LM35CA

LM35 LM35A LM35C LM35CA LM35D Precision Centigrade Temperature Sensors December 1994 LM35 LM35A LM35C LM35CA LM35D Precision Centigrade Temperature Sensors General Description The LM35 series are precision integrated-circuit temperature sensors whose output voltage is linearly proportional to the Celsius (Centigrade) temperature The LM35 thus has an advantage over linear temperature sensors calibrated in Kelvin as the user is not required to subtract a large constant voltage from its output to obtain convenient Centigrade scaling The LM35 does not require any external calibration or trimming to provide typical accuracies of g C at room temperature and g C over a full b55 to a 150 C temperature range Low cost is assured by trimming and calibration at the wafer level The LM35’s low output impedance linear output and precise inherent calibration make interfacing to readout or control circuitry especially easy It can be used with single power supplies or with plus and minus supplies As it draws only 60 mA from its supply it has very low self-heating less than 0 1 C in still air The LM35 is rated to operate over a b55 to a 150 C temperature range while the LM35C is rated for a b40 to a 110 C range (b10 with improved accuracy) The LM35 series is available packaged in hermetic TO-46 transistor packages while the LM35C LM35CA and LM35D are also available in the plastic TO-92 transistor package The LM35D is also available in an 8-lead surface mount small outline package and a plastic TO-202 package Features Y Y Y Y Y Y Y Y Y Y Y Calibrated directly in Celsius (Centigrade) Linear a 10 0 mV C scale factor 0 5 C accuracy guaranteeable (at a 25 C) Rated for full b55 to a 150 C range Suitable for remote applications Low cost due to wafer-level trimming Operates from 4 to 30 volts Less than 60 mA current drain Low self-heating 0 08 C in still air Nonlinearity only g C typical Low impedance output 0 1 X for 1 mA load Connection Diagrams TO-46 Metal Can Package TO-92 Plastic Package SO-8 Small Outline Molded Package TL H 5516 – 2 TL H 5516–1 TL H 5516 – 21 Case is connected to negative pin (GND) Order Number LM35H LM35AH LM35CH LM35CAH or LM35DH See NS Package Number H03H TO-202 Plastic Package Order Number LM35CZ LM35CAZ or LM35DZ See NS Package Number Z03A Top View N C e No Connection Order Number LM35DM See NS Package Number M08A Typical Applications TL H 5516 – 3 FIGURE 1 Basic Centigrade Temperature Sensor ( a 2 C to a 150 C) TL H 5516 – 4 Choose R1 e b VS 50 mA VOUT e a 1 500 mV at a 150 C e a 250 mV at a 25 C eb 550 mV at b 55 C TL H 5516–24 Order Number LM35DP See NS Package Number P03A TRI-STATE is a registered trademark of National Semiconductor Corporation C1995 National Semiconductor Corporation FIGURE 2 Full-Range Centigrade Temperature Sensor TL H 5516 RRD-B30M75 Printed in U S A Absolute Maximum Ratings (Note 10) If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications Supply Voltage a 35V to b 0 2V a 6V to b 1 0V Output Voltage Output Current 10 mA b 60 C to a 180 C Storage Temp TO-46 Package b 60 C to a 150 C TO-92 Package b 65 C to a 150 C SO-8 Package b 65 C to a 150 C TO-202 Package Lead Temp TO-46 Package (Soldering 10 seconds) 300 C TO-92 Package (Soldering 10 seconds) 260 C a 230 C TO-202 Package (Soldering 10 seconds) SO Package (Note 12) Vapor Phase (60 seconds) 215 C Infrared (15 seconds) 220 C ESD Susceptibility (Note 11) 2500V Specified Operating Temperature Range TMIN to TMAX (Note 2) b 55 C to a 150 C LM35 LM35A b 40 C to a 110 C LM35C LM35CA LM35D 0 C to a 100 C Electrical Characteristics (Note 1) (Note 6) LM35A Parameter Conditions Typical g0 2 g0 3 g0 4 g0 4 g 0 18 g1 0 g1 0 g 0 35 LM35CA Design Limit (Note 5) Typical g0 2 g0 3 g0 4 g0 4 g 0 15 g1 0 g1 5 g0 3 Tested Limit (Note 4) g0 5 Tested Limit (Note 4) g0 5 Design Limit (Note 5) g1 0 Units (Max ) C C C C C mV C mV mA mV mA mV V mV V mA mA mA mA mA mA mA C Accuracy (Note 7) TA e a 25 C TA eb10 C TA e TMAX TA e TMIN TMINsTAsTMAX TMINsTAsTMAX TA e a 25 C TMINsTAsTMAX