LM74 LM74 SPI/ MICROWIRE 12-Bit Plus Sign Temperature Sensor Literature Number: SNIS107J LM74 SPI/MICROWIRETM 12-Bit Plus Sign Temperature Sensor General Description Features The LM74 is a temperature sensor, Delta-Sigma analog-todigital converter with an SPI and MICROWIRE compatible interface. The host can query the LM74 at any time to read temperature. A shutdown mode decreases power consumption to less than 10 A. This mode is useful in systems where low average power consumption is critical. The LM74 has 12-bit plus sign temperature resolution (0.0625C per LSB) while operating over a temperature range of -55C to +150C. The LM74's 3.0V to 5.5V supply voltage range, low supply current and simple SPI interface make it ideal for a wide range of applications. These include thermal management and protection applications in hard disk drives, printers, electronic test equipment, and office electronics. The LM74 is available in the SO-8 package as well as an 5-Bump micro SMD package. 0.0625C temperature resolution. Shutdown mode conserves power between temperature Key Specifications Supply Voltage Supply Current System Thermal Management Personal Computers Disk Drives Office Electronics Electronic Test Equipment 3.0V or 2.65V to 5.5V operating 265A (typ) 520A (max) shutdown 3A (typ) -10C to 65C -25C to 110C -55C to 125C 1.25C(max) 2.1C(max) 3C(max) Temperature Accuracy Applications reading SPI and MICROWIRE Bus interface 5-Bump micro SMD package saves space Simplified Block Diagram 10090901 TRI-STATE(R) is a registered trademark of National Semiconductor Corporation. (c) 2011 National Semiconductor Corporation 100909 www.national.com LM74 SPI/MICROWIRE 12-Bit Plus Sign Temperature Sensor March 1, 2011 LM74 Connection Diagrams SO-8 5-Bump micro SMD 10090902 TOP VIEW NS Package Number M08A 10090924 Note: - Pin numbers are referenced to the package marking text orientation. Pin 1 is designated by the square. - Reference JEDEC Registration MO-211, variation BC - The top 4 characters designate the date code. The bottom 3 characters designate the device type (see ordering information). TOP VIEW NS Package Number BPD05MPB and TPD05QSA Ordering Information Order Number Package Marking NS Package Number Supply Voltage Transport Media LM74CIM-3 LM74CIM-3 SO-8, M08A 3.0V to 3.6V 95 Units in Rail LM74CIMX-3 LM74CIM-3 SO-8, M08A 3.0V to 3.6V 2500 Units in Tape and Reel LM74CIM-5 LM74CIM-5 SO-8, M08A 4.5V to 5.5V 95 Units in Rail LM74CIMX-5 LM74CIM-5 SO-8, M08A 4.5V to 5.5V 2500 Units in Tape and Reel 2.65V to 3.6V 250 Units in Tape and Reel 2.65V to 3.6V 3000 Units in Tape and Reel LM74CITP-3 T10 micro SMD, Thin Package, TPD05QSA LM74CITPX-3 T10 micro SMD, Thin Package, TPD05QSA www.national.com 2 LM74 Pin Descriptions SO-8 Pin # micro SMD Pin # SI/O 1 1 Slave Input/Output - Serial bus bi-directional data line. Schmitt trigger input. From and to Controller SC 2 5 Slave Clock - Serial bus clock Schmitt trigger input line. From Controller NC 3 No Connection No Connection GND 4 Power Supply Ground Ground NC 5 No Connection No Connection NC 6 No Connection No Connection CS 7 Chip Select input. From Controller Positive Supply Voltage Input DC Voltage from 3.0V to 5.5V for the LM74CIM and 2.65V to 5.5V for the LM74CIBP and LM74CITP. Bypass with a 0.1 F ceramic capacitor. Label V+ 8 4 3 2 Function Typical Connection Typical Application 10090903 FIGURE 1. COP Microcontroller Interface 3 www.national.com LM74 Machine Model 200V Soldering process must comply with National's Reflow Temperature Profile specifications. Refer to www.national.com/packaging. (Note 3) Absolute Maximum Ratings (Note 1) Supply Voltage -0.3V to 6.0V Voltage at any Pin -0.3V to V+ + 0.3V Input Current at any Pin (Note 2) 5 mA Package Input Current (Note 2) 20 mA Storage Temperature -65C to +150C ESD Susceptibility (Note 4) Human Body Model LM74CIBP and LM74CITP, pin A2 1900V (SC) LM74CIM,LM74CIBP, and 2000V LM74CITP all other pins Operating Ratings Specified Temperature Range TMIN to TMAX (Note 5) LM74CIBP and LM74CITP LM74CIM Supply Voltage Range (+VS) LM74CIBP and LM74CITP LM74CIM -40C to +125C -55C to +150C +2.65V to +5.5V +3.0V to +5.5V Temperature-to-Digital Converter Characteristics Unless otherwise noted, these specifications apply for V+ = 2.65V to 3.6V for the LM74CIBP -3, LM74CITP-3, V+ = 3.0V to 3.6V for the LM74CIM -3 and V+ = 4.5V to 5.5V for the LM74 -5 (Note 6). Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ=+25C, unless otherwise noted. Parameter Typical (Note 7) Conditions Temperature Error (Note 6) LM74-5 Limits (Note 8) LM74-3 Limits (Note 8) Units (Limit) TA = -10C to +65C 1.25 1.25 C (max) TA = -25C to +110C 2.1 +2.65/-2.15 C (max) TA = -40C to +85C +2.65/-1.65 2.15 C (max) TA = -40C to +110C +2.65/ -2.0 +2.65/-2.15 C (max) TA = -55C to +125C 3.0 3.5 C (max) TA = -55C to +150C 5.0 5.0 C (max) Resolution 13 Temperature Conversion Time Quiescent Current Bits SO-8 (Note 9) 280 425 425 ms (max) micro SMD (Note 9) 611 925 925 ms (max) 310 520 520 A (max) 265 470 470 A (max) SO-8 Serial Bus Inactive micro SMD 310 A 310 A SO-8 Shutdown Mode, + micro SMD V = 3.3V 7 A 3 A SO-8 Shutdown Mode, + micro SMD V = 5V 8 A 4 A SO-8 Serial Bus Active micro SMD Logic Electrical Characteristics DIGITAL DC CHARACTERISTICS Unless otherwise noted, these specifications apply for V+ = 2.65V to 3.6V for the LM74CIBP -3, LM74CITP-3, V+ = 3.0V to 3.6V for the LM74CIM -3 and V+ = 4.5V to 5.5V for the LM74 -5 (Note 6). Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ=+25C, unless otherwise noted. Symbol VIN(1) VIN(0) Parameter Conditions Typical (Note 7) Logical "1" Input Voltage Logical "0" Input Voltage Limits (Note 8) V+ x 0.7 V (min) V+ + 0.3 V (max) -0.3 V (min) V+ Input Hysteresis Voltage www.national.com Units (Limit) x 0.3 V (max) V+ = 3.0V to 3.6V 0.8 0.35 V (min) V+ 0.8 0.33 V (min) = 4.5V to 5.5V 4 Parameter Conditions Typical (Note 7) Limits (Note 8) Units (Limit) IIN(1) Logical "1" Input Current VIN = V+ 0.005 3.0 A (max) IIN(0) Logical "0" Input Current VIN = 0V -0.005 -3.0 A (min) CIN All Digital Inputs VOH High Level Output Voltage IOH = -400 A 2.4 V (min) VOL Low Level Output Voltage IOL = +2 mA 0.4 V (max) IO_TRI-STATE TRI-STATE Output Leakage Current VO = GND VO = V+ -1 +1 A (min) A (max) 20 pF SERIAL BUS DIGITAL SWITCHING CHARACTERISTICS Unless otherwise noted, these specifications apply for V+ = 2.65V to 3.6V for the LM74CIBP -3, LM74CITP-3, V+ = 3.0V to 3.6V for the LM74CIM -3 and V+ = 4.5V to 5.5V for the LM74 -5 (Note 6); CL (load capacitance) on output lines = 100 pF unless otherwise specified. Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = +25C, unless otherwise noted. Symbol Parameter Conditions Typical (Note 7) Limits (Note 8) Units (Limit) s (min) (max) t1 SC (Clock) Period 0.16 DC t2 CS Low to SC (Clock) High Set-Up Time 100 ns (min) t3 CS Low to Data Out (SO) Delay 70 ns (max) t4 SC (Clock) Low to Data Out (SO) Delay 100 ns (max) t5 CS High to Data Out (SO) TRI-STATE 200 ns (max) t6 SC (Clock) High to Data In (SI) Hold Time 50 ns (min) t7 Data In (SI) Set-Up Time to SC (Clock) High 30 ns (min) 10090904 FIGURE 2. Data Output Timing Diagram 5 www.national.com LM74 Symbol LM74 10090905 FIGURE 3. TRI-STATE Data Output Timing Diagram 10090906 FIGURE 4. Data Input Timing Diagram Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating the device beyond its rated operating conditions. Note 2: When the input voltage (VI) at any pin exceeds the power supplies (VI < GND or VI > +VS) the current at that pin should be limited to 5 mA. The 20 mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 5 mA to four. Note 3: Reflow temperature profiles are different for lead-free and non-lead-free packages. Note 4: Human body model, 100 pF discharged through a 1.5 k resistor. Machine model, 200 pF discharged directly into each pin. Note 5: The life expectancy of the LM74 will be reduced when operating at elevated temperatures. LM74 JA (thermal resistance, junction-to-ambient) when attached to a printed circuit board with 2 oz. foil is summarized in the table below: Device Number NS Package Number Thermal Resistance (JA) LM74CIM M08A 160C/W LM74CIBP BPD05MPB 250C/W LM74CITP TPD05QSA 250C/W Note 6: All SOP (LM74CIM) parts will function over the V+ supply voltage range of 3V to 5.5V. All micro SMD (LM74SIBP and LM75CITP) parts will function over the V+ supply voltage range of 2.65V to 5.5V. The SOP (LM74CIM) parts are tested and specified for rated temperature error at their nominal supply voltage for temperature ranges of -10C to +65C, -55C to +125C and -55C to +150C. For the SOP (LM74CIM) parts, the temperature error specifications for temperature ranges of -40C to +85C, -25C to +110C, and -40C to +110C include error induced by power supply variation of 5% from the nominal value. For the LM74CIM (SOP) parts, the temperature error will increase by 0.3C for a power supply voltage (V+) variation of 10% from the nominal value. For the LM74CIBP-3 and LM74CITP-3 (micro SMD) parts all accuracies are guaranteed over the supply range of 2.65V to 3.6V, except for the temperature ranges of -55C to 125C and -55C to +150C where the accuracy applies for the nominal supply voltage of 3.3V. For the LM74CIBP-5 and LM74CITP-5 (micro SMD) parts all accuracies are guranteed over the supply range of 4.75V to 5.25V, except for the temperature ranges of -55C to 125C and -55C to +150C where the accuracy applies for the nominal supply voltage of 5.0V. For the LM74CIBP and LM74CITP over -55C to 125C and -55C to +150C, a power supply variation of 10% will degrade the accuracy by 0.3C. Note 7: Typicals are at TA = 25C and represent most likely parametric norm. Note 8: Limits are guaranteed to National's AOQL (Average Outgoing Quality Level). Note 9: This specification is provided only to indicate how often temperature data is updated. The LM74 can be read at any time without regard to conversion state (and will yield last conversion result). A conversion in progress will not be interrupted. The output shift register will be updated at the completion of the read and a new conversion restarted. Note 10: For best accuracy, minimize output loading. Higher sink currents can affect sensor accuracy with internal heating. This can cause an error of 0.64C at full rated sink current and saturation voltage based on junction-to-ambient thermal resistance. www.national.com 6 LM74 Electrical Characteristics 10090908 FIGURE 5. Temperature-to-Digital Transfer Function (Non-linear scale for clarity) TRI-STATE Test Circuit 10090907 FIGURE 6. 7 www.national.com LM74 Typical Performance Characteristics Average Power-On Reset Voltage vs Temperature Static Supply Current vs Temperature (SO-8) 10090923 10090921 Static Supply Current vs Temperature (micro SMD) Temperature Error (SO-8) 10090925 10090922 The LM74 power-up default condition is continuous conversion mode. After completion of the first full temperature conversion, the register will contain temperature measurement data in bits D15 (the temperature data MSB) through D3 (the temperature data LSB). Bit D2 will be fixed high; bits D1 and D0 are undefined. See Section 1.5.3 for a diagram of the Temperature Regisiter contents after the first complete temperature conversion. Note that bit D2 represents a complete conversion flag. During POR it is low and, after the first temperature conversion is complete, it goes high. This bit can be polled to indicate when the POR data in the Temperature Register has been replaced with valid temperature data. After the first conversion, and any subsequent conversions, the value in the temperature register does not change until the completion of the next conversion, at which time the temperature register is updated with the latest temperature value. 