LM75
Digital Temperature Sensor and Thermal Watchdog with Two-Wire Interface
General Description
The LM75is a temperature sensor,Delta-Sigma analog-to-digital converter,and digital over-temperature detector with I 2C ®interface.The host can query the LM75at any time to read temperature.The open-drain Overtemperature Shut-down (O.S.)output becomes active when the temperature exceeds a programmable limit.This pin can operate in either “Comparator”or “Interrupt”mode.
The host can program both the temperature alarm threshold (T OS )and the temperature at which the alarm condition goes away (T HYST ).In addition,the host can read back the con-tents of the LM75’s T OS and T HYST registers.Three pins (A0,A1,A2)are available for address selection.The sensor powers up in Comparator mode with default thresholds of 80˚C T OS and 75˚C T HYST .
The LM75’s 3.0V to 5.5V supply voltage range,low supply current and I 2C interface make it ideal for a wide range of applications.These include thermal management and pro-tection applications in personal computers,electronic test equipment,and office electronics.
Features
n SOP-8and Mini SOP-8(MSOP)packages save space n I 2C Bus interface
n Separate open-drain output pin operates as interrupt or comparator/thermostat output
n Register readback capability
n Power up defaults permit stand-alone operation as thermostat
n Shutdown mode to minimize power consumption n Up to 8LM75s can be connected to a single bus n UL Recognized Component
Key Specifications
j Supply Voltage    3.0V to 5.5V
j Supply Current
operating 250µA (typ)1mA (max)shutdown
4µA (typ)
j Temperature Accuracy −25˚C to 100˚C ±2˚C(max)−55˚C to 125˚C
±3˚C(max)
Applications
n System Thermal Management n Personal Computers n Office Electronics
ndegrade
Electronic Test Equipment
Simplified Block Diagram
01265801
I 2C ®is a registered trademark of Philips Corporation.
February 2004
LM75Digital Temperature Sensor and Thermal Watchdog with Two-Wire Interface
©2004National Semiconductor Corporation DS012658www.national
Connection Diagram
SOP-8and Mini SOP-8
01265802
Ordering Information
Order Number Package Marking NS Package Number Supply Voltage Transport Media Noise Filter on SDA and
SCL LM75BIM-3LM75BIM-3M08A (SOP-8)  3.3V 95Units in Rail
Yes LM75BIMX-3LM75BIM-3M08A (SOP-8)  3.3V 2500Units on Tape and Reel Yes LM75BIMM-3T01B MUA08A (MSOP-8)  3.3V 1000Units on Tape and Reel Yes LM75BIMMX-3T01B MUA08A (MSOP-8)  3.3V 3500Units on Tape and Reel Yes LM75BIM-5LM75BIM-5M08A (SOP-8)5V 95Units in Rail
Yes LM75BIMX-5LM75BIM-5M08A (SOP-8)5V 2500Units on Tape and Reel Yes LM75BIMM-5T00B MUA08A (MSOP-8)5V 1000Units on Tape and Reel Yes LM75BIMMX-5T00B MUA08A (MSOP-8)5V 3500Units on Tape and Reel Yes
LM75CIM-3LM75CIM-3M08A (SOP-8)  3.3V 95Units in Rail
Not Available LM75CIMX-3LM75CIM-3M08A (SOP-8)  3.3V 2500Units on Tape and Reel Not Available LM75CIMM-3T01C MUA08A (MSOP-8)  3.3V 1000Units on Tape and Reel Not Available LM75CIMMX-3T01C MUA08A (MSOP-8)  3.3V 3500Units on Tape and Reel Not Available LM75CIM-5LM75CIM-5M08A (SOP-8)5V 95Units in Rail
Not Available LM75CIMX-5LM75CIM-5M08A (SOP-8)5V 2500Units on Tape and Reel Not Available LM75CIMM-5T00C MUA08A (MSOP-8)5V 1000Units on Tape and Reel Not Available LM75CIMMX-5
T00C
MUA08A (MSOP-8)
5V
3500Units on Tape and Reel
Not Available
Pin Description
Label Pin #Function
Typical Connection
SDA 1I 2C Serial Bi-Directional Data Line.Open Drain.
From Controller,tied to a pull-up SCL 2I 2C Clock Input
From Controller
O.S.3Overtemperature Shutdown Open Drain Output Pull–up Resistor,Controller Interrupt Line GND 4Power Supply Ground Ground
+V S
8
Positive Supply Voltage Input
DC Voltage from 3V to 5.5V;0.1µF bypass capacitor with 10µF bulk capacitance in the near vicinity
A0–A27,6,5User-Set I 2C Address Inputs
Ground (Low,“0”)or +V S (High,“1”)
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LM75 Pin Description(Continued)
01265803
FIGURE1.Typical Application
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Absolute Maximum Ratings (Note 1)
Supply Voltage −0.3V to 6.5V
Voltage at any Pin
−0.3V to +V S +0.3V
Input Current at any Pin (Note 2)5mA Package Input Current (Note 2)20mA O.S.Output Sink Current 10mA O.S.Output Voltage    6.5V
Storage Temperature
−65˚C to +150˚C
Soldering Information,Lead Temperature
SOP and MSOP Package (Note 3)Vapor Phase (60seconds)Infrared (15seconds)
215˚C 220˚C
ESD Susceptibility (Note 4)LM75B LM75C Human Body Model 2500V 1500V Machine Model
250V
100V
Operating Ratings
Specified Temperature Range T MIN to T MAX (Note 5)
−55˚C to +125˚C Supply Voltage Range (+V S )
+3.0V to +5.5V
Temperature-to-Digital Converter Characteristics
Unless otherwise noted,these specifications apply for +V S =+5Vdc for LM75BIM-5,LM75BIMM-5,LM75CIM-5,and
LM75CIMM-5and +V S =+3.3Vdc for LM75BIM-3,LM75BIMM-3,LM75CIM-3,and LM75CIMM-3(Note 6).Boldface limits apply for T A =T J =T MIN to T MAX ;all other limits T A =T J =+25˚C,unless otherwise noted.
