LM335Z

LM135/LM235/LM335, LM135A/LM235A/LM335A Precision Temperature Sensors November 2000 LM135/LM235/LM335, LM135A/LM235A/LM335A Precision Temperature Sensors General Description The LM135 series are precision, easily-calibrated, integrated circuit temperature sensors. Operating as a 2-terminal zener, the LM135 has a breakdown voltage directly proportional to absolute temperature at +10 mV/˚K. With less than 1Ω dynamic impedance the device operates over a current range of 400 µA to 5 mA with virtually no change in performance. When calibrated at 25˚C the LM135 has typically less than 1˚C error over a 100˚C temperature range. Unlike other sensors the LM135 has a linear output. Applications for the LM135 include almost any type of temperature sensing over a −55˚C to +150˚C temperature range. The low impedance and linear output make interfacing to readout or control circuitry especially easy. The LM135 operates over a −55˚C to +150˚C temperature range while the LM235 operates over a −40˚C to +125˚C temperature range. The LM335 operates from −40˚C to +100˚C. The LM135/LM235/LM335 are available packaged in hermetic TO-46 transistor packages while the LM335 is also available in plastic TO-92 packages. Features n n n n n n n n Directly calibrated in ˚Kelvin 1˚C initial accuracy available Operates from 400 µA to 5 mA Less than 1Ω dynamic impedance Easily calibrated Wide operating temperature range 200˚C overrange Low cost Schematic Diagram DS005698-1 © 2000 National Semiconductor Corporation DS005698 www.national.com LM135/LM235/LM335, LM135A/LM235A/LM335A Connection Diagrams TO-92 Plastic Package SO-8 Surface Mount Package TO-46 Metal Can Package* DS005698-8 Bottom View Order Number LM335Z or LM335AZ See NS Package Number Z03A DS005698-26 DS005698-25 *Case is connected to negative pin Order Number LM335M See NS Package Number M08A Bottom View Order Number LM135H, LM135H-MIL, LM235H, LM335H, LM135AH, LM235AH or LM335AH See NS Package Number H03H www.national.com 2 LM135/LM235/LM335, LM135A/LM235A/LM335A Absolute Maximum Ratings (Note 4) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Reverse Current Forward Current Storage Temperature TO-46 Package TO-92 Package SO-8 Package 15 mA 10 mA −60˚C to +180˚C −60˚C to +150˚C −65˚C to +150˚C Specified Operating Temp. Range Continuous LM135, LM135A −55˚C to +150˚C LM235, LM235A −40˚C to +125˚C LM335, LM335A −40˚C to +100˚C Lead Temp. (Soldering, 10 seconds) TO-92 Package: TO-46 Package: SO-8 Package: Vapor Phase (60 seconds): Infrared (15 seconds): Intermittent (Note 2) 150˚C to 200˚C 125˚C to 150˚C 100˚C to 125˚C 260˚C 300˚C 300˚C 215˚C 220˚C Temperature Accuracy (Note 1) LM135/LM235, LM135A/LM235A Parameter Operating Output Voltage Uncalibrated Temperature Error Uncalibrated Temperature Error Temperature Error with 25˚C Calibration Calibrated Error at Extended Temperatures Non-Linearity IR = 1 mA 0.3 0.5 0.3 1 ˚C TC = TMAX (Intermittent) 2 2 ˚C Conditions TC = 25˚C, IR = 1 mA TC = 25˚C, IR = 1 mA TMIN ≤ TC ≤ TMAX, IR = 1 mA TMIN ≤ TC ≤ TMAX, IR = 1 mA LM135A/LM235A Min 2.97 Typ 2.98 0.5 1.3 0.3 Max 2.99 1 2.7 1 LM135/LM235 Min 2.95 Typ 2.98 1 2 0.5 Max 3.01 3 5 1.5 V ˚C ˚C ˚C Units Temperature Accuracy (Note 1) LM335, LM335A Parameter Operating Output Voltage Uncalibrated Temperature Error Uncalibrated Temperature Error Temperature Error with 25˚C Calibration Calibrated Error at Extended Temperatures Non-Linearity IR = 1 mA 0.3 1.5 0.3 1.5 ˚C TC = TMAX (Intermittent) 2 2 ˚C Conditions Min TC = 25˚C, IR = 1 mA TC = 25˚C, IR = 1 mA TMIN ≤ TC ≤ TMAX, IR = 1 mA TMIN ≤ TC ≤ TMAX, IR = 1 mA 2.95 LM335A Typ 2.98 1 2 0.5 Max 3.01 3 5 1 Min 2.92 LM335 Typ 2.98 2 4 1 Max 3.04 6 9 2 V ˚C ˚C ˚C Units Electrical Characteristics (Note 1) LM135/LM235 Parameter Operating Output Voltage Change with Current Dynamic Impedance Output Voltage Temperature Coefficient Time Constant Still Air 100 ft/Min Air Stirred Oil Time Stability TC =125˚C 80 10 1 0.2 80 10 1 0.2 sec sec sec ˚C/khr Conditions 400 µA≤IR≤5 mA At Constant Temperature IR =1 mA 0.5 +10 0.6 +10 Ω mV/˚C LM135A/LM235A Min Typ 2.5 Max 10 Min LM335 LM335A Typ 3 Max 14 mV Units 3 www.national.com