19-3308; Rev 0; 6/04
MAX6695 Evaluation Kit/Evaluation System
General Description
The MAX6695 evaluation kit (EV kit) is an assembled and
tested PC board with a mounted MAX6695. The EV kit
allows full evaluation of the MAX6695 temperature sensor.
The MAX6695 monitors its own die temperature and the
junction temperature of two external diode-connected
transistors. It converts the temperature to 11-bit, 2-wire
serial data that can be accessed over a 2-wire serial bus.
The MAX6695 EV kit includes both external diode-con-
nected transistors (2N3906) soldered to the board,
which can be removed. The board can then be con-
nected through a twisted pair to remote diodes close to
your system.
The MAX6695 evaluation system consists of a Maxim
command module (CMOD232) and a MAX6695 EV kit.
The CMOD232 board connects to a computer’s
RS-232 serial port to provide a computer-controlled
SMBus™/I2C bus. Windows® 95/98/2000/XP-compati-
ble software provides a user-friendly interface to exer-
cise the features of the MAX6695. The program is menu
driven and offers a graphic interface with control but-
tons and status display.
Order the MAX6695EVCMOD2 for a complete PC-based
evaluation of the MAX6695. Order the MAX6695EVKIT if
you already have an SMBus interface.
Features
♦
Measure and Display Temperature of the
MAX6695 and the Remote Diodes
♦
Programmable Under/Over-Temperature Alarms
♦
Programmable Conversion Rate
♦
Programmable Over-Temperature Hysteresis
♦
SMBus/I
2
C Compatible
♦
Easy-to-Use Menu-Driven Software
♦
Fully Assembled and Tested
♦
Include Windows 95/98/2000/XP-Compatible
Software and Demo PC Board
Evaluate: MAX6695
Ordering Information
PART
MAX6695EVKIT
MAX6695EVCMOD2
TEMP
RANGE
0°C to +70°C
0°C to +70°C
SMBus
INTERFACE
TYPE
Not included
CMOD232
Note:
The MAX6695 EV kit software is provided with the
MAX6695EVKIT. However, the CMOD232 board is required to
interface the EV kit to the computer when using the software.
MAX6695EVCMOD2 (MAX6695
EV System) Component List
PART
MAX6695EVKIT
CMOD232
AC adapter
QTY
1
1
1
DESCRIPTION
MAX6695 evaluation kit
SMBus/I
2
C interface board
9VDC at 200mA
(powers the CMOD232 board)
Component List
DESIGNATION
QTY
DESCRIPTION
0.1µF
±10%,
16V X7R ceramic
capacitor (0603)
Murata GRM188R71C104KA01
TDK C1608X7R1C104K
2200pF
±10%,
50V X7R ceramic
capacitors (0603)
Murata GRM188R71H222K
TDK C1608X7R1H222K
2 x 10 right-angle female receptacle
Not installed
2N3906-type pnp transistors, SOT23
Central Semiconductor CMPT3906
Diodes Incorporated MMBT3906
Vishay Semiconductors MMBT3906
47Ω
±5%
resistor (0603)
4.7kΩ
±5%
resistors (0603)
MAX6695AUB (10-pin µMAX
®
)
C1
1
C2, C3
2
J1
1
0
SMBus is a trademark of Intel Corp.
JU1, JU2, JU3
Q1, Q2
2
R1
R2–R6
U1
1
5
1
µMAX is a registered trademark of Maxim Integrated Products,
Inc.
________________________________________________________________
Maxim Integrated Products
1
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.
MAX6695 Evaluation Kit/Evaluation System
Evaluate: MAX6695
Component Suppliers
SUPPLIER
Central Semiconductor
Diodes Incorporated
Murata
TDK
Vishay Semiconductor
PHONE
631-435-1110
805-446-4800
770-436-1300
847-803-6100
760-804-9258
FAX
631-435-1824
805-381-3899
770-436-3030
847-390-4405
760-804-9259
WEBSITE
www.centralsemi.com
www.diodes.com
www.murata.com
www.component.tdk.com
www.vishay.com
Note:
Indicate you are using the MAX6695 when contacting these manufacturers.
Quick Start
Recommended Equipment
Do not turn on the power until all connections are
made.
Before you begin, the following equipment is
needed:
• Computer running Windows 95, 98, 2000, or XP.
• RS-232 serial port (this is a 9-pin socket on the back
of the computer)
• Standard 9-pin, straight-through, male-to-female
cable to connect the computer’s serial port to the
Maxim CMOD232 board
• 3.3V, 100mA DC power supply
Detailed Description
User-Interface Panel
The user interface is easy to operate; use the mouse, or
press the Tab and arrow keys to navigate. The check-
boxes, edit fields, and radio buttons correspond to bits
in the MAX6695 registers. Clicking on them generates
the correct SMBus command and updates the registers.
