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 demonstrates the capabilities of the MAX9768 mono 10W
Class D speaker amplifier with volume control. The
MAX9768 EV kit also includes Windows ® 98SE/2000/XPcompatible 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 serialinterface 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.
PART
MAX9768EVKIT+
CMAXQUSB+
Component Lists
QTY
1
1
MAX9768 EV System
DESCRIPTION
MAX9768 EV kit
Serial-interface board
MAX9768 EV Kit
DESIGNATION QTY
U1 1
DESCRIPTION
MINIMAL COMPONENTS FOR CUSTOMER DESIGN
C1, C2 2
0.1µF ±10%, 16V X7R ceramic capacitors (0603)
Murata GRM188R71C104K
C3, C5
C4
C6, C8
C7, C21
R2, R3
2
1
1µF ±10%, 10V X7R ceramic capacitors (0603)
Murata GRM188R61A105K
0.47µF ±10%, 16V X7R ceramic capacitor (0805)
Murata GRM21BR71C474K
2
1µF ±10%, 16V X7R ceramic capacitors (0805)
Murata GRM21BR71C105K
2
22µF ±20%, 16V aluminum electrolytic capacitor (C case)
Panasonic EEEFC1C220R
2 20k
Ω ±1% resistors (0603)
Maxim 10W mono speaker amplifier with volume control
MAX9768ETG+ (24-pin, 4mm x 4mm x 0.8mm, TQFN-EP*)
* EP = Exposed paddle.
Features
♦ Fully Tested PCB
♦ 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
Ordering Information
PART
MAX9768EVKIT+
MAX9768EVCMAXQU+
TYPE
EV Kit
EV System
+ 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)
DESIGNATION QTY DESCRIPTION
OPTIONAL COMPONENTS FOR CUSTOMER EVALUATION
C9, C10
C11, C12
C13, C15
C14, C16, C20
C17
C18
0
2
2
3
1
1
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
________________________________________________________________ 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
DESIGNATION QTY
C19
J1
J2
J3–J6
JU1–JU5
JU6
JU7, JU8
L1, L2
L3, L4
L5, L6
R1, R5
R4
R6
DESCRIPTION
1
100pF ±5%, 50V C0G ceramic capacitor (0603)
Murata GRM1885C1H101J
1 2 x 10 right-angle female receptacle
1 White RCA mono jack
4 Binding posts, uninsulated
5 Single-row 3-pin headers
1 3-way-pin header
2 2-pin headers
2
60
Ω, 3A ferrite beads (0805)
Murata BLM21PG600SN1
2 Shorted with 0
Ω resistors (0603)
2
22µH, 1.9A inductors
TDK SLF10145T-220M1R9PF
2 10k
Ω ±5% resistors (0603)
1 20
Ω ±5% resistor (1206)
1
10k
Ω ±20% thumbwheel potentiometer
Panasonic EVL-HFAA05B14
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
Note: In the following sections, software-related items are identified by bolding. Text in bold refers to items
Component Lists (continued)
MAX9768 EV Kit (continued)
DESIGNATION QTY
U2
—
—
—
—
DESCRIPTION
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+
FILE
MAX9768 EV Kit Files
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 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 powersupply ground terminal to the PGND binding post.
3) Connect the 8Ω speaker across the FOUT+ and
FOUT- binding posts.
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.
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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.
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 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
Table 1. MAX9768 EV Kit Jumper Settings
JUMPER SHUNT POSITION
JU1
JU2
2-3*
1-2
1-2*
2-3
JU3, JU4
JU5
JU6
2-3*
Open
1-2*
DESCRIPTION
Normal operation
Speaker mute
Normal operation
Amplifier shutdown
I
2
C Address: disabled, standalone 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
JU7
1-2
1-2, 2-3
2-3, 1-2
2-3*
1-2
1-4*
1-2
1-3
JU8
Open
1-2*
Open
Open
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
* Default position.
the TROUBLESHOOTING_USB.PDF document included with the software if you have any problems 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 chosen 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 window and verify that the speaker volume changes.
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MAX9768 Evaluation Kit/Evaluation System
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 directly 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.
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 preamplifier 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 levels at the output of the Class D amplifier.
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 2. JU7 Jumper Setting
JUMPER SHUNT POSITION
1-2*
DESCRIPTION
On-board V
DD
generated by
MAX1726
JU7
Open
User-provided 3.3V V
DD power supply
* Default position.
Volume Control
Jumpers JU3, JU4, JU5, and JU8 select which volumecontrol mode is used. See Table 3 for details.
Table 3. Control-Mode Setting
JUMPER SHUNT POSITION
JU3, JU4
JU5
JU8
2-3*
1-2
1-2, 2-3
2-3, 1-2
2-3*
1-2
1-2*
Open
Open
DESCRIPTION
I
2
C Address: disabled, standalone 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
* Default position.
Shutdown Mode
Jumper JU2 sets the amplifier in normal operation or shutdown mode. See Table 4 for details.
Table 4. JU2 Setting
JUMPER SHUNT POSITION
JU2
1-2*
2-3
* Default position.
DESCRIPTION
Normal operation
Shutdown mode
Mute Control
Jumper JU1 controls the MUTE pin state. See Table 5 for details.
Table 5. JU1 Setting
JUMPER SHUNT POSITION
2-3*
JU1
1-2
* Default position.
DESCRIPTION
Normal operation
Speaker muted
4 _______________________________________________________________________________________
MAX9768 Evaluation Kit/Evaluation System
Modulation Schemes
Jumper JU6 sets the output modulation scheme. See
Table 6 for details.
Table 6. JU6 Setting
JUMPER SHUNT POSITION
JU6
1-4*
1-2
1-3
Open
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
* Default position.
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 modulation mode.
Figure 1. MAX9768 Evaluation Software Main Window
_______________________________________________________________________________________ 5
MAX9768 Evaluation Kit/Evaluation System
Figure 2. MAX9768 EV Kit Schematic
6 _______________________________________________________________________________________
MAX9768 Evaluation Kit/Evaluation System
Figure 3. MAX9768 EV Kit Component Placement Guide—Component Side
_______________________________________________________________________________________ 7
MAX9768 Evaluation Kit/Evaluation System
Figure 4. MAX9768 EV Kit PCB Layout—Component Side
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MAX9768 Evaluation Kit/Evaluation System
Figure 5. MAX9768 EV Kit PCB Layout—Solder 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.
