LM27-2PLMDA

LM27A SOT-23, ±3°C Accurate, 120°C-150°C Factory Preset Thermostat (LM27 in Die Form) July 2007 LM27A ±3°C Accurate, 120°C-150°C Factory Preset Thermostat (LM27 in Die Form) General Description This datasheet applies to the LM27A, which is the die form of the LM27. The LM27 is available in the SOT23-5 package. Please refer to the LM27 datasheet for detailed specifications pertaining to the packaged part. The LM27A is a precision, single digital-output, low-power thermostat comprised of an internal reference, DAC, temperature sensor and comparator. Utilizing factory programming, it can be manufactured with different trip points as well as different digital output functionality. The trip point (TOS) can be preset at the factory to any temperature in the range of +120°C to +150°C in 1°C increments. The LM27A has two digital output pads, one digital input (HYST) and one analog output (VTEMP). One digitial output is an active-high, push-pull output and the other is an active-low, open-drain output. Either of the outputs (but not both) are available. The LM27A is available in either an overtemperature shutdown or an undertemperature shutdown option. An LM27A with overtemperature shutdown is configured so that its thermostat outputs (OS and OS) will go active when a rising temperature crosses the trip point and the hysteresis will apply to a falling temperature. The thermostat outputs of an LM27A with an undertemperature shutdown (US and US) will trip on a falling temperature and hysteresis will apply on a rising temperature. For example, when the LM27A is preset as an overtemperature shutdown, the active-high output (OS) will go HIGH and the active-low output (OS) will go LOW to indicate that the die temperature is over the internally preset TOS . The outputs will reset to their normal states when the temperature goes below (TOS–THYST). Similarly, when preprogrammed as an undertemperature shutdown the activehigh output (US) will go HIGH and the active-low output (US) will go LOW to indicate that the temperature is below TUS . The outputs will reset when the temperature is above (TUS+THYST). The typical hysteresis, THYST, can be set to 2°C or 10°C and is controlled by the state of the HYST pin. The VTEMP analog output provides a voltage that is proportional to temperature and has a −10.7mV/°C output slope. Standard parts are available, see ordering information for details. For other part options, contact a National Semiconductor Distributor or Sales Representative for information on minimum-order qualification. Applications ■ ■ ■ ■ ■ ■ ■ Microprocessor Thermal Management Appliances Portable Battery Powered Systems Fan Control Industrial Process Control HVAC Systems Electronic System Protection Features ■ Internal comparator with pin selectable 2°C or 10°C hysteresis ■ No external components required ■ Open-drain or push-pull digital output; supports CMOS ■ ■ ■ ■ ■ logic levels Internal temperature sensor with VTEMP output pin VTEMP output allows after-assembly system testing Internal voltage reference and DAC for trip-point setting Excellent power supply noise rejection AEC-Q100 Qualified Key Specifications ■ Power Supply Voltage ■ Power Supply Current ■ Hysteresis Temperature ■ Temperature Trip Point Accuracy 2.7V to 5.5V 40µA(max) 15µA(typ) 2°C or 10°C(typ) ±3°C (max) © 2007 National Semiconductor Corporation 201530 www.national.com LM27A Ordering Information For more detailed information on the suffix meaning see the part number template at the end of the Electrical Characteristics Section. Contact National Semiconductor for other set points and output options. Order Number LM27-2PL MDA NS Package Number Die form, no package Trip Point Setting 145°C Output Function Push-Pull (OS) Open-Drain (OS) Transport Media 400 units in waffle trays Connection Diagram LM27A Bond Pad Layout 20153002 TOP VIEW 1130µm x 902µm Bond Pad Mechanical Dimensions Dimensions of bond pad coordinates are in micrometers. Origin of coordinates: center of die. X-Direction is in the longitudinal axis of the die. Coordinates refer to center of Bond Pad. Opening sizes for bond pads 1 through 6 are 85 µm × 85 µm. Pin# 1 2 3 4 5 6 BACK X –437 µm –437 µm –437 µm +437 µm +437 µm +437 µm Y +225 µm 0 –220 µm –220 µm +5 µm +225 µm www.national.com 2 LM27A Pin Descriptions Pin Number 1 2 (Note 8) Pin Name HYST OS Function Hysteresis control, digital input Overtemperature Shutdown pushpull active-high thermostat digital output Undertemperature Shutdown pushpull active-high thermostat digital output Overtemperature Shutdown opendrain active-low thermostat digital output Undertemperature Shutdown opendrain active low thermostat digital output Supply input Connection GND for 10°C or V+ for 2°C Controller interrupt, system or power supply shutdown US System or power