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 I2C 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
♦10W Output into 8Ω
ΩLoad at 13V Power Supply
♦Bridge-Tied Load (BTL) Output and Click-and-Pop
Suppression
♦Dual Mode™ Volume Control: Analog or I2C
♦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
MAX9768 Evaluation Kit/Evaluation System
________________________________________________________________
Maxim Integrated Products
1
19-1222; Rev 0; 11/07
Component Lists
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.
Ordering Information
PART
TYPE
MAX9768EVKIT+
EV Kit
MAX9768EVCMAXQU+
EV System
PART
QTY
DESCRIPTION
MAX9768EVKIT+
1
MAX9768 EV kit
CMAXQUSB+
1
Serial-interface board
MAX9768 EV System
DESIGNATION
QTY
DESCRIPTION
MINIMAL COMPONENTS FOR CUSTOMER DESIGN
C1, C2
2
0.1µF ±10%, 16V X7R ceramic
capacitors (0603)
Murata GRM188R71C104K
C3, C5
2
1µF ±10%, 10V X7R ceramic
capacitors (0603)
Murata GRM188R61A105K
C4
1
0.47µF ±10%, 16V X7R ceramic
capacitor (0805)
Murata GRM21BR71C474K
C6, C8
2
1µF ±10%, 16V X7R ceramic
capacitors (0805)
Murata GRM21BR71C105K
C7, C21
2
22µF ±20%, 16V aluminum
electrolytic capacitor (C case)
Panasonic EEEFC1C220R
R2, R3
2
20kΩ ±1% resistors (0603)
U1
1
Maxim 10W mono speaker amplifier
with volume control
MAX9768ETG+ (24-pin, 4mm x 4mm
x 0.8mm, TQFN-EP*)
MAX9768 EV Kit
DESIGNATION
QTY
DESCRIPTION
OPTIONAL COMPONENTS FOR CUSTOMER EVALUATION
C9, C10
0
Not installed, ceramic capacitors
(0603)
C11, C12
2
0.01µF ±10%, 50V X7R ceramic
capacitors (0805)
Murata GRM216R71H103K
C13, C15
2
0.22µF ±10%, 25V X7R ceramic
capacitors (1206)
Panasonic ECJ-3VB1E224K
C14, C16, C20
3
0.01µF ±10%, 16V X7R ceramic
capacitors (0603)
Murata GRM188R71C103K
C17
1
1µF ±10%, 16V X7R ceramic
capacitor (0805)
Murata GRM21BR71C105K
C18
1
1µF ±10%, 10V X7R ceramic
capacitor (0603)
Murata GRM188R61A105K
+
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 (continued)
*
EP = Exposed paddle.
Evaluate: MAX9768
MAX9768 Evaluation Kit/Evaluation System
2 _______________________________________________________________________________________
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, 1VRMS maximum output)
•8Ωspeaker
• 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
Note: In the following sections, software-related items
are identified by bolding. Text in bold refers to items
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 PVDD binding post, and the power-
supply ground terminal to the PGND binding post.
3) Connect the 8Ωspeaker across the FOUT+ and
FOUT- binding posts.
Component Suppliers
Component Lists (continued)
SUPPLIER PHONE WEBSITE
Murata Mfg. Co., Ltd. 770-436-1300 www.murata.com
Panasonic Corp. 800-344-2112 www.panasonic.com
TDK Corp. 847-803-6100 www.component.tdk.com
DESIGNATION
QTY
DESCRIPTION
C19
1
100pF ±5%, 50V C0G ceramic
capacitor (0603)
Murata GRM1885C1H101J
J1
1
2 x 10 right-angle female receptacle
J2
1
White RCA mono jack
J3–J6
4
Binding posts, uninsulated
JU1–JU5
5
Single-row 3-pin headers
JU6
1
3-way-pin header
JU7, JU8
2
2-pin headers
L1, L2
2
60
Ω
, 3A ferrite beads (0805)
Murata BLM21PG600SN1
L3, L4
2
Shorted with 0
Ω
resistors (0603)
L5, L6
2
22µH, 1.9A inductors
TDK SLF10145T-220M1R9PF
R1, R5
2
10k
Ω
±5% resistors (0603)
R4
1
20
Ω
±5% resistor (1206)
R6
1
10k
Ω
±20% thumbwheel
potentiometer
Panasonic EVL-HFAA05B14
DESIGNATION
QTY
DESCRIPTION
U2
1
M axi m 12V l ow - d r op out l i near r eg ul ator
MAX1726EUK33+ (5-pin SOT23)
—
8
Shunts
—
4
0.250in x 0.500in 4–40 round nylon
spacers
—
4
4–40 x 0.375in nylon machine screws
—
1
PCB: MAX9768 Evaluation Kit+
MAX9768 EV Kit (continued)
Note:
Indicate that you are using the MAX9768 when contacting these component suppliers.
MAX9768 EV Kit Files
FILE DESCRIPTION
INSTALL.EXE Installs the EV kit files
on your computer
MAX9768.EXE Application program
FTD2XX.INF USB device driver file
UNINST.INI Uninstalls the EV kit
software
TROUBLESHOOTING_USB.PDF USB driver installation
help file
Evaluate: MAX9768
MAX9768 Evaluation Kit/Evaluation System
_______________________________________________________________________________________ 3
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.
Procedure for I
2
C Interface
Volume Control
The MAX9768 EV kit is fully assembled and tested.
Follow the steps below to verify board operation for I2C
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 PVDD binding post, and the
power-supply ground terminal to the PGND binding
post.
10) Connect the 8Ωspeaker 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
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.
JUMPER
SHUNT POSITION
DESCRIPTION
2-3* Normal operation
JU1 1-2 Speaker mute
1-2* Normal operation
JU2 2-3 Amplifier shutdown
2-3* I
2
C Address: disabled, stand-
alone operation
1-2 I
2
C Address: 1001 011x
1-2, 2-3 I
2
C Address: 1001 001x
JU3, JU4
2-3, 1-2 I
2
C Address: 1001 010x
2-3* Stand-alone operation
JU5 1-2 I
2
C volume control mode
1-4* SYNC connected to GND
1-2 SYNC connected to V
DD
1-3 SYNC unconnected
JU6
Open SYNC connected to external
clock
1-2* V
DD
supplied by on-board
LDO regulator
JU7
Open V
DD
supplied by an external
power supply
1-2* In stand-alone operation:
classic PWM modulation
Open In stand-alone operation:
filterless modulation
JU8
Open I
2
C interface control mode
Table 1. MAX9768 EV Kit Jumper Settings
*
Default position.
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
I2C interface.
The EV kit has an on-board LDO (MAX1726) to power
the input buffers and the volume-control circuitry.
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 ≤1VRMS. If input
signals are ≥1VRMS, attenuate the input signal at the
preamplifier gain stage to avoid clipping at the pream-
plifier output. The preamplifier gain stage is defined as:
AV (preamplifier) = -R3 / R2
where R2 is in the 10kΩto 40kΩrange.
Define the preamplifier gain such that the output of the
preamplifier is ≤1VRMS (i.e., VIN x AV (preamplifier) ≤
1VRMS). 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.
Power Supplies
The power supply is applied on PVDD and PGND binding
posts. VDD is generated either by the on-board MAX1726
or by an external 3.3V power supply applied between the
VDD pad and PGND. See Table 2 for JU7 setting.
Volume Control
Jumpers JU3, JU4, JU5, and JU8 select which volume-
control mode is used. See Table 3 for details.
Shutdown Mode
Jumper JU2 sets the amplifier in normal operation or
shutdown mode. See Table 4 for details.
Mute Control
Jumper JU1 controls the MUTE pin state. See Table 5
for details.
Evaluate: MAX9768
MAX9768 Evaluation Kit/Evaluation System
4 _______________________________________________________________________________________
JUMPER SHUNT POSITION DESCRIPTION
1-2* Normal operation
JU2 2-3 Shutdown mode
Table 4. JU2 Setting
*
Default position.
