Texas Instruments LM75AEB User manual

User’s Guide
July 2012
LM75AEB User’s Guide
July2012 LM75AEB User’s Guide 1
CONTENTS
1
INTRODUCTION....................................................................................................... 1
2 SETUP....................................................................................................................... 1
3 BOARD LAYOUT ..................................................................................................... 8
4 SCHEMATIC........................................................................................................... 10
LIST OF FIGURES
1 I2C 7-bit Slave Address............................................................................................. 2
2 Three Least Significant Bits.......................................................................................2
3 LM75AEB Board Block Diagram................................................................................ 2
4 Top Assembly Layer.................................................................................................. 4
5 Top Layer Routing ..................................................................................................... 5
6 Bottom Layer Routing................................................................................................ 5
7 LM75AEB Schematic................................................................................................. 6
LIST OF TABLES
1 Device and Package Configurations.......................................................................... 1
2 I2C Address User Setting .......................................................................................... 2
3 LM75AEB Bill of Materials ....................................................................................... 11
1. Introduction
The Texas Instruments LM75AEB evaluation board (EB) helps designers evaluate the operation and
performance of the LM75A, an industry-standard digital temperature sensor with an integrated Sigma-Delta
analog-to-digital converter and I
2
C interface. The LM75A provides 9-bit digital temperature readings with an
accuracy of ±2°C from -25°C to 100°C and ±3°C over -55°C to 125°C.
The EVM contains one Digital Temperature Sensor (See Table 1).
Table 1: Device and Package Configurations
TEMP SENSOR IC PACKAGE
U6A1 LM75AIM SOP-8
2. Setup
This section describes the jumpers and connectors on the LM75AEB as well and how to properly connect, set
up and use the LM75AEB.

Setup
2 LM75AEB User’s Guide July 2012
2.1. Input/Output Connector Description
JP2 – Output is a header that allows user to probe the LM75AIM’s VDD, GND, A0, A1, A2, OS#, and I
2
C
pins.
JP4 – VDD is the power input terminal for the LM75AIM. The jumper terminal provides power to LM75AIM
VDD pin.
JP5 – A0 is bit 0 of the three least significant bits of the I2C slave address. At default, this jumper is pulling
high, and jumping the two terminals allows setting A0 low.
JP6 – A1 is bit 1 of the three least significant bits of the I2C slave address. At default, this jumper is pulling
high, and jumping the two terminals allows setting A1 low.
JP7 – A2 is bit 2 of the three least significant bits of the I2C slave address. At default, this jumper is pulling
high, and jumping the two terminals allows setting A2 low.
1001A2A1A0
MSBLSB
Figure 1: 7-bit Slave Address
JP5JP6JP7
A0A1A2
Figure 2: Three Significant Bits
A2A1A0
000
001
010
011
100
101
110
111
Table 1: I2C Address User Setting Input

Setup
3 LM75AEB User’s Guide SNIU007A July 2012
2.2. Setup
To ensure that you are using the latest version of SensorEval software, you can download from our website
at http://www.ti.com/tool/sensoreval. You must install the SensorEval software, before you connect
theLM75AEB to your PC.
To install the SensorEval Software:
•Click this link http://www.ti.com/tool/sensoreval then click on the red “download” button and click the
“Save” button to save the file to the known directory.
•To open the ZIP file you just download click on the “Open” button

Setup
4 LM75AEB User’s Guide July 2012
•Uncompress the file that you downloaded into a known directory, and run the
SensorEval_1.2.0_Setup.exe file
•When you see the Welcome screen as shown below, follow the instructions by clicking the “Next”
button on the screen to install the software
•When you finish the installation, please click “Finish” button

Setup
5 LM75AEB User’s Guide SNIU007A July 2012
•Before you launch the SensorEval software, connect LM75AEB device to one free USB port of your
PC. The “New Hardware” screen appears and click the “Next” button.
•A warning sign appears. Click “Continue Anyway” button

Setup
6 LM75AEB User’s Guide July 2012
2.3. Operation
For proper operation of the LM75AEB, JP4 should be jumpered. This will allow the LM75A’s VDD to be
sourced from an on-board 3.3V regulator. Jumping JP5 and JP6 will allow configuring the I2C slave address
to 4Ch.
For this quick start, connect the following jumpers:
1. JP4 to short
2. JP5 to short
3. JP6 to short
Figure 3: LM75AEB Board Block Diagram
USB
Input
EEPROM
Circuit
Voltage
Regulato
r
Circuit
Microcontrolle
r
Circuitry
USB D +
USB D
-
+ 5. 0 VDC GND
+ 3. 3 VDC
VDD
GND
GND
SCL
SDA
OS#
U6A1
LM
75AEB
JP6
A
1
JP5
A
0 JP7
A
2
GND
A
0
A
1
A
2
SDA
SCL

Setup
7 LM75AEB User’s Guide SNIU007A July 2012
•To run the SensorEval software, click the icon on the desktop. The dialog box appears to select the
definition file of LM75.
•A confirm screen appears. Click “OK” button.

Setup
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•The SensorEval software will populated based on the LM75’s definition file.
•Select the I2C Addr as “4c”
•Select the Read Cont as “All Regs”. This will read the values continuously.
•Changing the value of LM75A’s registers by clicking the white textbox on the Register Bits column

Board Layout
9 LM75AEB User’s Guide SNIU007A July 2012
3. Board Layout
Figure 4, Figure 5, and Figure 6 show the board layout for the LM75AEB. The EVM offers resistors,
capacitors, eeprom, microcontroller and jumpers to set three least significant bits of I2C slave address to run
the LM75AIM temperature sensor.
The LM75AEB have two additional package footprints MSOP-8 and LLP-8.
Figure 4: Top Assembly Layer

Board Layout
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Figure 5: Top Layer Routing
Figure 6: Bottom Layer Routing