LM95172Q

LM95172Q Digital Temperature Sensor in Die Form with ± 1°C Accuracy from 130°C to 160°C February 4, 2009 LM95172Q Digital Temperature Sensor in Die Form with ±1°C Accuracy from 130°C to 160°C General Description The LM95172Q is a digital temperature sensor with industryleading accuracy at temperatures up to 175°C. It features a linear Sigma-Delta Analog-to-Digital Converter (ADC) with fast conversion rates and low output noise. Communication with the LM95172Q is achieved over an easy-to-use Serial Peripheral Interface (SPI) with high noise immunity. The LM95172Q's resolution is user programmable from 0.0625°C to 0.0078125°C. When operating in 13-, 14- or 15bit resolution, the LM95172Q indicates a new conversion has been completed. The LM95172Q also features an over-temperature alarm output (OVERTEMP) that asserts when the die temperature exceeds a programmed high limit. The LM95172Q is specified for operation over the wide temperature range of -40°C to 175°C. It is available in die form which makes the LM95172Q ideal multi-chip modules or custom packaging to a wide variety of high-temperature applications. Features ■ AEC-Q100 Grade 0 qualified and is manufactured on an ■ ■ ■ ■ ■ Automotive Grade Flow. 0.0625°C to 0.0078125°C temperature resolution Wide −40°C to +175°C temperature range 35 ms conversion time tracks fast temp changes OVERTEMP digital output switches when TDIE > THIGH Shutdown mode saves power yet wakes up for one-shot temperature update Key Specifications ■ Analog and Digital Supply Voltage ■ Total Supply Current     Operating Shutdown −40°C to +140°C Shutdown −40°C to +175°C ■ Temperature Accuracy +130°C to +160°C +120°C to +130°C +160°C to +175°C −40°C to +120°C 3.0V to 5.5V 400 µA (typ) 4 µA (max) 12 µA (max) ±1.0°C (max) ±2.0°C (max) ±2.0°C (max) ±3.5°C (max) Applications ■ ■ ■ ■ ■ Automotive Process Monitoring Harsh-environment temperature monitoring Custom-package applications High-Temperature Modules ■ Temperature Resolution 13-bit mode 0.0625°C/LSB 16-bit mode 0.0078125°C/LSB ■ Conversion Time 13-bit mode 16-bit mode 35 ms (max) 280 ms (max) Simplified Block Diagram (Die Form) 30035701 MICROWIRE® is a registered trademark of National Semiconductor Corporation. TRI-STATE® is a registered trademark of National Semiconductor Corporation. © 2009 National Semiconductor Corporation 300357 www.national.com LM95172Q Connection Diagram LM95172Q Die Bond Pad Layout 30035702 Bond Pad Mechanical Dimensions Origin of coordinates: center of die. Coordinates refer to center of Bond Pad. X-Direction is in the longitudinal axis of the die. Opening Sizes (Pads 1-4, 6, 8, and 10) = 69.2 µm x 69.2 µm. No Connect = Do not connect to this pad. Manufacturer's test pad. Pad Number 1 2 3 4 5 6 7 8 9 10 X Coordinate (µm) 497.75 242.80 −147.35 −497.75 No Connect −497.75 No Connect 0.00 No Connect 497.75 Y Coordinate (µm) 728.80 728.80 728.80 728.80 No Connect −728.80 No Connect −728.80 No Connect −728.80 Pad Descriptions Pad Number 1 2 3 4 5 6 7 8 9 Name VDD ANALOG VDD IO OVERTEMP SC NC CS NC GND NC Type Power Power Output Input N/A Input N/A Ground N/A Description Analog Power Supply Voltage I/O Power Supply Voltage OVERTEMP Alarm Serial Clock input No Connect Chip Select input No Connect Power Supply Ground No Connect Typical Connection DC Voltage from 3.0V to 5.5V. Bypass with a 10 nF ceramic capacitor near the pad to ground. DC Voltage from 3.0V to 5.5V. Bypass with a 10 nF ceramic capacitor near the pad to ground. Over-temperature Alarm Output, Open-drain. Active Low on POR. Requires a pull-up resistor to VDD IO. Serial clock from the Controller Do not connect to this pad. Chip Select input for the bus. Low pass filtered. (Note 7) Do not connect to this pad. Ground Do not connect to this pad. www.national.com 2 LM95172Q Pad Number 10 Backside Name SI/O BACK Type Description Typical Connection Serial I/O Data line to or from the Controller May be connected to GND connection. Bidirectional Serial I/O N/A Substrate connection Ordering Information Order Number LM95172QA2 MDA NS Package Number Die form. No package. Transport Media 7000 units in 8 mm Surf Tape Typical Application 30035703 FIGURE 1. Microcontroller