1.0 Functional Description The LM74 temperature sensor incorporates a band-gap type temperature sensor and 12-bit plus sign ADC (Delta-Sigma Analog-to-Digital Converter). Compatibility of the LM74's three wire serial interface with SPI and MICROWIRE allows simple communications with common microcontrollers and processors. Shutdown mode can be used to optimize current drain for different applications. A Manufacture's/Device ID register identifies the LM74 as National Semiconductor product. 1.1 POWER UP AND POWER DOWN When the supply voltage is less than about 1.6V (typical), the LM74 is considered powered down. The LM74 always powers up in a known state. When the supply voltage rises above 1.6V (typical), an internal Power-On Reset (POR) occurs and the temperature register will then contain a value of 1111 1111 0000 00XX, where XX indicates undefined values. See Section 1.5.2 for a diagram of the Temperature Regisiter contents after POR but before completion of the first temperature conversion. www.national.com 1.2 SERIAL BUS INTERFACE The LM74 operates as a slave and is compatible with SPI or MICROWIRE bus specifications. Data is clocked out on the falling edge of the serial clock (SC), while data is clocked in on the rising edge of SC. A complete transmit/receive com- 8 tain the new temperature data. Until then, it will contain a "stale" temperature (the data that was in the register before going into shutdown mode). 1.3 TEMPERATURE DATA FORMAT Temperature data is represented by a 13-bit, two's complement word with an LSB (Least Significant Bit) equal to 0.0625 C: Temperature Digital Output Binary Hex +150C 0100 1011 0000 0111 4B 07h +125C 0011 1110 1000 0111 3E 87h +25C 0000 1100 1000 0111 0C 87h +0.0625C 0000 0000 0000 1111 00 0Fh 0C 0000 0000 0000 0111 00 07h -0.0625C 1111 1111 1111 1111 FF FFh -25C 1111 0011 1000 0111 F3 87h -55C 1110 0100 1000 0111 E4 87h Note: The last two bits are TRI-STATE and depicted as one in the table. The first data byte is the most significant byte with most significant bit first, permitting only as much data as necessary to be read to determine temperature condition. For instance, if the first four bits of the temperature data indicate an overtemperature condition, the host processor could immediately take action to remedy the excessive temperatures. 1.4 SHUTDOWN MODE/MANUFACTURER'S ID Shutdown mode is enabled by writing XX FF to the LM74 as shown in Figure 7c. The serial bus is still active when the LM74 is in shutdown. Current draw drops to less than 10 A between serial communications. When in shutdown mode the LM74 always will output 1000 0000 0000 00XX. This is the manufacturer's/Device ID information. The first 5-bits of the field (1000 0XXX) are reserved for manufacturer's ID. As mentioned in Section 1.2, writing a zero to the LM74 configuration register will take it out of shutdown mode and place it in conversion mode. In other words, any valid code listed in Section 1.2 other than XX FF will put it in conversion mode. After leaving shutdown, but before the first temperature conversion is complete, the temperature register will contain the last measured temperature which resided in the temperature register before entering shutdown mode. After the completion of the first conversion, the temperature register will be updated with the new temperature data. any others may place the part into a Test Mode. Test Modes are used by National Semiconductor to thoroughly test the function of the LM74 during production testing. Only eight bits have been defined above since only the last eight transmitted are detected by the LM74, before CS is taken HIGH. The following communication can be used to determine the Manufacturer's/Device ID and then immediately place the part into continuous conversion mode. With CS continuously low: * Read 16 bits of temperature data * Write 16 bits of data commanding shutdown * Read 16 bits of Manufacture's/Device ID data * Write 8 to 16 bits of data commanding Conversion Mode * Take CS HIGH. Note that one complete temperature conversion period will have to pass before the LM74 Temperature register