General Description
The MAX9706 evaluation kit (EV kit) is a fully assembled
and tested circuit board that evaluates the MAX9706
as well as the MAX9707 ICs. The MAX9706/MAX9707
contain three Class D amplifiers with an internal active
crossover to provide stereo highpass outputs and a
mono lowpass output. The IC does not require any
external components for the active crossover filter. The
MAX9706 also features a DirectDriveTM stereo head-
phone amplifier.
The MAX9706 speaker amplifier operates from a 4.5V
to 5.5V DC power supply, and delivers 2.3W continuous
power into each of three 4Ωspeakers. Three different
speaker output filtering options are available for ease of
evaluation (see the Output Filtering section).
The MAX9706 headphone amplifier operates from a 3V
to 5.5V DC power supply, and delivers up to 95mW per
channel into a 16Ωstereo headphone. When the
MAX9706 headphone sense detects the insertion of a
headphone, the MAX9706 automatically enters the
headphone mode.
The EV kit offers an option to select between fixed-fre-
quency modulation (FFM) mode or spread-spectrum
modulation (SSM) mode. The EV kit can be synchro-
nized with an external clock, and the EV kit provides a
synchronization output that allows multiple units to be
cascaded in a system.
The MAX9706 EV kit gain is jumper selectable. The EV
kit also features an option to select the crossover fre-
quency between the stereo highpass outputs and the
mono lowpass output. The MAX9706 shutdown supply
current is only 0.5µA (typ).
Features
♦4.5V to 5.5V Single DC Power-Supply Operation
♦Drives 3 x 2.3W into Three 4ΩSpeakers
(2.1 Speaker Solutions)
♦Drives 2 x 95mW into a 16ΩStereo Headphone
(MAX9706)
♦Internal Active Crossover Filter with Selectable
Crossover Frequency
♦Selectable Gains
♦Selectable Between Spread-Spectrum and Fixed-
Frequency Modulation
♦Input and Output Synchronization Signals
♦0.5µA (typ) Shutdown Current
♦Space-Saving 36-Pin TQFN (6mm x 6mm x 0.8mm)
Package
♦Fully Assembled and Tested
♦Evaluates MAX9707 (IC Replacement Required)
Evaluates: MAX9706/MAX9707
MAX9706 Evaluation Kit
________________________________________________________________ Maxim Integrated Products 1
19-3742; Rev 0; 9/05
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.
DESIGNATION
QTY
DESCRIPTION
C3, C5 2
0.1µF ±10%, 10V X7R ceramic
capacitors (0402)
TDK C1005X7R1A104K
C4, C6, C7, C10,
C12, C13, C14
7
1µF ±10%, 10V X7R ceramic
capacitors (0603)
TDK C1608X7R1A105K
C8, C9, C11 3
0.47µF ±10%, 10V X7R ceramic
capacitors (0603)
TDK C1608X7R1A474K
U1 1 MAX9706ETX
(36-pin TQFN-EP, 6mm x 6mm)
DESIGNATION
QTY
DESCRIPTION
OPTIONAL COMPONENTS FOR CUSTOMER EVALUATION
C1, C36 2
1000pF ±10%, 50V X7R ceramic
capacitors (0603)
TDK C1608X7R1H102K
C2†1
100µF ±20%, 6.3V X5R ceramic
capacitor (1210)
TDK C3225X5R0J107M
C15–C35 0 Not installed, capacitors (0603)
C37, C38 2
100pF ±10%, 50V C0G ceramic
capacitors (0603)
TDK C1608C0G1H101K
Ordering Information
PART TEMP RANGE IC PACKAGE
MAX9706EVKIT 0°C to +70°C* 36-TQFN-EP**
(6mm x 6mm x 0.8mm)
*This limited temperature range is for the EV kit PC board only.
The MAX9706 IC temperature range is -40°C to +85°C.
**EP = Exposed paddle.
Component List
Component List continued on next page.
†System-level requirement.
Evaluates: MAX9706/MAX9707
Quick Start
Recommended Equipment
• One 5V, 2A DC power supply
• Optional 3V, 1A DC power supply
• Audio source
• Three 4Ωto 8Ωspeakers
• Stereo headphone
Procedures
The MAX9706 EV kit is fully assembled and tested.
Follow the steps listed below to verify board operation.
Do not turn on the power supply until all connec-
tions are completed.
1) Install a shunt across pins 1 and 2 of jumper JU1
(EV kit ON).
2) Install a shunt across pins 1 and 2 of jumper JU2
(mono speaker gain offset = -7.5dB).