Interface - normal connection 3 www.national.com LM95172Q Absolute Maximum Ratings (Note 1) VDD ANALOG and VDD IO Supply Voltages −0.2V to 6.0V Voltage at any SI/O, SC, and CS −0.2V to (VDD IO + 0.2V) Pins (Note 7) Voltage at OVERTEMP Pin −0.3V to 5.5V Input Current at any Pin (Note 2) 5 mA Storage Temperature −65°C to +175°C ESD Susceptibility (Note 4) Human Body Model 2500 V Machine Model 250 V Charged Device Model 1000 V Operating Ratings Specified Temperature Range LM95172Q (Note 5) Analog Supply Voltage Range VDD ANALOG (Note 6) Digital Supply Voltage Range VDD IO (Note 6) TMIN to TMAX −40°C to +175°C +3.0V to +5.5V +3.0V to +5.5V Temperature-to-Digital Converter Characteristics Unless otherwise noted, these specifications apply for VDD ANALOG = VDD IO = 3.0V to 3.6V. Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25°C, unless otherwise noted. Parameter TA = +130°C to +160°C Temperature Accuracy (Note 6) TA = +120°C to +130°C TA = +160°C to +175°C TA = −40°C to +120°C Res 1 Bit 0 0 Resolution 1 1 Res 0 Bit 13 0.0625 14 0.03125 15 0.015625 16 0.0078125 35 70 140 280 TA = −40°C to 140°C TA = −40°C to 175°C TA = −40°C to 140°C TA = −40°C to 175°C TBD 400 456 510 4 12 0.9 2.1 0.75 2.1 V (min) V (max) V (min) V (max) μA (max) ms (max) Conditions Typical (Note 9) LM95172Q Limits (Note 10) ±1.0 ±2.0 ±2.0 ±3.5 Bits °C Bits °C Bits °C Bits °C °C (max) Units (Limit)  0  1  0  1 For 13 Bits Resolution Temperature Conversion Time For 14 Bits Resolution For 15 Bits Resolution For 16 BIts Resolution Bus Inactive Total Quiescent Current Continuous Conversion Mode (Note 8) Shutdown Mode TA = −40°C to 140°C TA = −40°C to 175°C Power-On Reset Threshold www.national.com 4 LM95172Q Logic Electrical Characteristics Digital DC Characteristics Unless otherwise noted, these specifications apply for VDD ANALOG = VDD IO = 3.0V to 3.6V. (Note 6). Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = +25°C, unless otherwise noted. Symbol VIH VIL VHYST IIH IIL VOH VOL Parameter Logical "1" Input Voltage Logical "0" Input Voltage VDD IO = 3.0V Digital Input Hysteresis Logical “1” Input Current Logical “0” Input Current Output High Voltage Output Low Voltage OVERTEMP Output Saturation Voltage VDD IO = 3.3V VDD IO = 3.6V VIN = VDD IO VIN = 0V IOH = 100 μA (Source) IOH = 2 mA (Source) IOL = 100 μA (Sink) IOL = 2 mA (Sink) IOL = 2 mA (Sink) 0.63 0.79 0.97 Conditions Typical (Note 9) Limits (Note 10) 0.75×VDD IO 0.25×VDD IO 0.42 0.56 0.72 1 −1 VDD IO − 0.2 VDD IO − 0.45 0.2 0.45 0.45 V(max) V (max) μA (max) μA (max) V (min) Units (Limit) V (min) V (max) V (min) 5 www.national.com LM95172Q Serial Bus Digital Switching Characteristics Unless otherwise noted, these specifications apply for VDD ANALOG = VDD IO = 3.0V to 3.6V (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 = +25°C, unless otherwise noted. See (Note 7)for CS voltage restriction. Symbol t1 t2 t3 t4 t5 t6 t7 t8 tTA tBUF SC (Serial Clock) Period CS (Chip Select) Low to SC High Set-Up Time (Note 13) CS Low to SI/O Output Delay (Note 13) SC Low to SI/O Output Delay CS High to Data Out (SI/O) TRI-STATE SC High to SI/O Input Hold Time SI/O Input to SC High Set-Up Time SC Low to CS High Hold Time Data Turn-Around Time: SI/O input (write to LM95172Q) to output (read from LM95172Q) Bus free time between communications: CS High to CS Low. (Note 13) Parameter Conditions Typical (Note 9) Limits (Note 10) 765 1.25 1 84 200 50 30 50 94 5 Units (Limit) ns (min) µs (min) µs (max) ns (max) ns (max) ns (min) ns (min) ns (min) ns (max) µs (min) 30035704 FIGURE 2. Data Output Timing Diagram 30035705 FIGURE 3. TRI-STATE Data Output Timing Diagram www.national.com 6 LM95172Q 30035706 FIGURE 4. Data Input Timing Diagram 30035709 FIGURE 5. tBUF Timing Definition Diagram 30035710 FIGURE 6. tTA Timing Definition 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 pad exceeds the power supplies (VI < GND or VI > [VDD ANALOG or VDD IO]) the current at that pad should be limited to 5 mA. Note 3: Invalid. The LM95172Q will return a "0" if read. If written to, no valid register will be modified. Note 4: Human body model, 100 pF discharged through a 1.5 kΩ resistor. Machine model, 200 pF discharged directly