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LMT01LPGM

LMT01LPGM

  • 厂商:

    BURR-BROWN(德州仪器)

  • 封装:

    TO92-2

  • 描述:

    温湿度传感器 TO-92-2 2~5.5V 34µA

  • 数据手册
  • 价格&库存
LMT01LPGM 数据手册
Order Now Product Folder Support & Community Tools & Software Technical Documents LMT01 SNIS189D – JUNE 2015 – REVISED JUNE 2018 LMT01 0.5°C Accurate 2-Pin Digital Output Temperature Sensor With Pulse Count Interface 1 Features 3 Description • The LMT01 device is a high-accuracy, 2-pin temperature sensor with an easy-to-use pulse count current loop interface, which makes it suitable for onboard and offboard applications in automotive, industrial, and consumer markets. The LMT01 digital pulse count output and high accuracy over a wide temperature range allow pairing with any MCU without concern for integrated ADC quality or availability, while minimizing software overhead. TI’s LMT01 device achieves a maximum ±0.5°C accuracy with very fine resolution (0.0625°C) over a temperature range of –20°C to 90°C without system calibration or hardware and software compensation. 1 • • • • • • • High Accuracy Over –50°C to 150°C Wide Temperature Range – –20°C to 90°C: ±0.5°C (Maximum) – 90°C to 150°C: ±0.625°C (Maximum) – –50°C to –20°C: ±0.7°C (Maximum) Precision Digital Temperature Measurement Simplified in a 2-Pin Package Pulse Count Current Loop Easily Read by Processor. Number of Output Pulses is Proportional to Temperature With 0.0625°C Resolution Communication Frequency: 88 kHz Conversion Current: 34 µA Continuous Conversion Plus Data-Transmission Period: 100 ms Floating 2-V to 5.5-V (VP–VN) Supply Operation With Integrated EMI Immunity Multiple 2-Pin Package Offerings: TO-92/LPG (3.1 mm × 4 mm × 1.5 mm) – ½ the Size of Traditional TO-92 and WSON With Wettable Flanks Device Information(1) 2 Applications • • • • • The LMT01’s pulse count interface is designed to directly interface with a GPIO or comparator input, thereby simplifying hardware implementation. Similarly, the LMT01's integrated EMI suppression and simple 2-pin architecture makes it suitable for onboard and offboard temperature sensing in a noisy environment. The LMT01 device can be easily converted into a two-wire temperature probe with a wire length up to two meters. See LMT01-Q1 for the automotive qualified version. PART NUMBER Digital Output Wired Probes White Goods HVAC Power Supplies Battery Management PACKAGE LMT01LPG TO-92 (2) 4.00 mm × 3.15 mm LMT01DQX WSON (2) 1.70 mm × 2.50 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. 2-Pin IC Temperature Sensor LMT01 Accuracy VDD: 3.0V to 5.5V GPIO 1.0 0.8 Temperature Accuracy (ƒC) BODY SIZE (NOM) Up to 2m Max Limit 0.6 VP 0.4 0.2 LMT01 0.0 VN Min 2.0V -0.2 MCU/ FPGA/ ASIC GPIO/ COMP -0.4 -0.6 LMT01 Pulse Count Interface Min Limit -0.8 Conversion Time -1.0 ±50 ±25 0 25 50 75 100 LMT01 Junction Temperaure (ƒC) Typical units plotted in center of curve. 125 ADC Conversion Result 150 Power Off C014 Power On 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. LMT01 SNIS189D – JUNE 2015 – REVISED JUNE 2018 www.ti.com Table of Contents 1 2 3 4 5 6 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 6.1 6.2 6.3 6.4 6.5 6.6 Absolute Maximum Ratings ...................................... 4 ESD Ratings.............................................................. 4 Recommended Operating Conditions ...................... 4 Thermal Information .................................................. 4 Electrical Characteristics........................................... 5 Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT................................................... 6 6.7 Electrical Characteristics - WSON/DQX Pulse Count to Temperature LUT................................................... 7 6.8 Switching Characteristics .......................................... 7 6.9 Timing Diagram......................................................... 8 6.10 Typical Characteristics ............................................ 9 7 Detailed Description ............................................ 13 7.2 Functional Block Diagram ....................................... 13 7.3 Feature Description................................................. 13 7.4 Device Functional Modes........................................ 16 8 Application and Implementation ........................ 17 8.1 Application Information............................................ 17 8.2 Typical Application .................................................. 