will con- 9 www.national.com LM74 munication will consist of 32 serial clocks. The first 16 clocks comprise the transmit phase of communication, while the second 16 clocks are the receive phase. When CS is high SI/O will be in TRI-STATE(R). Communication should be initiated by taking chip select (CS) low. This should not be done when SC is changing from a low to high state. Once CS is low the serial I/O pin (SI/O) will transmit the first bit of data. The master can then read this bit with the rising edge of SC. The remainder of the data will be clocked out by the falling edge of SC. Once the 14 bits of data (one sign bit, twelve temperature bits and 1 high bit) are transmitted the SI/ O line will go into TRI-STATE. CS can be taken high at any time during the transmit phase. If CS is brought low in the middle of a conversion the LM74 will complete the conversion and the output shift register will be updated after CS is brought back high. The receive phase of a communication starts after 16 SC periods. CS can remain low for 32 SC cycles. The LM74 will read the data available on the SI/O line on the rising edge of the serial clock. Input data is to an 8-bit shift register. The part will detect the last eight bits shifted into the register. The receive phase can last up to 16 SC periods. All ones must be shifted in order to place the part into shutdown. A zero in any location will take the LM74 out of shutdown. The following codes should only be transmitted to the LM74: * 00 hex * 01 hex * 03 hex * 07 hex * 0F hex * 1F hex * 3F hex * 7F hex * FF hex LM74 cation register. The temperature and manufacturer's/device identification registers are read only. The configuration register is write only. 1.5 INTERNAL REGISTER STRUCTURE The LM74 has three registers, the temperature register, the configuration register and the manufacturer's/device identifi1.5.1 Configuration Register (Selects shutdown or continuous conversion modes): (Write Only): D15 D14 D13 D12 D11 D10 D9 D8 X X X X X X X X D7 D6 D5 D4 D3 D2 D1 D0 Shutdown D0-D15 set to XX FF hex enables shutdown mode. D0-D15 set to 00 00 hex sets Continuous conversion mode. Note: setting D0-D15 to any other values may place the LM74 into a manufacturer's test mode, upon which the LM74 will stop responding as described. These test modes are to be used for National Semiconductor production testing only. See Section 1.2 Serial Bus Interface for a complete discussion. 1.5.2 Temperature Register (after power-up, before first complete temperature conversion) (Read Only): D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 X X D0-D1: Undefined. TRI-STATE will be output on SI/0. D2-D15: Power-on Reset (POR) values. 1.5.3 Temperature Register (after completion of first temperature conversion) (Read Only): D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 MSB Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 LSB 1 X X D0-D1: Undefined. TRI-STATE will be output on SI/0. D2: High. D3-D15: Temperature Data. One LSB = 0.0625C. Two's complement format. 1.5.4 Manufacturer's Device ID Register (Read Only): D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 X X D0-D1: Undefined. TRI-STATE will be output on SI/0. D2-D15: Manufacturer's/Device ID Data. This register is accessed whenever the LM74 is in shutdown mode. www.national.com 10 LM74 2.0 Serial Bus Timing Diagrams 10090914 a) Reading Continuous Conversion - Single Eight-Bit Frame 10090915 b) Reading Continuous Conversion - Two Eight-Bit Frames 10090918 c) Writing Shutdown Control FIGURE 7. Timing Diagrams 11 www.national.com LM74 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 insure that moisture cannot corrode the LM74 or its connections. 