Revision A
April 14, 2006
LM95235 Evaluation Board User’s Guide
© Copyright 2006 National Semiconductor Corporation
1
LM95235 Evaluation Board User’s Guide
References
1. “LM95235 Precision Remote Diode Temperature Sensor With SMBus Interface and
TruTherm™ Technology” datasheet.
The latest copy of the LM95235 datasheet can be obtained by going to the National
the LM95235.pdf file.
2. SensorEval Version 1.1.0a or later, Evaluation Board CD containing:
a. The SensorEval.exe executable program used to run the LM95235 Evaluation
Board.
b. A softcopy of this User’s Guide
c. A readme.txt file with useful information about the program.
d. A softcopy of the SensorEval Software manual.
© Copyright 2006 National Semiconductor Corporation
3
1.0 Introduction
The LM95235 Evaluation Board is used together
with the National Semiconductor SensorEval
software (provided in the kit), and with a USB cable
(not provided in the kit), and with an external
personal computer (PC). Power to the LM95235
Evaluation Board is provided by the +5 VDC line of
the USB connection. No external power supply or
signal sources are required for operation of the
LM95235 evaluation board.
The block diagram below describes the LM95235
Evaluation Board itself. The USB input provides the
+5.0 VDC power to the board, which is regulated
down to 3.3 VDC to power the IC’s. The EEPROM
is programmed at the factory with a unique ID code
for this particular board. When the USB cable is
plugged in, the PC interrogates the USB devices and
can identify this device as the LM95235 Evaluation
Board.
Before connecting the PC to the LM95235
The microcontroller on the board provides the serial
SMBus clock (SMBCLK), provides the SMBus data
(SMBDAT) signal, and relays the information from
the LM95235 to the PC via the USB lines.
evaluation board through the USB cable, the PC is
first turned on and allowed to go through its boot-up
procedure. The user installs and initiates the
SensorEval software. See Section 4.0 for details.
The block in the lower right of the Block Diagram
shows the signals that are available to probe by the
user for the LM95235 device on the board.
After the SensorEval software is running, the user
can connect the USB cable first to the computer and
then to the LM95235 Evaluation Board.
The PC should be able to recognize the board and
the user simply selects the LM95235 Eval Board
radio button.
1.1Block Diagram
USB D+
USB
USB D-
Input
SMBCLK
EEPROM
Microcontroller
Circuit
SMBDAT
GND
+5.0 VDC
Circuitry
GND
+3.3 VDC
Voltage
Regulator
Circuit
VDD
SMBCLK
SMBDAT
T_Crit
U2
LM95235
OS/A0
GND
GND
© Copyright 2006 National Semiconductor Corporation
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2.0 Quick Start
1. Install the CD into the CD drive of the computer
and install the SensorEval software (see Section
4.0).
2. Hookup the USB cable between the PC or
notebook computer and the LM95235EVAL
board as shown in Quick Start Diagram (See
Section 2.1).
3. Run the SensorEval software clicking the icon
on the desktop. The first screen after the
installation will look like this:
Select the LM95235 Evaluation Board.
Click OK.
5. The next screen will look like this:
If not, select “Another Device”. The next screen
should look like this:
Make sure that “4C” is selected in the upper left
box labeled “I2C Addr”. Select “All Regs” in the
“Read Cont” box to read all of the registers,
including the temperature registers continuously.
Select LM95235 and click on Open button.
4. The next screen (first screen after the first run of
the program) will look like this:
© Copyright 2006 National Semiconductor Corporation
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6.
The Screen should look like this:
.
The user can also select the 3904 diode or the
processor thermal diode called “90 nm”.
Local (on-chip) and remote temperatures should read
continuously. The user can experiment with the
different settings of Address BF.
7. If the user clicks the 06-FF tab the next screen
will look like this:
The user can experiment with the Mask settings. Also the
user can change the conversion rate. The next screen
shows the possibilities for the Conversion Rate.
© Copyright 2006 National Semiconductor Corporation
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8. If the user clicks on the Start Plot button a graph
box will appear and will graph the temperature. An
example is shown below
9. If the user selects the Start Log button the following
screen will appear. The user then enters the filename that
he chooses to log the data into.
© Copyright 2006 National Semiconductor Corporation
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2.1 Quick Start Diagram
Important! NO EXTERNAL POWER SUPPLY OR SIGNAL INPUTS ARE REQUIRED!
N/C
TCRIT#
N/C
USB Cable to
Computer
OS/A0
SCL
SDA
+3.3
JP2
LM95235
Computer
with
SensorEval
software
loaded
National Semiconductor
LM95235 Evaluation Board Rev. 1
© Copyright 2006 National Semiconductor Corporation
8
Power to the LM95235 Evaluation Board is taken
from the USB 5-Volt line. This +5 VDC is the input
to the on-board LM2950 low dropout voltage
regulator, which regulates the output voltage to +3.3
VDC. This output voltage powers the LM95235, the
on-board microcontroller, and the EEPROM chip
where the board ID information is stored.