into each pad. The Charged Device Model (CDM) is a specified circuit characterizing an ESD event that occurs when a device acquires charge through some triboelectric (frictional) or electrostatic induction processes and then abruptly touches a grounded object or surface. Note 5: The LM95172Q is specified for continuous operation at 150°C with occasional short-term excursions to 175°C. Note 6: The LM95172Q will operate properly over the VDD ANALOG = 3.0V to 5.5V and VDD IO = 3.0V to 5.5V supply voltage ranges. Note 7: The voltage on the Chip Select (CS) pad must be less than or equal to (VDD IO +0.2V) at all times. VDD IO must be fully powered-up before CS is allowed to go high. Note 8: Total Quiescent Current includes the sum of the currents into the VDD ANALOG and the VDD IO pads. Note 9: Typicals are at TA = 25°C and represent most likely parametric norm. Note 10: Limits are guaranteed to National's AOQL (Average Outgoing Quality Level). Note 11: This specification is provided only to indicate how often temperature data is updated. The LM95172Q 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 12: For best accuracy, minimize output loading. Higher sink currents can affect sensor accuracy with internal heating. Note 13: Guaranteed by design. 7 www.national.com LM95172Q TRI-STATE Test Circuit 30035707 FIGURE 7. Typical Performance Characteristics Steady State Power Supply Current vs Temperature 30035796 Temperature Error vs Temperature 30035797 www.national.com 8 LM95172Q 1.0 Functional Description The LM95172Q incorporates a temperature sensor and a 13bit to 16-bit ΣΔ ADC (Sigma-Delta Analog-to-Digital Converter). Compatibility of the LM95172Q's three-wire serial inter- face with SPI and MICROWIRE allows simple communications with common microcontrollers and processors. Shutdown mode minimizes current drain for different applications. See Figure 8 for the Functional Block Diagram. 30035722 FIGURE 8. LM95172Q Functional Block Diagram 9 www.national.com LM95172Q 1.1 INITIAL SOFTWARE RESET AND POWER-UP SEQUENCES AND POWER ON RESET (POR) 1.1.1 Software Reset Sequence A software reset sequence must be followed, after the initial VDD ANALOG and VDD IO supply voltages reach their specified minimum operating voltages, in order to ensure proper operation of the LM95172Q. The software reset sequence is as follows: 1. Allow VDD ANALOG and VDD IO to reach their specified minimum operating voltages, as specified in the Operating Ratings section, and in a manner as specified in section 1.1.2 below. 2. Write a “1” to the Shutdown bit, Bit 15 of the Control/Status Register, and hold it high for at least the specified maximum conversion time for the initial default of 13-bits resolution, in order to ensure that a complete reset operation has occurred. (See the Temperature Conversion Time specifications within the Temperature-to-Digital Characteristics section.) 3. Write a “0” to the Shutdown bit to restore the LM95172Q to normal mode. 4. Wait for at least the specified maximum conversion time for the initial default of 13-bits resolution in order to ensure that accurate data appears in the Temperature Register. 1.1.2 Power-Up Sequence A. Linear Power-up In the case where the VDD ANALOG and VDD IO voltage-vs.-time function is linear, the specified minimum operating voltage must be reached in 5 ms or less. B. Resistor-Capacitor (R-C) Charging Exponential Power-up In the case where the VDD ANALOG and VDD IO voltage-vs.-time function is as a typical R-C Charging exponential function the time constant must be less than or equal to 1.25 ms. C. Other Power-up Functions In the case where the VDD ANALOG and VDD IO voltage-vs.-time characteristic follows another function the following requirements must be met: (1) The specified minimum operating voltage values for VDD ANALOG and VDD IO must be reached in 5 ms or less. (2) The slope of the VDD ANALOG and VDD IO power-up curves must be greater than or equal to 0.7 V/ms at any time before the specified minimum operating voltage is reached. (3) The slope of the VDD ANALOG and VDD IO power-up curves must not allow ringing such that the voltage is allowed to drop below the specified minimum operating voltage at any time after the specified minimum operating voltage is reached. 