3.0 Application Hints To get the expected results when measuring temperature with an integrated circuit temperature sensor like the LM74, it is important to understand that the sensor measures its own die temperature. For the LM74, the best thermal path between the die and the outside world is through the LM74's pins. In the SO-8 package all the pins on the LM74 will have an equal effect on the die temperature. Because the pins represent a good thermal path to the LM74 die, the LM74 will provide an accurate measurement of the temperature of the printed circuit board on which it is mounted. There is a less efficient thermal path between the plastic package and the LM74 die. If the ambient air temperature is significantly different from the printed circuit board temperature, it will have a small effect on the measured temperature. In probe-type applications, the LM74 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 LM74 and accompanying wiring and circuits must be kept insulated and dry, to avoid leakage and corrosion. This is 3.1 micro SMD LIGHT SENSITIVITY The LM74 in the micro SMD package should not be exposed to ultraviolet light. The micro SMD package does not completely encapsulate the LM74 die in epoxy. Exposing the LM74 micro SMD package to bright sunlight will not immediatly cause a change in the output reading. Our experiments show that directly exposing the circuit side (bump side) of the die to high intensity ( 1mW/cm2) ultraviolet light, centered at a wavelength of 254nm, for greater than 20 minutes will deprogram the EEPROM cells in the LM74. Since the EEPROM is used for storing calibration coefficients, the LM74 will function but the temperature accuracy will no longer be as specified. Light can penetrate through the side of the package as well, so exposure to ultra violet radiation is not recommended even after mounting. 4.0 Typical Applications 10090920 FIGURE 8. Temperature monitor using Intel 196 processor www.national.com 12 LM74 10090919 FIGURE 9. LM74 digital input control using micro-controller's general purpose I/O. 13 www.national.com LM74 Physical Dimensions inches (millimeters) unless otherwise noted 8-Lead Molded Small Outline Package Order Number LM74CIM-3, LM74CIMX-3, LM74CIM-5 or LM74CIMX-5 NS Package Number M08A 5-Bump micro SMD Ball Grid Array Thick Package Order Number LM74CIBP-3,LM74CIBPX-3, LM74CIBP-5, LM74CIBPX-5 NS Package Number BPD05MPB The following dimensions apply to the BPD05MPB package shown above: X1=1565m 30m, X2=1615m 30m, X3=850m 50m. www.national.com 14 LM74 5-Bump micro SMD Ball Grid Array Thin Package Order Number LM74CITP-3,LM74CITPX-3, LM74CITP-5, LM74CITPX-5 NS Package Number TPD05QSA The following dimensions apply to the TPD05QSA package shown above: X1=1590m 30m, X2=1641m 30m, X3=500m 75m. 15 www.national.com LM74 SPI/MICROWIRE 12-Bit Plus Sign Temperature Sensor Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Design Support Amplifiers www.national.com/amplifiers WEBENCH(R) Tools www.national.com/webench Audio www.national.com/audio App Notes www.national.com/appnotes Clock and Timing www.national.com/timing Reference Designs www.national.com/refdesigns Data Converters www.national.com/adc Samples www.national.com/samples Interface www.national.com/interface Eval Boards www.national.com/evalboards LVDS www.national.com/lvds Packaging www.national.com/packaging Power Management www.national.com/power Green Compliance www.national.com/quality/green Switching Regulators www.national.com/switchers Distributors www.national.com/contacts LDOs www.national.com/ldo Quality and Reliability www.national.com/quality LED Lighting www.national.com/led Feedback/Support www.national.com/feedback Voltage References www.national.com/vref Design Made Easy www.national.com/easy www.national.com/powerwise Applications & Markets www.national.com/solutions Mil/Aero www.national.com/milaero PowerWise(R) Solutions Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors SolarMagicTM www.national.com/solarmagic PLL/VCO www.national.com/wireless www.national.com/training PowerWise(R) Design University THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION ("NATIONAL") PRODUCTS. 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