LM20 2.4V, 10A, SC70, micro SMD Temperature Sensor General Description The LM20 is a precision analog output CMOS integrated-circuit temperature sensor that operates over a -55C to +130C temperature range. The power supply operating range is +2.4 V to +5.5 V. The transfer function of LM20 is predominately linear, yet has a slight predictable parabolic curvature. The accuracy of the LM20 when specified to a parabolic transfer function is 1.5C at an ambient temperature of +30C. The temperature error increases linearly and reaches a maximum of 2.5C at the temperature range extremes. The temperature range is affected by the power supply voltage. At a power supply voltage of 2.7 V to 5.5 V the temperature range extremes are +130C and -55C. Decreasing the power supply voltage to 2.4 V changes the negative extreme to -30C, while the positive remains at +130C. The LM20's quiescent current is less than 10 A. Therefore, self-heating is less than 0.02C in still air. Shutdown capability for the LM20 is intrinsic because its inherent low power consumption allows it to be powered directly from the output of many logic gates or does not necessitate shutdown at all. n n n n n n Battery Management FAX Machines Printers HVAC Disk Drives Appliances Features n n n n Rated for full -55C to +130C range Available in an SC70 and a micro SMD package Predictable curvature error Suitable for remote applications Key Specifications j Accuracy at +130C & -55C 1.5 to 4 C (max) 2.5 to 5 C (max) j Power Supply Voltage Range +2.4V to +5.5V j Accuracy at +30C j Current Drain 10 A (max) j Nonlinearity 0.4 % (typ) Applications j Output Impedance 160 (max) n Cellular Phones n Computers n Power Supply Modules j Load Regulation 0 A < IL < +16 A -2.5 mV (max) Typical Application Full-Range Celsius (Centigrade) Temperature Sensor (-55C to +130C) Operating from a Single Li-Ion Battery Cell Output Voltage vs Temperature 10090802 VO = (-3.88x10-6xT2) + (-1.15x10-2xT) + 1.8639 10090824 where: T is temperature, and VO is the measured output voltage of the LM20. (c) 2002 National Semiconductor Corporation Temperature (T) Typical VO +130C +303 mV DS100908 www.national.com LM20 2.4V, 10A, SC70, micro SMD Temperature Sensor June 2002 LM20 Typical Application (Continued) Temperature (T) Typical VO +100C +675 mV +80C +919 mV +30C +1515 mV +25C +1574 mV 0C +1863.9 mV -30C +2205 mV -40C +2318 mV -55C +2485 mV Connection Diagrams SC70-5 micro SMD 10090801 Note: 10090832 - GND (pin 2) may be grounded or left floating. For optimum thermal conductivity to the pc board ground plane pin 2 should be grounded. Note: - NC (pin 1) should be left floating or grounded. Other signal traces should not be connected to this pin. - Pin numbers are referenced to the package marking text orientation. - Reference JEDEC Registration MO-211, variation BA - The actual physical placement of package marking will vary slightly from part to part. The package marking will designate the date code and will vary considerably. Package marking does not correlate to device type in any way. Top View See NS Package Number MAA05A Top View See NS Package Number BPA04DDC Ordering Information Order Temperature Temperature NS Package Device Number Accuracy Range Number Marking -55C to +130C MAA05A T2B -55C to +130C MAA05A T2B 3000 Units on Tape and Reel -55C to +130C MAA05A T2C 1000 Units on Tape and Reel LM20SIBP 2.5C 2.5C 5C 5C 3.5C LM20SIBPX 3.5C LM20BIM7 LM20BIM7X LM20CIM7 LM20CIM7X www.national.com Transport Media 1000 Units on Tape and Reel -55C to +130C MAA05A T2C 3000 Units on Tape and Reel -40C to +125C BPA04DDC Date Code 250 Units on Tape and Reel -40C to +125C BPA04DDC Date Code 3000 Units on Tape and Reel 2 Supply Voltage LM20 Absolute Maximum Ratings (Note 1) Operating Ratings(Note 1) +6.5V to -0.2V + Output Voltage (V + 0.6 V) to -0.6 V Output Current LM20B, LM20C with 2.4 V V+ 2.7 V 10 mA Input Current at any pin (Note 2) 5 mA Storage Temperature -55C TA +130C LM20S with 2.4 V V+ 5.5 V -30C TA +125C +150C LM20S with 2.7 V V+ 5.5 V -40C TA +125C 2500 V Supply Voltage Range (V+) ESD Susceptibility (Note 3) : Human Body Model -30C TA +130C LM20B, LM20C with 2.7 V V+ 5.5 V -65C to +150C Maximum Junction Temperature (TJMAX) TMIN TA TMAX Specified