LMT89 www.ti.com SNIS176 – MARCH 2013 LMT89 2.4V, 10µA, SC70, Temperature Sensor Check for Samples: LMT89 FEATURES DESCRIPTION • • • • • The LMT89 is a precision analog output CMOS integrated-circuit temperature sensor that operates over a −55°C to 130°C temperature range. The power supply operating range is 2.4 V to 5.5 V. The transfer function of LMT89 is predominately linear, yet has a slight predictable parabolic curvature. The accuracy of the LMT89 when specified to a parabolic transfer function is ±1.5°C at an ambient temperature of 30°C. The temperature error increases linearly and reaches a maximum of ±2.5°C 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 130°C and −55°C. Decreasing the power supply voltage to 2.4 V changes the negative extreme to −30°C, while the positive remains at 130°C. 1 2 Cost-Effective Alternative to Thermistors Rated for full −55°C to +130°C range Available in an SC70 Package Predictable Curvature Error Suitable for Remote Applications APPLICATIONS • • • • • • • • • • • • Industrial HVAC Automotive Disk Drives Portable Medical Instruments Computers Battery Management Printers Power Supply Modules FAX Machines Mobile Phones Automotive The LMT89 quiescent current is less than 10 μA. Therefore, self-heating is less than 0.02°C in still air. Shutdown capability for the LMT89 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 LMT89 is a cost-competitive alternative to thermistors. TYPICAL APPLICATION Full-Range Celsius (Centigrade) Temperature Sensor (−55°C TO 130°C) Operating From a Single LI-Ion Battery Cell V+ VO LMT89 GND NC VO = (−3.88×10−6×T2) + (−1.15×10−2×T) + 1.8639 spacer between the 2 equations (1.8639 VO ) 6 T 1481.96 2.1962 u 10 6 3.88 u 10 where: T is temperature, and VO is the measured output voltage of the LMT89. 1 2 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2013, Texas Instruments Incorporated LMT89 SNIS176 – MARCH 2013 www.ti.com Figure 1. Output Voltage vs Temperature Table 1. Output Voltage vs Temperature TEMPERATURE (T) TYPICAL VO 130°C 303 mV 100°C 675 mV 80°C 919 mV 30°C 1515 mV 25°C 1574 mV 0°C 1863.9 mV –30°C 2205 mV −40°C 2318 mV −55°C 2485 mV CONNECTION DIAGRAMS V+ 4 3 VO LMT89 5 GND 2 GND 1 NC GND (pin 2) may be grounded or left floating. For optimum thermal conductivity to the pc board ground plane, pin 2 must be grounded. NC (pin 1) must be left floating or grounded. Other signal traces must not be connected to this pin. Figure 2. SC70-5 Top View 2 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LMT89 LMT89 www.ti.com SNIS176 – MARCH 2013 ABSOLUTE MAXIMUM RATINGS (1) VALUES Supply Voltage 6.5V to −0.2V Output Voltage (V+ + 0.6 V) to −0.6 V Output Current 10 mA Input Current at any pin (2) 5 mA −65°C to 150°C Storage Temperature Maximum Junction Temperature (TJMAX) ESD Susceptibility (3) 150°C Human Body Model 2500 V Machine Model 250 V Soldering process must comply with the Reflow Temperature Profile specifications. Refer to www.ti.com/packaging. (4) (1) (2) (3) (4) 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 specifications and test conditions, see the ELECTRICAL CHARACTERISTICS. The specified specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions. 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. The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200 pF capacitor discharged directly into each pin. Reflow temperature profiles are different for lead-free and non-lead-free packages. OPERATION RATINGS TMIN ≤ TA ≤ TMAX Specified Temperature Range: + LMT89 with 2.4 V ≤ V ≤ 2.7 V −30°C ≤ TA ≤ 130°C LMT89 with 2.7 V ≤ V+≤ 5.5 V −55°C ≤ TA ≤ 130°C Supply Voltage Range (V+) 2.4 V to 5.5 V Thermal Resistance, θJA (1) SC70 415°C/W (1) The junction to ambient thermal resistance (θJA) is specified without a heat sink in still air using the printed circuit board layout shown in PCB Layouts Used For Thermal Measurements. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LMT89 3 LMT89 SNIS176 – MARCH 2013 www.ti.com 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 = 25°C; Unless otherwise noted. PARAMETER Temperature to Voltage Error VO = (−3.88×10−6×T2) + (−1.15×10−2×T) + 1.8639V (3) CONDITIONS TA = 25°C to 30°C TYPICAL (1) MAX (2) ±1.5 TA = –55°C UNIT (Limit) °C ±2.5 °C Output Voltage at 0°C 1.8639 V Variance from Curve ±1.0 °C (4) –20°C ≤ TA ≤ 80°C ±0.4% Sensor Gain (Temperature Sensitivity or Average Slope) to equation: VO=−11.77 mV/ °C×T+1.860V –30°C ≤ TA ≤ 100°C −11.77 Output Impedance 0 μA ≤ IL ≤ 16 μA (5) (6) 160 Ω Load Regulation (7) 0 μA ≤ IL ≤ 16 μA (5) (6) −2.5 mV 2.4 V ≤ V+ ≤ 5.0V 3.3 mV/V 5.0 V ≤ V+ ≤ 5.5 V 11 mV 7 μA Non-Linearity Line Regulation (8) 2.4V ≤ V+ ≤ 5.0V Quiescent Current Change of Quiescent Current + (1) (2) (3) (4) (5) (6) (7) (8) 4 mV/°C (min) mV/°C (max) 5.0V ≤ V ≤ 5.5V 4.5 9 μA 2.4V ≤ V+ ≤ 5.0V 4.5 10 μA 2.4 V ≤ V+ ≤ 5.5V 0.7 μA −11 nA/°C V+ ≤ 0.8 V 0.02 μA Temperature Coefficient of Quiescent Current Shutdown Current 4.5 −11.4 −12.2 Typicals are at TJ = TA = 25°C and represent most likely parametric norm. Limits are specified to TI's AOQL (Average Outgoing Quality Level). 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. Negative currents are flowing into the LMT89. Positive currents are flowing out of the LMT89. Using this convention the LMT89 can at most sink −1 μA and source 16 μA. Load regulation or output impedance specifications apply over the supply voltage range of 2.4V to 5.5V. 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 © 2013, Texas Instruments Incorporated Product Folder Links: LMT89 LMT89 www.ti.com SNIS176 – MARCH 2013 TYPICAL PERFORMANCE CHARACTERISTICS Temperature Error vs Temperature PCB Layouts Used For Thermal Measurements Figure 3. Layout Used For No Heat Sink Measurements Figure 4. Layout Used For Measurements With Small Heat Sink LMT89 TRANSFER FUNCTION The LMT89 transfer function can be described in different ways with varying levels of precision. A simple linear transfer function, with good accuracy near 25°C, is VO = −11.69 mV/°C × T + 1.8663 V (1) Over the full operating temperature range of −55°C to 130°C, best accuracy can be obtained by using the parabolic transfer function. VO = (−3.88×10−6×T2) + (−1.15×10−2×T) + 1.8639 (2) solving for T: T 1481.96 2.1962 u 10 6 (1.8639 VO ) 3.88 u 10 6 (3) 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 LMT89. The slope of the linear transfer function can be calculated using the following equation: m = −7.76 × 10−6× T − 0.0115, (4) 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 = +100°C: T = 35°C (5) m = −11.77 mV/°C (6) and The offset of the linear transfer function can be calculated using the following equation: Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LMT89 5 LMT89 SNIS176 – MARCH 2013 www.ti.com b = (VOP(TMAX) + VOP(T) − m × (TMAX+T))/2 (7) 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 Table 2. As shown in Table 2 the error that is introduced by the linear transfer function increases with wider temperature ranges. Table 2. First Order Equations Optimized for Different Temperature Ranges TEMPERATURE RANGE LINEAR EQUATION MAXIMUM DEVIATION OF LINEAR EQUATION FROM PARABOLIC EQUATION (°C) 130 VO = −11.79 mV/°C × T + 1.8528 V ±1.41 110 VO = −11.77 mV/°C × T + 1.8577 V ±0.93 −30 100 VO = −11.77 mV/°C × T + 1.8605 V ±0.70 ±0.65 Tmin (°C) Tmax (°C) −55 −40 -40 85 VO = −11.67 mV/°C × T + 1.8583 V −10 65 VO = −11.71 mV/°C × T + 1.8641 V ±0.23 35 45 VO = −11.81 mV/°C × T + 1.8701 V ±0.004 20 30 VO = –11.69 mV/°C × T + 1.8663 V ±0.004 MOUNTING The LMT89 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 LMT89 is sensing will be within about +0.02°C of the surface temperature to which the LMT89'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 LMT89 die is directly attached to the pin 2 GND pin. The tempertures of the lands and traces to the other leads of the LMT89 will also affect the temperature that is being sensed. Alternatively, the LMT89 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 LMT89 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 ensure that moisture cannot corrode the LMT89 or its connections. The thermal resistance junction to ambient (θJA) is the parameter used to calculate the rise of a device junction temperature due to its power dissipation. For the LMT89 the equation used to calculate the rise in the die temperature is as follows: TJ = TA + θJA [(V+ IQ) + (V+ − VO) IL] where IQ is the quiescent current and ILis the load current on the output. Since the LMT89's junction temperature is the actual temperature being measured care should be taken to minimize the load current that the LMT89 is required to drive. The tables shown in Table 3 summarize the rise in die temperature of the LMT89 without any loading, and the thermal resistance for different conditions. 