Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1) (2)
Storage Temperature, T stg TO-CAN, TO-92 Package –60 150
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
ESD Ratings
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) ±2500 V
Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
Specified operating temperature: T MIN to
(1) For more information about traditional and new thermal metrics, see theIC Package Thermal Metricsapplication report,SPRA953.
(2) For additional thermal resistance information, seeTypical Application.
Thermal Information
RθJA Junction-to-ambient thermal resistance 400 180 220 90
R θJC(top) Junction-to-case (top) thermal resistance 24 — — — °C/W
(1) Tested Limits are ensured and 100% tested in production.
(2) Design Limits are ensured (but not 100% production tested) over the indicated temperature and supply voltage ranges These limits are not used to calculate outgoing quality levels.
(3) Accuracy is defined as the error between the output voltage and 10 mv/°C times the case temperature of the device, at specified conditions of voltage, current, and temperature (expressed in °C).
(4) Non-linearity is defined as the deviation of the output-voltage-versus-temperature curve from the best-fit straight line, over the rated temperature range of the device.
Regulation is assessed at a stable junction temperature through pulse testing with a low duty cycle To calculate the output variations caused by heating effects, one can multiply the internal dissipation by the thermal resistance.
(6) Quiescent current is defined in the circuit ofFigure 14.
Electrical Characteristics: LM35A, LM35CA Limits
Unless otherwise noted, these specifications apply:−55°C≤T J ≤150°C for the LM35 and LM35A;−40°C≤T J ≤110°C for the LM35C and LM35CA; and 0°C≤T J ≤100°C for the LM35D V S = 5 Vdc and I LOAD = 50μA, in the circuit ofFull-Range
Centigrade Temperature Sensor These specifications also apply from 2°C to T MAX in the circuit ofFigure 14.
Temperature coefficient of quiescent current
Minimum temperature for rate accuracy In circuit ofFigure 14, IL= 0 1.5 2 1.5 2 °C
Long term stability T J = T MAX , for 1000 hours ±0.08 ±0.08 °C
Electrical Characteristics: LM35A, LM35CA
Unless otherwise noted, these specifications apply:−55°C≤T J ≤150°C for the LM35 and LM35A;−40°C≤T J ≤110°C for the LM35C and LM35CA; and 0°C≤T J ≤100°C for the LM35D V S = 5 Vdc and I LOAD = 50μA, in the circuit ofFull-Range
Centigrade Temperature Sensor These specifications also apply from 2°C to T MAX in the circuit ofFigure 14.
PARAMETER TEST CONDITIONS LM35A LM35CA
MIN TYP MAX TYP TYP MAX UNIT
Electrical Characteristics: LM35A, LM35CA (continued)
Unless otherwise noted, these specifications apply:−55°C≤T J ≤150°C for the LM35 and LM35A;−40°C≤T J ≤110°C for the LM35C and LM35CA; and 0°C≤T J ≤100°C for the LM35D V S = 5 Vdc and I LOAD = 50μA, in the circuit ofFull-Range
Centigrade Temperature Sensor These specifications also apply from 2°C to T MAX in the circuit ofFigure 14.
PARAMETER TEST CONDITIONS LM35A LM35CA
MIN TYP MAX TYP TYP MAX UNIT
(6) Quiescent current is defined in the circuit ofFigure 14.
Temperature coefficient of quiescent current
Minimum temperature for rate accuracy
Long term stability TJ= TMAX, for 1000 hours ±0.08 ±0.08 °C
(1) Tested Limits are ensured and 100% tested in production.
(2) Design Limits are ensured (but not 100% production tested) over the indicated temperature and supply voltage ranges These limits are not used to calculate outgoing quality levels.
(3) Accuracy is defined as the error between the output voltage and 10 mv/°C times the case temperature of the device, at specified conditions of voltage, current, and temperature (expressed in °C).
(4) Non-linearity is defined as the deviation of the output-voltage-versus-temperature curve from the best-fit straight line, over the rated temperature range of the device.
Regulation is evaluated at a constant junction temperature through pulse testing with a low duty cycle The impact of heating on output can be determined by calculating the internal dissipation and multiplying it by the thermal resistance.
(6) Quiescent current is defined in the circuit ofFigure 14.
Electrical Characteristics: LM35, LM35C, LM35D Limits
Unless otherwise noted, these specifications apply:−55°C≤T J ≤150°C for the LM35 and LM35A;−40°C≤T J ≤110°C for the LM35C and LM35CA; and 0°C≤T J ≤100°C for the LM35D V S = 5 Vdc and I LOAD = 50μA, in the circuit ofFull-Range
Centigrade Temperature Sensor These specifications also apply from 2°C to T MAX in the circuit ofFigure 14.