Parameter
Conditions
Typical (Note 12)Limits (Note 7)Units (Limit)Accuracy T A =−25˚C to +100˚C ±2.0˚C (max)T A =−55˚C to +125˚C
±3.0
˚C (max)Resolution
9Bits Temperature Conversion Time (Note 8)100ms
Quiescent Current
LM75B
I 2
C Inactive
0.250.5
mA (max)
Shutdown Mode,+V S =3V 4µA Shutdown Mode,+V S =5V
6µA LM75C
I 2C Inactive
0.25  1.0mA (max)
Shutdown Mode,+V S =3V 4µA Shutdown Mode,+V S =5V
6
µA O.S.Output Saturation Voltage I OUT =4.0mA 0.8V (max)
(Note 9)O.S.Delay
(Note 10)1Conversions (min)6
Conversions (max)
T OS Default Temperature (Note 11)80˚C T HYST Default Temperature
(Note 11)
75
˚C
Logic Electrical Characteristics
DIGITAL DC CHARACTERISTICS Unless otherwise noted,these specifications apply for +V S =+5Vdc for LM75BIM-5,LM75BIMM-5,LM75CIM-5,and LM75CIMM-5and +V S =+3.3Vdc for LM75BIM-3,LM75BIMM-3,LM75CIM-3,and
LM75CIMM-3(Note 6).Boldface limits apply for T A =T J =T MIN to T MAX ;all other limits T A =T J =+25˚C,unless otherwise noted.Symbol Parameter
Conditions
Typical (Note 12)Limits (Note 7)Units (Limit)V IN(1)Logical “1”Input Voltage +V S x 0.7V (min)+V S +0.5V (max)V IN(0)Logical “0”Input Voltage −0.3V (min)+V S x 0.3
V (max)I IN(1)Logical “1”Input Current V IN =5V 0.005  1.0µA (max)I IN(0)Logical “0”Input Current V IN =0V −0.005−1.0µA (max)C IN All Digital Inputs
20
pF I OH High Level Output Current V OH =5V 100µA (max)V OL Low Level Output Voltage I OL =3mA 0.4V (max)t OF
Output Fall Time
C L =400pF
250
ns (max)
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Logic Electrical Characteristics(Continued)
DIGITAL DC CHARACTERISTICS Unless otherwise noted,these specifications apply for+V S=+5Vdc for LM75BIM-5,
LM75BIMM-5,LM75CIM-5,and LM75CIMM-5and+V S=+3.3Vdc for LM75BIM-3,LM75BIMM-3,LM75CIM-3,and
LM75CIMM-3(Note6).Boldface limits apply for T A=T J=T MIN to T MAX;all other limits T A=T J=+25˚C,unless otherwise noted.
Symbol Parameter Conditions
Typical
(Note12)
Limits
(Note7)
Units
(Limit)
I O=3mA
I2C DIGITAL SWITCHING CHARACTERISTICS Unless otherwise noted,these specifications apply for+V S=+5Vdc for
LM75BIM-5,LM75BIMM-5,LM75CIM-5,and LM75CIMM-5and+V S=+3.3Vdc for LM75BIM-3,LM75BIMM-3,LM75CIM-3, and LM75CIMM-3.C L(load capacitance)on output lines=80pF unless otherwise specified.Boldface limits apply for T A= T J=T MIN to T MAX;all other limits T A=T J=+25˚C,
unless otherwise noted.The switching characteristics of the LM75fully meet or exceed the published specifications of the I2C bus.The following parameters are the timing relationships between SCL and SDA signals related to the LM75.They are not the I2C bus specifications.
Symbol Parameter Conditions
Typical
(Note12)
Limits
(Note7)
Units
(Limit)
t1SCL(Clock)Period  2.5µs(min) t2Data in Set-Up Time to SCL High100ns(min) t3Data Out Stable after SCL Low0ns(min) t4SDA Low Set-Up Time to SCL Low(Start Condition)100ns(min) t5SDA High Hold Time after SCL High(Stop Condition)100ns(min)
t TIMEOUT SDA Time Low for Reset of Serial Interface(Note13)LM75B75
325ms(min) ms(max)
LM75C Not
Applicable
01265804
Note1:Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.DC and AC electrical specifications do not apply when operating
the device beyond its rated operating conditions.
Note2:When the input voltage(V I)at any pin exceeds the power supplies(V I<GND or V I>+V S)the current at that pin should be limited to5mA.The20mA maximum package input current rating limits the number of pins that can safely exceedthe power supplies with an input current of5mA to four.
Note3:See AN-450“Surface Mounting Methods and Their Effect on Product Reliability”or the section t
itled“Surface Mount”found in a current National Semiconductor Linear Data Book for other methods of soldering surface mount devices.
Note4:Human body model,100pF discharged through a1.5kΩresistor.Machine model,200pF discharged directly into each pin.
LM75
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