FM20 Low Voltage Ultra-Low-Power Temperature Sensor General Description ■ Temperature Range: -55°C to 130°C The FM20 is a precision CMOS temperature sensor that provides a cost-effective solution for space-constrained applications. ■ Output Ramp is Calibrated to Degrees Celsius ■ Linear Output Ramp (-11.77mV/°C) ■ Low Self Heating (0.02°C max in still air) The output voltage ramp of the FM20 has a negative slope of -11.77mV/°C. With a supply voltage of 2.4V to 6V, the FM20 is typically accurate to ±1°C at 25°C, to ±3°C over the range of -55°C to 130°C. Reducing the supply voltage to 2.4V does not change the negative temperature extreme from -55°C, and the positive extreme also remains at +130°C. ■ Uses a Single Positive Supply ■ Operating Voltage Range: +2.4V to +6V Applications ■ Cellular Telephones The FM20 does not require external calibration. Calibration of the FM20 is performed at the factory. ■ Computers The FM20 is available in 5-pin SC70 and 3-pin SOT-23 surface mount packages. ■ FAX Machines/Printers/Copiers Features ■ HVAC ■ Battery Management ■ Portable Medical Instruments ■ Power Supply Modules ■ Extremely Low Power ■ Disk Drives ■ Precision Calibrated to ±1°C (typical) at 25°C ■ Appliances 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 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.) © 2001 Fairchild Semiconductor Corporation FM20 Rev. A.5 1 www.fairchildsemi.com FM20 Low Voltage Ultra-Low-Power Temperature Sensor June 2001 FM20 Low Voltage Ultra-Low-Power Temperature Sensor Typical Applications (continued) 5V 30KΩ VTemp 8 IN FM20 PARALLEL DATA OUTPUT Parallel Output Analog-to-Digital Converter _ VREF 5KΩ + INTR 1.75V 1µF CS 15KΩ RD WR Parallel Output Temperature to Digital Converter (Full Scale = +125°C) V+ RHYST RV+ RVD1 VREF VTRIP Shunt Voltage Reference VCONTROL 0.1µF RVD2 V+ FM20 VOUT VHYST2 = VHYST2 (VREF) • (RVD2) (RVD2) • (RHYST) RVD1 + RHYST + RVD2 VHYST1 VOUT VCONTROL VHYST1 = (VREF) • (RVD2) 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. Thermostat/ Fan Controller 2 FM20 Rev. A.5 www.fairchildsemi.com FM20 Low Voltage Ultra-Low-Power Temperature Sensor Typical Applications (continued) GND CFILTER 0.1µF FM20 Bypass Cap RFILTER Microcontroller Analog to Digital Converter VOUT VDD Digital Temperature Output Through a Microcontroller Pin Configuration SC-70 (Top View) SOT-23 (Top View) VOUT GND N/C GND 3 2 1 3 FM20 FM20 4 5 1 2 VDD GND VDD VOUT 3 FM20 Rev. A.5 www.fairchildsemi.com Part Number Package Temperature Range How Supplied FM20P5x 5-Pin SC70 -55°C to +130°C 3000 units on T&R FM20S3x 3-Pin SOT-23 -55°C to +130°C 3000 units on T&R Absolute Maximum Ratings (Note 1) Rating Storage Temperature Range -60°C to +150°C Supply Voltage +7V Lead Soldering Temperature 220°C Output Voltage VDD + 0.5V Output Current -20/+1µA ESD2 Human Body Model Machine Model 2000V 250V Parameter 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. Recommended Operating Ratings Symbol Min Max Units VDD Supply Voltage Parameter +2.4 +6 V VOUT Output Voltage 0 VDD V -55 +130 °C Operating Temperature Range TA Electrical Characteristics4 Limits apply for -55°C ≤ TA ≤ +130°C and VDD = +5.0V unless otherwise noted. Parameter Symbol Accuracy4 Conditions TA = +25°C TA = -55°C (TMIN) TA = +130°C (TMAX) Non-linearity5 Min Typ Max Units -2 -3 -5 ±1 ±2 ±2 +2 +3 +5 °C °C °C +2 °C 10.5 12 µA µA -5 Quiescent Supply Current Output Floating IDD TA = +25°C -55°C ≤ TA ≤ +130°C Output Sink Capability6 IOL VDD = +5V 20 µA Output Source Capability6 IOH VDD = +5V 1 µA -11.77 mV/°C +1863.9 mV Average Output Slope (Sensor Gain) AOUT Output Voltage VOUT Capacitive Load7 TA = 0°C CL Self Heating 7.5 5 0 SOT-23 SC70 9 9 1000 pF 0.02016 0.02082 °C °C 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. 