Temperature coefficient of quiescent current
Minimum temperature for rate accuracy In circuit ofFigure 14, IL= 0 1.5 2 1.5 2 °C
Long term stability T J = T MAX , for 1000 hours ±0.08 ±0.08 °C
(1) Accuracy is defined as the error between the output voltage and 10 mv/°C times the case temperature of the device, at specified conditions of voltage, current, and temperature (expressed in °C).
(2) Tested Limits are ensured and 100% tested in production.
(3) Design Limits are ensured (but not 100% production tested) over the indicated temperature and supply voltage ranges These limits are not used to calculate outgoing quality levels.
(4) Non-linearity is defined as the deviation of the output-voltage-versus-temperature curve from the best-fit straight line, over the rated temperature range of the device.
Regulation is assessed at a constant junction temperature through pulse testing with a low duty cycle The impact of heating effects on output can be determined by calculating the internal dissipation and multiplying it by the thermal resistance.
Electrical Characteristics: LM35, LM35C, LM35D
Unless otherwise noted, these specifications apply:−55°C≤T J ≤150°C for the LM35 and LM35A;−40°C≤T J ≤110°C for the LM35C and LM35CA; and 0°C≤T J ≤100°C for the LM35D V S = 5 Vdc and I LOAD = 50μA, in the circuit ofFull-Range
Centigrade Temperature Sensor These specifications also apply from 2°C to T MAX in the circuit ofFigure 14.
PARAMETER TEST CONDITIONS LM35 LM35C, LM35D
MIN TYP MAX MIN TYP MAX UNIT
Electrical Characteristics: LM35, LM35C, LM35D (continued)
Unless otherwise noted, these specifications apply:−55°C≤T J ≤150°C for the LM35 and LM35A;−40°C≤T J ≤110°C for the LM35C and LM35CA; and 0°C≤T J ≤100°C for the LM35D V S = 5 Vdc and I LOAD = 50μA, in the circuit ofFull-Range
Centigrade Temperature Sensor These specifications also apply from 2°C to T MAX in the circuit ofFigure 14.
PARAMETER TEST CONDITIONS LM35 LM35C, LM35D
MIN TYP MAX MIN TYP MAX UNIT
(6) Quiescent current is defined in the circuit ofFigure 14.
Temperature coefficient of quiescent current
Minimum temperature for rate accuracy
Long term stability TJ= TMAX, for 1000 hours ±0.08 ±0.08 °C
QUI E S CE NT CU RR E NT ( A )
T HE RM A L RE S IS T A NC E ( ƒ C/W )
Typical Characteristics
Figure 1 Thermal Resistance Junction To Air Figure 2 Thermal Time Constant
Figure 3 Thermal Response In Still Air Figure 4 Thermal Response In Stirred Oil Bath
Figure 5 Minimum Supply Voltage vs Temperature Figure 6 Quiescent Current vs Temperature (in Circuit of
QUI E S CE NT CU RR E NT ( A )
Figure 7 Quiescent Current vs Temperature (in Circuit of
Full-Range Centigrade Temperature Sensor)
Figure 8 Accuracy vs Temperature (Ensured)
Figure 9 Accuracy vs Temperature (Ensured) Figure 10 Noise Voltage
Overview
The LM35-series temperature sensors are precision integrated circuits that provide an output voltage directly proportional to Centigrade temperatures, eliminating the need for users to subtract a large constant voltage as required by Kelvin-calibrated sensors They offer typical accuracies of ± 0.5 °C at room temperature and ± 0.75 °C across a wide range of −55°C to 150°C, without the need for external calibration With low output impedance and inherent calibration, the LM35 is easy to interface with control circuitry and operates efficiently on single or dual power supplies, drawing only 60 μA and resulting in minimal self-heating of less than 0.1°C The LM35 is available in various models, including the LM35C, which is rated for a temperature range of −40°C to 110°C with improved accuracy.
The temperature-sensing element is buffered by an amplifier before being delivered to the VOUT pin This amplifier features a straightforward class A output stage with a typical output impedance of 0.5 Ω, as illustrated in the Functional Block Diagram Consequently, the LM35 is designed to source current, with its sinking capability restricted to just 1 μA.
Feature Description
The accuracy specifications of the LM35 are given with respect to a simple linear transfer function:
• V OUT is the LM35 output voltage
Device Functional Modes
The only functional mode of the LM35 is that it has an analog output directly proportional to temperature.
HEAVY CAPACITIVE LOAD, WIRING, ETC.
2 k HEAVY CAPACITIVE LOAD, WIRING, ETC.