Temperature Range: Machine Model Lead Temperature SC-70 Package (Note 4) : Vapor Phase (60 seconds) +215C Infrared (15 seconds) +220C +2.4 V to +5.5 V Thermal Resistance, JA(Note 5) SC-70 micro SMD 250 V 415C/W 340C/W Electrical Characteristics Unless otherwise noted, these specifications apply for V+ = +2.7 VDC. Boldface limits apply for TA = TJ = TMIN to TMAX ; all other limits TA = TJ = 25C; Unless otherwise noted. Parameter Temperature to Voltage Error VO = (-3.88x10-6xT2) + (-1.15x10-2xT) + 1.8639V (Note 8) Conditions Typical (Note 6) TA = +25C to +30C TA = +130C TA = +125C TA = +100C TA = +85C TA = +80C TA = 0C TA = -30C TA = -40C TA = -55C LM20B LM20C LM20S Limits Limits Limits (Note 7) (Note 7) (Note 7) 1.5 2.5 2.5 2.2 2.1 2.0 1.9 2.2 2.3 2.5 4.0 5.0 5.0 4.7 4.6 4.5 4.4 4.7 4.8 5.0 2.5 Units (Limit) C (max) C (max) 3.5 3.2 3.1 3.0 2.9 3.3 3.5 C (max) C (max) C (max) C (max) C (max) C (min) C (max) C (max) Output Voltage at 0C +1.8639 V Variance from Curve C Non-Linearity (Note 9) -20C TA +80C 1.0 0.4 Sensor Gain (Temperature Sensitivity or Average Slope) to equation: VO =-11.77 mV/CxT+1.860V -30C TA +100C -11.77 Output Impedance % -11.4 -12.2 -11.0 -12.6 -11.0 -12.6 mV/C (min) mV/C (max) 0 A IL +16 A (Notes 11, 12) 160 160 160 (max) Load Regulation(Note 10) 0 A IL +16 A (Notes 11, 12) -2.5 -2.5 -2.5 mV (max) Line Regulation +2. 4 V V+ +5.0V +3.3 +3.7 +3.7 mV/V (max) +5.0 V V+ +5.5 V +11 +11 +11 mV (max) Quiescent Current Change of Quiescent Current +2. 4 V V+ +5.5V 4.5 7 7 7 A (max) +2. 4 V V+ +5.0V 4.5 10 10 10 A (max) +2. 4 V V+ +5.5V +0.7 A -11 nA/C Temperature Coefficient of Quiescent Current 3 www.national.com LM20 Electrical Characteristics (Continued) Unless otherwise noted, these specifications apply for V+ = +2.7 VDC. Boldface limits apply for TA = TJ = TMIN to TMAX ; all other limits TA = TJ = 25C; Unless otherwise noted. Parameter Shutdown Current Conditions Typical (Note 6) V+ +0.8 V LM20B LM20C LM20S Limits Limits Limits (Note 7) (Note 7) (Note 7) 0.02 Units (Limit) A Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions. Note 2: When the input voltage (VI) at any pin exceeds power supplies (VI < GND or VI > V+), the current at that pin should be limited to 5 mA. Note 3: The human body model is a 100 pF capacitor discharged through a 1.5 k resistor into each pin. The machine model is a 200 pF capacitor discharged directly into each pin. Note 4: See AN-450 "Surface Mounting Methods and Their Effect on Product Reliability" or the section titled "Surface Mount" found in any post 1986 National Semiconductor Linear Data Book for other methods of soldering surface mount devices. Note 5: The junction to ambient thermal resistance (JA) is specified without a heat sink in still air using the printed circuit board layout shown in Figure 1. Note 6: Typicals are at TJ = TA = 25C and represent most likely parametric norm. Note 7: Limits are guaranteed to National's AOQL (Average Outgoing Quality Level). Note 8: Accuracy is defined as the error between the measured and calculated output voltage at the specified conditions of voltage, current, and temperature (expressed inC). Note 9: Non-Linearity is defined as the deviation of the calculated output-voltage-versus-temperature curve from the best-fit straight line, over the temperature range specified. Note 10: 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 11: Negative currents are flowing into the LM20. Positive currents are flowing out of the LM20. Using this convention the LM20 can at most sink -1 A and source +16 A. Note 12: Load regulation or output impedance specifications apply over the supply voltage range of +2.4V to +5.5V. Note 13: Line regulation is calculated by subtracting the output voltage at the highest supply input voltage from the output voltage at the lowest supply input voltage. Typical Performance Characteristics Temperature Error vs Temperature 10090825 PCB Layouts Used for Thermal Measurements 10090830 10090829 b) Layout used for measurements with small heat hink. a) Layout used for no heat sink measurements. FIGURE 1. PCB Lyouts used for thermal measurements. www.national.com 4 The LM20's transfer function can be described in different ways with varying levels of precision. A