LM135

LM135 LM235-LM335,A PRECISION TEMPERATURE SENSORS . . . . DIRECTLY CALIBRATED IN oK 1oC INITIAL ACCURACY OPERATES FROM 450µA TO 5mA LESS THAN 1Ω DYNAMIC IMPEDANCE Z TO92 (Plastic Package DESCRIPTION The LM135, LM235, LM335 are precision temperature sensors which can be easily calibrated. They operate as a 2-terminal Zener and the breakdown voltage is directly proportional to the absolute temperature at 10mV/oK. The circuit has a dynamic impedance of less than 1Ω and operates within a range of current from 450µA to 5mA without alteration of its characteristics. Calibrated at +25oC, the LM135, LM235, LM335 have a typical error of less than 1oC over a 100oC temperature range. Unlike other sensors, the LM135, LM235, LM335 have a linear output. PIN CONNECTIONS TO92 (Bottom view) V+ 8 D SO8 (Plastic Micropackage) ORDER CODES Part number LM135 LM235 LM335,A Temperature Range –55 C, +150 C –40 C, +125 C –40 C, +100 C o o o o o o Package Z • • • D • • • SO8 (Top view) NC 7 NC 6 ADJ 5 ADJ V+ V- 135-01.EPS 1 NC 2 NC 3 NC 4 V October 1997 135-02.EPS LM135-LM235-LM335,A SCHEMATIC DIAGRAM 1V 50kΩ 49kΩ 49kΩ 15.6k Ω 3 pF 10k Ω 1 2pF 60 0Ω 30kΩ 2 AD J 13.8k Ω 2 kΩ 1.1kΩ 3V ABSOLUTE MAXIMUM RATINGS Symbol IR IF Toper Current Reverse Forward Operating Free-air Temperature Range - (note 1) Continuous Intermittent Storage Temperature Range o Parameter LM135 15 10 –55 to +150 +150 to +200 –65 to +150 LM235 15 10 –40 to +125 +125 to +150 –65 to +150 LM335,A 15 10 Unit mA o C –40 to +100 +100 to +125 –65 to +150 o Tstg C Note : 1. Tj ≤ 150 C 2/11 LM135-LM235-LM335,A TEMPERATURE ACCURACY Parameter Operating Output Voltage Tcase = +25oC, IR = 1mA Uncalibrated Temperature Error (IR = 1mA) o Tcase = +25 C Tmin. ≤ Tcase ≤ Tmax. Temperature Error with 25 C Calibration Tmin. ≤ Tcase ≤ Tmax., IR = 1mA LM135 - LM235 LM335 LM335A Calibrated Error at Extended Temperature Tcase = Tmax. (intermittent) Non-linearity (IR = 1mA) LM135 - LM235 LM335 LM335A o LM135 - LM235 LM335A Min. 2.95 Typ. 2.98 1 2 0.5 0.5 2 0.3 0.3 1 Max. 3.01 3 5 1.5 Min. 2.92 LM335 Typ. 2.98 2 4 Max. Unit V 3.04 o C 6 9 o C 1 1 2 o C C 2 o 0.3 1.5 1.5 ELECTRICAL CHARACTERISTICS - (note 1) Parameter Operating output voltage change with current 450µA ≤ IR ≤ 5mA at constant temperature Dynamic Impedance (IR = 1mA) Output Voltage Temperature Drift Time Constant o LM135 - LM235 Min. Typ. 2.5 0.5 +10 Still Air Air 0.5m/s Stirred Oil 80 10 1 0.2 Max. 10 Min. LM335,A Typ. 3 0.6 +10 80 10 1 0.2 o Max. 14 Unit mV Ω mV/ C s o Time Stability (Tcase = +125 C) C/kh Note : 1. Accuracy measurements are made in a well-stirred oil bath. For other conditions, self heating must be considered. 3/11 L M135-LM235-LM335,A 4/11 L M135-LM235-LM335,A 5/11 LM135-LM235-LM335,A APPLICATION HINTS There is an easy method of calibrating the device for higher accuracies (see typical applications). The single point calibration works because the output of the LM135, LM235, LM335 is proportional to the absolute temperature with the extrapolated output of sensor going to 0V at 0oK ( –273.15oC). Errors in outputvoltage versus temperature are only slope. Thus a calibration of the slope at one temperature corrects errors at all temperatures. The output of the circuit (calibrated or not) can be T given by the equation : VOT = VOTO x To where T is the unknown temperature and TO is the reference temperature (in oK). TYPICAL APPLICATIONS BASIC TEMPERATURE SENSOR Nominally the output is calibrated at 10mV/oK. Precautions should be taken to ensure good sensing accuracy. As in the case ofall temperaturessensors, self heating can decrease accuracy. The LM135, LM235, LM335 should operate with a low current, but sufficient to drive the sensor and its calibration circuit to their maximum operating temperature. If the sensor is used in surroundings where the thermal resistane is constant,the errors due to