LM135/LM235/LM335, LM135A/LM235A/LM335A Electrical Characteristics (Note 1) Note 3: (Continued) Note 1: Accuracy measurements are made in a well-stirred oil bath. For other conditions, self heating must be considered. Note 2: Continuous operation at these temperatures for 10,000 hours for H package and 5,000 hours for Z package may decrease life expectancy of the device. Thermal Resistance θJA (junction to ambient) θJC (junction to case) TO-92 202˚C/W 170˚C/W TO-46 400˚C/W N/A SO-8 165˚C/W N/A Note 4: Refer to RETS135H for military specifications. Typical Performance Characteristics Reverse Voltage Change Calibrated Error Reverse Characteristics DS005698-27 DS005698-28 DS005698-29 Response Time Dynamic Impedance Noise Voltage DS005698-30 DS005698-31 DS005698-32 Thermal Resistance Junction to Air Thermal Time Constant Thermal Response in Still Air DS005698-34 DS005698-33 DS005698-35 www.national.com 4 LM135/LM235/LM335, LM135A/LM235A/LM335A Typical Performance Characteristics Thermal Response in Stirred Oil Bath (Continued) Forward Characteristics DS005698-36 DS005698-37 Application Hints CALIBRATING THE LM135 Included on the LM135 chip is an easy method of calibrating the device for higher accuracies. A pot connected across the LM135 with the arm tied to the adjustment terminal allows a 1-point calibration of the sensor that corrects for inaccuracy over the full temperature range. This single point calibration works because the output of the LM135 is proportional to absolute temperature with the extrapolated output of sensor going to 0V output at 0˚K (−273.15˚C). Errors in output voltage versus temperature are only slope (or scale factor) errors so a slope calibration at one temperature corrects at all temperatures. The output of the device (calibrated or uncalibrated) can be expressed as: To insure good sensing accuracy several precautions must be taken. Like any temperature sensing device, self heating can reduce accuracy. The LM135 should be operated at the lowest current suitable for the application. Sufficient current, of course, must be available to drive both the sensor and the calibration pot at the maximum operating temperature as well as any external loads. If the sensor is used in an ambient where the thermal resistance is constant, self heating errors can be calibrated out. This is possible if the device is run with a temperature stable current. Heating will then be proportional to zener voltage and therefore temperature. This makes the self heating error proportional to absolute temperature the same as scale factor errors. WATERPROOFING SENSORS Meltable inner core heat shrinkable tubing such as manufactured by Raychem can be used to make low-cost waterproof sensors. The LM335 is inserted into the tubing about 1⁄2" from the end and the tubing heated above the melting point of the core. The unfilled 1⁄2" end melts and provides a seal over the device. where T is the unknown temperature and To is a reference temperature, both expressed in degrees Kelvin. By calibrating the output to read correctly at one temperature the output at all temperatures is correct. Nominally the output is calibrated at 10 mV/˚K. Typical Applications Basic Temperature Sensor Calibrated Sensor Wide Operating Supply DS005698-2 DS005698-9 *Calibrate for 2.982V at 25˚C DS005698-10 5 www.national.com LM135/LM235/LM335, LM135A/LM235A/LM335A Typical Applications (Continued) Average Temperature Sensing Remote Temperature Sensing Minimum Temperature Sensing DS005698-4 DS005698-19 Wire length for 1˚C error due to wire drop DS005698-18 IR = 1 mA AWG 14 16 18 20 22 24 FEET 4000 2500 1600 1000 625 400 IR = 0.5 mA* FEET 8000 5000 3200 2000 1250 800 *For IR = 0.5 mA, the trim pot must be deleted. Isolated Temperature Sensor DS005698-20 www.national.com 6 LM135/LM235/LM335, LM135A/LM235A/LM335A Typical Applications (Continued) Simple Temperature Controller DS005698-5 Simple Temperature Control DS005698-21 Ground Referred Fahrenheit Thermometer Centigrade Thermometer DS005698-22 *Adjust R2 for 2.554V across LM336. Adjust R1 for correct output. DS005698-23 *Adjust for 2.7315V at output of LM308 7 www.national.com LM135/LM235/LM335, LM135A/LM235A/LM335A Typical Applications (Continued) Fahrenheit Thermometer DS005698-24 *To calibrate adjust R2 for 2.554V across LM336. Adjust R1 for correct output. THERMOCOUPLE COLD JUNCTION COMPENSATION Compensation for Grounded Thermocouple DS005698-6 *Select R3 for proper thermocouple type THERMOCOUPLE J T K S R3 ( ± 1%) 377Ω 308Ω 293Ω 45.8Ω SEEBECK COEFFICIENT 52.3 µV/˚C 42.8 µV/˚C 40.8 µV/˚C 6.4 µV/˚C Adjustments: Compensates for both sensor and resistor tolerances 1. Short LM329B 2. Adjust R1 for Seebeck Coefficient times ambient temperature (in degrees K) across R3. 