simple linear transfer function, with good accuracy near 25C, is VO = -11.69 mV/C x T + 1.8663 V T=35C and m = -11.77 mV/C The offset of the linear transfer function can be calculated using the following equation: b = (VOP(Tmax) + VOP(T) + m x (Tmax+T))/2 Over the full operating temperature range of -55C to +130C, best accuracy can be obtained by using the parabolic transfer function VO = (-3.88x10-6xT2) + (-1.15x10-2xT) + 1.8639 , where: * VOP(Tmax) is the calculated output voltage at Tmax using the parabolic transfer function for VO * VOP(T) is the calculated output voltage at T using the parabolic transfer function for VO. Using this procedure the best fit linear transfer function for many popular temperature ranges was calculated in Figure 2. As shown in Figure 2 the error that is introduced by the linear transfer function increases with wider temperature ranges. solving for T: A linear transfer function can be used over a limited temperature range by calculating a slope and offset that give best results over that range. A linear transfer function can be calculated from the parabolic transfer function of the LM20. The slope of the linear transfer function can be calculated using the following equation: m = -7.76 x 10-6x T - 0.0115, Temperature Range Tmin (C) Tmax (C) Linear Equation VO = Maximum Deviation of Linear Equation from Parabolic Equation (C) 1.41 0.93 0.70 0.65 0.23 0.004 0.004 -55 +130 -11.79 mV/C x T + 1.8528 V -40 +110 -11.77 mV/C x T + 1.8577 V -30 +100 -11.77 mV/C x T + 1.8605 V -40 +85 -11.67 mV/C x T + 1.8583 V -10 +65 -11.71 mV/C x T + 1.8641 V +35 +45 -11.81 mV/C x T + 1.8701 V +20 +30 -11.69 mV/C x T + 1.8663 V FIGURE 2. First order equations optimized for different temperature ranges. as Humiseal and epoxy paints or dips are often used to ensure that moisture cannot corrode the LM20 or its connections. The thermal resistance junction to ambient (JA) is the parameter used to calculate the rise of a device junction temperature due to its power dissipation. For the LM20 the equation used to calculate the rise in the die temperature is as follows: TJ = TA + JA [(V+ IQ) + (V+ - VO) IL] where IQ is the quiescent current and ILis the load current on the output. Since the LM20's junction temperature is the actual temperature being measured care should be taken to minimize the load current that the LM20 is required to drive. The tables shown in Figure 3 summarize the rise in die temperature of the LM20 without any loading, and the thermal resistance for different conditions. 2.0 Mounting The LM20 can be applied easily in the same way as other integrated-circuit temperature sensors. It can be glued or cemented to a surface. The temperature that the LM20 is sensing will be within about +0.02C of the surface temperature to which the LM20's leads are attached to. 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 measured would be at an intermediate temperature between the surface temperature and the air temperature. To ensure good thermal conductivity the backside of the LM20 die is directly attached to the pin 2 GND pin. The tempertures of the lands and traces to the other leads of the LM20 will also affect the temperature that is being sensed. Alternatively, the LM20 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 LM20 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 5 www.national.com LM20 where T is the middle of the temperature range of interest and m is in V/C. For example for the temperature range of Tmin =-30 to Tmax =+100C: 1.0 LM20 Transfer Function LM20 2.0 Mounting 3.0 Capacitive Loads (Continued) SC70-5 SC70-5 no heat sink small heat sink JA TJ - T A JA (C/W) (C) (C/W) (C) Still air 412 0.2 350 0.19 Moving air 312 0.17 266 0.15 The LM20 handles capacitive loading well. Without any precautions, the LM20 can drive any capacitive load less than 300 pF as shown in Figure 4. Over the specified temperature range the LM20 has a maximum output impedance of 160 . In an extremely noisy environment it may be necessary to add some filtering to minimize noise pickup. It is recommended that 0.1 F be added from V+ to GND to bypass the power supply voltage, as shown in Figure 5. In a noisy environment it may even be necessary to add a