19-1980; Rev 1; 5/07
MAX6651 Evaluation Kit/Evaluation System
General Description
The MAX6651 evaluation kit (EV kit) is an assembled
and tested printed-circuit board (PCB) that demon-
strates the MAX6651 intelligent fan controller IC.
Windows
®
98SE/2000/XP-compatible software provides
a handy user interface to exercise the MAX6651’s fea-
tures. Order the MAX6651 EV system for complete eval-
uation of the MAX6651, including a Maxim SMBus
interface board (CMAXQUSB). Order the MAX6651 EV
kit if you already have an SMBus interface.
o
Proven PCB Layout
o
Convenient On-Board Test Points
o
Fully Assembled and Tested
o
EV System Includes USB Connectivity
Features
Evaluate: MAX6651
Ordering Information
PART
MAX6651EVKIT
MAX6651EVCMAXQU
TEMP
RANGE
0°C to +70°C*
0°C to +70°C*
INTERFACE
TYPE
User supplied
Windows software
SMBus is a trademark of Intel Corp.
Windows is a registered trademark of Microsoft Corp.
*This
limited temperature range applies to the EV kit PCB only.
The MAX6651 IC temperature range is -40°C to +85°C.
Component Lists
MAX6651 EV Kit
DESIGNATION
C1
C2
C3
J1–J5, J7–J12
LED1
P1
QTY
1
0
1
11
1
1
DESCRIPTION
10µF, 25V radial leaded
electrolytic capacitor
Open
0.1µF ceramic capacitor (1206)
2-pin headers
Light-emitting diode
2 x 10 right-angle socket
SamTec SSW-110-02-S-D-RA
TO-220 logic-level N-channel FET
International Rectifier IRFZ24N
(Rdson < 0.1Ω at 5Vgs, 30Vbdss)
Heatsink, thermalloy 6028
No. 4 nut
4-40 x 1/4in machine screw
10kΩ ±1% resistor (1206)
100kΩ ±1% resistor (1206)
560Ω ±5% resistor (1206)
49.9kΩ ±1% resistors (1206)
SIP resistor network, 10kΩ, 6 pins,
common
MAX6651EEE
Shunts (J1, J5, J8–J12)
PCB: MAX6651 Evaluation Kit
PART
MAX6651EVKIT
CMAXQUSB+
QTY
1
1
MAX6651 EV System
DESCRIPTION
MAX6651 EV kit
Serial interface board
+Denotes
lead-free and RoHS-compliant.
Quick Start
Recommended Equipment
Before beginning, the following equipment is needed:
• MAX6651 EV system:
MAX6651 EV kit
Maxim CMAXQUSB interface board (USB cable
included)
• A user-supplied Windows 98SE/2000/XP computer
with a spare USB port
• A 12VDC power supply
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.
1
Q1
1
1
1
R1
R2
R3
R4–R8
RP1
U1
—
—
1
1
1
5
1
1
7
1
________________________________________________________________
Maxim Integrated Products
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX6651 Evaluation Kit/Evaluation System
Evaluate: MAX6651
Procedure
The MAX6651 EV kit is fully assembled and tested.
Follow the steps below to verify board operation.
Caution: Do not turn on the power supply until all
connections are completed.
1) Visit the Maxim website (www.maxim-ic.com/evkit-
software) to download the latest version of the EV
kit software, 6651Rxx.ZIP.
2) Install the MAX6651 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 the shunt of
jumper JU1 is in the 5V position.
4) Carefully connect the boards by aligning the 20-pin
connector of the MAX6651 EV kit with the 20-pin
header of the CMAXQUSB interface board. Gently
press them together.
5) Also connect the 12VDC supply to the MAX6651 EV
kit at the pad labeled FAN SUPPLY (±) (the
MAX6651’s +5V supply comes from the CMAXQUSB
board).
6) Ensure that the jumper settings are in the default
position (Table 1).