18 8.3 System Examples .................................................. 20 9 Power Supply Recommendations...................... 22 10 Layout................................................................... 23 10.1 Layout Guidelines ................................................. 23 10.2 Layout Example .................................................... 23 11 Device and Documentation Support ................. 24 11.1 11.2 11.3 11.4 11.5 Receiving Notification of Documentation Updates Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 24 24 24 24 24 12 Mechanical, Packaging, and Orderable Information ........................................................... 24 7.1 Overview ................................................................. 13 4 Revision History Changes from Revision C (June 2017) to Revision D Page • Added device stamp to the TO-92 pinout top view ................................................................................................................ 3 • Changed the TO-92S pin numbers in the Pin Functions........................................................................................................ 3 Changes from Revision B (April 2017) to Revision C Page • Removed Electrical Characteristics: WSON/DQX table; Combined the LPG and DQX Electrical Characteristics tables together ........................................................................................................................................................................ 5 • Changed IOL maximum value from: 39 µA to: 40 µA .............................................................................................................. 5 • Changed leakage value from: 1 µA to 3.5 µA ........................................................................................................................ 5 • Moved the thermal response time parameters to the Electrical Characteristics table ........................................................... 5 • Added Missing Cross References ........................................................................................................................................ 13 Changes from Revision A (June 2015) to Revision B Page • Added new WSON/DQX package throughout data sheet ..................................................................................................... 1 • Changed updated package information. ................................................................................................................................ 3 • Added Electrical Characteristics - WSON/DQX Pulse Count to Temperature LUT ............................................................... 7 • Added -40 for Sample Calculations Table ........................................................................................................................... 14 • Added missing cross reference ........................................................................................................................................... 15 Changes from Original (June 2015) to Revision A Page • Added full datasheet. ............................................................................................................................................................. 1 • Added clarification note. ........................................................................................................................................................ 1 2 Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 LMT01 www.ti.com SNIS189D – JUNE 2015 – REVISED JUNE 2018 5 Pin Configuration and Functions DQX Package 2-Pin WSON Bottom View VP VN LPG Package 2-Pin TO-92 Top View LM YM LL F T0 1 VN VP Pin Functions PIN NAME TO-92S WSON VP 2 1 VN 1 2 TYPE Input DESCRIPTION Positive voltage pin; may be connected to system power supply or bias resistor. Output Negative voltage pin; may be connected to system ground or a bias resistor. Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 3 LMT01 SNIS189D – JUNE 2015 – REVISED JUNE 2018 www.ti.com 6 Specifications 6.1 Absolute Maximum Ratings (1) (2) See . MIN MAX UNIT Voltage drop (VP – VN) −0.3 6 V Storage temperature, Tstg −65 175 °C (1) (2) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. Soldering process must comply with Reflow Temperature Profile specifications. Refer to www.ti.com/packaging. 