supply shutdown 3 (Note 8) OS Controller interrupt, system or power supply shutdown; pull-up resistor ≥ 10kΩ System or power supply shutdown; pull-up resistor ≥ 10kΩ 2.7V to 5.5V with a 0.1µF bypass capacitor. For PSRR information see Section Titled NOISE CONSIDERATIONS. System ground US 4 V+ 5 6 7 - 14 BACK GND VTEMP NC Backside Power supply ground Analog output voltage proportional to Leave floating or connect to a high impedance node. temperature Do not connect Can go to GND connection (Note: GND must be connected. The back is not a system ground connection). Note: Only connect to one of the output pads, Pad 2 or Pad 3, not both. Either push-pull (Pad 2) or open-drain (Pad 3) can be used but they can not both be used on the same die. 3 www.national.com LM27A Absolute Maximum Ratings (Note 1) Input Voltage Input Current at any pin (Note 2) Package Input Current(Note 2) Storage Temperature ESD Susceptibility (Note 3) Human Body Model Machine Model 6.0V 5mA 20mA −65°C to + 175°C 2500V 250V Operating Ratings Specified Temperature Range LM27A Positive Supply Voltage (V+) Maximum VOUT (Note 1) −40°C ≤ TA ≤ +150°C TMIN ≤ TA ≤ TMAX +2.7V to +5.5V +5.5V LM27A Electrical Characteristics The following specifications apply for V+ = 2.7VDC to 5.5VDC, and VTEMP load current = 0µA unless otherwise specified. Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25°C unless otherwise specified. Symbol Temperature Sensor Trip Point Accuracy (Includes VREF, DAC, +120°CLOW) Calculate Ttrig using Equation 2. (1) same value resistor will work for either placement of the resistor. If an additional capacitive load is placed directly on the LM27A output, rather than across CLOAD, it should be at least a factor of 10 smaller than CLOAD. TABLE 1. Resistive compensation for capacitive loading of VTEMP CLOAD R (Ω) 0 8200 3000 1000 430 ≤100pF 1nF 10nF 100nF ≥1µF 2. 20153017 a) R in series with capacitor 3. 20153018 b) R in series with signal path FIGURE 1. Resistor placement for capacitive loading compensation of VTEMP NOISE CONSIDERATIONS The LM27A has excellent power supply noise rejection. Listed below is a variety of signals used to test the LM27A power supply rejection. False triggering of the output was not observed when these signals where coupled into the V+ pin of the LM27A. • square wave 400kHz, 1Vp-p • square wave 2kHz, 200mVp-p • sine wave 100Hz to 1MHz, 200mVp-p Testing was done while maintaining the temperature of the LM27A one degree centigrade way from the trip point with the output not activated. VTEMP LOADING The VTEMP output has very weak drive capability (1 µA source, 40 µA sink). So care should be taken when attaching circuitry to this pin. Capacitive loading may cause the VTEMP output to oscillate. Simply adding a resistor in series as shown in Figure 1 will prevent oscillations from occurring. To determine the value of the resistor follow the guidelines given in Table 1. The www.national.com 6 LM27A Typical Applications 20153003 Note: The fan's control pin has internal pull-up. The 10k pull-down sets a slow fan speed. When the output of the LM27A goes low, the fan will speed up. FIGURE 2. Two Speed Fan Speed Control 20153020 FIGURE 3. Fan High Side Drive 20153021 FIGURE 4. Fan Low Side Drive 7 www.national.com LM27A 20153022 FIGURE 5. Audio Power Amplifier Thermal Protection 20153023 FIGURE 6. Simple Thermostat Physical Dimensions for Die Product 20153002 Order Number LM27-2PL MDA Bare Die TOP VIEW 1130µm × 902µm For Bond Pad Mechanical Dimensions, see Connection Diagram Section www.national.com 8 LM27A 9 www.national.com LM27A SOT-23, ±3°C Accurate, 120°C-150°C Factory Preset Thermostat (LM27 in Die Form) Notes THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE CHANGES TO SPECIFICATIONS AND PRODUCT DESCRIPTIONS AT ANY TIME WITHOUT NOTICE. NO LICENSE, WHETHER EXPRESS, IMPLIED, ARISING BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS DOCUMENT. TESTING AND OTHER QUALITY CONTROLS ARE USED TO THE EXTENT NATIONAL DEEMS NECESSARY TO SUPPORT NATIONAL’S PRODUCT WARRANTY. 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All other brand or product names may be trademarks or registered trademarks of their respective holders. Copyright© 2007 National Semiconductor Corporation For the most current product information visit us at www.national.com National Semiconductor Americas Customer Support Center Email: new.feedback@nsc.com Tel: 1-800-272-9959 National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530-85-86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +49 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 National Semiconductor Asia Pacific Customer Support Center Email: ap.support@nsc.com National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: jpn.feedback@nsc.com Tel: 81-3-5639-7560 www.national.com