3.0 Functional Description
The LM95235 Evaluation Board, along with the
SensorEval Software, provides the system designer
with a convenient way to learn about the operation of
the LM95235 Temperature Sensor chip. The user
simply has to install the SensorEval software on his
PC, run it, connect the USB cable from the PC to the
Evaluation Board, and the user can read the
temperatures. It’s that simple! The user doesn’t have
to provide any power or external signals to the
evaluation board.
The microcontroller provides the SMBus Clock
(SMBCLK) signal and the SMBus Data (SMBDAT)
signal to the LM95235 chip. This communication
between the LM95235 and the PC USB data lines is
controlled by the microcontroller. For all of the
details of this communication protocol see the latest
3.1 LM95235 Evaluation Board Connection Table
Connector Label
Pin
Description
Number
USB Cable Input. Connect the USB cable to this jack after
the SensorEval software has been loaded on the PC.
J1
N/A
1
VDD. The +3.3 VDC voltage supplied by the on-board
voltage regulator to the LM95235 VDD input pin. Do not
connect an external power supply to this pin!
2
3
SMBDAT. Data signal for the SMBus.
JP2
Output header provides
user with signals for test
purposes only.
SMBCLK. Clock signal for SMBus.
OS#/A0. When this pin is pulled low it enables the
Overtemperature Shutdown (OS) feature. When this pin is
pulled high it is the Address pin function.
Do not apply any
4
external power or
signals to any of the
pins on these headers!
5
6
7
No Connection.
T_Crit#. This is the signal that goes low when the Set
Temperature is exceeded.
No Connection.
J4
Connection to
3, 4
1, 2
Connect for D+ connection
temperature diodes
Do not apply any
external power or
signals to any of the
pins on these headers!
Connect for D- connection
© Copyright 2006 National Semiconductor Corporation
9
4.0 Software Installation and Operation
4.1 Installation
4.2 Operation
The CD provided in the LM95235 Evaluation Board Kit
contains the SensorEval software used to make the LM95235
Evaluation Board operate with the user’s PC. It is assumed
that the user will be using a PC with a Pentium® III or higher
processor and Microsoft Windows® XP/2000/98/ME
operating system.
Follow the following procedure for operation the LM95235
Evaluation Board using the SensorEval software:
1. Run the SensorEval program by either double-
clicking on the icon on the desktop or by selecting
Start, Program Files, National Semiconductor,
SensorEval.
2. Plug in the USB cable on both the PC and the
LM95235 Evaluation Board.
The software is installed as follows:
1. Insert the SensorEval CD into the CD drive of the
PC. See details in the readme.txt file.
2. The software manual, provided on the CD, may be
useful to the user during this process.
Follow the register setup steps given in section 2.0 Quick Start
of this User’s Guide. Make sure that you are following the
given procedure for the specific evaluation board you are
working with.
3. Follow all of the Installation instructions in the
windows as the SensorEval software is installing.
4. The installation process will put an icon on the PC
desktop so that the SensorEval program will run
when the icon is double-clicked.
Refer to the electrical schematic, layout and connector
diagrams for proper connections to external remote thermal
diodes.
© Copyright 2006 National Semiconductor Corporation
10
5.0 Electrical and Mechanical Specifications
5.1 Electrical Specifications
Power Requirements
The Board uses the +5.0 VDC and GND lines from the USB connection.
This +5.0 VDC voltage is regulated down to +3.3 VDC for board power.
* NO EXTERNAL POWER SUPPLY INPUTS ARE REQUIRED *
+5.0 ± 0.1 V,
100 mA max.
5.2 Electrical Schematic
+ 3.3 VDC
TP1
GND
Use a 0.1 uF capacitor for each
Vcc pin of U2 and Reserved_6 pin.
+ 3.3 VDC
C1
0.1uF
C2
0.1uF
C3
0.1uF
C4
0.1uF
C5
0.1uF
C6
0.1uF
R1
0
+ 3.3 VDC
TP2
GND
U1
Y1
12 MHz
LP2950CDT-3.3/TO252
1
3
C9
33pF
C10
33pF
IN
OUT
GND
R4
1M
C11
C12
C13
R2
1.5K
L1
R3
100k
R15
2.2uF
0.1uF
100 pF
1.5K
1 uH
C14
2.2uF
C15
0.1uF
C16
2.2uF
C17
0.1uF
TP3
GND
JP2
1
C18
0.1uF
Q1
LM95235
SMBCLK
+3.3 VDC
SCL
U3
MMBT3904/SOT
J3
USB-B
J4
HEADER 2x2
1
8
7
6
5
SCL
SDA
VDD
D+
3
2
4
5
6
7
28
24
25
18
RESET#
USBD-
1
2
35
4
2
3
1
C19
100 pF
2
3
4
SDA
VBUS
PB6/INT6
PB7/T2OUT
CTL2/AOUTFLAG
CTL0/AINFLAG
PC0/RxD0
SMBDAT
OS/A0
GND
R7 22
R9 22
R11 1.5K
36
37
41
43
44
OS/A0
OS/A0
D-
D-
Shunt to select the PCB
temperature diode.