TA e a 25 C 4VsVSs30V VS e a 5V a 25 C VS e a 5V VS e a 30V a 25 C VS e a 30V 4VsVSs30V a 25 C 4VsVSs30V Nonlinearity (Note 8) Sensor Gain (Average Slope) Load Regulation (Note 3) 0sILs1 mA Line Regulation (Note 3) Quiescent Current (Note 9) a 10 0 g0 4 g0 5 g 0 01 g 0 02 a9 9 a 10 1 g1 0 g3 0 g 0 05 g0 1 a 10 0 g0 4 g0 5 g 0 01 g 0 02 g 0 05 g1 0 a9 9 a 10 1 g3 0 g0 1 56 105 56 2 105 5 02 05 a 0 39 67 131 68 133 10 20 a0 5 56 91 56 2 91 5 02 05 a 0 39 67 114 68 116 10 20 a0 5 Change of Quiescent Current (Note 3) Temperature Coefficient of Quiescent Current Minimum Temperature for Rated Accuracy Long Term Stability In circuit of Figure 1 IL e 0 TJ e TMAX for 1000 hours a1 5 g 0 08 a2 0 a1 5 g 0 08 a2 0 C C Note 1 Unless otherwise noted these specifications apply b 55 C s TJ s a 150 C for the LM35 and LM35A b 40 s TJ s a 110 C for the LM35C and LM35CA and 0 s TJ s a 100 C for the LM35D VS e a 5Vdc and ILOAD e 50 mA in the circuit of Figure 2 These specifications also apply from a 2 C to TMAX in the circuit of Figure 1 Specifications in boldface apply over the full rated temperature range Note 2 Thermal resistance of the TO-46 package is 400 C W junction to ambient and 24 C W junction to case Thermal resistance of the TO-92 package is 180 C W junction to ambient Thermal resistance of the small outline molded package is 220 C W junction to ambient Thermal resistance of the TO-202 package is 85 C W junction to ambient For additional thermal resistance information see table in the Applications section 2 Electrical Characteristics (Note 1) (Note 6) Parameter Conditions (Continued) LM35 LM35C LM35D Design Limit (Note 5) Typical g0 4 g0 5 g1 5 g1 5 g0 8 g0 8 g0 6 g0 9 g0 9 g1 5 g2 0 g2 0 g0 5 Typical g0 4 g0 5 g0 8 g0 8 Tested Limit (Note 4) g1 0 Tested Limit (Note 4) g1 0 Design Limit (Note 5) g1 5 g1 5 g2 0 Units (Max ) C C C C C C C C mV C mV mA mV mA mV V mV V mA mA mA mA mA mA mA C Accuracy LM35 LM35C (Note 7) Accuracy LM35D (Note 7) Nonlinearity (Note 8) Sensor Gain (Average Slope) Load Regulation (Note 3) 0sILs1 mA Line Regulation (Note 3) Quiescent Current (Note 9) TA e a 25 C TA eb10 C TA e TMAX TA e TMIN TA e a 25 C TA e TMAX TA e TMIN TMINsTAsTMAX TMINsTAsTMAX TA e a 25 C TMINsTAsTMAX TA e a 25 C 4VsVSs30V VS e a 5V a 25 C VS e a 5V VS e a 30V a 25 C VS e a 30V 4VsVSs30V a 25 C 4VsVSs30V g0 3 g0 5 g0 2 a 10 0 g0 4 g0 5 g 0 01 g 0 02 a9 8 a 10 2 g2 0 g5 0 g0 1 g0 2 a 10 0 g0 4 g0 5 g 0 01 g 0 02 g0 1 g2 0 a9 8 a 10 2 g5 0 g0 2 56 105 56 2 105 5 02 05 a 0 39 80 158 82 161 20 30 a0 7 56 91 56 2 91 5 02 05 a 0 39 80 138 82 141 20 30 a0 7 Change of Quiescent Current (Note 3) Temperature Coefficient of Quiescent Current Minimum Temperature for Rated Accuracy Long Term Stability In circuit of Figure 1 IL e 0 TJ e TMAX for 1000 hours a1 5 g 0 08 a2 0 a1 5 g 0 08 a2 0 C C Note 3 Regulation is measured at constant junction temperature using pulse testing with a low duty cycle Changes in output due to heating effects can be computed by multiplying the internal dissipation by the thermal resistance Note 4 Tested Limits are guaranteed and 100% tested in production Note 5 Design Limits are guaranteed (but not 100% production tested) over the indicated temperature and supply voltage ranges These limits are not used to calculate outgoing quality levels Note 6 Specifications in boldface apply over the full rated temperature range Note 7 Accuracy is defined as the error between the output voltage and 10mv C times the device’s case temperature at specified conditions of voltage current and temperature (expressed in C) Note 8 Nonlinearity is defined as the deviation of the output-voltage-versus-temperature curve from the best-fit straight line over the device’s rated temperature range Note 9 Quiescent current is defined in the circuit of Figure 1 Note 10 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 See Note 1 Note 11 Human body model 100 pF discharged through a 1 5 kX resistor Note 12 See AN-450 ‘‘Surface Mounting Methods and Their Effect on Product Reliability’’ or the section titled ‘‘Surface Mount’’ found in a current National Semiconductor Linear Data Book for other methods of soldering surface mount devices 3 Typical Performance Characteristics Thermal Resistance Junction to Air Thermal Time Constant Thermal Response in Still Air Thermal Response in Stirred Oil Bath Minimum Supply Voltage vs Temperature Quiescent Current vs Temperature (In Circuit of Figure 1 ) TL H 5516 – 17 Quiescent Current vs Temperature (In Circuit of Figure 2 ) Accuracy vs Temperature (Guaranteed) Accuracy vs Temperature (Guaranteed) TL H 5516 – 18 Noise Voltage Start-Up Response TL H 5516 – 22 4 Applications The LM35 can be applied easily in the same way as other integrated-circuit temperature sensors It can be glued or cemented to a surface and its temperature will be within about 0 01 C of the surface temperature This presumes that the ambient air temperature is almost the same as the surface temperature if the air temperature were much higher or lower than the surface temperature the actual temperature of the LM35 die would be at an intermediate temperature between the surface temperature and the air temperature This is expecially true for the TO-92 plastic package where the copper leads are the principal thermal path to carry heat into the device so its temperature might be closer to the air temperature than to the surface temperature To minimize this problem be sure that the wiring to the LM35 as it leaves the device is held at the same temperature as the surface of interest The easiest way to do this is to cover up these wires with a bead of epoxy which will insure that the leads and wires are all at the same temperature as the surface and that the LM35 die’s temperature will not be affected by the air temperature TO-46 TO-46 no heat sink small heat fin 100 C W 400 C W 40 C W 100 C W 40 C W 100 C W 30 C W 50 C W (24 C W) The TO-46 metal package can also be soldered to a metal surface or pipe without damage Of course in that case the Vb terminal of the circuit will be grounded to that metal Alternatively the LM35 can be mounted inside a sealed-end metal tube and can then be dipped into a bath or screwed into a threaded hole in a tank As with any IC the LM35 and accompanying wiring and circuits must be kept insulated and dry to avoid leakage and corrosion This is especially true if the circuit may operate at cold temperatures where condensation can occur Printed-circuit coatings and varnishes such as Humiseal and epoxy paints or dips are often used to insure that moisture cannot corrode the LM35 or its connections These devices are sometimes soldered to a small lightweight heat fin to decrease the thermal time constant and speed up the response in slowly-moving air On the other hand a small thermal mass may be added to the sensor to give the steadiest reading despite small deviations in the air temperature Temperature Rise of LM35 Due To Self-heating (Thermal Resistance) TO-92 TO-92 no heat sink small heat fin 180 C W 140 C W 90 C W 70 C W 90 C W 70 C W 45 C W 40 C W SO-8 SO-8 no heat sink small heat fin 220 C W 110 C W 105 C W 90 C W TO-202 TO-202 no heat sink small heat fin 85 C W 60 C W 25 C W 40 C W Still air Moving air Still oil Stirred oil (Clamped to metal Infinite heat sink) (55 C W) (23 C W) Wakefield type 201 or 1 disc of 0 020 sheet brass soldered to case or similar TO-92 and SO-8 packages glued and leads soldered to 1 square of printed circuit board with 2 oz foil or similar Typical Applications (Continued) TL H 5516 – 19 FIGURE 3 LM35 with Decoupling from Capacitive Load TL H 5516 – 20 FIGURE 4 LM35 with R-C Damper CAPACITIVE LOADS Like most micropower circuits the LM35 has a limited ability to drive heavy capacitive loads The LM35 by itself is able to drive 50 pf without special precautions If heavier loads are anticipated it is easy to isolate or decouple the load with a resistor see Figure 3 Or you can improve the tolerance of capacitance with a series R-C damper from output to ground see Figure 4 When the