1.1.3 Power On Reset (POR) After the requirements of section 1.1.1 and 1.1.2 above are met each register will then contain its defined POR default value. Any of the following actions may cause register values to change from their POR value: 1. The master writes different data to any Read/Write (R/W) bits, or 2. The LM95172Q is powered down. The specific POR Value of each register is listed in Section 1.7 under Internal Register Structure. www.national.com 10 LM95172Q 1.2 ONE SHOT CONVERSION The LM95172Q features a one-shot conversion bit, which is used to initiate a singe conversion and comparison cycle when the LM95172Q is in shutdown mode. While the LM95172Q is in shutdown mode, writing a "1" to the One-Shot bit in the Control/Status Register will cause the LM95172Q to perform a single temperature conversion and update the Temperature Register and the affected status bits. Operating the LM95172Q in this one-shot mode allows for extremely low average-power comsumption, making it ideal for low-power applications. When the One-shot bit is set, the LM95172Q initiates a temperature conversion. After this initiation, but before the completion of the conversion, and resultant register updates, the LM95172Q is in a "one-shot" state. During this state, the Data Available (DAV) flag in the Control/Status Register is "0" and the Temperature Register contains the value 8000h (-256°C). All other registers contain the data that was present before initiating the one-shot conversion. After the temperature measurement is complete, the DAV flag will be set to "1" and the temperature register will contain the resultant measured temperature. 1.3 OVERTEMP OUTPUT The Over-temperature (OVERTEMP) output is a temperature switch signal that indicates when the measured temperature exceeds the THIGH programmed limit. The programmable THIGH register sets the high temperature limit and the TLOW register is used to set the hysteresis. The TLOW register also sets the temperature below which the OVERTEMP output resets. The OVERTEMP output of the LM95172Q behaves as a temperature comparator. The following explains the operation of OVERTEMP. Figure 9 illustrates the OVERTEMP output behavior. 30035721 FIGURE 9. LM95172Q OVERTEMP vs. Temperature Response Diagram The OVERTEMP Output will assert when the measured temperature is greater than the THIGH value. OVERTEMP will reset if any of the following events happens: 1. The temperature falls below the value stored in the TLOW register, or 2. A "1" is written to the OVERTEMP Reset bit in the Control/ Status Register. If OVERTEMP is cleared by the master writing a "1" to the OVERTEMP Reset bit while the measured temperature still exceeds the THIGH value, OVERTEMP will assert again after the completion of the next temperature conversion. Placing the LM95172Q in shutdown mode or triggering a one-shot conversion does not cause OVERTEMP to reset. 11 www.national.com LM95172Q 1.4 COMMUNICATING WITH THE LM95172Q The serial interface consists of three lines: CS (Chip Select), SC (Serial Clock), and the bi-directional SI/O (Serial I/O) data line. See (Note 7)for CS voltage restriction. A high-to-low transition of the CS line initiates the communication. The master (processor) always drives the chip select and the clock. The first 16 clocks shift the temperature data out of the LM95172Q on the SI/O line (a temperature read). Raising the CS at anytime during the communication will terminate this read operation. Following this temperature read, the SI/O line becomes an input and a command byte can be written to the LM95172Q. This command byte contains a R/W bit and the address of the register to be communicated with next (see Section 1.7 Internal Register Structure). When writing, the data is latched in after every 8 bits. The processor must write at least 8 bits in order to latch the data. If CS is raised before the falling edge of the 8th command bit, no data will be latched into the command byte. If CS is raised after the 8th data-register write bit, but before the 16th bit, only the most significant byte of the data will be latched. This command-data-command-data sequence may be performed as many times as desired. 