Product Folder Sample & Buy Support & Community Tools & Software Technical Documents LM20 SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 LM20 2.4-V, 10-A, SC70, DSBGA Temperature Sensor 1 Features * * * * * * 1 * * * * * 3 Description Rated for -55C to 130C Range Available in SC70 and DSBGA Package Predictable Curvature Error Suitable for Remote Applications Accuracy at 30C 1.5 to 4C (Maximum) Accuracy at 130C and -55C 2.5 to 5C (Maximum) Power Supply Voltage Range 2.4 V to 5.5 V Current Drain 10 A (Maximum) Nonlinearity 0.4% (Typical) Output Impedance 160 (Maximum) Load Regulation 0 A < IL< 16 A -2.5 mV (Maximum) 2 Applications * * * * * * * * * Cellular Phones Computers Power Supply Modules Battery Management FAX Machines Printers HVAC Disk Drives Appliances Simplified Schematic The LM20 is a precision analog output CMOS integrated-circuit temperature sensor that operates over -55C to 130C. 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 extreme remains at 130C. The LM20 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. Device Information(1) PART NUMBER LM20 PACKAGE BODY SIZE (NOM) SC70 (5) 2.00 mm x 1.25 mm DSBGA (4) 0.96 mm x 0.96 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. Output Voltage vs Temperature 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. LM20 SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 3 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 3 4 4 4 4 5 6 7 Absolute Maximum Ratings ...................................... ESD Ratings ............................................................ Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics: LM20B ............................ Electrical Characteristics: LM20C ............................ Electrical Characteristics: LM20S ............................ Typical Characteristics ............................................. 7.3 Feature Description................................................... 8 7.4 Device Functional Modes.......................................... 9 8 Application and Implementation ........................ 10 8.1 Application Information............................................ 10 8.2 Typical Applications ................................................ 11 8.3 System Examples ................................................... 14 9 Power Supply Recommendations...................... 15 10 Layout................................................................... 15 10.1 Layout Guidelines ................................................. 15 10.2 Layout Examples................................................... 15 10.3 Thermal Considerations ........................................ 15 11 Device and Documentation Support ................. 17 Detailed Description .............................................. 8 11.1 Trademarks ........................................................... 17 11.2 Electrostatic Discharge Caution ............................ 17 11.3 Glossary ................................................................ 17 7.1 Overview ................................................................... 8 7.2 Functional Block Diagram ......................................... 8 12 Mechanical, Packaging, and Orderable Information ........................................................... 17 4 Revision History Changes from Revision P (Feburary 2013) to Revision Q * Added Pin Configuration and Functions section, ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section .............................. 1 Changes from Revision O (February 2013) to Revision P * 2 Page Page Changed layout of National Data Sheet to TI Format .......................................................................................................... 