LM60BIM3X

LM60 2.7V, SOT-23 or TO-92 Temperature Sensor August 2005 LM60 2.7V, SOT-23 or TO-92 Temperature Sensor General Description The LM60 is a precision integrated-circuit temperature sensor that can sense a −40˚C to +125˚C temperature range while operating from a single +2.7V supply. The LM60’s output voltage is linearly proportional to Celsius (Centigrade) temperature (+6.25 mV/˚C) and has a DC offset of +424 mV. The offset allows reading negative temperatures without the need for a negative supply. The nominal output voltage of the LM60 ranges from +174 mV to +1205 mV for a −40˚C to +125˚C temperature range. The LM60 is calibrated to provide accuracies of ± 2.0˚C at room temperature and ± 3˚C over the full −25˚C to +125˚C temperature range. The LM60’s linear output, +424 mV offset, and factory calibration simplify external circuitry required in a single supply environment where reading negative temperatures is required. Because the LM60’s quiescent current is less than 110 µA, self-heating is limited to a very low 0.1˚C in still air in the SOT-23 package. Shutdown capability for the LM60 is intrinsic because its inherent low power consumption allows it to be powered directly from the output of many logic gates. n Available in SOT-23 and TO-92 packages Applications n n n n n n n n n Cellular Phones Computers Power Supply Modules Battery Management FAX Machines Printers HVAC Disk Drives Appliances Key Specifications n n n n n n n n Features n Calibrated linear scale factor of +6.25 mV/˚C n Rated for full −40˚ to +125˚C range n Suitable for remote applications ± 2.0 and ± 3.0˚C (max) Accuracy at 25˚C: ± 4.0˚C (max) Accuracy for −40˚C to +125˚C: ± 3.0˚C (max) Accuracy for −25˚C to +125˚C: Temperature Slope: +6.25mV/˚C Power Supply Voltage Range: +2.7V to +10V Current Drain @ 25˚C: 110µA (max) Nonlinearity: ± 0.8˚C (max) Output Impedance: 800Ω (max) Typical Application Connection Diagrams SOT-23 01268101 01268102 VO = (+6.25 mV/˚C x T ˚C) + 424 mV Top View See NS Package Number mf03a TO-92 Temperature (T) +125˚C +100˚C +25˚C 0˚C −25˚C −40˚C Typical VO +1205 mV +1049 mV +580 mV +424 mV +268 mV +174 mV 01268123 See NS Package Number Z03A FIGURE 1. Full-Range Centigrade Temperature Sensor (−40˚C to +125˚C) Operating from a Single Li-Ion Battery Cell © 2005 National Semiconductor Corporation DS012681 www.national.com LM60 Ordering Information Order Number LM60BIM3 LM60BIM3X LM60CIM3 LM60CIM3X LM60BIZ LM60CIZ Device Top Mark T6B T6B T6C T6C LM60BIZ LM60CIZ Supplied In Accuracy Over Specified Temperature Range Specified Temperature Range −25˚C ≤ TA ≤ +125˚C −40˚C ≤ TA ≤ +125˚C −25˚C ≤ TA ≤ +125˚C −40˚C ≤ TA ≤ +125˚C Package Type 1000 Units, Tape and Reel 3000 Units, Tape and Reel 1000 Units, Tape and Reel 3000 Units, Tape and Reel Bulk Bulk ±3 ±4 ±3 ±4 SOT-23 TO-92 www.national.com 2 LM60 Absolute Maximum Ratings (Note 1) Supply Voltage Output Voltage Output Current Input Current at any pin (Note 2) ESD Susceptibility (Note 3) : Human Body Model Machine Model SOT-23 TO-92 Storage Temperature Maximum Junction Temperature (TJMAX) 2500V 250V 200V −65˚C to +150˚C +125˚C +12V to −0.2V (+VS + 0.6V) to −0.6V 10 mA 5 mA Operating Ratings(Note 1) Specified Temperature Range: LM60B LM60C Supply Voltage Range (+VS) Thermal Resistance, θJA (Note 5) SOT-23 TO-92 TMIN ≤ TA ≤ TMAX −25˚C ≤ TA ≤ +125˚C −40˚C ≤ TA ≤ +125˚C +2.7V to +10V 450˚C/W 180˚C/W Soldering process must comply with National Semiconductor’s Reflow Temperature Profile specifications. Refer to www.national.com/packaging. (Note 4) Electrical Characteristics Unless otherwise noted, these specifications apply for +VS = +3.0 VDC and I TMIN to TMAX ; all other limits TA = TJ = 25˚C. Parameter Conditions Typical (Note 6) LOAD = 1 µA. Boldface limits apply for TA = TJ = LM60B Limits LM60C Limits (Note 7) Units (Limit) ˚C (max) ˚C (max) mV ˚C (max) mV/˚C (min) mV/˚C (max) Ω (max) mV/V (max) mV (max) µA (max) µA (max) µA (max) µA/˚C ˚C (Note 7) Accuracy (Note 8) Output Voltage at 0˚C Nonlinearity (Note 9) Sensor Gain (Average Slope) Output Impedance Line Regulation (Note 10) Quiescent Current Change of Quiescent Current Temperature Coefficient of Quiescent Current Long Term Stability (Note 11) T J=TMAX=+125˚C, for 1000 hours +3.0V ≤ +V +2.7V ≤ +V +2.7V ≤ +V +2.7V ≤ +V S S S ± 2.0 ± 3.0 +424 ± 3.0 ± 4.0 ± 0.8 +6.00 +6.50 800 ± 0.6 +6.25 +6.06 +6.44 800 ≤ +10V ≤ +3.3V ≤ +10V ≤ +10V 82 ± 0.3 ± 2.3 110 125 ± 0.3 ± 2.3 110 125 S ± 5.0 0.2 ± 0.2 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 > +VS), 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 kΩ resistor into each pin. The machine model is a 200 pF capacitor discharged directly into each pin. Note 4: Reflow temperature profiles are different for lead-free and non-lead-free packages. Note 5: The junction to ambient thermal resistance (θJA) is specified without a heat sink in still air. Note 6: Typicals are at TJ = TA = 25˚C 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 output voltage and +6.25 mV/˚C times the device’s case temperature plus 424 mV, at specified conditions of voltage, current, and temperature (expressed in ˚C). Note 9: Nonlinearity is defined as the deviation of the output-voltage-versus-temperature curve from the best-fit straight line, over the device’s rated temperature range. 