3. Short LM335 and adjust R2 for voltage across R3 corresponding to thermocouple type J T 14.32 mV 11.79 mV K S 11.17 mV 1.768 mV www.national.com 8 LM135/LM235/LM335, LM135A/LM235A/LM335A Typical Applications (Continued) Single Power Supply Cold Junction Compensation DS005698-11 *Select R3 and R4 for thermocouple type THERMOCOUPLE J T K S R3 1.05K 856Ω 816Ω 128Ω R4 385Ω 315Ω 300Ω 46.3Ω SEEBECK COEFFICIENT 52.3 µV/˚C 42.8 µV/˚C 40.8 µV/˚C 6.4 µV/˚C Adjustments: 1. Adjust R1 for the voltage across R3 equal to the Seebeck Coefficient times ambient temperature in degrees Kelvin. 2. Adjust R2 for voltage across R4 corresponding to thermocouple J T K S 14.32 mV 11.79 mV 11.17 mV 1.768 mV 9 www.national.com LM135/LM235/LM335, LM135A/LM235A/LM335A Typical Applications (Continued) Centigrade Calibrated Thermocouple Thermometer DS005698-12 Terminate thermocouple reference junction in close proximity to LM335. Adjustments: 1. Apply signal in place of thermocouple and adjust R3 for a gain of 245.7. 2. Short non-inverting input of LM308A and output of LM329B to ground. 3. Adjust R1 so that VOUT = 2.982V @ 25˚C. 4. Remove short across LM329B and adjust R2 so that VOUT = 246 mV @ 25˚C. 5. Remove short across thermocouple. Fast Charger for Nickel-Cadmium Batteries Differential Temperature Sensor DS005698-7 DS005698-13 †Adjust D1 to 50 mV greater VZ than D2. Charge terminates on 5˚C temperature rise. Couple D2 to battery. www.national.com 10 LM135/LM235/LM335, LM135A/LM235A/LM335A Typical Applications (Continued) Differential Temperature Sensor DS005698-14 Variable Offset Thermometer DS005698-15 †Adjust for zero with sensor at 0˚C and 10T pot set at 0˚C *Adjust for zero output with 10T pot set at 100˚C and sensor at 100˚C Output reads difference between temperature and dial setting of 10T pot 11 www.national.com LM135/LM235/LM335, LM135A/LM235A/LM335A Typical Applications (Continued) Air Flow Detector* Ground Referred Centigrade Thermometer DS005698-17 *Self heating is used to detect air flow DS005698-16 Definition of Terms Operating Output Voltage: The voltage appearing across the positive and negative terminals of the device at specified conditions of operating temperature and current. Uncalibrated Temperature Error: The error between the operating output voltage at 10 mV/˚K and case temperature at specified conditions of current and case temperature. Calibrated Temperature Error: The error between operating output voltage and case temperature at 10 mV/˚K over a temperature range at a specified operating current with the 25˚C error adjusted to zero. www.national.com 12 LM135/LM235/LM335, LM135A/LM235A/LM335A Physical Dimensions inches (millimeters) unless otherwise noted Metal Can Package (H) Order Number LM135H, LM235H, LM335H, LM135AH, LM235AH or LM335AH NS Package Number H03H 8-Lead Molded Small Outline Package (M) Order Number LM335M NS Package Number M08A 13 www.national.com LM135/LM235/LM335, LM135A/LM235A/LM335A Precision Temperature Sensors Physical Dimensions inches (millimeters) unless otherwise noted (Continued) Plastic Package Order Number LM335Z or LM335AZ NS Package 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 AND GENERAL COUNSEL 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 Americas Tel: 1-800-272-9959 Fax: 1-800-737-7018 Email: support@nsc.com www.national.com National Semiconductor Europe Fax: +49 (0) 180-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 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. 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