions
EFFICIENCY vs. OUTPUT POWER
100
MAX9714
90
80
70
60
50
40
EFFICIENCY (%)
30
20
10
0
0246
CLASS AB
OUTPUT POWER (W)
VDD = 15V
f = 1kHz
= 16Ω
R
L
Page 10
MAX9713/MAX9714
In the class D case, an 8mV offset into 8Ω equates
to an additional power drain of 8µW. Due to the high
efficiency of the class D amplifier, this represents an
additional quiescent current draw of: 8µW/(VDD/100 ✕ η),
which is on the order of a few microamps.
Input Amplifier
Differential Input
The MAX9713/MAX9714 feature a differential input structure, making them compatible with many CODECs, and
offering improved noise immunity over a single-ended
input amplifier. In devices such as PCs, noisy digital signals can be picked up by the amplifier’s input traces.
The signals appear at the amplifiers’ inputs as commonmode noise. A differential input amplifier amplifies the
difference of the two inputs, any signal common to both
inputs is canceled.
Single-Ended Input
The MAX9713/MAX9714 can be configured as singleended input amplifiers by capacitively coupling either
input to GND and driving the other input (Figure 4).
Component Selection
Input Filter
An input capacitor, CIN, in conjunction with the input
impedance of the MAX9713/MAX9714, forms a highpass filter that removes the DC bias from an incoming
signal. 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:
Choose C
IN
so f
-3dB
is well below the lowest frequency
of interest. Setting f
-3dB
too high affects the low-fre-
quency response of the amplifier. Use capacitors
whose dielectrics have low-voltage coefficients, such
as tantalum or aluminum electrolytic. 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.
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. Increasing the value of
C1 improves load regulation and reduces the chargepump output resistance to an extent. Above 1µF, the onresistance of the switches and the ESR of C1 and C2
dominate.
Output Capacitor (C2)
The output capacitor value and ESR directly affect the
ripple at CHOLD. Increasing 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.
Output Filter
The MAX9713/MAX9714 do not require an output filter.
The device passes FCC emissions standards with
36cm of unshielded speaker cables. However, output
filtering can be used if a design is failing radiated emissions due to board layout or cable length, or the circuit
is near EMI-sensitive devices. Use a ferrite bead filter
when radiated frequencies above 10MHz are of concern. Use an LC filter when radiated frequencies below
10MHz are of concern, or when long leads connect the
amplifier to the speaker. Refer to the MAX9714
Evaluation Kit schematic for details of this filter.
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
10 ______________________________________________________________________________________
Table 2. Gain Settings
)
)
(W)
Figure 4. Single-Ended Input
GAIN (dB
13.0 1.79 16 8
16.1 1.25 16 8
19.1 0.89 16 8
22.1 1.79 16 8
13.0 1.10 8 6
16.1 0.77 8 6
19.1 0.54 8 6
22.1 0.38 8 6
INPUT (V
RMS
RL (Ω)P
OUT
f
-3dB
1
RC
2=π
IN IN
0.47µF
0.47µF
IN+
MAX9713/
IN-
MAX9714
SINGLE-ENDED
AUDIO INPUT
Page 11
Sharing Input Sources
In certain systems, a single audio source can be shared
by multiple devices (speaker and headphone amplifiers). When sharing inputs, it is common to mute the
unused device, rather than completely shutting it down,
preventing the unused device inputs from distorting the
input signal. Mute the MAX9713/MAX9714 by driving SS
low through an open-drain output or MOSFET (see the
System Diagram). Driving SS low turns off the class D
output stage, but does not affect the input bias levels of
the MAX9713/MAX9714. Be aware that during normal
operation, the voltage at SS can be up to 7V, depending
on the MAX9713/MAX9714 supply.
Supply Bypassing/Layout
Proper power-supply bypassing ensures low distortion
operation. For optimum performance, bypass V
DD
to
PGND with a 0.1µF capacitor as close to each V
DD
pin
as possible. A low-impedance, high-current power-supply connection to VDDis assumed. Additional bulk
capacitance should be added as required depending on
the application and power-supply characteristics. AGND
and PGND should be star connected to system ground.
Refer to the MAX9714 Evaluation Kit for layout guidance.
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
______________________________________________________________________________________ 11
Pin Configurations
Chip Information
MAX9713 TRANSISTOR COUNT: 3093
MAX9714 TRANSISTOR COUNT: 4630
PROCESS: BiCMOS
TOP VIEW
PGND
V
V
C1N
C1P
CHOLD
N.C.
DD
DD
N.C.
N.C.
OUT+
32313029282726
1PGND
2
3
4
5
6
7
8
MAX9713
9
101112
IN-
REG
AGND
TQFN (5mm x 5mm)
OUT+
IN+
OUT-
OUT-
131415
SS
SHDN
N.C.
G1
25 N.C.
16G2
24 PGND
23
PGND
22
V
DD
21
V
DD
20
N.C.
19
FS2
18
FS1
17
N.C.
OUTL+
OUTL+
OUTL-
OUTL-
OUTR+
OUTR+
OUTR-
REG
15
INR-
25 OUTR-
16INR+
24 PGND
23
PGND
22
V
DD
21
V
DD
20
FS2
19
FS1
18
G2
17
G1
PGND
V
V
C1N
C1P
CHOLD
N.C.