30035714 FIGURE 10. Reading the Temperature Register 30035716 FIGURE 11. Reading the Temperature Register followed by a read or write from another register (Control/Status, THIGH, TLOW, or Identification register) 30035715 FIGURE 12. Reading the Temperature Register followed by repeated commands and Data Register accesses (Control/ Status, THIGH, TLOW, or Identification register) www.national.com 12 LM95172Q 1.5 TEMPERATURE DATA FORMAT Temperature data is represented by a 13- to 16-bit, two's complement word with a Least Significant Bit (LSB) equal to 0.0625 °C (13-bits), 0.03125 °C (14-bits), 0.015625 °C (15bits) or 0.0078125 °C (16-bits). See Section 1.7.2 for definition of the bits in the Temperature Register. 13-Bit Resolution. First Bit (D15) is Sign, the last bit (D0) is Toggle and bits D1 and D2 are always 0. 13-bit Resolution Digital Output Temperature 16-bit Binary 0101011110000 000 0101011110000 001 0100101100000 000 0100101100000 001 0010100000000 000 0010100000000 001 0000110010000 000 0000110010000 001 0000000000001 000 0000000000001 001 0000000000000 000 0000000000000 001 1111111111111 000 1111111111111 001 1110110000000 000 1110110000000 001 All 16 Bits Hex 5780 5781 4B00 4B01 2800 2801 0C80 0C81 0008 0009 0000 0001 FFF8 FFF9 EC00 EC01 Bits D15 - D3 Hex 0AF0 0960 0500 0190 0001 0000 1FFF 1D80 +175°C +150°C +80°C +25°C +0.0625°C 0°C −0.0625°C −40°C 14-Bit Resolution. First bit (D15) is Sign, the last bit (D0) is Toggle and bit D1 is always 0. 14-bit Resolution Digital Output Temperature 16-bit Binary 01010111100000 00 01010111100000 01 01001011000000 00 01001011000000 01 00101000000000 00 00101000000000 01 00001100100000 00 00001100100000 01 00000000000001 00 00000000000001 01 00000000000000 00 00000000000000 01 11111111111111 00 11111111111111 01 11101100000000 00 11101100000000 01 All 16 Bits Hex 5780 5781 4B00 4B01 2800 2801 0C80 0C81 0004 0005 0000 0001 FFFC FFFD EC00 EC01 Bits D15 - D2 Hex 15E0 12C0 0A00 0320 0001 0000 3FFF 3B00 +175°C +150°C +80°C +25°C +0.03125°C 0°C −0.03125°C −40°C 13 www.national.com LM95172Q 15-Bit Resolution. First bit (D15) is Sign and the last bit (D0) is Toggle. 15-bit Resolution Digital Output Temperature 16-bit Binary 010101111000000 0 010101111000000 1 010010110000000 0 010010110000000 1 001010000000000 0 001010000000000 1 000011001000000 0 000011001000000 1 000000000000001 0 000000000000001 1 000000000000000 0 000000000000000 1 111111111111111 0 111111111111111 1 111011000000000 0 111011000000000 1 All 16 Bits Hex 5780 5781 4B00 4B01 2800 2801 0C80 0C81 0002 0003 0000 0001 FFFE FFFF EC00 EC01 Bits D15 - D1 Hex 2BC0 2580 1400 0640 0001 0000 7FFF 7600 +175°C +150°C +80°C +25°C +0.015625°C 0°C −0.015625°C −40°C 16-Bit Resolution. First bit (D15) is Sign and the last bit (D0) is the LSB. 16-bit Resolution Digital Output Temperature +175°C +150°C +80°C +25°C +0.0078125°C 0°C −0.0078125°C −40°C 16-bit Binary 0101 0111 1000 0000 0100 1011 0000 0000 0010 1000 0000 0000 0000 1100 1000 0000 0000 0000 0000 0001 0000 0000 0000 0000 1111 1111 1111 1111 1110 1100 0000 0000 All 16 Bits Hex 5780 4B00 2800 0C80 0001 0000 FFFF EC00 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. 1.6 SHUTDOWN MODE Shutdown Mode is enabled by writing a “1” to the Shutdown Bit, Bit 15 of the Control/Status Register, and holding it high for at least the specified maximum conversion time at the ex- isting temperature resolution setting. (see Temperature Conversion Time specifications under the Temperature-to-Digital Characteristics section). For example, if the LM95172Q is set for 16-bit resolution before shutdown, then Bit 15 of the Control/Status register must go high and stay high for the specified maximum conversion time for 16-bits resolution. The LM95172Q will always finish a temperature conversion and update the temperature registers before shutting down. Writing a “0” to the Shutdown Bit restores the LM95172Q to normal mode. www.national.com 14 LM95172Q 1.7 INTERNAL REGISTER STRUCTURE The LM95172Q has four registers that are accessible by issuing a command byte (a R/W Bit plus the register address: Control/Status, THIGH, TLOW, and Identification. Which of these registers will be read or written is determined by the Command Byte. See Section 1.4, "Communicating with the LM95172Q", for a complete description of the serial communication protocol. The following diagram describes the Command Byte and lists the addresses of the various registers. The temperature is read by lowering the CS line and then 1.7.1 Command Byte P7 R/W P6 0 P5 0 P4 0 clocking the data out from the 16-Bit temperature register; all other registers are accessed by writing a Command Byte after reading the temperature. All registers can be communicated with, either in Continuous Conversion mode or in Shutdown mode. When the LM95172Q has been placed in Shutdown Mode, the Temperature register will contain the temperature data which resulted from the last temperature conversion (whether it was the result of a continuous-conversion reading or a one-shot reading). P3 0 P2 P1 P0 Register Select Bit Read/Write Bit. Tells the LM95172Q if the host will be writing to, or reading from, the register to which this byte is pointing. Bits Not Used. These Bits must be zero. If an illegal address is written, the LM95172Q will return 0000h on the subsequent read. Bits Pointer Address Bits. Points to desired register. See table below. P2 0 0 0 0 1 1 1 1 Power-On Reset state: 00h Reset Conditions: Upon Power-on Reset P1 0 0 1 1 0 0 1 1 P0 0 1 0 1 0 1 0 1 Identification Invalid. (Note 3) Register Invalid. (Note 3) Control/Status THIGH TLOW 15 www.national.com LM95172Q 1.7.2 Temperature Register (Read Only): Default Register D15 Sign D7 1°C D6 0.5°C D5 0.25°C D14 128°C D4 0.125°C D13 64°C D3 0.0625°C D12 32°C D11 16°C D2 0.03125°C D10 8°C D1 0.015625°C D9 4°C D8 2°C D0 Conversion - Toggle/ 0.0078125°C Bit : Temperature Data Byte. Represents the temperature that was measured by the most recent temperature conversion in two's complement form. On power-up, this data is invalid until the DAV Bit in the Control/Status Register is high (that is, after completion of the first conversion). The resolution is user-programmable from 13-Bit resolution (0.0625°C) through 16-Bit resolution (0.0078125°C). The desired resolution is programmed through Bits 4 and 5 of the Control/Status Register. See the description of the Control/Status Register for details on resolution selection. The Bits not used for a selected resolution are always set to "0" and are not to be considered part of a valid temperature reading. For example, for 14-Bit resolution, Bit is not used and, therefore, it is invalid and is always zero. Bit : Conversion Toggle or, if 16-Bit resolution has been selected, this is the 16-Bit temperature LSB. When in 13-Bit, 14-Bit, or 15-Bit resolution mode, this Bit toggles each time the Temperature register is read if a conversion has completed since the last read. If conversion has not completed, the value will be the same as the last read. When in 16-Bit resolution mode, this is the Least Significant Bit of the temperature data. Reset Conditions: See Sections 1.1.1 through 1.1.3 for reset conditions. One-Shot State: 8000h (-256°C) www.national.com 16 LM95172Q 1.7.3 Control/Status Register (Read/Write) Pointer Address: 81h (Read); 01h (Write) D15 SD D14 One-Shot D7 OVERTEMP Disable D13 OVERTEMP Reset D6 OVERTEMP POL D12 Conversion Toggle D5 RES1 D4 RES0 D11 OVERTEMP Status D3 0 D2 reserved D10 THIGH D1 reserved D9 TLOW D8 DAV D0 0 Bit : Shutdown (SD) Bit. Writing a “1” to this bit and holding it high for at least the specified maximum conversion time, at the existing temperature resolution setting, enables the Shutdown Mode. Writing a “0” to this bit restores the LM95172Q to normal mode. Bit : One-Shot Bit. When in shutdown mode (Bit is "1"), initates a single temperature conversion and update of the temperature register with new temperature data. Has no effect when in continuous conversion mode (i.e., when Bit is "0"). Always returns a "0" when read. Bit : OVERTEMP Reset Bit. Writing a "1" to this Bit resets the OVERTEMP Status bit and, after a possible wait up to one temperature conversion time, the OVERTEMP pad. It will always return a "0" when read. Bit : Conversion Toggle Bit. Toggles