19-1222; Rev 0; 11/07
MAX9768 Evaluation Kit/Evaluation System
General Description
The MAX9768 evaluation kit (EV kit) is a fully assembled
and tested printed-circuit board (PCB) that demon-
strates the capabilities of the MAX9768 mono 10W
Class D speaker amplifier with volume control. The
MAX9768 EV kit also includes Windows
®
98SE/2000/XP-
compatible software that provides a simple graphical user
interface (GUI) for exercising the features of the MAX9768.
The MAX9768 evaluation system (EV system) consists of the
MAX9768 EV kit and a companion CMAXQUSB serial-
interface board. The CMAXQUSB interface board allows
a PC to control an I
2
C interface using its USB port. Order
the MAX9768 EV system (MAX9768EVCMAXQU+) for a
complete PC-based evaluation of the MAX9768. Order
the MAX9768 EV kit (MAX9768EVKIT+) if you already
have a MAX9768-compatible serial interface.
Windows is a registered trademark of Microsoft Corp.
Dual Mode is a trademark of Maxim Integrated Products, Inc.
Features
♦
Fully Tested PCB
Ω
♦
10W Output into 8Ω Load at 13V Power Supply
♦
Bridge-Tied Load (BTL) Output and Click-and-Pop
Suppression
♦
Dual Mode™ Volume Control: Analog or I
2
C
♦
Dual Modulation Schemes: Fixed Frequency and
Spread Spectrum
♦
Shut-Down Mode and Speaker Mute Mode
♦
On-Board LDO for Low-Voltage Analog Power
Supply
♦
Windows 98SE/2000/XP-Compatible Evaluation
Software
♦
EV System Includes USB Connectivity
Evaluate: MAX9768
Ordering Information
PART
MAX9768EVKIT+
MAX9768EVCMAXQU+
TYPE
EV Kit
EV System
Component Lists
MAX9768 EV System
PART
MAX9768EVKIT+
CMAXQUSB+
QTY
1
1
DESCRIPTION
MAX9768 EV kit
Serial-interface board
+Denotes
lead-free and RoHS-compliant.
Note:
The MAX9768 EV kit software is designed for use with
the complete EV system. The EV system includes both the
Maxim CMAXQUSB interface board and the EV kit. If the
Windows software will not be used, the EV kit board can be
purchased without the Maxim CMAXQUSB board.
MAX9768 EV Kit
DESIGNATION QTY
DESCRIPTION
0.1µF ±10%, 16V X7R ceramic
capacitors (0603)
Murata GRM188R71C104K
1µF ±10%, 10V X7R ceramic
capacitors (0603)
Murata GRM188R61A105K
0.47µF ±10%, 16V X7R ceramic
capacitor (0805)
Murata GRM21BR71C474K
1µF ±10%, 16V X7R ceramic
capacitors (0805)
Murata GRM21BR71C105K
22µF ±20%, 16V aluminum
electrolytic capacitor (C case)
Panasonic EEEFC1C220R
20kΩ ±1% resistors (0603)
Maxim 10W mono speaker amplifier
with volume control
MAX9768ETG+ (24-pin, 4mm x 4mm
x 0.8mm, TQFN-EP*)
MINIMAL COMPONENTS FOR CUSTOMER DESIGN
C1, C2
2
MAX9768 EV Kit (continued)
DESIGNATION QTY
DESCRIPTION
OPTIONAL COMPONENTS FOR CUSTOMER EVALUATION
C9, C10
0
Not installed, ceramic capacitors
(0603)
0.01µF ±10%, 50V X7R ceramic
capacitors (0805)
Murata GRM216R71H103K
0.22µF ±10%, 25V X7R ceramic
capacitors (1206)
Panasonic ECJ-3VB1E224K
0.01µF ±10%, 16V X7R ceramic
capacitors (0603)
Murata GRM188R71C103K
1µF ±10%, 16V X7R ceramic
capacitor (0805)
Murata GRM21BR71C105K
1µF ±10%, 10V X7R ceramic
capacitor (0603)
Murata GRM188R61A105K
C3, C5
2
C11, C12
2
C4
1
C13, C15
2
C6, C8
2
C14, C16, C20
3
C7, C21
R2, R3
2
2
C17
1
U1
1
C18
1
*EP
= Exposed paddle.
________________________________________________________________
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.
MAX9768 Evaluation Kit/Evaluation System
Evaluate: MAX9768
Component Lists (continued)
MAX9768 EV Kit (continued)
DESIGNATION QTY
C19
J1
J2
J3–J6
JU1–JU5
JU6
JU7, JU8
L1, L2
L3, L4
L5, L6
R1, R5
R4
R6
1
1
1
4
5
1
2
2
2
2
2
1
1
DESCRIPTION
100pF ±5%, 50V C0G ceramic
capacitor (0603)
Murata GRM1885C1H101J
2 x 10 right-angle female receptacle
White RCA mono jack
Binding posts, uninsulated
Single-row 3-pin headers
3-way-pin header
2-pin headers
60Ω, 3A ferrite beads (0805)
Murata BLM21PG600SN1
Shorted with 0Ω resistors (0603)
22µH, 1.9A inductors
TDK SLF10145T-220M1R9PF
10kΩ ±5% resistors (0603)
20Ω ±5% resistor (1206)
10kΩ ±20% thumbwheel
potentiometer
Panasonic EVL-HFAA05B14
—
—
—
4
4
1
DESIGNATION QTY
U2
—
1
8
DESCRIPTION
Maxim 12V low-dropout linear regulator
MAX1726EUK33+ (5-pin SOT23)
Shunts
0.250in x 0.500in 4–40 round nylon
spacers
4–40 x 0.375in nylon machine screws
PCB: MAX9768 Evaluation Kit+
MAX9768 EV Kit Files
FILE
INSTALL.EXE
MAX9768.EXE
FTD2XX.INF
UNINST.INI
TROUBLESHOOTING_USB.PDF
DESCRIPTION
Installs the EV kit files
on your computer
Application program
USB device driver file
Uninstalls the EV kit
software
USB driver installation
help file
Quick Start
Recommended Equipment
Before proceeding, the following equipment is needed:
• 4.5V to 14V DC, 3A power supply
•
•
•
Audio source (i.e., CD player, 1V
RMS
maximum output)
8Ω speaker
MAX9768 EV system
MAX9768 EV kit
Maxim CMAXQUSB interface board
(USB cable included)
•
A user-supplied Windows 98SE/2000/XP PC with a
spare USB port
directly from the EV kit software. Text in
bold and
underlined
refers to items from the Windows 98SE/
2000/XP operating system.
Procedure for Stand-Alone Operation
The MAX9768 EV kit is fully assembled and tested.
Follow the steps below to verify board operation for
analog volume control.
Do not turn on the power sup-
ply until all connections are completed.
1) On the MAX9768 EV kit, make sure the shunts are in
the default positions (see Table 1).
2) Connect the positive terminal of the 4.5V to 14V DC
power supply to the PV
DD
binding post, and the power-
supply ground terminal to the PGND binding post.
3) Connect the 8Ω speaker across the FOUT+ and
FOUT- binding posts.
Note:
In the following sections, software-related items
are identified by bolding. Text in
bold
refers to items
Component Suppliers
SUPPLIER
Murata Mfg. Co., Ltd.
Panasonic Corp.
TDK Corp.
PHONE
770-436-1300
800-344-2112
847-803-6100
WEBSITE
www.murata.com
www.panasonic.com
www.component.tdk.com
Note:
Indicate that you are using the MAX9768 when contacting these component suppliers.
2
_______________________________________________________________________________________
MAX9768 Evaluation Kit/Evaluation System
4) Plug the audio source to the RCA jack.
5) Turn on the audio source.
6) Turn on the 4.5V to 14V DC power supply.