self heating can be externally calibrated. This is possible if the circuit is biased with a temperature stable current. Heating will then be proportional to zener voltage and therefore temperature. In this way the error due to self heating is proportional to the absolute temperature as scale factor errors. WIDE OPERATING SUPPLY Vi +5 to +40V LM134, LM234 LM334 V R1 LM135 LM235 LM335 Output 10mV/°K 68Ω LM135 LM235 LM335 Output 10mV/°K CALIBRATED SENSOR AVERAGE TEMPERATURE SENSING +15V 6kΩ V R1 Output 10mV/°K LM135 LM235 LM335 10kΩ* Output 30mV/°K LM135 LM235 LM335 * Calibrate for 2.982V at +25oC 6/11 LM135-LM235-LM335,A ISOLATED TEMPERATURE SENSOR LM135 LM235 LM335 +15V 50kΩ 3kΩ 01.µF 1kΩ 2kΩ 3 2 4 8 LM311 1 10kΩ 5 6 7 1N4148 200pF 27kΩ 100kΩ 510Ω 10kΩ 1 3 LF398 84 5 6 7 Output 10mV/°K m=1 +15V 1N457 0.1µF -15V 1N4148 -15V 1000pF SIMPLE TEMPERATURE CONTROLLER +10V to +30V 2kΩ 10kΩ 5kΩ 2 5 6 10kΩ Heater 0.01µF 1N4568 10kΩ 3 1 8 4 LM311 7 BUV26 4kΩ LM135 LM235 LM335 7/11 LM135-LM235-LM335,A CENTIGRADE THERMOMETER 1kΩ +15V +15V 6kΩ 2 7 6 +15V 12kΩ 3 4 8 8.5kΩ LM136 2kΩ * LM135 LM235 LM335 10kΩ 100pF * Adjust for 2.7315V at output of LM308 DIFFERENTIAL TEMPERATURE SENSOR +15V 12kΩ 12kΩ 20kΩ 2 200kΩ +15V 7 6 8 4 20kΩ 3 LM308 Output 100mV/°C 180kΩ LM135 LM235 LM335 -15V 100pF 50kΩ 8/11 { LM308 Output 10mV/°C LM135-LM235-LM335,A THERMOCOUPLE COLD JUNCTION COMPENSATION (compensation for grounded thermocouple) Thermocouple +15V 4.7kΩ 200kΩ R2 10 kΩ 1% 1M Ω 1% R3 377Ω 308Ω 293Ω 45.8Ω Seebeck Coefficient 52.3µV/oC 42.8µV/oC o 40.8µV/ C o 6.4µV/ C J T K S R3* 1N4568 LM135 LM235 LM335 12kΩ R1 10kΩ 71.5kΩ 1% Thermocouple Adjustments : compensates for both sensor and resistor tolerances. 1. Short 1N4568. 2. Adjust R1 for SEEBECK coefficient times ambient temperature (in degrees K) across R3. 3. Short LM135 and adjust R2 for voltage across R3 corresponding to thermocouple type. J 14.32mV K 11.17mV T 11.79mV S 1.768mV -15V * Select R3 for proper thermocouple type SINGLE POWER SUPPLY COLD JUNCTION COMPENSATION Thermocouple J T K S Thermocouple LM135 LM235 LM335 R1 10kΩ R3* +15V 10kΩ 200kΩ R3 1.05kΩ 856Ω 816Ω 128Ω R4 365Ω 315Ω 300Ω 46.3Ω Seebeck Coefficient 52.3µV/oC 42.8µV/ C o 40.8µV/ C o 6.4µV/ C o +15V 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 14.32mV K 11.17mV T 11.79mV S 1.768mV 1N4568 R2 10 kΩ 200kΩ 1MΩ Output R4* * Select R3 and R4 for proper thermocouple 9/11 LM135-LM235-LM335,A PACKAGE MECHANICAL DATA 8 PINS - PLASTIC MICROPACKAGE (SO) Dimensions A a1 a2 a3 b b1 C c1 D E e e3 F L M S Min. 0.1 0.65 0.35 0.19 0.25 4.8 5.8 Millimeters Typ. Max. 1.75 0.25 1.65 0.85 0.48 0.25 0.5 45 (typ.) 5.0 6.2 o Min. 0.004 0.026 0.014 0.007 0.010 0.189 0.228 Inches Typ. Max. 0.069 0.010 0.065 0.033 0.019 0.010 0.020 0.197 0.244 1.27 3.81 3.8 0.4 4.0 1.27 0.6 8 (max.) o 0.050 0.150 0.150 0.016 0.157 0.050 0.024 10/11 SO8.TBL PM-SO8.EPS LM135-LM235-LM335,A PACKAGE MECHANICAL DATA 3 PINS - PLASTIC PACKAGE TO92 Dimensions L B O1 C K O2 a Min. 3.2 4.45 4.58 12.7 0.407 0.35 Millimeters Typ. 1.27 3.7 5.00 5.03 0.5 Max. 4.2 5.2 5.33 0.508 Min. 0.126 0.1752 0.1803 0.5 0.016 0.0138 Inches Typ. 0.05 0.1457 0.1969 0.198 0.0197 Max. 0.1654 0.2047 0.2098 TO92TBL 0.02 Information furnished is believed to be accurate and reliable. However, SGS-THO MSON Microelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specification mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGS-THOMSON Microelectronics products are not author ized for use as critical componen ts in life support devices or systems without express written approval of SGS-THOMSON Microelectronics. ORDER CODE : © 1997 SGS-THOMSON Microelectronics – Printed in Italy – All Rights Reserved SGS-THOMSON Microelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco The Netherlands - Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdo m - U.S.A. 11/11 PM-TO92.IMG