3) Install a shunt across pins 1 and 2 of jumpers JU3
and JU4 (stereo speaker gain = +13.5dB, mono
speaker gain = +12dB, headphone gain = +3dB).
4) Install a shunt across pins 1 and 2 of jumpers JU5
and JU6 (crossover frequency = 2133.3Hz).
5) Install a shunt across pins 1 and 2 of jumper JU7
(SSM mode with frequency = 1150kHz ±50kHz).
6) Install a shunt on jumper JU8 (speaker enable).
7) Connect the first speaker to the OUTL+ and the
OUTL- test points.
8) Connect the second speaker to the OUTR+ and the
OUTR- test points.
9) Connect the third speaker to the OUTM+ and the
OUTM- test points.
10) Connect the +5V DC power supply to the VDD pad.
Connect the power-supply ground to the GND pad.
11) Connect the +3V DC power supply to the HPVDD
pad. Connect the power-supply ground to the GND
pad. If the optional +3V DC power supply is not
available, connect the HPVDD pad to the VDD pad.
12) Connect the audio source to the IN_L and the IN_R
pads. Connect the audio source ground to the
GND pad.
13) Turn on both power supplies and the audio source.
14) To test the headphone, plug the headphone to the
phone jack J1.
Detailed Description
The MAX9706 EV kit is designed to evaluate the
MAX9706 as well as the MAX9707 ICs. The MAX9706/
MAX9707 contain three Class D amplifiers with an inter-
nal active crossover to provide stereo highpass outputs
and a mono lowpass output. The MAX9706 also fea-
tures a DirectDrive stereo headphone amplifier. The EV
kit comes with the MAX9706 IC installed.
MAX9706 Evaluation Kit
2 ____________________________________________________________________________________________________
SUPPLIER PHONE FAX WEBSITE
Sumida USA 847-545-6700 847-545-6720 www.sumida.com
TDK 847-803-6100 847-390-4405 www.component.tdk.com
Component Suppliers
Note: Indicate that you are using the MAX9706 EV kit when contacting these component suppliers.
DESIGNATION
QTY
DESCRIPTION
OPTIONAL COMPONENTS FOR CUSTOMER EVALUATION
J1 1 3.5mm switched stereo jack
JU1–JU7 7 3-pin headers
JU8 1 2-pin header
L1 1
Ferrite bead, 30Ω at 100MHz,
10mΩ DCR, 5A (0805)
TDK MPZ2012S300A
L2, L3, L10 3
Ferrite beads, 100Ω at 100MHz,
50mΩ DCR, 3A (0603)
TDK MPZ1608S101A
DESIGNATION QTY
DESCRIPTION
OPTIONAL COMPONENTS FOR CUSTOMER EVALUATION
L4–L9 0
Not installed, inductors
Sumida CDRH6D38 series
recommended
R1–R6 0 Not installed, resistors (0603)
T1, T2, T3 0
Not installed,
common-mode chokes
50VDC, 1.5ADC, 600Ω at 100MHz
TDK ACM4532-601-2P-X
recommended
— 8 Shunts
— 1 MAX9706 EV kit PC board
Component List (continued)
The EV kit’s speaker amplifiers operate from a 4.5V to
5.5V DC power supply, and deliver 3 x 2.3W continu-
ous power into three 4Ωspeakers. Three different
speaker output filtering options are available for ease of
evaluation. See the Output Filtering section.
The EV kit’s DirectDrive headphone amplifier operates
from a 3V to 5.5V DC power supply, and delivers 95mW
per channel into a 16Ωstereo headphone. Both the
speaker and headphone power supplies must be pre-
sent to operate the EV kit. The EV kit can be powered
by a single 4.5V to 5.5V DC power supply.
The EV kit offers an option to select between two frequen-
cies when in fixed-frequency modulation (FFM) mode or a
single-center frequency in spread-spectrum modulation
(SSM) mode. The MAX9706 EV kit features a synchro-
nization input (SYNCIN) PC board pad that allows the
MAX9706 to synchronize with an external clock. The EV
kit also provides a synchronization output (SYNCOUT) PC
board pad to synchronize other devices to the MAX9706.
Refer to the Operating Modes section in the MAX9706/
MAX9707 IC data sheet for additional information on FFM,
SSM, SYNCIN, and SYNCOUT.
The MAX9706’s speaker and headphone amplifier gain
is configurable using jumpers JU3 and JU4. The mono
output gain offset is configurable using jumper JU2.
The MAX9706 EV kit also provides a line-level mono-
output MONO_OUT PC board pad.