each time the Control/Status register is read if a conversion has completed since the last read. If conversion has not been completed, the value will be the same as last read. Bit : OVERTEMP pad Status Bit. This Bit is "0" when OVERTEMP output is low and "1" when OVERTEMP output is high. The OVERTEMP output is reset under the following conditions: (1) Cleared by writing a "1" to the OVERTEMP Reset Bit (Bit ) in this register or (2) Measured temperature falls below the TLOW limit. If the temperature is still above THIGH, and OVERTEMP Reset is set to "1", then the Bit and the pad clear until the next conversion, at which point the Bit and pad would assert again. Bit : Temperature High (THIGH) Flag Bit. This Bit is set to "1" when the measured temperature exceeds the THIGH limit stored in the programmable THIGH register. The flag is reset to "0" when both of two conditions are met: (1) temperature no longer exceeds the programmed THIGH limit and (2) upon reading the Control/Status Register. If the temperature no longer exceeds the THIGH limit, the status Bit remains set until it is read by the master so that the system can check the history of what caused the OVERTEMP to assert. Bit : Temperature Low (TLOW) Flag Bit. This Bit is set to "1" when the measured temperature falls below the TLOW limit stored in the programmable TLOW register. The flag is reset to "0" when both of two conditions are met: (1) temperature is no longer below the programmed TLOW limit and (2) upon reading the Control/Status Register. If the temperature is no longer below, or equal to, the TLOW limit, the status Bit remains set until it is read by the master so that the system can check the history of what caused the OVERTEMP to assert. Bit : Data Available (DAV) Status Bit. This Bit is "0" when the temperature sensor is in the process of converting a new temperature. It is "1" when the conversion is done. It is reset after each read and goes high again after one temperature conversion is done. In one-shot mode: after initiating a temperature conversion while operating, this status Bit can be monitored to indicate when the conversion is done. After triggering the one-shot conversion, the data in the temperature register is invalid until this Bit is high (i.e., after completion of the first conversion). Bit : OVERTEMP Disable Bit. When set to "0" the OVERTEMP output is enabled. When set to "1" the OVERTEMP output is disabled. This Bit also controls the OVERTEMP Status Bit (this register, Bit ) since that Bit reflects the state of the OVERTEMP pad. Bit : OVERTEMP Polarity Bit. When set to "1", OVERTEMP is active-high. When "0" it is active-low. Bit : Temperature Resolution Bits. Selects one of four user-programmable temperature data resolutions as indicated in the following table. Control/Status Register Bit 5 0 0 1 1 Bit : Always write a zero to this Bit. Bit : Reserved Bits. Will return whatever was last written to them. Value is zero on power-up. Bit : Always write a zero to this Bit. Reset State: 0000h Reset Conditions: Upon Power-on Reset. 17 www.national.com Resolution Bits 13 14 15 16 °C 0.0625 0.03125 0.015625 0.0078125 Bit 4 0 1 0 1 LM95172Q 1.7.4 THIGH: Upper Limit Register (Read/Write) Pointer Address: 82h (Read); 02h (Write) D15 Sign D7 1°C D14 128°C D6 0.5°C D13 64°C D5 0.25°C D12 32°C D4 D11 16°C D3 D10 8°C D2 Reserved D9 4°C D1 D8 2°C D0 Bit : Upper-Limit Temperature byte. If the measured temperature, stored in the temperature register, exceeds this userprogrammable temperature limit, the OVERTEMP pad will assert and the THIGH flag in the Control/Status register will be set to "1". Bit : Reserved. Returns all zeroes when read. Reset State: 4880h (+145°C) Reset Conditions: Upon Power-on Reset. 1.7.5 TLOW: Lower Limit Register (Read/Write) Pointer Address: 83h (Read); 03h (Write) D15 Sign D7 1°C D14 128°C D6 0.5°C D13 64°C D5 0.25°C D12 32°C D4 D11 16°C D3 D10 8°C D2 Reserved D9 4°C D1 D8 2°C D0 Bit : Lower-Limit Temperature byte. If the measured temperature that is stored in the temperature register falls below this user-programmable temperature limit, the OVERTEMP pad will not assert and the TLOW flag in the Control/Status register will be set to "1". Bit : Reserved. Returns all zeroes when read. Reset State: 4600h (+140°C) Reset Conditions: Upon Power-on Reset. 