Note:
Words in bold are user-selectable features in
the software.
Temperature
The MAX6695 monitors its own temperature and the
temperature of two external diodes. All temperature
measurements are capable of either 8-bit or 11-bit
(extended) resolution; 8-bit resolution results in temper-
ature resolution of 1°C/LSB. Extended resolution results
in temperature resolution of 0.125°C/LSB. Enable
extended resolution by selecting the
Extended
Resolution
checkbox (Figure 1).
Note:
Extended reso-
lution is only valid for conversion rates of 2Hz or less.
Read the temperatures by clicking on the
Read Temp
buttons (Figure 1). The temperature is shown to the
right of the buttons.
The MAX6695 has high, low, and over-temperature limit
registers. Temperatures exceeding either the high- or
low-limit registers generate an alert interrupt.
Exceeding the over-temperature limit sets the over-tem-
perature bit in the status register and asserts the over-
temperature output pin.
Read the high, low, and over-temperature limits by
clicking on the
Read High, Read Low, Read Over1,
or
Read Over2
buttons, respectively (Figure 1). The value
(in Celsius) is shown to the right of the button. Change
the high, low, and over-temperature limits by entering
the value (in Celsius) into the appropriate edit field.
Pressing Enter, after typing in the new value, updates
the internal register.
The MAX6695 includes hysteresis on the over-tempera-
ture alarms to prevent the
OT1
and
OT2
pins from oscil-
Procedure
1) Carefully connect the boards by aligning the 20-pin
connector of the MAX6695 EV kit with the 20-pin
header of the CMOD232 board. Gently press them
together.
2) Disable the pullup resistors on the CMOD232 board
by moving switch SW1 to the OFF position.
3) Connect a cable from the computer’s serial port to
the CMOD232 board. Use a straight-through, 9-pin,
male-to-female cable.
4) Install the software by running the INSTALL.EXE pro-
gram. The install program copies the files and cre-
ates icons for them in the Windows 95/98/2000/XP
Start menu. (To remove the software at any time,
click on the UNINSTALL icon.)
5) Connect the 9V adapter to the CMOD232 board.
6) Connect the +3.3V supply to the pads labeled VCC
and GND on the MAX6695 EV kit.
7) Turn on the power supply.
8) Start the MAX6695 program by opening its icon in
the Start menu.
9) Wait until the program automatically detects the
address of the MAX6695 and displays the user-
interface panel (Figure 1).
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MAX6695 Evaluation Kit/Evaluation System
lating. The hysteresis sets the amount the temperature
must decrease from the over-temperature limit to
deassert the
OT1
and
OT2
pins.
Read the hysteresis register by clicking on the
Read
Hysteresis
button (Figure 1). The value (in Celsius) is
shown to the right of the button.
Change the hysteresis by entering the value (in
Celsius) into the edit field. Pressing Enter, after typing
in the new value, updates the internal register.
Conversion Rate
The conversion rate sets the number of temperature
samples the MAX6695 takes per second.
Note:
The
MAX6695 operates up to 4Hz; however, the EV kit soft-
ware reads the device a maximum of two times per
second (2Hz).
Read the conversion rate register by clicking on the
Read Conversion Rate
button (Figure 3). Change the
conversion rate by clicking on the radio button next to
the desired frequency.
Evaluate: MAX6695
External Diodes
The MAX6695 remote temperature sensor is optimized
for use with a diode-connected transistor whose ideality
factor is equal to 1.008. Transistors with different ideali-
ty factors produce different remote temperature read-
ings. Some typical discrete transistors may produce
readings that vary up to 3°C from the correct value.
Refer to the Maxim website (www.maxim-ic.com)
Application Note:
Compensating for Ideality Factor and
Series Resistance Differences Between Thermal Sense
Diodes
for additional information.
Status
The status boxes (status1 and status2) display the criti-
cal and fault conditions that occur. Status1 also dis-
plays BUSY if the MAX6695 is performing a conversion
at the time the status is read. Each line corresponds to
a bit in the registers. See Tables 2 and 3 for a list of the
status conditions.
Read the status by clicking on the
Read Status
button.
Alert
The message ALERT appears in the Alert box when an
interrupt condition occurs unless the configuration reg-
ister is set to mask the alert. The cause of the interrupt
is shown in the status boxes. To clear the interrupt, first
eliminate the condition that caused it and click on
Read Alert.
Configuration
The configuration register has several functions. Figure
2 shows the checkboxes that configure the register.
Each checkbox corresponds to a bit in the register.
Table 1 describes the function of each checkbox.
