www.fairchildsemi.com FM20 Ultra-Low-Power Analog Temperature Sensor Features Description • • • • • • • As a precision CMOS temperature sensor, the FM20 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 1µA. For normal operation, the load on VOUT should be 5MΩ or less. Analog Output, -11.77mV/°C Range, -55 to 130°C Accuracy, ±1°C at 25°C Supply Current, 9µA typical Output Drive, 1µA Self-heating < 0.021°C Operating Voltage: +2.4V to +6V In a typical application, a remotely mounted FM20 is monitored by a microcontroller with an analog A/D converter input. Alternatively, the FM20 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 ±1°C at room temperature; and better than ±2.5°C from 0 to 50°C. Available packages are surface mount 5-pin SC70 and 3-pin SOT-23. Thermal Response VOUT (mV) 1863.9 391 -50 -40 -25 0 25 50 75 100 125 Temperature (˚C) Temperature (˚C) = VOUT – 1863.9mV –11.77mV/˚C FM20 Output Voltage vs. Temperature REV. 1.0.6 1/9/03 FM20 PRODUCT SPECIFICATION Pin Assignments VOUT GND N/C GND 3 2 1 3 FM20 FM20 4 5 1 2 VDD GND VDD VOUT Pin Descriptions Pin No. Pin Name SC-70 SOT-23 2 Type Function VOUT 3 2 Analog Output Temperature Sense. Analog output voltage indicating temperature. VOUT = 1863.9 – 11.77 T(°C) mV VDD 4 1 Power Supply Voltage. 2.4 to 6.0V GND 2, 5 3 Power Ground. REV. 1.0.6 1/9/03 PRODUCT SPECIFICATION FM20 Absolute Maximum Ratings1 Parameter Min. Supply Voltage Output Voltage Output Current Storage Temperature Range Lead Soldering Temperature ESD2 Human Body Model Machine Model Typ. -60 Max. +7 VDD + 0.5 -20/+1 +150 220 Units V V µA °C °C 2000 250 V V 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. Human Body Model: 100pF capacitor discharged through a 1.5kΩ resistor into each pin. Machine Model: 200pF capacitor discharged directly into each pin. Electrical Characteristics3 Limits apply for -55°C ≤ TA ≤ +130°C and VDD = +5.0V unless otherwise noted. Parameter Transfer Characteristic Sensitivity Output at 0°C Accuracy4 Temperature Range Non-Linearity5 Output Output Voltage Range Output Current Source6 Output Current Sink6 Output resistance Load regulation Capacitive Load7 Power Supply Voltage Quiescent Supply Current Output Floating Package Self Heating Symbol Conditions Min TA = +25°C TA = -55°C (TMIN) TA = +130°C (TMAX) -2 -3 -5 -55 -0.5 VOUT < VDD Sensing Surge 300 Typ -11.77 1863.9 ±1 ±2 ±2 Max Units +2 +3 +5 +130 +0.2 mV/°C mV °C °C °C °C °C CL 100 1000 mV µA mA µA kΩ mV/mA pF VDD IDD 2.4 6.0 11.5 14 V µA µA 0.02016 0.02082 °C °C IONSN IONSG IOL 2550 1 20 TA = 25°C TA = +25°C -55°C ≤ TA ≤ +130°C SOT-23 SC70 9 9 Notes: 3. These specifications are guaranteed only for the test conditions listed. 4. Accuracy (expressed in °C) = Difference between calculated output voltage and measured output voltage. Calculated output voltage = -11.77mV/°C multiplied by device’s case temperature at specified conditions of temperature, voltage and power supply plus an offset of 1863.9 mV at 0°C. 5. 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. 6. Lowest output current should be targeted; higher currents result in more self-heating of the device. 7. High capacitive loads may be driven by the output in a static mode, but it may require a delay time before initial read at power up to allow for the RC time constant of the charging capacitor. REV. 1.0.6 1/9/03 3 FM20 PRODUCT SPECIFICATION Typical Performance Characteristics Quiescent Current (µA) 12 VDD = +5V 11 10 9 8 7 6 -50 -25 0 25 50 75 100 125 Temperature (°C) Figure 1. Quiescent Current vs. Temperature VDD =+5V 3 Accuracy (°C) 2 upper spec limit 1 0 -1 -2 -3 -4 lower spec limit -5 -50 0 50 100 Temperature (°C) Figure 2. Accuracy vs. Temperature Applications Information Mounting The FM20 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 FM20 die will be at an intermediate temperature between the surface temperature and the air temperature. To ensure good thermal conductivity, the backside of the FM20 die is directly attached to the GND pin. The lands and traces to the FM20 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 FM20’s temperature to deviate from the desired temperature. Alternatively, the FM20 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 