14 Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 LM20 www.ti.com SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 5 Pin Configuration and Functions DCK Package 5-Pin SC70 (Top View) YZR Package 4-Pin DSBGA (Top View) Pin Functions PIN TYPE DESCRIPTION 2 GND Device substrate and die attach paddle, connect to power supply negative terminal. For optimum thermal conductivity to the PC board ground plane, pin 2 must be grounded. This pin may also be left floating. A2 5 GND Device ground pin, connect to power supply negative terminal. NC A1 1 -- VO B1 3 Analog Output Temperature sensor analog output + B2 4 Power Positive power supply pin NAME DSBGA SC70 GND -- GND V NC (pin 1) must be left floating or grounded. Other signal traces must not be connected to this pin. 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) (2) MIN MAX UNIT Supply Voltage -0.2 6.5 V Output Voltage -0.6 (V+ + 0.6 ) V Output Current 10 mA Input Current at any pin (3) 5 mA 150 C 150 C Maximum Junction Temperature (TJMAX) -65 Storage temperature, Tstg (1) (2) (3) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. Soldering process must comply with TI's Reflow Temperature Profile specifications. Refer to http://www.ti.com/packaging. 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. Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 3 LM20 SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 www.ti.com 6.2 ESD Ratings VALUE V(ESD) (1) (2) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) 2500 Charged-device model (CDM), per JEDEC specification JESD22-C101 (2) 250 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 6.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) (1) MIN MAX UNIT + LM20B, LM20C with 2.4 V V 2.7 V -30 130 C LM20B, LM20C with 2.7 V V+ 5.5 V -55 130 C LM20S with 2.4 V V+ 5.5 V -30 125 C LM20S with 2.7 V V+ 5.5 V -40 125 C 2.4 5.5 V + Supply Voltage Range (V ) (1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 6.4 Thermal Information LM20 THERMAL METRIC (1) DCK (SC70) YZR (DSBGA) 5 PINS 4 PINS 197 RJA Junction-to-ambient thermal resistance 282 RJC(top) Junction-to-case (top) thermal resistance 93 2 RJB Junction-to-board thermal resistance 62 40 JT Junction-to-top characterization parameter 1.6 11 JB Junction-to-board characterization parameter 62 40 RJC(bot) Junction-to-case (bottom) thermal resistance -- -- (1) UNIT C/W For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953. 6.5 Electrical Characteristics: LM20B Unless otherwise noted, these specifications apply for V+ = 2.7 VDC. All limits TA = TJ = TMIN to TMAX, unless otherwise noted. PARAMETER Temperature to Voltage Error VO = (-3.88x10-6x T 2) + (-1.15x10-2x T) + 1.8639 V (3) TEST CONDITIONS MAX (1) UNIT -1.5 1.5 C TA = 130C -2.5 2.5 C TA = 125C -2.5 2.5 C TA = 100C -2.2 2.2 C TA = 85C -2.1 2.1 C TA = 80C -2.0 2.0 C TA = 0C -1.9 1.9 C TA = -30C -2.2 2.2 C TA = -40C -2.3 2.3 C TA = -55C -2.5 2.5 C Variance from Curve 4 TYP (2) TA = 25C to 30C Output Voltage at 0C (1) (2) (3) MIN (1) 1.8639 V 1.0 C Limits are ensured to TI's AOQL (Average Outgoing Quality Level). Typicals are at TJ = TA = 25C and represent most likely parametric norm. Accuracy is defined as the error between the measured and calculated output voltage at the specified conditions of voltage, current, and temperature (expressed in C). Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 LM20 www.ti.com SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 Electrical Characteristics: LM20B (continued) Unless otherwise noted, these specifications apply for V+ = 2.7 VDC. All limits TA = TJ = TMIN to TMAX, unless otherwise noted. PARAMETER Non-linearity (4) TEST CONDITIONS MIN (1) -20C TA 80C TYP (2) MAX (1) UNIT -11.4 mV/C 0.4% Sensor Gain (Temperature Sensitivity or Average Slope) to equation: -30C TA 100C VO=-11.77 mV / CxT+1.860 V -12.2 -11.77 Output Impedance Sourcing IL 0 A to 16 A (5) (6) 160 (7) Sourcing IL 0 A to 16 A (3) (6) -2.5 mV 2.4 V V+ 5.0 V 3.3 mV/V 5.0 V V+ 5.5 V 11 mV Load Regulation Line Regulation (8) Quiescent Current 2.4 V V+ 5.0 V; TA = 25C 4.5 7 A 5.0 V V+ 5.5 V; TA = 25C 4.5 9 A 2.4 V V 5.0 V 4.5 10 A 2.4 V V+ 5.5 V 0.7 A -11 nA/C 0.02 A + Change of Quiescent Current Temperature Coefficient of Quiescent Current Shutdown Current (4) (5) (6) (7) (8) + V 0.8 V 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. The LM20 can at most sink 1 A and source 16 A. Load regulation or output impedance specifications apply over the supply voltage range of 2.4 V to 5.5 V. 