The MAX9706 EV kit features an option to select the
crossover frequency between the stereo highpass and
mono lowpass frequencies. The crossover frequency is
jumper selectable using jumpers JU5 and JU6. Refer to
the Crossover Frequency section in the MAX9706/
MAX9707 IC data sheet for additional information on
the internal active crossover.
The speaker and headphone outputs on the EV kit can be
selected by jumper JU8 and headphone jack J1. See
Table 8 in the Jumper Selection section.
The EV kit can also evaluate the MAX9707. To evaluate
the MAX9707, replace the MAX9706 with the MAX9707.
See the Evaluating the MAX9707 section.
Output Filtering
The speaker outputs (OUTL+/-, OUTR+/-, and OUTM+/-)
can be connected directly to three speaker loads without
any filtering. Use the OUTL+/-, OUTR+/-, and OUTM+/-
test points to connect the left, right, and mono speakers
directly to the EV kit.
The MAX9706 EV kit features PC board pads for filters
that can be added to ease evaluation. Audio analyzers
typically cannot accept pulse-width-modulated (PWM)
signals at their inputs. The PWM output signal can be
lowpass-filtered by installing components: L4–L9,
C21–C35, and R1–R6 to use the filtering output pads
(FOUTL+/-, FOUTR+/-, and FOUTM+/-). See Table 1 for
the suggested filtering component values to evaluate a
4Ωload with a 30kHz cutoff frequency.
The MAX9706/MAX9707 are designed to pass FCC
Class B RF emissions without additional filtering. In
applications where a long cable is required, or the cir-
cuit is near EMI-sensitive devices, output capacitors
C15–C20, and common-mode chokes T1–T3, can be
added to reduce radiated emissions. Table 2 lists the
recommended EMI filter components. Refer to the
Applications Information, Filterless Class D Operation
section in the MAX9706/MAX9707 IC data sheet for
additional information.
Evaluates: MAX9706/MAX9707
MAX9706 Evaluation Kit
_______________________________________________________________________________________ 3
Table 1. Suggested Filtering Components
for a 4ΩLoad with a 30kHz Cutoff
Frequency
Table 2. Recommended EMI Filter
Components
COMPONENT DESCRIPTION
C21–C26
0.033µF ±10%, 25V X7R ceramic
capacitors (0603)
TDK C1608X7R1E333K
C27, C28, C29
0.15µF ±10%, 25V X7R ceramic
capacitors (0603)
TDK C1608X7R1E154K
C30–C35
0.068µF ±10%, 25V X7R ceramic
capacitors (0603)
TDK C1608X7R1E683K
L4–L9 22µH ±20%, 1.3A inductors
Sumida CDRH6D38-220
R1–R6 22Ω ±5% resistors (0603)
COMPONENT DESCRIPTION
C15–C20
100pF ±10%, 50V C0G ceramic
capacitors (0603)
TDK C1608C0G1H101K
T1, T2, T3
Common-mode chokes, 50VDC,
1.5ADC, 600Ω at 100MHz
TDK ACM4532-601-2P-X
Evaluates: MAX9706/MAX9707
Jumper Selection
Shutdown Mode (
SHDN
)
Jumper JU1 controls the shutdown mode (SHDN) of the
MAX9706/MAX9707 ICs. The shutdown mode can also
be controlled by an external logic controller connected
to the EV kit SHDN PC board pad. Remove the shunt
from jumper JU1 before connecting an external con-
troller to the SHDN PC board pad. See Table 3 for
shunt positions.
Mono Gain Offset Selection (MGAIN)
The MAX9706/MAX9707’s mono channel is the sum of
the left and right channels. Therefore, the mono chan-
nel has a +6dB gain higher than that of the left or the
right channels. The MAX9706/MAX9707 provides an
option to offset this +6dB gain. Jumper JU2 selects the
mono amplifier gain offset on the EV kit. See Table 4 for
shunt positions.
Gain Selection (GAIN1, GAIN2)
Jumpers JU3 and JU4 provide an option to set the
speaker and headphone amplifiers’ gain on the EV kit.
See Table 5 for shunt positions. Note that the stereo
speaker outputs are highpass-filtered by the crossover
circuitry. The mono speaker output is lowpass-filtered
by the crossover circuitry while the stereo headphone
output has full bandwidth.
Crossover Frequency Selection (FS0, FS1)
Jumpers JU5 and JU6 provide an option to set the
crossover frequency between stereo highpass outputs
and the mono lowpass output for the MAX9706 EV kit.