6 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LMT89 LMT89 www.ti.com SNIS176 – MARCH 2013 Table 3. Temperature Rise of LMT89 Due to Self-Heating and Thermal Resistance (θJA) (1) SC70-5 SC70-5 NO HEAT SINK SMALL HEAT SINK θJA (°C/W) TJ − TA (°C) θJA (°C/W) TJ − TA (°C) Still air 412 0.2 350 0.19 Moving air 312 0.17 266 0.15 (1) See PCB Layouts Used For Thermal Measurements for PCB layout samples. CAPACITIVE LOADS The LMT89 handles capacitive loading well. Without any precautions, the LMT89 can drive any capacitive load less than 300 pF as shown in . Over the specified temperature range the LMT89 has a maximum output impedance of 160 Ω. In an extremely noisy environment it may be necessary to add some filtering to minimize noise pickup. It is recommended that 0.1 μF 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 μF output capacitor with the 160 Ω maximum output impedance and a 200 Ω series resistor will form a 442 Hz lowpass filter. Since the thermal time constant of the LMT89 is much slower, the overall response time of the LMT89 will not be significantly affected. + Heavy Capacitive Load, Wiring, Etc. LMT89 To A High-Impedance Load OUT d Figure 5. LMT89 No Decoupling Required for Capacitive Loads Less Than 300 pF R (Ω) C (µF) 200 1 470 0.1 680 0.01 1k 0.001 + LMT89 0.1 µF Bypass Optional Heavy Capacitive Load, Wiring, Etc. OUT d R C + Heavy Capacitive Load, Wiring, Etc. R LMT89 0.1 µF Bypass Optional OUT d C Figure 6. LMT89 with Filter for Noisy Environment and Capacitive Loading Greater Than 300 pF NOTE Either placement of resistor as shown above is just as effective. Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LMT89 7 LMT89 SNIS176 – MARCH 2013 www.ti.com APPLICATION CIRCUITS V+ VTEMP R3 VT1 R4 VT2 LM4040 V+ VT R1 4.1V U3 0.1 PF LMT89 (High = overtemp alarm) + U1 - R2 VOUT VOUT LM7211 VTemp U2 VT1 = (4.1)R2 R2 + R1||R3 VT2 = (4.1)R2||R3 R1 + R2||R3 Figure 7. Centigrade Thermostat +VS SHUTDOWN VO LMT89 Any logic device output Figure 8. Conserving Power Dissipation with Shutdown V+ (+5.0V) 1k 1 0.1 PF LM4040BIM3-4.1 4 5 3 V+ VO LMT89 2 GND GND NC 1 470 Ÿ V+ 6 3 VIN 5 4 0.1 PF 2 CS DO CLK ADCV0831 GND Figure 9. Suggested Connection to a Sampling 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 LMT89 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. 8 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated Product Folder Links: LMT89 PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish (2) MSL Peak Temp Op Temp (°C) Top-Side Markings (3) (4) LMT89DCKR ACTIVE SC70 DCK 5 3000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -55 to 130 T3B LMT89DCKT ACTIVE SC70 DCK 5 250 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -55 to 130 T3B (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) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) Multiple Top-Side Markings will be inside parentheses. Only one Top-Side 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 Top-Side Marking for that device. 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Addendum-Page 1 Samples PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-2013 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 LMT89DCKR SC70 DCK 5 3000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LMT89DCKT SC70 DCK 5 250 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LMT89DCKR SC70 DCK 5 3000 210.0 185.0 35.0 LMT89DCKT SC70 DCK 5 250 210.0 185.0 35.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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