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. 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. 6.6 Electrical Characteristics: LM20C Unless otherwise noted, these specifications apply for V+ = 2.7 VDC. All limits TA = TJ = TMIN to TMAX, unless otherwise noted. PARAMETER Temperature to Voltage Error VO = (-3.88x10-6x T 2) + (-1.15x10-2x T) + 1.8639 V (3) TEST CONDITIONS MIN (1) 5 C TA = 130C -5 5 C TA = 125C -5 5 C TA = 100C -4.7 4.7 C TA = 85C -4.6 4.6 C TA = 80C -4.5 4.5 C TA = 0C -4.4 4.4 C TA = -30C -4.7 4.7 C TA = -40C -4.8 4.8 C TA = -55C -5.0 5.0 C -20C TA 80C (1) (2) (3) (4) (5) (6) Sourcing IL 0 A to 16 A 1.8639 V 1.0 C 0.4% Sensor Gain (Temperature Sensitivity or Average Slope) to equation: -30C TA 100C VO=-11.77 mV / CxT+1.860 V Output Impedance UNIT -4 Variance from Curve (4) MAX (1) TA = 25C to 30C Output Voltage at 0C Non-Linearity TYP (2) -12.6 (5) (6) -11.77 -11.0 mV/C 160 Limits are ensured to TI's AOQL (Average Outgoing Quality Level). Typicals are at TJ = TA = 25C and represent most likely parametric norm. Accuracy is defined as the error between the measured and calculated output voltage at the specified conditions of voltage, current, and temperature (expressed in C). 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. The LM20 can at most sink 1 A and source 16 A. Load regulation or output impedance specifications apply over the supply voltage range of 2.4 V to 5.5 V. Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 5 LM20 SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 www.ti.com Electrical Characteristics: LM20C (continued) Unless otherwise noted, these specifications apply for V+ = 2.7 VDC. All limits TA = TJ = TMIN to TMAX, unless otherwise noted. PARAMETER Load Regulation (7) Line Regulation (8) TEST CONDITIONS Sourcing IL 0 A to 16 A MIN (1) Change of Quiescent Current (7) (8) UNIT -2.5 mV 3.7 mV/V 5.0 V V+ 5.5 V 11 mV 2.4 V V 5.0 V; TA = 25C 4.5 7 A 5.0 V V+ 5.5 V; TA = 25C 4.5 9 A 2.4 V V+ 5.0 V 4.5 10 A 2.4 V V+ 5.5 V 0.7 A -11 nA/C 0.02 A Temperature Coefficient of Quiescent Current Shutdown Current MAX (1) 2.4 V V+ 5.0 V + Quiescent Current TYP (2) (5) (6) + V 0.8 V 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. 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. 6.7 Electrical Characteristics: LM20S Unless otherwise noted, these specifications apply for V+ = 2.7 VDC. All limits TA = TJ = TMIN to TMAX, unless otherwise noted. MIN (1) TYP (2) MAX (1) TA = 25C to 30C -2.5 1.5 2.5 C TA = 125C -3.5 3.5 C TA = 100C -3.2 3.2 C TA = 85C -3.1 3.1 C TA = 80C -3.0 3.0 C TA = 0C -2.9 2.9 C TA = -30C -3.3 3.3 C TA = -40C -3.5 3.5 C PARAMETER Temperature to Voltage Error VO = (-3.88x10-6xT 2) + (-1.15x10-2x T) + 1.8639 V (3) TEST CONDITIONS Output Voltage at 0C Variance from Curve Non-Linearity (4) -20C TA 80C Sensor Gain (Temperature Sensitivity or Average Slope) to equation: -30C TA 100C VO= -11.77 mV/ C x T + 1.860 V UNIT 1.8639 V 1.0 C 0.4% -12.6 -11.77 -11.0 mV/C Output Impedance Sourcing IL 0 A to 16 A (5) (6) 160 (7) Sourcing IL 0 A to 16 A (5) (6) -2.5 mV 2.4 V V+ 5.0 V 3.7 mV/V 5.0 V V+ 5.5 V 11 mV Load Regulation Line Regulation (8) + Quiescent Current (1) (2) (3) (4) (5) (6) (7) (8) 6 2.4 V V 5.0 V; TA = 25C 4.5 7 A 5.0 V V+ 5.5 V; TA = 25C 4.5 9 A 2.4 V V+ 5.0 V 4.5 10 A Limits are ensured to TI's AOQL (Average Outgoing Quality Level). Typicals are at TJ = TA = 25C and represent most likely parametric norm. Accuracy is defined as the error between the measured and calculated output voltage at the specified conditions of voltage, current, and temperature (expressed in C). 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. The LM20 can at most sink 1 A and source 16 A. Load regulation or output impedance specifications apply over the supply voltage range of 2.4 V to 5.5 V. 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. 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. Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 LM20 www.ti.com SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 Electrical Characteristics: LM20S (continued) Unless otherwise noted, these specifications apply for V+ = 2.7 VDC. All limits TA = TJ = TMIN to TMAX, unless otherwise noted. PARAMETER Change of Quiescent Current TEST CONDITIONS + 2.4 V V 5.5 V Temperature Coefficient of Quiescent Current Shutdown Current V+ 0.8 V MIN (1) TYP (2) MAX (1) UNIT 0.7 A -11 nA/C 0.02 A 6.8 Typical Characteristics Figure 1. Temperature Error vs Temperature Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 7 LM20 SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 www.ti.com 7 Detailed Description 7.1 Overview The LM20 device is a precision analog output CMOS integrated-circuit temperature sensor that operates over a temperature range of -55C to 130C. 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 typically 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 for the LM20. 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 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. The temperature sensing element is comprised of a simple base emitter junction that is forward biased by a current source. The temperature sensing element is then buffered by an amplifier and provided to the OUT pin. The amplifier has a simple class A output stage thus providing a low impedance output that can source 16 A and sink 1 A. 7.2 Functional Block Diagram V+ VO Thermal Diodes GND 7.3 Feature Description 7.3.1 LM20 Transfer Function The LM20 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 (1) 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 (2) Using Equation 2, the following temperature to voltage output characteristic table can be generated. Table 1. Temperature to Voltage Output Characteristic Table 8 TEMP (C) VOUT (V) TEMP (C) VOUT (V) TEMP (C) VOUT (V) TEMP (C) VOUT (V) TEMP (C) VOUT (V) TEMP (C) VOUT (V) TEMP (C) VOUT (V) -55 2.4847 -28 2.1829 -1 1.8754 26 1.5623 53 1.2435 80 0.9191 107 0.5890 -54 2.4736 -27 2.1716 0 1.8639 27 1.5506 54 1.2316 81 0.9069 108 0.5766 -53 2.4625 -26 2.1603 1 1.8524 28 1.5389 55 1.2197 82 0.8948 109 0.5643 -52 2.4514 -25 2.1490 2 1.8409 29 1.5271 56 1.2077 83 0.8827 110 0.5520 -51 2.4403 -24 2.1377 3 1.8294 30 1.5154 57 1.1958 84 0.8705 111 0.5396 -50 2.4292 -23 2.1263 4 1.8178 31 1.5037 58 1.1838 85 0.8584 112 0.5272 Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 LM20 www.ti.com SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 Feature Description (continued) Table 1. Temperature to Voltage Output Characteristic Table (continued) TEMP (C) VOUT (V) TEMP (C) VOUT (V) TEMP (C) VOUT (V) TEMP (C) VOUT (V) TEMP (C) VOUT (V) TEMP (C) VOUT (V) TEMP (C) VOUT (V) -49 2.4181 -22 2.1150 5 1.8063 32 1.4919 59 1.1719 86 0.8462 113 0.5149 -48 2.4070 -21 2.1037 6 1.7948 33 1.4802 60 1.1599 87 0.8340 114 0.5025 -47 2.3958 -20 2.0923 7 1.7832 34 1.4684 61 1.1480 88 0.8219 115 0.4901 -46 2.3847 -19 2.0810 8 1.7717 35 1.4566 62 1.1360 89 0.8097 116 0.4777 -45 2.3735 -18 2.0696 9 1.7601 36 1.4449 63 1.1240 90 0.7975 117 0.4653 -44 2.3624 -17 2.0583 10 1.7485 37 1.4331 64 1.1120 91 0.7853 118 0.4529 -43 2.3512 -16 2.0469 11 1.7369 38 1.4213 65 1.1000 92 0.7731 119 0.4405 -42 2.3401 -15 2.0355 12 1.7253 39 1.4095 66 1.0880 93 0.7608 120 0.4280 -41 2.3289 -14 2.0241 13 1.7137 40 1.3977 67 1.0760 94 0.7486 121 0.4156 -40 2.3177 -13 2.0127 14 1.7021 41 1.3859 68 1.0640 95 0.7364 122 0.4032 -39 2.3065 -12 2.0013 15 1.6905 42 1.3741 69 1.0519 96 0.7241 123 0.3907 -38 2.2953 -11 1.9899 16 1.6789 43 1.3622 70 1.0399 97 0.7119 124 0.3782 -37 2.2841 -10 1.9785 17 1.6673 44 1.3504 71 1.0278 98 0.6996 125 0.3658 -36 2.2729 -9 1.9671 18 1.6556 45 1.3385 72 1.0158 99 0.6874 126 0.3533 -35 2.2616 -8 1.9557 19 1.6440 46 1.3267 73 1.0037 100 0.6751 127 0.3408 -34 2.2504 -7 1.9442 20 1.6323 47 1.3148 74 0.9917 101 0.6628 128 0.3283 -33 2.2392 -6 1.9328 21 1.6207 48 1.3030 75 0.9796 102 0.6505 129 0.3158 -32 2.2279 -5 1.9213 22 1.6090 49 1.2911 76 0.9675 103 0.6382 130 0.3033 -31 2.2167 -4 1.9098 23 1.5973 50 1.2792 77 0.9554 104 0.6259 -- -- -30 2.2054 -3 1.8984 24 1.5857 51 1.2673 78 0.9433 105 0.6136 -- -- -29 2.1941 -2 1.8869 25 1.5740 52 1.2554 79 0.9312 106 0.6013 -- -- Solving Equation 2 for T: (3) 7.4 Device Functional Modes The only functional mode of the LM20 is that it has an analog output inversely proportional to temperature. Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 9 LM20 SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 www.ti.com 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI's customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 8.1 Application Information The LM20 features make it suitable for many general temperature sensing applications. Multiple package options expand on its, flexibility. 8.1.1 Capacitive Loads The LM20 handles capacitive loading well. Without any precautions, the LM20 can drive any capacitive load less than 300 pF as shown in Figure 2. 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 4. 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 4. A 1-F output capacitor with the 160- maximum output impedance and a 200- series resistor will form a 442-Hz lowpass filter. Because the thermal time constant of the LM20 is much slower, the overall response time of the LM20 will not be significantly affected. In situations where a transient load current is placed on the circuit output the series resistance value may be increased to compensate for any ringing that may be observed. Figure 2. LM20 No Decoupling Required for Capacitive Loads Less Than 300 pF Table 2. Capacitive Loading Isolation Minimum R () C (F) 200 1 470 0.1 680 0.01 1k 0.001 Figure 3. LM20 With Compensation for Capacitive Loading Greater Than 300 pF 10 Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 LM20 www.ti.com SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 Figure 4. LM20 With Filter for Noisy Environment and Capacitive Loading Greater Than 300 pF NOTE Either placement of resistor, as shown in Figure 3 and Figure 4, is just as effective. 8.1.2 LM20 DSBGA Light Sensitivity Exposing the LM20 DSBGA package to bright sunlight may cause the output reading of the LM20 to drop by 1.5 V. In a normal office environment of fluorescent lighting the output voltage is minimally affected (less than a millivolt drop). In either case, TI recommends that the LM20 DSBGA 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 the output voltage of the LM20 to recover to the proper value. 8.2 Typical Applications 8.2.1 Full-Range Celsius (Centigrade) Temperature Sensor (-55C to 130C) Operating from a Single LiIon Battery Cell The LM20 has a very low supply current and a wide supply range; therefore, it can easily be driven by a battery as shown in Figure 5. Figure 5. Full-Range Celsius (Centigrade) Temperature Sensor (-55C To 130C) Operating from a Single Li-Ion Battery Cell 8.2.1.1 Design Requirements Because the LM20 is a simple temperature sensor that provides an analog output, design requirements related to layout are more important than electrical requirements. Refer to the Layout section for a detailed description. 8.2.1.2 Detailed Design Procedure The LM20 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 (4) 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 (5) Solving Equation 5 for T: Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 11 LM20 SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 www.ti.com Typical Applications (continued) (6) An alternative to the quadratic equation a second order transfer function can be determined using the leastsquares method: T = (-2.3654xVO 2) + (-78.154xVO ) + 153.857 where * T is temperature express in C and VO is the output voltage expressed in volts. (7) 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 Equation 8 equation: m = -7.76 x 10-6x T - 0.0115, where * T is the middle of the temperature range of interest and m is in V/C. (8) For example for the temperature range of TMIN = -30 to TMAX = 100C: T = 35C (9) and m = -11.77 mV/C (10) The offset of the linear transfer function can be calculated using the Equation 11 equation: b = (VOP(TMAX) + VOP(T) - m x (TMAX+T))/2 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. (11) The best fit linear transfer function for many popular temperature ranges was calculated in Table 3. As shown in Table 3, the error introduced by the linear transfer function increases with wider temperature ranges. Table 3. First Order Equations Optimized for Different Temperature Ranges Temperature Range 12 Linear Equation Maximum Deviation of Linear Equation from Parabolic Equation (C) Tmin (C) Tmax (C) -55 130 VO = -11.79 mV/C x T + 1.8528 V 1.41 -40 110 VO = -11.77 mV/C x T + 1.8577 V 0.93 -30 100 VO = -11.77 mV/C x T + 1.8605 V 0.70 0.65 -40 85 VO = -11.67 mV/C x T + 1.8583 V -10 65 VO = -11.71 mV/C x T + 1.8641 V 0.23 35 45 VO = -11.81 mV/C x T + 1.8701 V 0.004 20 30 VO = -11.69 mV/C x T + 1.8663 V 0.004 Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 LM20 www.ti.com SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 Table 4. Output Voltage vs Temperature Temperature (T) Typical VO 130C 303 mV 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 8.2.1.3 Application Curve Figure 6. Output Voltage vs Temperature 8.2.2 Centigrade Thermostat V+ R3 R4 LM4040 V+ VT R1 4.1V U3 0.1 PF LM20 R2 (High = overtemp alarm) + U1 - VOUT LM7211 VTemp U2 Figure 7. Centigrade Thermostat 8.2.2.1 Design Requirements A simple thermostat can be created by using a reference (LM4040) and a comparator (LM7211) as shown in Figure 7. 8.2.2.2 Detailed Design Procedure The threshold values can be calculated using Equation 12 and Equation 13. Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 13 LM20 SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 www.ti.com (4.1)R2 R2 + R1||R3 (12) (4.1)R2||R3 VT2 = R1 + R2||R3 (13) VT1 = 8.2.2.3 Application Curve VTEMP VT1 VT2 VOUT Figure 8. Thermostat Output Waveform 8.3 System Examples 8.3.1 Conserving Power Dissipation With Shutdown The LM20 draws very little power; therefore, it can simply be shutdown by driving its supply pin with the output of an logic gate as shown in Figure 9. Figure 9. Conserving Power Dissipation With Shutdown 8.3.2 Analog-to-Digital Converter Input Stage 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 operational amplifiers. 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. Because not all ADCsFigure 10 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, refer to devices such as the LM74. Figure 10. Suggested Connection to a Sampling Analog to Digital Converter Input Stage 14 Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 LM20 www.ti.com SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 9 Power Supply Recommendations The LM20 has a very wide 2.4-V to 5.5-V power supply voltage range that makes ideal for many applications. In noisy environments, TI recommends adding at minimum 0.1 F from V+ to GND to bypass the power supply voltage. Larger capacitances maybe required and are dependent on the power-supply noise. 10 Layout 10.1 Layout Guidelines The LM20 can be easily applied 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 is within approximately 0.02C of the surface temperature to which the leads of the LM20 are attached. Implementing the integrated-circuit temperature sensors 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. The temperatures of the lands and traces to the other leads of the LM20 will also affect the temperature that is 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 as a conformal coating and epoxy paints or dips are often used to ensure that moisture cannot corrode the LM20 or its connections. 