32313029282726
1PGND
2
3
DD
4
DD
5
6
7
8
MAX9714
9
1011121314
INL-
SS
INL+
SHDN
AGND
TQFN (7mm x 7mm)
Page 12
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
12 ______________________________________________________________________________________
Functional Diagrams
10V TO +25V
100µF
0.47µF
0.47µF
12
18
V
REG
19
V
0.47µF
REG
14
V
IH
15
V
REG
16
V
REG
13
9
10 AGND
0.18µF
LOGIC INPUTS SHOWN FOR A
0.1µF
1 34212223242
PGND V
IN+11
MODULATOR
IN-
FS1
OSCILLATOR
FS2
SHDN
G1
G2
SS
REG
= 16dB (SSM).
V
GAIN
CONTROL
SHUTDOWN
CONTROL
0.1µF
DD
V
DD
H-BRIDGE
PGND
OUT+
OUT+
OUT-
OUT-
30
29
28
27
MAX9713
6
C1P
CHARGE PUMP
CHOLD
7
C2
1µF
V
DD
C1N
C1
0.1µF
5
Page 13
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
______________________________________________________________________________________ 13
Functional Diagrams (continued)
0.47µF
0.47µF
V
REG
V
REG
0.47µF
0.47µF
100µF
9
19
20
16
1 34212223242
INL+10
INL-
FS1
FS2
INR+15
INR-
0.1µF
PGND V
MODULATOR
OSCILLATOR
MODULATOR
10V TO +25V
DD
0.1µF
V
DD
H-BRIDGE
H-BRIDGE
PGND
OUTL+
OUTL+
OUTR+
OUTR+
OUTL-
OUTL-
OUTR-
OUTR-
32
31
30
29
26
25
28
27
0.18µF
0.47µF
LOGIC INPUTS SHOWN FOR A
11
V
IH
V
REG
V
REG
SHDN
17
G1
18
G2
12
SS
REG
14
13 AGND
GAIN
CONTROL
SHUTDOWN
CONTROL
= 16dB (SSM).
V
MAX9714
CHARGE PUMP
CHOLD
7
C2
1µF
V
DD
C1P
C1N
6
C1
0.1µF
5
Page 14
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
14 ______________________________________________________________________________________
System Diagram
V
DD
1µF
CODEC
1µF
15kΩ
1µF
15kΩ
0.47µF
0.47µF
0.47µF
0.47µF
1µF
0.18µF
SHDN
INL-
MAX9722B
INL+
INR+
V
INL-
DD
SHDN
OUTL-
OUTL+INL+
MAX9714
INR+ OUTR+
INR-
SS
OUTL
OUTR
OUTR-
V
DD
100kΩ
5V
1µF
1µF
INR-
30kΩ 30kΩ
LOGIC INPUTS SHOWN FOR AV = 16dB (SSM)
C1P
1µF
CIN
PV
SS
SV
SS
1µF
Page 15
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
______________________________________________________________________________________ 15
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
.)
D2
D
D/2
E/2
E
(NE-1) X e
DETAIL A
k
e
C
L
C
L
(ND-1) X e
D2/2
b
E2/2
C
E2
L
k
L
C
L
32, 44, 48L QFN .EPS
A1AA2
L
e
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE
32, 44, 48L QFN THIN, 7x7x0.8 mm
APPROVAL
DOCUMENT CONTROL NO.
21-0144
L
e
REV.
1
B
2
Page 16
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
16 ______________________________________________________________________________________
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
.)
COMMON DIMENSIONS
EXPOSED PAD VARIATIONS
** NOTE: T4877-1 IS A CUSTOM 48L PKG. WITH 4 LEADS DEPOPULATED.
TOTAL NUMBER OF LEADS ARE 44.
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE
32, 44, 48L QFN THIN, 7x7x0.8 mm
DOCUMENT CONTROL NO.APPROVAL
21-0144
REV.
2
B
2
Page 17
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
______________________________________________________________________________________ 17
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
.)
D/2
e
(ND-1) X e
L
D2
b
0.10 M
PIN # 1 I.D.
0.35x45∞
E2/2
C
k
L
L
C A B
E2
CC
L
C
L
D2/2
0.15 C A
E/2
0.15
C B
E
(NE-1) X e
DETAIL A
k
D
PIN # 1
I.D.
QFN THIN.EPS
REV.
L
1
C
2
L
0.10
C
A
0.08 C
C
A3
A1
e e
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE
16, 20, 28, 32L, QFN THIN, 5x5x0.8 mm
APPROVAL
DOCUMENT CONTROL NO.
21-0140
Page 18
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
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
© 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
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
.)
COMMON DIMENSIONS
NOTES:
1. DIMENSIONING & TOLERANCING CONFORM TO ASME Y14.5M-1994.
2. ALL DIMENSIONS ARE IN MILLIMETERS. ANGLES ARE IN DEGREES.
3. N IS THE TOTAL NUMBER OF TERMINALS.
4. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO JESD 95-1
SPP-012. DETAILS OF TERMINAL #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE
ZONE INDICATED. THE TERMINAL #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE.
5. DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.25 mm AND 0.30 mm
FROM TERMINAL TIP.
6. ND AND NE REFER TO THE NUMBER OF TERMINALS ON EACH D AND E SIDE RESPECTIVELY.
7. DEPOPULATION IS POSSIBLE IN A SYMMETRICAL FASHION.
8. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS.
9. DRAWING CONFORMS TO JEDEC MO220.
10. WARPAGE SHALL NOT EXCEED 0.10 mm.
EXPOSED PAD VARIATIONS
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE
16, 20, 28, 32L, QFN THIN, 5x5x0.8 mm
21-0140
REV.DOCUMENT CONTROL NO.APPROVAL
2
C
2
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