See Table 6 for shunt positions.
Synchronous Switching Input (SYNCIN)
The MAX9706 EV kit provides a SYNCIN PC board pad
that allows the MAX9706/MAX9707 switching frequency
to synchronize to an external TTL clock. The external
clock frequency can range from 1MHz to 1.5MHz and
can have any duty cycle, but the minimum pulse width
must be greater than 100ns. The SYNCIN input on the
EV kit also selects between the FFM and SSM mode for
the MAX9706. Jumper JU7 selects between the FFM
and SSM mode options for the MAX9706/MAX9707 ICs.
See Table 7 for shunt positions.
MAX9706 Evaluation Kit
4 _______________________________________________________________________________________
Table 3. JU1 Jumper Selection (SHDN)
SHUNT
POSITION SHDN PIN EV KIT
FUNCTION
1-2
(Default) High Enabled
2-3 Low Disabled
None.
External logic
controller connected
to SHDN pad.
Connected to
external
controller.
SHDN driven by
external logic
controller. Shutdown
is active low.
Table 5. JU3 and JU4 Jumper Selection (GAIN)
SHUNT
POSITION
JU3
(GAIN2)
JU4
(GAIN1)
SPEAKER GAIN (dB)
JU8 INSTALLED
JU2 NOT INSTALLED
HEADPHONE GAIN (dB)
JU8 NOT INSTALLED
2-3 (Low) 2-3 (Low) +9.0 0
2-3 (Low) 1-2 (High) +10.5 0
1-2 (High) 2-3 (Low) +12.0 +3
1-2 (High) 1-2 (High) +13.5 +3
Table 4. JU2 Jumper Selection (MGAIN
Offset)
SHUNT
POSITION
MGAIN
PIN
MONO AMPLIFIER
GAIN OFFSET
(dB)
1-2* High -7.5
Not Installed* Unconnected -6.0
2-3* Low -4.5
*JU8 installed. Headphone not plugged in.
Evaluates: MAX9706/MAX9707
MAX9706 Evaluation Kit
_______________________________________________________________________________________ 5
Table 7. JU7 Jumper Selection (Switching
Frequency)
SHUNT
POSITION
SYNC_IN
CONNECTED
TO
OPERATING
MODE
1-2
(Default) VDD
SSM with
fOSC = 1150kHz
± 50kHz
Not Installed Unconnected FFM with
fOSC = 1340kHz
2-3 GND FFM with
fOSC = 1100kHz
Not Installed.
External clock source
connected to
SYNCIN pad.
External clock
source from
1MHz to
1.5MHz.
FFM with
fOSC = external
clock frequency.
Table 8. JU8 Jumper Selection (SPKR/HP)
SHUNT
POSITION
EV KIT
FUNCTION
Not Installed Forced headphone
mode
Installed
(No headphone plugged into J1) Speaker mode
Installed
(Headphone plugged into J1) Headphone mode
Table 6. JU5 and JU6 Jumper Selection
(Crossover Frequency)
SHUNT POSITION
JU5
(FS0)
JU6
(FS1)
CROSSOVER
FREQUENCY (Hz)
2-3 (Low) 2-3 (Low) 800
2-3 (Low) 1-2 (High) 1066.7
1-2 (High) 2-3 (Low) 1600
1-2 (High) 1-2 (High) 2133.3
Speaker/Headphone Mode (HPS)
Jumper JU8 selects between the speaker mode and the
headphone mode for the MAX9706 EV kit. See Table 8
for shunt positions.
Evaluating the MAX9707
To evaluate the MAX9707, replace the MAX9706 IC with
the MAX9707 IC. Refer to the MAX9706/MAX9707 IC
data sheet for the pinout and function.