10.2 Layout Examples NC GND GND Vo V+ Figure 11. Layout Used for No Heat Sink Measurements NC GND GND NC Vo V+ Figure 12. Layout Used for Measurements With Small Heat Sink 10.3 Thermal Considerations The thermal resistance junction to ambient (RJA) 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 + RJA [(V+ IQ) + (V+ - VO) IL] where * IQ is the quiescent current and ILis the load current on the output. Because the junction temperature of LM20 is the actual temperature being measured, take care to minimize the load current that the LM20 is required to drive. (14) Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 15 LM20 SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 www.ti.com Thermal Considerations (continued) Table 5 summarizes the rise in die temperature of the LM20 without any loading and the thermal resistance for different conditions. Table 5. Temperature Rise of LM20 Due to Self-Heating and Thermal Resistance (RJA) See more Layout Examples SC70-5 SC70-5 No Heat Sink Small Heat Sink RJA TJ - TA RJA TJ - TA (C/W) (C) (C/W) (C) Still air 412 0.2 350 0.19 Moving air 312 0.17 266 0.15 DSBGA No Heat Sink Still air 16 RJA TJ - TA (C/W) (C) 340 0.18 Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 LM20 www.ti.com SNIS106Q - DECEMBER 1999 - REVISED JANUARY 2015 11 Device and Documentation Support 11.1 Trademarks All trademarks are the property of their respective owners. 11.2 Electrostatic Discharge Caution These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 11.3 Glossary SLYZ022 -- TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. Submit Documentation Feedback Copyright (c) 1999-2015, Texas Instruments Incorporated Product Folder Links: LM20 17 PACKAGE OPTION ADDENDUM www.ti.com 11-Jan-2021 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (C) Device Marking (3) (4/5) (6) LM20BIM7 NRND SC70 DCK 5 1000 Non-RoHS & Green Call TI Call TI -55 to 130 T2B LM20BIM7/NOPB ACTIVE SC70 DCK 5 1000 RoHS & Green SN Level-1-260C-UNLIM -55 to 130 T2B LM20BIM7X NRND SC70 DCK 5 3000 Non-RoHS & Green Call TI Call TI -55 to 130 T2B LM20BIM7X/NOPB ACTIVE SC70 DCK 5 3000 RoHS & Green Call TI | SN Level-1-260C-UNLIM -55 to 130 T2B LM20CIM7/NOPB ACTIVE SC70 DCK 5 1000 RoHS & Green SN Level-1-260C-UNLIM -55 to 130 T2C LM20CIM7X NRND SC70 DCK 5 3000 Non-RoHS & Green Call TI Call TI -55 to 130 T2C LM20CIM7X/NOPB ACTIVE SC70 DCK 5 3000 RoHS & Green SN Level-1-260C-UNLIM -55 to 130 T2C LM20SITL/NOPB ACTIVE DSBGA YZR 4 250 RoHS & Green SNAGCU Level-1-260C-UNLIM -40 to 125 LM20SITLX/NOPB ACTIVE DSBGA YZR 4 3000 RoHS & Green SNAGCU Level-1-260C-UNLIM -40 to 125 (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. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". 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. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 11-Jan-2021 (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 29-Sep-2019 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LM20BIM7 SC70 DCK 5 1000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LM20BIM7/NOPB SC70 DCK 5 1000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LM20BIM7X SC70 DCK 5 3000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LM20BIM7X/NOPB SC70 DCK 5 3000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LM20CIM7/NOPB SC70 DCK 5 1000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LM20CIM7X SC70 DCK 5 3000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LM20CIM7X/NOPB SC70 DCK 5 3000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LM20SITL/NOPB DSBGA YZR 4 250 178.0 8.4 1.04 1.04 0.76 4.0 8.0 Q1 LM20SITLX/NOPB DSBGA YZR 4 3000 178.0 8.4 1.04 1.04 0.76 4.0 8.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 29-Sep-2019 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM20BIM7 SC70 DCK 5 1000 210.0 185.0 35.0 LM20BIM7/NOPB SC70 DCK 5 1000 210.0 185.0 35.0 LM20BIM7X SC70 DCK 5 3000 210.0 185.0 35.0 LM20BIM7X/NOPB SC70 DCK 5 3000 210.0 185.0 35.0 LM20CIM7/NOPB SC70 DCK 5 1000 210.0 185.0 35.0 LM20CIM7X SC70 DCK 5 3000 210.0 185.0 35.0 LM20CIM7X/NOPB SC70 DCK 5 3000 210.0 185.0 35.0 LM20SITL/NOPB DSBGA YZR 4 250 210.0 185.0 35.0 LM20SITLX/NOPB DSBGA YZR 4 3000 210.0 185.0 35.0 Pack Materials-Page 2 MECHANICAL DATA YZR0004xxx D 0.6000.075 E TLA04XXX (Rev D) D: Max = 0.994 mm, Min =0.933 mm E: Max = 0.994 mm, Min =0.933 mm 4215042/A NOTES: A. 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