LM35 is applied with a 200X load resistor as shown in Figure 5 6 or 8 it is relatively immune to wiring capacitance because the capacitance forms a bypass from ground to input not on the output However as with any linear circuit connected to wires in a hostile environment its performance can be affected adversely by intense electromagnetic sources such as relays radio transmitters motors with arcing brushes SCR transients etc as its wiring can act as a receiving antenna and its internal junctions can act as rectifiers For best results in such cases a bypass capacitor from VIN to ground and a series R-C damper such as 75X in series with 0 2 or 1 mF from output to ground are often useful These are shown in Figures 13 14 and 16 5 Typical Applications (Continued) TL H 5516 – 6 FIGURE 6 Two-Wire Remote Temperature Sensor (Output Referred to Ground) TL H 5516–5 FIGURE 5 Two-Wire Remote Temperature Sensor (Grounded Sensor) TL H 5516–7 FIGURE 7 Temperature Sensor Single Supply b55 to a 150 C TL H 5516 – 8 FIGURE 8 Two-Wire Remote Temperature Sensor (Output Referred to Ground) TL H 5516–9 FIGURE 9 4-To-20 mA Current Source (0 C to a 100 C) TL H 5516 – 10 FIGURE 10 Fahrenheit Thermometer 6 Typical Applications (Continued) TL H 5516– 11 FIGURE 11 Centigrade Thermometer (Analog Meter) TL H 5516 – 12 FIGURE 12 Expanded Scale Thermometer (50 to 80 Fahrenheit for Example Shown) TL H 5516 – 13 FIGURE 13 Temperature To Digital Converter (Serial Output) ( a 128 C Full Scale) TL H 5516 – 14 FIGURE 14 Temperature To Digital Converter (Parallel TRI-STATE Outputs for Standard Data Bus to mP Interface) (128 C Full Scale) 7 Typical Applications (Continued) TL H 5516 – 16 e 1% or 2% film resistor -Trim RB for VB e 3 075V -Trim RC for VC e 1 955V -Trim RA for VA e 0 075V a 100mV C c Tambient -Example VA e 2 275V at 22 C FIGURE 15 Bar-Graph Temperature Display (Dot Mode) TL H 5516 – 15 FIGURE 16 LM35 With Voltage-To-Frequency Converter And Isolated Output (2 C to a 150 C 20 Hz to 1500 Hz) 8 Block Diagram TL H 5516 – 23 9 Physical Dimensions inches (millimeters) TO-46 Metal Can Package (H) Order Number LM35H LM35AH LM35CH LM35CAH or LM35DH NS Package Number H03H SO-8 Molded Small Outline Package (M) Order Number LM35DM NS Package Number M08A 10 Physical Dimensions inches (millimeters) (Continued) Power Package TO-202 (P) Order Number LM35DP NS Package Number P03A 11 LM35 LM35A LM35C LM35CA LM35D Precision Centigrade Temperature Sensors Physical Dimensions inches (millimeters) (Continued) TO-92 Plastic Package (Z) Order Number LM35CZ LM35CAZ or LM35DZ NS Package Number Z03A LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION As used herein 1 Life support devices or systems are devices or systems which (a) are intended for surgical implant into the body or (b) 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 National Semiconductor Corporation 2900 Semiconductor Drive P O Box 58090 Santa Clara CA 95052-8090 Tel 1(800) 272-9959 TWX (910) 339-9240 National Semiconductor GmbH Livry-Gargan-Str 10 D-82256 F4urstenfeldbruck Germany Tel (81-41) 35-0 Telex 527649 Fax (81-41) 35-1 National Semiconductor Japan Ltd Sumitomo Chemical Engineering Center Bldg 7F 1-7-1 Nakase Mihama-Ku Chiba-City Ciba Prefecture 261 Tel (043) 299-2300 Fax (043) 299-2500 2 A critical component is any component of 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 National Semiconductor Hong Kong Ltd 13th Floor Straight Block Ocean Centre 5 Canton Rd Tsimshatsui Kowloon Hong Kong Tel (852) 2737-1600 Fax (852) 2736-9960 National Semiconductores Do Brazil Ltda Rue Deputado Lacorda Franco 120-3A Sao Paulo-SP Brazil 05418-000 Tel (55-11) 212-5066 Telex 391-1131931 NSBR BR Fax (55-11) 212-1181 National Semiconductor (Australia) Pty Ltd Building 16 Business Park Drive Monash Business Park Nottinghill Melbourne Victoria 3168 Australia Tel (3) 558-9999 Fax (3) 558-9998 National does not assume any responsibility for use of any circuitry described no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications