www.fairchildsemi.com FM50 Analog Temperature Sensor Features Description • • • • • • • As a precision CMOS temperature sensor, the FM50 is cost-effective for accurate low-power temperature monitoring applications. Output voltage versus temperature is extremely linear. With no load, the supply current is typically 130µA. For normal operation, the load on VOUT should be 100KΩ or less. Analog output: 10 mV/°C Range: -40 to 125°C range: Accuracy: ±1°C at 25°C Supply Current, 170 µA max. Output Drive, 25 µA Self-heating < 0.1°C Operating Voltage: +2.4V to +6V In a typical application, a remotely mounted FM50 is monitored by a microcontroller with an analog A/D converter input. Alternatively, the FM50 can drive a comparator with a high impedance input. Applications • • • • • • • • Mobile Phones Computers Battery Management Office Equipment HVAC Power Supply Modules Disk Drives Automotive Accuracy is typically ± 0.5°C at room temperature; and better than ±2°C from 0 to 75°C. Package is a 3-pin SOT-23 Thermal Response VOUT (mV) 1750 750 500 100 -50 -40 -25 0 25 50 75 100 125 Temperature ( C) Temperature ( C) = VOUT - 500 mV 10 mV/ C FM50 Output Voltage vs. Temperature REV. 1.0.8 9/12/02 FM50 PRODUCT SPECIFICATION Pin Assignments GND 3 FM50 1 2 VDD VOUT Pin Descriptions Pin Name Pin No. 2 Type Function VOUT 2 Analog Output Temperature Sense. Analog output voltage indicating temperature. VOUT = 500+10T(°C) mV VDD 1 Power Supply Voltage. 2.4 to 6.0V GND 3 Power Ground. REV. 1.0.8 9/12/02 PRODUCT SPECIFICATION FM50 Absolute Maximum Ratings1 Parameter Min. Typ. Max. Units Supply Voltage +7 V Output Voltage VDD + 0.5 V 10 µA -50 +150 °C -60 +150 °C Lead Soldering Temperature 220 °C ESD2 Human Body Model Machine Model 2000 250 V V Output Current Operating Temperature Range2 Storage Temperature Range Notes: 1. Absolute maximum ratings are limits beyond which operation may cause permanent damage to the device. These are stress ratings only; functional operation at or above these limits is not implied. 2. Operating ratings are conditions for which the device is intended to be functional without specific guaranteed performance limits. For guaranteed specifications and test conditions refer to Electrical Characteristics. 3. Human Body Model: 100pF capacitor discharged through a 1.5kOhm resistor into each pin. Machine Model: 200pF capacitor discharged directly into each pin. Electrical Characteristics4 Limits apply for -40°C ≤ TA ≤ +125°C and VDD = +5.0V unless otherwise noted. Parameter Transfer Characteristic Sensitivity Output at 25°C Accuracy5 Temperature Range Non-Linearity6 Output Output Voltage Range Output Current Source Output Current Sink Output resistance Load regulation Power Supply Voltage Quiescent Current Package Thermal Resistance Symbol Conditions Min Typ Max Units 10 750 10.3 760 mV/°C mV TA = +25°C TA = -40°C (TMIN) TA = +125°C (TMAX) 9.7 740 -1 -3.5 -3 ±0.5 ±1 ±1 +1 +3.5 +3 °C °C °C °C °C AOUT -40 -0.8 +125 +0.8 100 IONSN IONSG IOL Sensing Surge 50 100kΩ load at 25°C VDD IS 1500 25 1 10 2.4 6.0 170 No output load 260 mV µA mA µA kΩ mV/mA V µA °C/W Notes: 4. These specifications are guaranteed only for the test conditions listed. 5. Accuracy (expressed in °C) = Difference between calculated output voltage and measured output voltage. Calculated output voltage = 10mV/°C multiplied by the device’s case temperature at specified conditions of temperature, voltage and power supply, added to 500mV. 6. Non-linearity 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. REV. 1.0.8 9/12/02 3 FM50 PRODUCT SPECIFICATION Typical Performance Characteristics 4.0 upper spec limit 3.0 VDD = +5V Accuracy (°C) 2.0 1.0 0.0 -1.0 -2.0 -3.0 lower spec limit -4.0 0 -50 50 150 100 Temperature (°C) Figure 1. Accuracy vs. Temperature VOUT Deviation from 5V Value (mV) 140.0 Supply Current (uA) 120.0 100.0 80.0 60.0 40.0 20.0 0.0 -50 -30 -10 10 30 50 70 90 110 130 Temperature (°C) Figure 2. Typical IDD versus Temperature Description Within the FM50 are a thermal diode, calibration circuits and amplifiers. Since the FM50 is calibrated at 33°C, the nominal output in mV is: V OUT = 830 + 10 • ( T – 33 ) 5.0 4.0 3.0 2.0 1.0 0.0 -1.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 VDD Volts Figure 3. Typical Sensitivity to Supply Voltage These values accommodate the specified accuracies at -40, 25 and +125°C. Output structure of the FM50 is an n-channel CMOS transistor driving a p-channel load. Available current is typically 50 µA to ground. Series resistance is typically 7 kΩ, charging and 2 kΩ, discharging through a capacitor connected from VOUT to ground. where T is the thermal junction temperature expressed in °C. At 33°C, the tolerances are as follows: 1. Offset is ±3mV 2. Slope, ±0.3mV/°C 4 Following application of power to VDD, VOUT is accurate following a delay of approximately 80 msec. REV. 1.0.8 9/12/02 PRODUCT SPECIFICATION FM50 Applications Information Although the FM50 is a simple device, care must be taken to ensure that temperature is measured accurately. There are two major sources of errors: 3. Voltage errors. 4. Thermal Delay Errors. 5. Location errors Location Errors Position is another source of error. Even within a controlled thermal environment, changing location by a few inches can lead to errors of several tenths of 1°C Mounting The FM50 can be easily mounted by gluing or cementing it to a surface. In this case, its temperature will be within about 0.2°C of the temperature of the surface it is attached to if the ambient air temperature is almost the same as the surface temperature. If the air temperature is much higher or lower than the surface temperature, the actual temperature of the FM50 die will be at an intermediate temperature between the surface temperature and the air temperature. Voltage Errors VDD FM50 GND(power) VOUT GND(sense) Figure 4. Recommended Electrical Connections A Kelvin connection is recommended to avoid errors due to voltage drops in the ground connections. Although the typical 130µA supply current draw of the FM50 will only cause a 130µV error if the series resistance is 1Ω, a 100 mA current supply to adjacent circuits can cause a 10mV drop across 100mΩ (10mΩ is a typical value for soldered joints or contact resistance), leading to a 1°C error. For this reason, the FM50 should be Kelvin connected as shown in Figure 4. Thermal Delay Errors To ensure good thermal conductivity, the backside of the FM50 die is directly attached to the GND pin. The lands and traces to the FM50 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 FM50’s temperature to deviate from the desired temperature. Alternatively, the FM50 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 FM50 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 paint or dips can be used to ensure that moisture cannot corrode the FM50 or its connections. For measurement accuracy of the order of tenths of 1°C, adequate settling time must be allowed. For a typical circuit board installation, 15 minutes should be allowed to elapse following reading of temperature within 1 - 2°C of the expected final value. Once VOUT has ceased to slew and is stable (with or without about ±0.1°C noise) for about 5 minutes, temperature can be calculated. REV. 1.0.8 9/12/02 5 FM50 PRODUCT SPECIFICATION Typical Applications Circuits 3.9K VTEMP IN REF 1.75V FM50 U1 Serial Analog-to-Digital Converter SERIAL DATA OUT U3 100K FB 1µF Adjustable Shunt Voltage Reference CLOCK U2 10K ENABLE Figure 4. Serial Output Temperature to Digital Converter (Full Scale = +125°C) 5V 30K PARALLEL DATA OUTPUT 8 VTEMP FM50 IN U1 + 5K 1µF Parallel Output Analog-to-Digital Converter VREF U2 1.75V INTR U3 CS RD 15K WR Figure 5. Parallel Output Temperature to Digital Converter (Full Scale = +125°C) 6 REV. 1.0.8 9/12/02 PRODUCT SPECIFICATION FM50 Typical Applications (continued) V+ R3 R4 R1 VT 4.1V Shunt Voltage Reference U1 U3 0.1µF R2 V+ - FM50 VOUT + VTEMP U2 Figure 6. Thermostat/Fan Controller REV. 1.0.8 9/12/02 7 FM50 PRODUCT SPECIFICATION Mechanical Dimensions inches (millimeters) unless otherwise noted SOT-23 FS Package Code AU 0.110 (2.800) 0.120 (3.040) 0.047 (1.20) 0.055 (1.40) 0.083 (2.100) 0.104 (2.640) PIN 1 0.035 (0.890) 0.041 (1.030) 0.070 (1.780) 0.081 (2.050) 0.017 (0.450) 0.024 (0.600) 0.035 (0.890) 0.044 (1.120) 0.0005 (0.013) 0.004 (0.100) SEATING PLANE 0.015 (0.370) 0.020 (0.510) 0.015 (0.085) 0.007 (0.180) 10° 0° 0.0217 REF (0.55) REF Ordering Information Part Number FM50S3X Package Temperature Range Shipping 3-Pin SOT-23 -40°C to +125°C Tape and Reel, 3000 units/reel DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD 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 (c) 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 of the user. 2. A critical component in 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. www.fairchildsemi.com 9/12/02 0.0m 003 Stock#DS30000050 2002 Fairchild Semiconductor Corporation