capacitor from the output to ground with a series resistor as shown in Figure 5. A 1 F output capacitor with the 160 maximum output impedance and a 200 series resistor will form a 442 Hz lowpass filter. Since the thermal time constant of the LM20 is much slower, the overall response time of the LM20 will not be significantly affected. T J - TA See Figure 1 for PCB layout samples. micro SMD micro SMD no heat sink small heat fin JA TJ - T A JA (C/W) (C) (C/W) (C) Still air 340 0.18 TBD TBD Moving air TBD TBD TBD TBD T J - TA FIGURE 3. Temperature Rise of LM20 Due to Self-Heating and Thermal Resistance (JA) 10090815 FIGURE 4. LM20 No Decoupling Required for Capacitive Loads Less than 300 pF. R () C (F) 200 1 470 0.1 680 0.01 1k 0.001 10090816 10090833 FIGURE 5. LM20 with Filter for Noisy Environment and Capacitive Loading greater than 300 pF. Either placement of resistor as shown above is just as effective. either case it is recommended that the LM20 micro SMD be placed inside an enclosure of some type that minimizes its light exposure. Most chassis provide more than ample protection. The LM20 does not sustain permanent damage from light exposure. Removing the light source will cause LM20's output voltage to recover to the proper value. 4.0 LM20 micro SMD Light Sensitivity Exposing the LM20 micro SMD package to bright sunlight may cause the output reading of the LM20 to drop by 1.5V. In a normal office environment of fluorescent lighting the output voltage is minimally affected (less than a millivolt drop). In www.national.com 6 LM20 5.0 Applications Circuits 10090818 FIGURE 6. Centigrade Thermostat 10090819 FIGURE 7. Conserving Power Dissipation with Shutdown 10090828 Most CMOS ADCs found in ASICs have a sampled data comparator input structure that is notorious for causing grief to analog output devices such as the LM20 and many op amps. The cause of this grief is the requirement of instantaneous charge of the input sampling capacitor in the ADC. This requirement is easily accommodated by the addition of a capacitor. Since not all ADCs have identical input stages, the charge requirements will vary necessitating a different value of compensating capacitor. This ADC is shown as an example only. If a digital output temperature is required please refer to devices such as the LM74. FIGURE 8. Suggested Connection to a Sampling Analog to Digital Converter Input Stage 7 www.national.com LM20 Physical Dimensions inches (millimeters) unless otherwise noted 5-Lead SC70 Molded Package Order Number LM20BIM7 or LM20CIM7X NS Package Number MAA05A www.national.com 8 LM20 2.4V, 10A, SC70, micro SMD Temperature Sensor Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 4-Bump micro SMD Ball Grid Array Package Order Number LM20SIBP or LM20SIBPX NS Package Number BPA04DDC The following dimensions apply to the BPA04DDC package shown above: X1=X2 = 853m 30m, X3= 900m 50m 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 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 Francais 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. National Semiconductor Asia Pacific Customer Response Group Tel: 65-2544466 Fax: 65-2504466 Email: ap.support@nsc.com National Semiconductor Japan Ltd. Tel: 81-3-5639-7560 Fax: 81-3-5639-7507 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. National P/N LM20 - 2.4V, 10A, SC70, micro SMD Temperature Sensor See Microcontroller Products Products > Analog - Thermal Management > LM20 LM20 Product Folder 2.4V, 10A, SC70, micro SMD Temperature Sensor Generic P/N 20 General Description Features Package & Models Datasheet Parametric Table Samples & Pricing Design Tools Application Notes Parametric Table Operating Temperature Range -40 to +125 Deg C, -55 to +130 Deg C Sensor Gain (Tmin to Tmax) -11.7 mV/Deg C Supply Voltage Range +2.4V 5.5V Quiesent Current (mA) .01 Min. Accuracy -3.5 Deg C, -2.5 Deg C, -5 Deg C Max. Accuracy +3.5 Deg C, +2.5 Deg C, +5 Deg C Temp. Resolution Analog Output Datasheet Size in Date Kbytes Title LM20 2.4V, 10A, SC70, micro SMD Temperature Sensor View Online Download 6213 Jun- View Online Kbytes 02 LM20 2.4V, 10A, SC70, micro SMD Temperature Sensor (JAPANESE) 120 Kbytes View Online Download Download Receive via Email Receive via