TCRIT#
3
D+
USBD+
PC1/TxD0
TCRIT
TCRIT
OS/A0
4
5
6
45
GND
SHELL_1
SHELL_2
PC2/INT0#
PC3/INT1#
U2
DISCON#
46
HEADER 1X7
CY7C64603-52NC
+ 3.3 VDC
10
11
12
PA4/FWR#
PA5/FRD#
CLKOUT
R12
48
49
50
51
TP4
GND
PC4/T0
PC5/T1
PC6/WR#
PC7/RD#
1M
U4
AT24C02-10SI-2.7
1
8
7
6
5
R13
1.5K
R14
1.5K
C20
0.1uF
A0
Vcc
WP
2
A1
SCL
SDA
3
2
3
A2
SCL
SDA
SCL
SDA
4
Vss
SCL
SDA
Schematic of the LM95235 Evaluation Board
© Copyright 2006 National Semiconductor Corporation
11
5.3 Evaluation Board Layout
Figure 5.3 Layout diagram of the LM95235 Evaluation Board
(Note: socket and socket area not stuffed.)
© Copyright 2006 National Semiconductor Corporation
12
5.4 Bill of Materials for LM95235 Evaluation Board
Item
Qty
Reference
Part
PCB Footprint
1
11
C1,C2,C3,C4,C5,C6,
Capacitor, SMD, ceramic, 0.1uF
sm/c_0805
C12,C15,C17,C20
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
2
3
2
1
1
1
1
1
2
2
5
1
1
1
1
1
1
C9, C10
C11,C14,C16
Capacitor, SMD, ceramic, 33 pF
Capacitor, SMD, ceramic, 2.2 uF
Capacitor, SMD, ceramic, 100 pF
Connector, USB-B
sm/c_0805
sm/ct_3216_12
sm/c_0805
C13,C19
J3
J4
L1
Q1
tm/usb_typeb
blkcon.100/vh/tm1sqs/w.100/4
sm/l_1206
HEADER 2x2
Filter, 1uH, Stewart MI1206K900R-00
Transistor, SMD, MMBT3904/SOT
Resistor, SMD, 0 Ohms
sm/mmbt3904a
sm/r_0805
R1
R4,R12
R7,R9
R2,R11,R13,R14,R15
Resistor, SMD, 1M
Resistor, SMD, 22 Ohms
Resistor, SMD, 1.5K
sm/r_0805
sm/r_0805
sm/r_0805
sm/r_0805
R3
U1
U2
U4
U3
Y1
Resistor, SMD, 100k Ohms
IC, National LP2950CDT-3.3/TO252
IC, Cypress CY7C64613-52NC
IC, EPROM, Atmel AT24C02-10SI-2.7
LM95235CIMM
to252ab/dpak
sm/PQFP-52
sog.050/8/wg.244/l.200
sm/msop-8
Crystal, 12 MHz, Pletronics
2S1200G140
tm/hc-49
© Copyright 2006 National Semiconductor Corporation
13
5.4 Mechanical Specifications
5.4.1 Operating Mechanical and Environmental Specifications
Minimum
Typical
Maximum
Temperature
0°C
25°C
70°C
5.4.2 Evaluation Board Basic Dimensions
2.45 in/6.22 cm
3.25 in/8.76 cm
5.4.3 Electrostatic Discharge (ESD) Precautions
The user shall use ESD precautions as specified in National Semiconductor ESD control document
© Copyright 2006 National Semiconductor Corporation
14
BY USING THIS PRODUCT, YOU ARE AGREEING TO BE BOUND BY THE TERMS AND CONDITIONS OF
NATIONAL SEMICONDUCTOR'S END USER LICENSE AGREEMENT. DO NOT USE THIS PRODUCT UNTIL YOU
HAVE READ AND AGREED TO THE TERMS AND CONDITIONS OF THAT AGREEMENT. IF YOU DO NOT AGREE
WITH THEM, CONTACT THE VENDOR WITHIN TEN (10) DAYS OF RECEIPT FOR INSTRUCTIONS ON RETURN OF
THE UNUSED PRODUCT FOR A REFUND OF THE PURCHASE PRICE PAID, IF ANY.
The LM95235 Evaluation Boards are intended for product evaluation purposes only and are not
intended for resale to end consumers, are not authorized for such use and are not designed for
compliance with European EMC Directive 89/336/EEC, or for compliance with any other
electromagnetic compatibility requirements.
National Semiconductor Corporation does not assume any responsibility for use of any circuitry or
software supplied or described. No circuit patent licenses are implied.
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support or sustain life, and whose failure to
perform, when properly used in accordance
with instructions for use provided in the
labeling, can be reasonably expected to
result in a significant injury to the user.
2. A critical component is any component in a
life support device or system whose failure to
perform can be reasonably expected to cause
the failure of the life support device or system,
or to affect its safety or effectiveness.
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© Copyright 2006 National Semiconductor Corporation
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