Table 1. Configuration Register Checkboxes
BIT
7
6
5
4
3
NAME
Mask alert
STOP
Fault queue
Reserved
Remote 2 select
STATE
Checked
Unchecked
Checked
Unchecked
Checked
Unchecked
—
Checked
Unchecked
Checked
Unchecked
1
0
Mask alert CH2
Mask alert CH1
Checked
Unchecked
Checked
Unchecked
Disables the
ALERT
interrupts.
Enables the
ALERT
interrupts.
Places the MAX6695 in software standby mode.
Places the MAX6695 in operational mode.
MAX6695 requires four consecutive faults before over-temperature2 output is set.
MAX6695 requires only one fault before any over-temperature2 output is set.
Not used.
Selects external 2 sensor for reading and writing.
Selects external 1 sensor for reading and writing.
Disables the SMBus timeout, as well as alert response, thus providing true I
2
C
compatibility.
Enables the SMBus timeout.
Disables any alert response caused by external 2 sensor.
Enables alert response caused by external 2 sensor.
Disables any alert response caused by external 1 sensor.
Enables alert response caused by external 1 sensor.
DESCRIPTION
2
SMB timeout disabled
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3
MAX6695 Evaluation Kit/Evaluation System
Evaluate: MAX6695
Table 2. Status1 Register
BIT
7
6
5
4
3
2
1
0
Busy
Internal high (hot) limit
Internal low (cold) limit
External 1 high (hot) limit
External 1 low (cold) limit
Diode 1 open
External 1 OverTemp1
Internal OverTemp1
NAME
DESCRIPTION
The MAX6695 is performing a conversion at the time the status is read.
The temperature of the MAX6695 is above the value set in the internal high (hot) limit register.
The temperature of the MAX6695 is below the value set in the internal low (cold) limit register.
The temperature of the external 1 sensor is above the value set in the external 1 hot limit register.
The temperature of the external 1 sensor is below the value set in the external 1 cold limit register.
External 1 sensor diode is open.
The temperature of the external 1 sensor is above the value set in the external 1 OverTemp1 limit
register.
The temperature of the MAX6695 is above the value set in the internal OverTemp1 limit register.
Table 3. Status2 Register
BIT
7
6
5
4
3
2
1
0
NAME
Internal OverTemp2
External 2 OverTemp2
External 1 OverTemp2
External 2 high (hot) limit
External 2 low (cold) limit
Diode 2 open
External 2 OverTemp1
Reserved
DESCRIPTION
The temperature of the MAX6695 is above the value set in the internal OverTemp2 limit register.
The temperature of the external 2 sensor is above the value set in the external 2 OverTemp2 limit
register.
The temperature of the external 1 sensor is above the value set in the external 1 OverTemp2 limit
register.
The temperature of the external 2 sensor is above the value set in the external 2 high (hot) limit
register.
The temperature of the external 2 sensor is below the value set in the external 2 low (cold) limit
register.
External 2 sensor diode is open.
The temperature of the external 2 sensor is above the value set in the external 2 OverTemp1 limit
register.
Not used.
Automatic Read
The program polls the device for new temperature and
status data a maximum two times per second (2Hz). To
disable the polling of data, deselect
Automatic Read
on the
Action
menu.
Simple SMBus Commands
There are two methods for communicating with the
MAX6695: through the normal user-interface panel or
through the SMBus commands available by selecting
Interface
on the
Debug
menu. A display pops up that
allows the SMBus protocols, such as read byte and
write byte, to be executed. To stop normal user-inter-
face execution so it does not override the manually set
values, turn off the update timer by deselecting
Automatic Read
on the
Action
menu.
The SMBus dialog boxes accept numeric data in bina-
ry, decimal, or hexadecimal. Hexadecimal numbers
should be prefixed by $ or 0x. Binary numbers must be
exactly eight digits.
Note:
In places where the slave
address asks for an 8-bit value, it must be the 7-bit
slave address of the MAX6695 with the last bit set to
one for a read operation and zero for a write.
Data Logging
Select
Data Logging
on the
Action
menu to activate
data logging. Data logging saves temperature, voltage,
and status data to a text file that includes a time/date
stamp next to each data point. If automatic read is
enabled, data is sampled at 2Hz; however, the data is
logged to the file only if the temperature or status has
changed. This slows the growth of the data-logging file.
When automatic read is disabled, the data is logged
each time
Read All
is selected on the
Action
menu. To
stop data logging, deselect
Data Logging
on the
Action
menu.
4
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MAX6695 Evaluation Kit/Evaluation System
Evaluate: MAX6695
Figure 1. Main Window for the MAX6695 EV Kit Software
Jumpers JU1 and JU2
Jumpers JU1 and JU2 connect the 2N3906 transistors
as the external diodes. To use different diodes, cut the
trace, short the two pins of JU1 and JU2, and connect
the diodes (through twisted-pair wire) to pads DXP1,
DXN, and DXP2.
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