Evaluates: MAX9706/MAX9707
MAX9706 Evaluation Kit
6 _______________________________________________________________________________________
VDD
INR
27
BIAS
SGND
C3
0.1µF
C9
0.47µF
C7
1µF
C1N
12
C1P
10
C10
1µF
SYNC_OUT
4
14 SYNC_IN
24 SHDN
25
FS1
26
FS0
29
GAIN1
30
MGAIN
28
GAIN2
3
4
2
1
J1
HPR 17
HPL 18
HPS 15
OUTM+ 33
OUTM- 32
PVDD
PGND
PVDD
20
PGND 23
VDD
C13
1µF
PVDD
34
PGND 31
VDD
C14
1µF
8
MONO_OUT 35
5
VDD
C12
1µF
MAX97O6
U1
INL
36
CPGND
11
VSS
16
CPVSS
13
C8
0.47µF
C6
1µF
C5
0.1µF
C4
1µF
HPVDD
19
1
GND
2
VDD
3
CPVDD
9
C11
0.47µF
OUTR+ 21
OUTR-
VDD
LEFT-CHANNEL
AUDIO INPUT
RIGHT-CHANNEL
AUDIO INPUT
22
OUTL+ 7
OUTL- 6
SGND
Figure 1. MAX9706 Customer Design Schematic
Evaluates: MAX9706/MAX9707
MAX9706 Evaluation Kit
_______________________________________________________________________________________ 7
VDD
VDD
GND
IN_R
INR
27
BIAS
SGND
C3
0.1µF
C2
100µF
C1
1000pF
C9
0.47µF
C7
1µF
SGND
C38
100pF
C1N
12
C1P
10
C10
1µF
1
2
3
SYNC_OUT
4
14
JU7
JU1
SYNCIN
SYNCOUT
SYNC_IN
1
2
3
24
SHDN
SHDN
25
JU5
JU6
1
2
3
VDD
VDD FS1
26
1
2
3
VDD
FS0
29
JU3
JU4
1
2
3
VDD
VDD
GAIN1
30
1
2
3
VDD
JU2 MGAIN
28
1
2
3
VDD
GAIN2
HPL
HPR
JU8 3
4
2
2
1
1
J1
HPR 17
HPL 18
HPS 15
OUTM+
33
OUTM- 32
PVDD
PGND
PVDD
20
PGND 23
VDD
C13
1µF
PVDD
34
PGND 31
VDD
C14
1µF
8
MONO_OUT 35
5
VDD
C12
1µF
MAX97O6
U1
L3
FERRITE
IN_L
INL
36
CPGND
11
VSS
16
CPVSS
13
C8
0.47µF
SGND
C37
100pF
C6
1µF
C5
0.1µF
C4
1µF
L2
FERRITE
HPVDD
HPVDD
19
1
GND
SGND
2
VDD
3
CPVDD
9
C36
1000pF
L10
FERRITE
MONO_OUT
C11
0.47µF
OUTR+ 21
OUTR- 22
2
4
1
3
C17
OPEN
C23
OPEN
C28
OPEN
C24
OPEN
L7
OPEN
L6
OPEN
C32
OPEN
R3
OPEN
C18
OPEN
T2
OPEN
C33
OPEN R4
OPEN
FOUTR+
FOUTR-
OUTR-
OUTR+
TOUTR-
TOUTR+
OUTL+ 7
OUTL- 6
1
3
2
4
C15
OPEN
C21
OPEN
C27
OPEN
C22
OPEN
L5
OPEN
L4
OPEN
C30
OPEN
R1
OPEN
C16
OPEN
T1
OPEN
C31
OPEN R2
OPEN
FOUTL+
FOUTL-
OUTL-
OUTL+
TOUTL-
SGND
TOUTL+
23
14
C19
OPEN
C25
OPEN
C29
OPEN
C26
OPEN
L9
OPEN
L8
OPEN
C34
OPEN
R5
OPEN
C20
OPEN
T3
OPEN
C35
OPEN
R6
OPEN
FOUTM+
FOUTM-
OUTM-
TOUTM-
TOUTM+
OUTM+
L1
FERRITE
Figure 2. MAX9706 EV Kit Schematic
Evaluates: MAX9706/MAX9707
MAX9706 Evaluation Kit
8 _______________________________________________________________________________________
Figure 3. MAX9706 EV Kit Component Placement Guide—Component Side
Evaluates: MAX9706/MAX9707
MAX9706 Evaluation Kit
_______________________________________________________________________________________ 9
Figure 4. MAX9706 EV Kit PC Board Layout—Component Side
Evaluates: MAX9706/MAX9707
MAX9706 Evaluation Kit
10 ______________________________________________________________________________________
Figure 5. MAX9706 EV Kit PC Board Layout—GND Layer 2
Evaluates: MAX9706/MAX9707
MAX9706 Evaluation Kit
______________________________________________________________________________________ 11
Figure 6. MAX9706 EV Kit PC Board Layout—VDD Layer 3
Evaluates: MAX9706/MAX9707
MAX9706 Evaluation Kit
12 ______________________________________________________________________________________
Figure 7. MAX9706 EV Kit PC Board Layout—Solder Side
Evaluates: MAX9706/MAX9707
MAX9706 Evaluation Kit
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 ____________________ 13
© 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.
Figure 8. MAX9706 EV Kit Component Placement Guide—Solder Side