7) Connect a 12V tachometer-output fan to the
FAN0+, FAN0-, and FAN0T terminals. Additional
fans may be connected at FAN1+/FAN1-,
FAN2+/FAN2-, and FAN3+/FAN3-. Optional
tachometer inputs FAN1T, FAN2T, and FAN3T may
be used to monitor the auxiliary fans’ speed.
8) Connect the USB cable from the PC to the CMAX-
QUSB 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 30 seconds,
remove the USB cable from the CMAXQUSB and
reconnect it. Administrator privileges are required
to install the USB device driver on Windows
98SE/2000/XP. Refer to the TROUBLESHOOT-
ING_USB.PDF document included with the software
if you have any problems during this step.
9) 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\MAX6651
(or the directory cho-
sen during installation) using the
Browse
button.
10) Turn on the power supply. The fan will turn on at full
speed.
11) Start the MAX6651 program by opening its icon in
the Windows
Start
menu.
12) Click the
Registers
panel at the top of the program.
In the
Config
register, drop down the full-on combo
box and choose closed-loop mode.
13) In the
Speed
register, type in the value "100."
Adjust this value up or down to choose the target
fan speed. Increasing the
Speed
value makes the
closed-loop set point a slower fan speed.
14) Observe measured fan speed in the
Tach0
tachometer display.
Detailed Description
of Software
The main window (Figure 1) shows a block diagram of
the MAX6651 EV kit, which allows the user to configure
the
Fan Mode
and
Speed.
The
Registers
tab (Figure
2) shows the register values of the MAX6651. Register
bit fields are presented as drop-down combo boxes.
The
Speed
and
Tach0-3
register values are also trans-
lated into the corresponding fan (RPMs).
Detailed Description
of Hardware
U1, the MAX6651, is an intelligent fan controller. MOS-
FET Q1 regulates the fan voltage (measured by the FB
input). In closed-loop mode, adjusting the fan voltage
set point regulates the main fan’s tachometer output.
PCB Layout Tips
For best results, keep the Q1 gate drive trace as short
as possible.
See Figure 3, which shows the MAX6651 EV kit
schematic, and refer to the MAX6651 IC data sheet.
2
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MAX6651 Evaluation Kit/Evaluation System
Evaluate: MAX6651
Table 1. Jumper Functions
JUMPER
J1
J2
J3
J4
J5
J7
J8
J9
J10
J11
J12
POSITION
Open*
Open*
Open*
Closed*
Closed*
Open
Closed
Open*
Closed*
Open
Closed*
Open
Closed*
Open
Closed*
Open
Closed*
Open
See Table 2.
See Table 2.
See Table 2.
See Table 2.
Connect on-board LED to GPIO0 output.
Disconnect on-board LED from GPIO0 output.
Connect GPIO0 to GPIO1.
GPIO0 is not connected to GPIO1.
Fan 3 tachometer connects to FAN3T directly.
Fan 3 tachometer connects to FAN3T through 49.9kΩ resistor R8.
Fan 2 tachometer connects to FAN2T directly.
Fan 2 tachometer connects to FAN2T through 49.9kΩ resistor R7.
Fan 1 tachometer connects to FAN1T directly.
Fan 1 tachometer connects to FAN1T through 49.9kΩ resistor R6.
Fan 0 tachometer connects to FAN0T directly.
Fan 0 tachometer connects to FAN0T through 49.9kΩ resistor R5.
FB feedback input connects to Q1 drain directly.
FB feedback input connects to Q1 drain through 49.9kΩ resistor R4.
FUNCTION
*Default
position.
Table 2. Address Selection Jumpers
J1
Closed
Open
Open
Open*
J2
Open
Closed
Open
Open*
J3
Open
Open
Closed
Open*
J4
Open
Open
Open
Closed*
ADDRESS
1001 011R
0011 111R
1001 000R
0011 011R
*Default
position.
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5
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