The information provided in the applications sections is not included in the TI component specification, and TI does not guarantee its accuracy or completeness It is the responsibility of TI's customers to assess the suitability of components for their specific applications Customers are encouraged to validate and test their design implementations to ensure proper system functionality.
Application Information
The features of the LM35 make it suitable for many general temperature sensing applications Multiple package options expand on it's flexibility.
The LM35 device, like many micropower circuits, has a limited capacity to handle heavy capacitive loads, managing up to 50 pF without additional precautions For heavier loads, it is advisable to isolate or decouple the load using a resistor Additionally, implementing a series R-C damper from the output to ground can enhance capacitance tolerance.
When using the LM35 device with a 200-Ω load resistor, it demonstrates immunity to wiring capacitance since the capacitance bypasses to ground rather than affecting the output However, performance can be compromised in environments with strong electromagnetic interference from sources like relays, motors, and radio transmitters, as wiring can act as an antenna and internal junctions may function as rectifiers To enhance performance in such conditions, it is advisable to implement a bypass capacitor from V IN to ground and a series R-C damper (such as 75 Ω in series with 0.2 or 1 μF) from the output to ground.
Figure 12 LM35 with Decoupling from Capacitive Load
Typical Application
Figure 14 Basic Centigrade Temperature Sensor (2 °C to 150 °C)
The LM35 temperature sensor is a straightforward device that delivers an analog output, making layout design considerations more critical than electrical specifications For comprehensive guidance, please consult the Layout section.
Figure 15 Accuracy vs Temperature (Ensured)
V OUT = 10 mV/°C (T AMBIENT = 10 °C) FROM t 5 °C TO + 40 °C
VOUT = 10 mV/°C (TAMBIENT = 1 °C) FROM + 2 °C TO + 40 °C v
VOUT = 10 mV/°C (TAMBIENT = 1 °C) FROM + 2 °C TO + 40 °C v
OR 10K RHEOSTAT FOR GAIN ADJUST
System Examples
Figure 16 Two-Wire Remote Temperature Sensor
Figure 17 Two-Wire Remote Temperature Sensor
Figure 18 Temperature Sensor, Single Supply
Figure 19 Two-Wire Remote Temperature Sensor
Figure 20 4-To-20 mA Current Source
Scale Thermometer (50°F to 80°F, for Example Shown)
Figure 24 Temperature to Digital Converter
Figure 25 Temperature to Digital Converter (Parallel TRI-STATE Outputs for Standard Data Bus to μP Interface) (128°C Full Scale)
Figure 26 Bar-Graph Temperature Display
Figure 27 LM35 With Voltage-To-Frequency Converter and Isolated Output (2°C to 150°C; 20 to 1500 Hz)
The LM35 sensor operates effectively within a broad power supply voltage range of 4-V to 30-V, making it suitable for various applications To enhance performance in noisy environments, Texas Instruments suggests incorporating a 0.1 μF capacitor from V+ to GND to bypass power supply noise, with larger capacitance values potentially necessary based on the level of noise present.
(1) Wakefield type 201, or 1-in disc of 0.02-in sheet brass, soldered to case, or similar.
(2) TO-92 and SOIC-8 packages glued and leads soldered to 1-in square of 1/16-in printed circuit board with 2-oz foil or similar.
Layout Guidelines
The LM35 temperature sensor can be easily mounted like other integrated-circuit sensors; simply adhere it to a surface using glue or cement, and it will measure the temperature with an accuracy of approximately 0.01°C of the surface temperature.
The 0.01°C proximity presumes that the ambient air temperature is almost the same as the surface temperature.
The temperature of the LM35 die is influenced by the surrounding air temperature, especially in the TO-92 plastic package If the air temperature significantly deviates from the surface temperature, the die's temperature will settle at an intermediate level between these two temperatures This effect is pronounced due to the copper leads in the TO-92 package, which serve as the primary thermal pathway, causing the die's temperature to align more closely with the air temperature than the surface temperature.
To minimize temperature discrepancies, ensure that the wiring from the LM35 device is maintained at the same temperature as the surface being measured A simple solution is to cover the wires with a bead of epoxy, which will help keep the leads and wires at the same temperature as the surface and prevent the LM35 die's temperature from being influenced by surrounding air temperature.
The TO-46 metal package is designed for durability, allowing it to be soldered to metal surfaces or pipes without risk of damage, provided the V− terminal is grounded For enhanced protection, the LM35 can be housed within a sealed metal tube and immersed in a bath or secured in a threaded hole To prevent leakage and corrosion, it is crucial to keep the LM35 and its wiring insulated and dry, especially in cold environments where condensation may occur Utilizing printed-circuit coatings, such as conformal coatings and epoxy paints or dips, can effectively safeguard the LM35 device and its connections from moisture-related damage.