7) Adjust the potentiometer R6 to change the speaker
volume.
JU1
JU2
Evaluate: MAX9768
Table 1. MAX9768 EV Kit Jumper Settings
JUMPER
SHUNT POSITION
2-3*
1-2
1-2*
2-3
2-3*
JU3, JU4
1-2
1-2, 2-3
2-3, 1-2
JU5
2-3*
1-2
1-4*
1-2
JU6
1-3
Open
1-2*
JU7
Open
1-2*
JU8
Open
Open
DESCRIPTION
Normal operation
Speaker mute
Normal operation
Amplifier shutdown
I
2
C Address: disabled, stand-
alone operation
I
2
C Address: 1001 011x
I
2
C Address: 1001 001x
I
2
C Address: 1001 010x
Stand-alone operation
I
2
C volume control mode
SYNC connected to GND
SYNC connected to V
DD
SYNC unconnected
SYNC connected to external
clock
V
DD
supplied by on-board
LDO regulator
V
DD
supplied by an external
power supply
In stand-alone operation:
classic PWM modulation
In stand-alone operation:
filterless modulation
I
2
C interface control mode
Procedure for
Interface
Volume Control
The MAX9768 EV kit is fully assembled and tested.
Follow the steps below to verify board operation for I
2
C
volume control.
Caution: Do not turn on the power
supply until all connections are completed.
1) Visit www.maxim-ic.com/evkitsoftware to download
the latest version of the EV kit software,
9768Rxx.ZIP.
2) Install the MAX9768 evaluation software on your
computer by running the INSTALL.EXE program.
The program files are copied and icons are created
in the Windows
Start
menu.
3) On the CMAXQUSB board, ensure that the shunt of
JU1 is in the 3.3V position.
4) Carefully connect the boards by aligning the
MAX9768 EV kit’s 20-pin connector with the 20-pin
connector of the CMAXQUSB board.
5) Ensure shunts on JU1, JU2, JU4, JU6, and JU7 are
in their default positions (see Table 1).
6) Place the shunt on JU3 across pins 1-2.
7) Place the shunt on JU5 across pins 1-2.
8) Remove the shunt on JU8.
9) Connect the positive terminal of the 4.5V to 14V DC
power supply to the PV
DD
binding post, and the
power-supply ground terminal to the PGND binding
post.
10) Connect the 8Ω speaker across the FOUT+ and
FOUT- binding posts.
11) Plug the audio source to the RCA jack.
12) Turn on the audio source.
13) Turn on the 4.5V to 14V DC power supply.
14) Connect the USB cable from the PC to the
CMAXQUSB board. A
Building Driver Database
window pops up in addition to a
New Hardware
Found
message. If you do not see a window that is
similar to the one described above after 30s, remove
the USB cable from the CMAXQUSB and reconnect
it. Administrator privileges are required to install the
USB device driver on Windows 2000/XP. Refer to
I
2
C
*Default
position.
the TROUBLESHOOTING_USB.PDF document
included with the software if you have any prob-
lems during this step.
15) Follow the directions of the
Add New Hardware
Wizard
to install the USB device driver. Choose the
Search for the Best Driver for your Device
option.
Specify the location of the device driver to be
C:\Program Files\MAX9768
(or the directory cho-
sen during installation) using the
Browse
button.
16) Start the MAX9768 EV kit software by opening its
icon in the
Start
menu. The GUI main window
appears, as shown in Figure 1.
17) Move the volume-control slider on the software win-
dow and verify that the speaker volume changes.
_______________________________________________________________________________________
3
MAX9768 Evaluation Kit/Evaluation System
Evaluate: MAX9768
Detailed Description of Hardware
The MAX9768 is a mono, switch-mode (Class D) audio
power amplifier. The EV kit is designed to be driven by
the lineout or headphone jack of a CD player, or direct-
ly connected to any audio source. A thumbwheel
potentiometer mounted on-board is provided to control
the volume. The volume can also be controlled by the
I
2
C interface.