1.7.6 MFGID: Manufacturer, Product, and Step ID Register (Read Only) Pointer Address: 87h D15 1 D7 0 D14 0 D6 0 D13 0 D5 1 D12 0 D4 1 D11 0 D3 0 D10 0 D2 0 D9 0 D1 0 D8 0 D0 0 Bit : Manufacturer Identification Byte. Always returns 80h to uniquely identify the manufacturer as National Semiconductor Corporation. Bit : Product Identification Nibble. Always returns 30h to uniquely identify this part as the LM95172Q. Bit : Die Revision Nibble. Returns 0h to uniquely identify the revision level as zero. Reset State: 8030h Reset Conditions: Upon Power-on Reset. www.national.com 18 LM95172Q 1.8 NOISE IMMUNITY OF THE SERIAL I/O (SI/O) AND SERIAL CLOCK (SC) LINES The LM95172Q's Serial I/O and Serial Clock lines have high noise immunity making it an excellent choice in challenging electromagnetic environments. Some typical bench tests, taken at room temperature, were done to show the noise immunity in the case of an injected sinewave signal used to simulate an interfering noise signal. Figure 13 below shows the Test Setup used for the bench test. A function generator was used to create the noise signal. I the first test this signal was AC-coupled to the SI/O line through a 1 nF capacitor. The amplitude of the signal from the generator was adjusted so that the peak-to-peak voltage at the pad was 400 mVpp, the maximum that is compatible with the Absolute Maximum requirements. Figure 14 below shows the combined waveform for the Serial digital and injected noise signals. 30035712 FIGURE 14. Typical Waveforms for Noise Immunity Test The LM95172Q's temperature output was read continuously while the noise signal was injected on the serial I/O line. The frequency was increased from 1 to 20 MHz in 1 MHz steps. In the same manner, the Serial Clock (SC) line was tested by injecting a 400 mVpp sinusoidal signal at the serial clock pad and monitoring the continuously reading the LM95172Q temperature. The Result: No temperature change resulted from the interfering signal. 30035711 FIGURE 13. Test Setup for Noise Immunity Test 19 www.national.com LM95172Q 2.0 Typical Applications 30035720 FIGURE 15. Temperature monitor using Intel 196 processor 30035719 FIGURE 16. LM95172Q digital input control using microcontroller's general purpose I/O. www.national.com 20 LM95172Q Physical Dimensions 30035702 Order Number LM95172QA2 MDA Die Form For Bond Pad Mechanical Dimensions, see Connection Diagram Section 30035723 Orientation of Die in 8 mm Surf Tape 21 www.national.com LM95172Q 30035799 Dimensions of Surf Tape Transport Media. Use Option 01. www.national.com 22 LM95172Q Notes 23 www.national.com LM95172Q Digital Temperature Sensor in Die Form with ± 1°C Accuracy from 130°C to 160°C Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Amplifiers Audio Clock and Timing Data Converters Interface LVDS Power Management Switching Regulators LDOs LED Lighting Voltage Reference PowerWise® Solutions Serial Digital Interface (SDI) Temperature Sensors Wireless (PLL/VCO) www.national.com/amplifiers www.national.com/audio www.national.com/timing www.national.com/adc www.national.com/interface www.national.com/lvds www.national.com/power www.national.com/switchers www.national.com/ldo www.national.com/led www.national.com/vref www.national.com/powerwise www.national.com/sdi www.national.com/tempsensors www.national.com/wireless WEBENCH® Tools App Notes Reference Designs Samples Eval Boards Packaging Green Compliance Distributors Design Support www.national.com/webench www.national.com/appnotes www.national.com/refdesigns www.national.com/samples www.national.com/evalboards www.national.com/packaging www.national.com/quality/green www.national.com/contacts www.national.com/quality www.national.com/feedback www.national.com/easy www.national.com/solutions www.national.com/milaero www.national.com/solarmagic www.national.com/AU Quality and Reliability Feedback/Support Design Made Easy Solutions Mil/Aero SolarMagic™ Analog University® THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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