Email Receive via Email If you have trouble printing or viewing PDF file(s), see Printing Problems. Package Availability, Models, Samples & Pricing Part Number Package Type Pins MSL Status Samples & Budgetary Pricing Electronic SPICE IBIS Qty $US each Orders Models LM20SIBP LM20SIBPX microSMD 4 MSL Full production N/A N/A 4 MSL Full production N/A N/A Buy Now Package Marking 1K+ $0.3000 reel of 250 1 $I 1K+ $0.3000 reel of 3000 1 $I Samples microSMD Std Pack Size file:///H|/imaging/BITTING/cpl/20020808_1/08062002_10/NATL/08062002_HTML/LM20.html (1 of 4) [Aug-09-2002 1:56:35 PM] National P/N LM20 - 2.4V, 10A, SC70, micro SMD Temperature Sensor 1K+ $0.3500 reel of 1000 T2B 1T 1K+ $0.3000 reel of 1000 T2C 1T 1K+ $0.3500 reel of 3000 T2B 1T 1K+ $0.3000 reel of 3000 T2C 1T Samples LM20BIM7 SC-70 5 MSL Full production LM20CIM7 SC-70 5 MSL Full production N/A N/A LM20BIM7X SC-70 5 MSL Full production N/A N/A LM20CIM7X SC-70 5 MSL Full production N/A N/A N/A N/A Buy Now Samples Buy Now Buy Now Buy Now LM20BI MDC Die Full production N/A N/A Samples tray of N/A - LM20CI MDC Die Full production N/A N/A Samples tray of N/A - LM20BI MWC Wafer Full production N/A N/A wafer jar of N/A - General Description The LM20 is a precision analog output CMOS integrated-circuit temperature sensor that operates over a 55C to +130C temperature range. The power supply operating range is +2.4 V to +5.5 V. The transfer function of LM20 is predominately linear, yet has a slight predictable parabolic curvature. The accuracy of the LM20 when specified to a parabolic transfer function is 1.5C at an ambient temperature of +30C. The temperature error increases linearly and reaches a maximum of 2.5C at the temperature range extremes. The temperature range is affected by the power supply voltage. At a power supply voltage of 2.7 V to 5.5 V the temperature range extremes are +130C and -55C. Decreasing the power supply voltage to 2.4 V changes the negative extreme to -30C, while the positive remains at +130C. The LM20's quiescent current is less than 10 A. Therefore, self-heating is less than 0.02C in still air. Shutdown capability for the LM20 is intrinsic because its inherent low power consumption allows it to be powered directly from the output of many logic gates or does not necessitate shutdown at all. Features Rated for full -55C to +130C range Available in an SC70 and a micro SMD package Predictable curvature error Suitable for remote applications Key Specification file:///H|/imaging/BITTING/cpl/20020808_1/08062002_10/NATL/08062002_HTML/LM20.html (2 of 4) [Aug-09-2002 1:56:35 PM] National P/N LM20 - 2.4V, 10A, SC70, micro SMD Temperature Sensor Accuracy at +30C 1.5 to 4 C (max) Accuracy at +130C & -55C 2.5 to 5 C (max) Power Supply Voltage Range +2.4V to +5.5V Current Drain 10 A (max) Nonlinearity 0.4 % (typ) Output Impedance 160 Load Regulation 0 A < IL< +16 A (max) -2.5 mV (max) Applications Cellular Phones Computers Power Supply Modules Battery Management FAX Machines Printers HVAC Disk Drives Appliances Design Tools Title Size in Kbytes Date View Online Download Receive via Email Buy LM20 Evaluation Board - SC70 Package View Buy LM20 Evaluation Board - micro SMD Package View If you have trouble printing or viewing PDF file(s), see Printing Problems. Application Notes Title Size in Date Kbytes View Online Download 27AN-1112: Application Note 1112 Micro SMD Wafer Level 620 Mar- View Online Kbytes Chip Scale Package 02 Application Note 1112 Micro SMD Wafer Level Chip Scale Package (JAPANESE) 171 Kbytes View Online Download Download Receive via Email Receive via Email Receive via Email If you have trouble printing or viewing PDF file(s), see Printing Problems. [Information as of 5-Aug-2002] file:///H|/imaging/BITTING/cpl/20020808_1/08062002_10/NATL/08062002_HTML/LM20.html (3 of 4) [Aug-09-2002 1:56:35 PM] National P/N LM20 - 2.4V, 10A, SC70, micro SMD Temperature Sensor Search Design Purchasing Quality Company Home About Languages . Website Guide . About "Cookies" . National is QS 9000 Certified . Privacy/Security Statement . Contact Us . Site Terms & Conditions of Use . Copyright 2002 (c) National Semiconductor Corporation . My Preferences . 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