4 FM20 Rev. A.5 www.fairchildsemi.com FM20 Low Voltage Ultra-Low-Power Temperature Sensor Ordering Information FM20 Low Voltage Ultra-Low-Power Temperature Sensor 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 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. 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 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. 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 5 FM20 Rev. A.5 www.fairchildsemi.com FM20 Low Voltage Ultra-Low-Power Temperature Sensor Typical Performance Characteristics Quiescent Current vs. Temperature Quiescent Current (µA) 12 VDD = +5V 11 10 9 8 7 6 -50 -25 0 25 50 75 100 125 Temperature (°C) Accuracy 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) 6 FM20 Rev. A.5 www.fairchildsemi.com 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. 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 constant 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 RFILTER Bypass Cap VDD VOUT CL CFILTER GND 0.1µF Bypass Cap VDD VOUT CL RFILTER FM20 with Filter Network for Noisy Environments or for Capacitive Loads Greater than 300pF Resistor/Capacitor Combinations for Filter Network RFILTER CFILTER 200Ω 1µF 470Ω 0.1µF 680Ω 0.01µF 1000Ω 1000pF 10kΩ 100pF 100kΩ 10pF 7 FM20 Rev. A.5 www.fairchildsemi.com FM20 Low Voltage Ultra-Low-Power Temperature Sensor Loading 0.20 MIN 0.45~0.60 2.40 ±0.10 1.30 ±0.10 0.40 ±0.03 0.03~0.10 0.38 REF 0.40 ±0.03 +0.05 0.12 –0.023 0.96~1.14 0.97REF 2.90 ±0.10 0.95 ±0.03 0.95 ±0.03 1.90 ±0.03 0.508REF SOT-23 Package Dimensions FS Package Code MA03A 8 FM20 Rev. A.5 www.fairchildsemi.com FM20 Low Voltage Ultra-Low-Power Temperature Sensor Physical Dimensions inches (millimeters) unless otherwise noted FM20 Low Voltage Ultra-Low-Power Temperature Sensor Physical Dimensions inches (millimeters) unless otherwise noted SC70 5-pin Package Dimensions FS Package Code MAA05A 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 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 to the user. Fairchild Semiconductor Americas Customer Response Center Tel. 1-888-522-5372 2. A critical component is 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. Fairchild Semiconductor Europe Fax: +44 (0) 1793-856858 Deutsch Tel: +49 (0) 8141-6102-0 English Tel: +44 (0) 1793-856856 Français Tel: +33 (0) 1-6930-3696 Italiano Tel: +39 (0) 2-249111-1 Fairchild Semiconductor Hong Kong 8/F, Room 808, Empire Centre 68 Mody Road, Tsimshatsui East Kowloon. Hong Kong Tel; +852-2722-8338 Fax: +852-2722-8383 Fairchild Semiconductor Japan Ltd. 4F, Natsume Bldg. 2-18-6, Yushima, Bunkyo-ku Tokyo, 113-0034 Japan Tel: 81-3-3818-8840 Fax: 81-3-3818-8841 Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right at any time without notice to change said circuitry and specifications. 9 FM20 Rev. A.5 www.fairchildsemi.com