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: For best long-term stability, any precision circuit will give best results if the unit is aged at a warm temperature, and/or temperature cycled for at least 46 hours before long-term life test begins. This is especially true when a small (Surface-Mount) part is wave-soldered; allow time for stress relaxation to occur. The majority of the drift will occur in the first 1000 hours at elevated temperatures. The drift after 1000 hours will not continue at the first 1000 hour rate. 3 www.national.com LM60 Typical Performance Characteristics printed circuit board as shown in Figure 2. Thermal Resistance Junction to Air To generate these curves the LM60 was mounted to a Thermal Time Constant 01268103 01268104 Thermal Response in Still Air with Heat Sink Thermal Response in Stirred Oil Bath with Heat Sink 01268105 01268106 Start-Up Voltage vs. Temperature Thermal Response in Still Air without a Heat Sink 01268107 01268108 www.national.com 4 LM60 Typical Performance Characteristics To generate these curves the LM60 was mounted to a printed circuit board as shown in Figure 2. (Continued) Quiescent Current vs. Temperature Accuracy vs Temperature 01268109 01268110 Noise Voltage Supply Voltage vs Supply Current 01268111 01268112 Start-Up Response 01268122 5 www.national.com LM60 Typical Performance Characteristics To generate these curves the LM60 was mounted to a printed circuit board as shown in Figure 2. (Continued) 01268114 FIGURE 2. Printed Circuit Board Used for Heat Sink to Generate All Curves. 1⁄2" Square Printed Circuit Board with 2 oz. Copper Foil or Similar. 1.0 Mounting The LM60 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 LM60 is sensing will be within about +0.1˚C of the surface temperature that LM60’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 of the LM60 die would be at an intermediate temperature between the surface temperature and the air temperature. To ensure good thermal conductivity the backside of the LM60 die is directly attached to the GND pin. The lands and traces to the LM60 will, of course, be part of the printed circuit board, which is the object whose temperature is being measured. These printed circuit board lands and traces will not cause the LM60’s temperature to deviate from the desired temperature. Alternatively, the LM60 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 LM60 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 LM60 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 the device power dissipation. For the LM60 the equation used to calculate the rise in the die temperature is as follows: TJ = TA + θ JA [(+VS IQ) + (+VS − VO) IL] where IQ is the quiescent current and ILis the load current on the output. The table shown in Figure 3 summarizes the rise in die temperature of the LM60 without any loading, and the thermal resistance for different conditions. www.national.com 6 LM60 1.0 Mounting (Continued) SOT-23* no heat sink θ JA (˚C/W) Still air Moving air *-Part soldered to 30 gauge wire. 450 T − TA SOT-23** small heat fin θ JA (˚C/W) 260 180 T − TA TO-92* no heat fin θ JA 180 90 T − TA TO-92*** small heat fin θ JA 140 70 T − TA J J J J (˚C) 0.17 (˚C) 0.1 0.07 0.07 0.034 0.05 0.026 **-Heat sink used is 1⁄2" square printed circuit board with 2 oz. foil with part attached as shown in Figure 2 . ***-Part glued or leads soldered to 1” square of 1/16” printed circuit board with 2 oz. foil or similar. FIGURE 3. Temperature Rise of LM60 Due to Self-Heating and Thermal Resistance (θJA) 2.0 Capacitive Loads The LM60 handles capacitive loading well. Without any special precautions, the LM60 can drive any capacitive load as shown in Figure 4. Over the specified temperature range the LM60 has a maximum output impedance of 800Ω. 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 S to GND to bypass the power supply voltage, as shown in Figure 5. In a noisy environment it may be necessary to add a capacitor from the output to ground. A 1 µF output capacitor with the 800Ω output impedance will form a 199 Hz lowpass filter. Since the thermal time constant of the LM60 is much slower than the 6.3 ms time constant formed by the RC, the overall response time of the LM60 will not be significantly affected. For much larger capacitors this additional time lag will increase the overall response time of the LM60. 01268116 FIGURE 5. LM60 with Filter for Noisy Environment 01268115 FIGURE 4. LM60 No Decoupling Required for Capacitive Load 7 www.national.com LM60 2.0 Capacitive Loads (Continued) 01268117 FIGURE 6. Simplified Schematic www.national.com 8 LM60 3.0 Applications Circuits 01268118 FIGURE 7. Centigrade Thermostat 01268119 FIGURE 8. Conserving Power Dissipation with Shutdown 9 www.national.com LM60 Physical Dimensions inches (millimeters) unless otherwise noted SOT-23 Molded Small Outline Transistor Package (M3) Order Number LM60BIM3 or LM60CIM3 NS Package Number mf03a www.national.com 10 LM60 2.7V, SOT-23 or TO-92 Temperature Sensor Physical Dimensions inches (millimeters) unless otherwise noted (Continued) TO-92 Molded Plastic Package (Z) Order Number LM60BIZ or LM60CIZ Package Number Z03A 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. For the most current product information visit us at www.national.com. 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