The EV kit has an on-board LDO (MAX1726) to power
the input buffers and the volume-control circuitry.
Volume Control
Jumpers JU3, JU4, JU5, and JU8 select which volume-
control mode is used. See Table 3 for details.
Table 3. Control-Mode Setting
JUMPER
SHUNT POSITION
2-3*
JU3, JU4
1-2
1-2, 2-3
2-3, 1-2
JU5
2-3*
1-2
1-2*
JU8
Open
Open
DESCRIPTION
I
2
C Address: disabled, stand-
alone operation
I
2
C Address: 1001 011x
I
2
C Address: 1001 001x
I
2
C Address: 1001 010x
Stand-alone operation
I
2
C volume control mode
In stand-alone operation:
classic PWM modulation
In stand-alone operation:
filterless modulation
I
2
C interface control mode
Preamplifier Gain Configuration
The preamplifier gain stage of the MAX9768 EV kit is
configured to 0dB. To avoid clipping at the amplifier
input stage, ensure input signals are
≤
1V
RMS
. If input
signals are
≥
1V
RMS
, attenuate the input signal at the
preamplifier gain stage to avoid clipping at the pream-
plifier output. The preamplifier gain stage is defined as:
A
V (preamplifier)
= -R3 / R2
where R2 is in the 10kΩ to 40kΩ range.
Define the preamplifier gain such that the output of the
preamplifier is
≤
1V
RMS
(i.e., V
IN
x A
V (preamplifier)
≤
1V
RMS
). Once the preamplifier gain is fixed, use the
amplifier’s volume-control block to set the clipping lev-
els at the output of the Class D amplifier.
*Default
position.
Shutdown Mode
Jumper JU2 sets the amplifier in normal operation or
shutdown mode. See Table 4 for details.
Power Supplies
The power supply is applied on PV
DD
and PGND binding
posts. V
DD
is generated either by the on-board MAX1726
or by an external 3.3V power supply applied between the
V
DD
pad and PGND. See Table 2 for JU7 setting.
Table 4. JU2 Setting
JUMPER
JU2
SHUNT POSITION
1-2*
2-3
DESCRIPTION
Normal operation
Shutdown mode
*Default
position.
Table 2. JU7 Jumper Setting
JUMPER
SHUNT POSITION
1-2*
JU7
Open
User-provided 3.3V V
DD
power supply
DESCRIPTION
On-board V
DD
generated by
MAX1726
Mute Control
Jumper JU1 controls the MUTE pin state. See Table 5
for details.
Table 5. JU1 Setting
JUMPER
JU1
SHUNT POSITION
2-3*
1-2
DESCRIPTION
Normal operation
Speaker muted
*Default
position.
*Default
position.
4
_______________________________________________________________________________________
MAX9768 Evaluation Kit/Evaluation System
Modulation Schemes
Jumper JU6 sets the output modulation scheme. See
Table 6 for details.
Detailed Description of Software
To start the MAX9768 EV kit software, double-click the
MAX9768 EV kit icon created during installation. The
GUI main window appears, as shown in Figure 1. Wait
approximately 2s while the MAX9768 EV kit software
connects to the CMAXQUSB board and automatically
detects the I
2
C address of the device.
On the left side of the window, the scrollbar is used to
increment/decrement the speaker volume by one step.
On the right side of the window, a user can manually
change the device I
2
C address, set volume directly by
programming the volume register, and set the modula-
tion mode.
Evaluate: MAX9768
Table 6. JU6 Setting
JUMPER
SHUNT POSITION
1-4*
1-2
JU6
1-3
DESCRIPTION
Fixed-frequency mode with
f
SW
= 300kHz
Spread-spectrum mode with
f
S
= 300kHz ±7.5kHz
Fixed-frequency mode with
f
S
= 360kHz
Fixed-frequency mode with
f
S
= 1/4 external clock
frequency
Open
*Default
position.
Figure 1. MAX9768 Evaluation Software Main Window
_______________________________________________________________________________________
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