FM20 and 4 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 FM20 or its connections. Loading The FM20 will handle sizable capacitive loads up to 300pF without any special considerations. In an extremely noisy environment it may be advisable to add some filtering to minimize noise in the output voltage. It is also recommended that a 0.1µF bypass capacitor be added between the supply voltage and ground. This is due to the instant current demand caused by switching CMOS transistors. Normally it is unadvisable to put a sufficiently large supply (particularly in portable electronics) to be able to handle the dynamic currents of CMOS transistors. It is a much simpler solution to use a bypass capacitor to sustain the supply voltage during this short demand period. REV. 1.0.6 1/9/03 PRODUCT SPECIFICATION FM20 In environments that are particularly noisy it may be necessary to add a low-pass filter network to the output of the device. As shown below, a 1µF capacitor in addition to the output impedance of the device and a 200Ω series resistor for a low-pass filter that will pass the slow thermal time con- stant of the FM20, while filtering the higher frequency noise. The response time of the FM20 can be affected by this filter network, therefore values for CFILTER < 1500pF are recommended. CFILTER GND 0.1µF Bypass Cap RFILTER VDD VOUT CL CFILTER GND 0.1µF Bypass Cap VDD VOUT CL RFILTER Figure 3. FM20 with Filter Network for Noisy Environments or for Capacitive Loads Greater than 300pF Table 1. Resistor/Capacitor Combinations for Filter Network RFILTER CFILTER 200Ω 1µF 470Ω 0.1µF 680Ω 0.01µF 1000Ω 1000pF 10kΩ 100pF 100kΩ 10pF REV. 1.0.6 1/9/03 5 FM20 PRODUCT SPECIFICATION Example Applications Circuits Typical Applications 5V 3.9KΩ VTemp FM20 IN Serial REF Analog-to-Digital Converter 1.75V SERIAL DATA OUT + 100KΩ FB Adjustable Shunt Voltage Reference CLOCK 1µF 10KΩ ENABLE Figure 4. Serial Output Temperature to Digital Converter (The full scale of the A-to-D Converter will typically be limited to +125°C simply by the number of bits available in the conversion. The FM20 would still be capable of its full output swing.) 5V 30KΩ VTemp 8 IN FM20 Parallel Output Analog-to-Digital Converter _ VREF 5KΩ + PARALLEL DATA OUTPUT 1.75V INTR 1µF CS 15KΩ RD WR Figure 5. Parallel Output Temperature to Digital Converter (Full Scale = +125°C) 6 REV. 1.0.6 1/9/03 PRODUCT SPECIFICATION FM20 Typical Applications (continued) V+ RHYST RV+ RVD1 VREF VTRIP Shunt Voltage Reference VCONTROL 0.1µF RVD2 V+ FM20 VOUT (VREF) • (RVD2) VHYST2 = VHYST2 (RVD2) • (RHYST) RVD1 + RHYST + RVD2 VHYST1 VOUT VCONTROL (VREF) • (RVD2) VHYST1 = RVD2 + (RVD1) • (RHYST) RHYST + RVD1 VREF is set by the Shunt Voltage Reference. VCONTROL high is an alarm state or control for activating cooling/fan. Figure 6. Thermostat/Fan Controller GND CFILTER 0.1µF Bypass Cap FM20 VOUT VDD RFILTER Microcontroller Analog to Digital Converter Figure 7. Digital Temperature Output Through a Microcontroller REV. 1.0.6 1/9/03 7 FM20 PRODUCT SPECIFICATION Mechanical Dimensions inches (millimeters) unless otherwise noted SOT-23 FS Package Code MA03A 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) 0.017 (0.450) 0.024 (0.600) 0.070 (1.780) 0.081 (2.050) 0.035 (0.890) 0.044 (1.120) 0.0005 (0.013) 0.004 (0.100) 0.015 (0.370) 0.020 (0.510) SEATING PLANE 10° 0° 0.015 (0.085) 0.007 (0.180) 0.0217 REF (0.55) REF SC70 5-pin FS Package Code MAA05A 0.65 -A- 2.00±0.20 0.65 5 .5 min 4 1.9 -B- 1.25±0.10 1 0.25 2 2.10±0.10 3 0.4 min +0.10 0.20 -0.05 LAND PATTERN RECOMMENDATION max 0.1 M SEE DETAIL A 0.9±.10 0.25 0.10 0.95±.15 0.10 0.00 6.00° max 0.1 R0.14 GAGE PLANE R0.10 0°-30° 0.20 6.00° 0.45 0.10 0.425 NOMINAL DETAIL A NOTES: A. CONFORMS TO EIAJ REGISTERED OUTLINE DRAWING SC88A. B. DIMENSIONS DO NOT INCLUDE BURRS OR MOLD FLASH. C. DIMENSIONS ARE IN MILLIMETERS. 8 REV. 1.0.6 1/9/03 FM20 PRODUCT SPECIFICATION Ordering Information Part Number Package Temperature Range Shipping FM20P5X 5-Pin SC70 -55°C to +130°C Tape and Reel, 3000 units/reel FM20S3X 3-Pin SOT-23 -55°C to +130°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 1/9/03 0.0m 003 Stock#DS30000020 2002 Fairchild Semiconductor Corporation