To enhance response times in slowly-moving air, these devices are often soldered to lightweight heat fins that reduce the thermal time constant Additionally, incorporating a small thermal mass into the sensor ensures stable readings, effectively minimizing the impact of minor fluctuations in air temperature.
Table 2 Temperature Rise of LM35 Due To Self-heating (Thermal Resistance, R θJA )
(Clamped to metal, Infinite heat sink)
Layout Example
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Electrostatic Discharge Caution
To prevent electrostatic damage to MOS gates, it is crucial to ensure that devices with limited built-in ESD protection are stored or handled properly This can be achieved by shorting the leads together or placing the device in conductive foam during these processes.
Glossary
This glossary lists and explains terms, acronyms, and definitions.
12 Mechanical, Packaging, and Orderable Information
The following pages present the latest mechanical, packaging, and orderable information for the specified devices Please note that this data may change without prior notice, and the document may be revised accordingly For browser-based access to this data sheet, please consult the left-hand navigation.
LM35AH ACTIVE TO NDV 3 500 TBD Call TI Call TI -55 to 150 ( LM35AH, LM35AH)
LM35AH/NOPB ACTIVE TO NDV 3 500 Green (RoHS
Call TI Level-1-NA-UNLIM -55 to 150 ( LM35AH, LM35AH)
LM35CAH ACTIVE TO NDV 3 500 TBD Call TI Call TI -40 to 110 ( LM35CAH, LM35CAH
LM35CAH/NOPB ACTIVE TO NDV 3 500 Green (RoHS
Call TI Level-1-NA-UNLIM -40 to 110 ( LM35CAH, LM35CAH
LM35CAZ/LFT4 ACTIVE TO-92 LP 3 2000 Green (RoHS
CU SN N / A for Pkg Type LM35
LM35CAZ/NOPB ACTIVE TO-92 LP 3 1800 Green (RoHS
CU SN N / A for Pkg Type -40 to 110 LM35
LM35CH ACTIVE TO NDV 3 500 TBD Call TI Call TI -40 to 110 ( LM35CH, LM35CH)
LM35CH/NOPB ACTIVE TO NDV 3 500 Green (RoHS
Call TI Level-1-NA-UNLIM -40 to 110 ( LM35CH, LM35CH)
LM35CZ/LFT1 ACTIVE TO-92 LP 3 2000 Green (RoHS
CU SN N / A for Pkg Type LM35
LM35CZ/NOPB ACTIVE TO-92 LP 3 1800 Green (RoHS
CU SN N / A for Pkg Type -40 to 110 LM35
LM35DH ACTIVE TO NDV 3 1000 TBD Call TI Call TI 0 to 70 ( LM35DH, LM35DH)
LM35DH/NOPB ACTIVE TO NDV 3 1000 Green (RoHS
Call TI | POST-PLATE Level-1-NA-UNLIM 0 to 70 ( LM35DH, LM35DH)
LM35DM NRND SOIC D 8 95 TBD Call TI Call TI 0 to 100 LM35D
LM35DM/NOPB ACTIVE SOIC D 8 95 Green (RoHS
CU SN Level-1-260C-UNLIM 0 to 100 LM35D
LM35DZ/LFT1 ACTIVE TO-92 LP 3 2000 Green (RoHS
CU SN N / A for Pkg Type LM35
LM35DZ/LFT4 ACTIVE TO-92 LP 3 2000 Green (RoHS
CU SN N / A for Pkg Type LM35
LM35DZ/NOPB ACTIVE TO-92 LP 3 1800 Green (RoHS
CU SN N / A for Pkg Type 0 to 100 LM35
LM35H ACTIVE TO NDV 3 500 TBD Call TI Call TI -55 to 150 ( LM35H, LM35H)
LM35H/NOPB ACTIVE TO NDV 3 500 Green (RoHS
Call TI Level-1-NA-UNLIM -55 to 150 ( LM35H, LM35H)
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
TI defines "RoHS" as semiconductor products that comply with the latest EU RoHS regulations concerning all 10 RoHS substances, ensuring that these substances do not exceed 0.1% by weight in homogeneous materials Additionally, products designed for high-temperature soldering are suitable for specified lead-free processes and may be labeled as "Pb-Free" by TI.
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
TI defines "Green" as flame retardants containing Chlorine (Cl) and Bromine (Br) that comply with JS709B low halogen standards, specifically maintaining a threshold of less than 00ppm Additionally, flame retardants based on antimony trioxide must also adhere to this