JUMPER
SHUNT POSITION
DESCRIPTION
2-3* I2C Address: disabled, stand-
alone operation
1-2 I2C Address: 1001 011x
1-2, 2-3 I2C Address: 1001 001x
JU3, JU4
2-3, 1-2 I2C Address: 1001 010x
2-3* Stand-alone operation
JU5 1-2 I2C volume control mode
1-2* In stand-alone operation:
classic PWM modulation
Open In stand-alone operation:
filterless modulation
JU8
Open I2C interface control mode
Table 3. Control-Mode Setting
*
Default position.
JUMPER
SHUNT POSITION
DESCRIPTION
2-3* Normal operation
JU1 1-2 Speaker muted
Table 5. JU1 Setting
*
Default position.
JUMPER
SHUNT POSITION
DESCRIPTION
1-2* On-board VDD generated by
MAX1726
JU7
Open User-provided 3.3V VDD
power supply
Table 2. JU7 Jumper Setting
*
Default position.
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 I2C 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 I2C address, set volume directly by
programming the volume register, and set the modula-
tion mode.
Evaluate: MAX9768
MAX9768 Evaluation Kit/Evaluation System
_______________________________________________________________________________________ 5
JUMPER SHUNT POSITION DESCRIPTION
1-4* Fixed-frequency mode with
f
SW
= 300kHz
1-2 Spread-spectrum mode with
f
S
= 300kHz ±7.5kHz
1-3 Fixed-frequency mode with
f
S
= 360kHz
JU6
Open
Fixed-frequency mode with
f
S
= 1/4 external clock
frequency
Table 6. JU6 Setting
*
Default position.
Figure 1. MAX9768 Evaluation Software Main Window
Evaluate: MAX9768
MAX9768 Evaluation Kit/Evaluation System
6 _______________________________________________________________________________________
MAX9768
U1
2
J1
SDA
PVDD
J4 13
2
4
IN OUT
SHDN
5
L2
SCLK
L4
L5
22μH
C11
0.01μF
C15
0.22μF
C13
0.22μF
R4
20Ω
C9
OPEN
SDA/VOL
FB
IN
SYNC
SCLK
SCLK
VDD
PVDD
JU8
65 3 4 2
20
19
1
R1
10kΩ
VDD
VDD
R5
10kΩ
R6
10kΩ
20% C16
0.01μF
C1
0.1μF
C8
1μF
C7
22μF
SCLK
PVDD BOOT+ OUT+ OUT+
MUTE
OUT+ FOUT+
J5
VDD
L1 VDD
PVDD
U2
JU7
2
1
4
3
JU6
VDD
1
2
3
12
2
1
3
JU5
1
2
3
JU1
VDD
23
ADDR2
1
2
3
JU4
VDD
22
PGND 21
PGND
24
ADDR1
1
2
3
JU3
VDD
1
2
3
JU2
VDD
SDA/VOL
IN
J2
SGND
SYNCOUT
SDA
16 1514
7
8
12
BIAS
GND
GND
10
11
9
C6
1μF
C21
22μF
C14
0.01μF
C2
0.1μF
PVDD
PVDD BOOT- OUT- OUT-VDD
SYNCOUT
C5
1μF
VDD
R2
20kΩ
1%
C3
1μF
C4
0.47μF
R3
20kΩ
1%
C19
100pF
C17
1μF
C18
1μF
C20
0.01μF
PGND
J3
L3
L6
22μH
C12
0.01μF
C10
OPEN
OUT- FOUT-
J6
SHDN
1718
SYNC
1
4
6
8
3
5
7
10
12
14
16
18
20
9
11
13
15
17
19
MAX1726EUK33
GND
GND
13
Figure 2. MAX9768 EV Kit Schematic
Evaluate: MAX9768
MAX9768 Evaluation Kit/Evaluation System
_______________________________________________________________________________________ 7
Figure 3. MAX9768 EV Kit Component Placement Guide—Component Side
Evaluate: MAX9768
MAX9768 Evaluation Kit/Evaluation System
8 _______________________________________________________________________________________
Figure 4. MAX9768 EV Kit PCB Layout—Component Side
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 _____________________
9
© 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
Evaluate: MAX9768
MAX9768 Evaluation Kit/Evaluation System
Figure 5. MAX9768 EV Kit PCB Layout—Solder Side