6.2 ESD Ratings VALUE V(ESD) (1) (2) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) ±2000 Charged-device model (CDM), per JEDEC specification JESD22-C101 (2) ±750 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 6.3 Recommended Operating Conditions Free-air temperature MIN MAX UNIT −50 150 °C 2 5.5 V Voltage drop (VP – VN) 6.4 Thermal Information LMT01 THERMAL METRIC (1) DQX (WSON) LPG (TO-92) 2 PINS 2 PINS UNIT RθJA Junction-to-ambient thermal resistance 213 177 °C/W RθJC(top) Junction-to-case (top) thermal resistance 71 94 °C/W RθJB Junction-to-board thermal resistance 81 152 °C/W ψJT Junction-to-top characterization parameter 2.4 33 °C/W ψJB Junction-to-board characterization parameter 79 152 °C/W (1) 4 For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report. Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 LMT01 www.ti.com SNIS189D – JUNE 2015 – REVISED JUNE 2018 6.5 Electrical Characteristics Over operating free-air temperature range and operating VP-VN range (unless otherwise noted). PARAMETER TEST CONDITIONS MIN TYP MAX UNIT ACCURACY Temperature accuracy Temperature accuracy (1) (2) (1) (2) 150°C –0.625 0.625 °C 125°C -0.625 0.625 °C 120°C –0.625 0.625 °C 110°C –0.5625 0.5625 °C 100°C VP – VN of 2.15 V to 5.5 V 90°C –0.5625 0.5625 °C –0.5 0.5 °C 25°C –0.5 0.5 °C –20°C –0.5 0.5 °C –30°C –0.5625 0.5625 °C –40°C –0.625 0.625 °C VP – VN of –50°C 2.15 V to 5.5 V –0.6875 ±0.4 0.6875 °C 800 808 ±0.125 PULSE COUNT TRANSFER FUNCTION Number of pulses at 0°C Output pulse range Theoretical max (exceeds device rating) 816 15 3228 1 4095 Resolution of one pulse 0.0625 °C OUTPUT CURRENT IOL IOH Output current variation Low level 28 34 40 µA High level 112.5 125 143 µA 3.1 3.7 4.5 40 133 m°C/V 0.002 3.5 µA High-to-Low level output current ratio POWER SUPPLY Accuracy sensitivity to change in VP – VN 2.15 V ≤ VP – VN ≤ 5. 0 V (3) Leakage Current VP – VN VDD ≤ 0.4 V THERMAL RESPONSE Stirred oil thermal response time to 63% of final value DQX (WSON) (package only) LPG (TO-92) 0.4 DQX (WSON) 9.4 LPG (TO-92) 28 Still air thermal response time to 63% of final value (package only) (1) (2) (3) 0.8 s s Calculated using Pulse Count to Temperature LUT and 0.0625°C resolution per pulse, see section Electrical Characteristics - TO92/LPG Pulse Count to Temperature LUT and Electrical Characteristics - WSON/DQX Pulse Count to Temperature LUT. Error can be linearly interpolated between temperatures given in table as shown in the Accuracy vs Temperature curves in section Typical Characteristics. Limit is using end point calculation. Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 5 LMT01 SNIS189D – JUNE 2015 – REVISED JUNE 2018 www.ti.com 6.6 Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT Over operating free-air temperature range and VP-VN operating range (unless otherwise noted). LUT is short for Look-up Table. PARAMETER Digital output code 6 MIN TYP MAX –50°C TEST CONDITIONS 15 26 37 –40°C 172 181 190 –30°C 329 338 347 –20°C 486 494 502 –10°C 643 651 659 0°C 800 808 816 10°C 958 966 974 20°C 1117 1125 1133 30°C 1276 1284 1292 40°C 1435 1443 1451 50°C 1594 1602 1610 60°C 1754 1762 1770 70°C 1915 1923 1931 80°C 2076 2084 2092 90°C 2237 2245 2253 100°C 2398 2407 2416 110°C 2560 2569 2578 120°C 2721 2731 2741 130°C 2883 2893 2903 140°C 3047 3057 3067 150°C 3208 3218 3228 Submit Documentation Feedback UNIT pulses Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 LMT01 www.ti.com SNIS189D – JUNE 2015 – REVISED JUNE 2018 6.7 Electrical Characteristics - WSON/DQX Pulse Count to Temperature LUT Over operating free-air temperature range and 2.15 V ≤ VP – VN ≤ 5. 0 V power supply operating range (unless otherwise noted). LUT is short for Look-up Table. PARAMETER Digital output code MIN TYP MAX –50°C TEST CONDITIONS 15 26 37 –40°C 172 181 190 –30°C 328 337 346 –20°C 486 494 502 –10°C 643 651 659 0°C 800 808 816 10°C 958 966 974 20°C 1117 1125 1133 30°C 1276 1284 1292 40°C 1435 1443 1451 50°C 1594 1603 1611 60°C 1754 1762 1771 70°C 1915 1923 1931 80°C 2076 2084 2092 90°C 2237 2245 2254 100°C 2398 2407 2416 110°C 2560 2569 2578 120°C 2721 2731 2741 125°C 2802 2814 2826 130°C 2883 2894 2904 140°C 3047 3058 3068 150°C 3210 3221 3231 UNIT pulses 6.8 Switching Characteristics Over operating free-air temperature range and operating VP – VN range (unless otherwise noted). PARAMETER tR, tF Output current rise and fall time fP Output current pulse frequency TEST CONDITIONS Output current duty cycle tCONV Temperature conversion time (1) tDATA Data transmission time (1) MIN CL = 10 pF, RL = 8 k 2.15 V to 5.5 V TYP MAX 1.45 UNIT µs 82 88 94 40% 50% 60% kHz 46 50 54 ms 44 47 50 ms Conversion time includes power up time or device turn on time that is typically 3 ms after POR threshold of 1.2 V is exceeded. Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 7 LMT01 SNIS189D – JUNE 2015 – REVISED JUNE 2018 www.ti.com 6.9 Timing Diagram tCONV tDATA Power 125µA 34µA tR Power Off Output Current tF 1/fP Figure 1. Timing Specification Waveform 8 Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 LMT01 www.ti.com SNIS189D – JUNE 2015 – REVISED JUNE 2018 6.10 Typical Characteristics 1.0 1.0 0.8 Max Limit Temperature Accuracy (ƒC) Temperature Accuracy (ƒC) 0.8 0.6 0.4 0.2 0.0 -0.2 -0.4 -0.6 Min Limit -0.8 0.2 0.0 -0.2 -0.4 -0.6 Min Limit -1.0 ±50 ±25 0 25 50 75 100 125 LMT01 Junction Temperaure (ƒC) 150 ±50 ±25 0 25 50 75 100 125 LMT01 Junction Temperaure (ƒC) C017 Using Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT VP – VN = 2.15 V 150 C016 Using Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT VP – VN = 2.4 V Figure 2. Accuracy vs LMT01 Junction Temperature Figure 3. Accuracy vs LMT01 Junction Temperature 1.0 1.0 0.8 0.8 Max Limit Temperature Accuracy (ƒC) Temperature Accuracy (ƒC) 0.4 -0.8 -1.0 0.6 0.4 0.2 0.0 -0.2 -0.4 -0.6 Min Limit -0.8 Max Limit 0.6 0.4 0.2 0.0 -0.2 -0.4 -0.6 Min Limit -0.8 -1.0 -1.0 ±50 ±25 0 25 50 75 100 125 LMT01 Junction Temperaure (ƒC) 150 ±50 ±25 0 25 50 75 100 125 LMT01 Junction Temperaure (ƒC) C015 Using Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT VP – VN = 2.7 V 150 C014 Using Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT VP – VN = 3 V Figure 4. Accuracy vs LMT01 Junction Temperature Figure 5. Accuracy vs LMT01 Junction Temperature 1.0 1.0 0.8 0.8 Max Limit Temperature Accuracy (ƒC) Temperature Accuracy (ƒC) Max Limit 0.6 0.6 0.4 0.2 0.0 -0.2 -0.4 -0.6 Min Limit -0.8 Max Limit 0.6 0.4 0.2 0.0 -0.2 -0.4 -0.6 Min Limit -0.8 -1.0 -1.0 ±50 ±25 0 25 50 75 100 125 LMT01 Junction Temperaure (ƒC) 150 ±50 Using Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT VP – VN = 4 V Figure 6. Accuracy vs LMT01 Junction Temperature ±25 0 25 50 75 100 125 LMT01 Junction Temperaure (ƒC) C013 150 C012 Using Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT VP – VN = 5 V Figure 7. Accuracy vs LMT01 Junction Temperature Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 9 LMT01 SNIS189D – JUNE 2015 – REVISED JUNE 2018 www.ti.com Typical Characteristics (continued) 1.00 -0.625°C Min Limit Max Limit 0.60 0.625°C Max Limit 0.40 Frequency Temperature Accuracy (ƒC) 0.80 0.20 0.00 -0.20 -0.40 -0.60 Min Limit -0.80 -1.00 ±50 ±25 0 25 50 75 100 125 150 LMT01 Junction Temperature (ƒC) -1 Using Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT VP – VN = 5.5 V Figure 9. Accuracy Histogram at 150°C 0.5°C Max Limit Frequency +1 0 Accuracy (ƒC) -1 C024 Using Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT VP – VN = 2.15 V to 5.5 V Figure 11. Accuracy Histogram at –20°C 0.5625°C Max Limit -0.5625°C Min Limit Frequency +1 0 Accuracy (ƒC) -1 C022 Using LUT Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT VP – VN = 2.15 V to 5.5 V 0.5625°C Max Limit 0 Accuracy (ƒC) +1 C021 Using Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT VP – VN = 2.15 V to 5.5 V Figure 12. Accuracy Histogram at -30°C 10 C023 Frequency -0.5625°C Min Limit +1 0 Accuracy (ƒC) Using Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT VP – VN = 2.15 V to 5.5 V Figure 10. Accuracy Histogram at 30°C -1 0.5°C Max Limit -0.5°C Min Limit Frequency -1 C025 Using Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT VP – VN = 2.15 V to 5.5 V Figure 8. Accuracy vs LMT01 Junction Temperature -0.5°C Min Limit +1 0 Accuracy (ƒC) C011 Submit Documentation Feedback Figure 13. Accuracy Histogram at -40°C Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 LMT01 www.ti.com SNIS189D – JUNE 2015 – REVISED JUNE 2018 Typical Characteristics (continued) 3.0 Temperature Accuracy (ƒC) 2.5 0.6875°C Max Limit Frequency -0.6875°C Min Limit 2.0 1.5 1.0 0.5 0.0 -0.5 -1.0 -1 +1 0 Accuracy (ƒC) ±50 Using LUT Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT VP – VN = 2.15 V to 5.5 V 25 50 75 100 125 150 C018 Using Temp = (PC/4096 × 256°C ) – 50°C VP – VN = 2.15 V Figure 15. Accuracy Using Linear Transfer Function 3.0 150 2.5 125 2.0 Output Current (µA) Temperature Accuracy (ƒC) 0 LMT01 Junction Temperaure (ƒC) Figure 14. Accuracy Histogram at -50°C 1.5 1.0 0.5 0.0 High Level Current 100 75 Low Level Current 50 25 -0.5 -1.0 0 ±50 ±25 0 25 50 75 100 125 LMT01 Junction Temperaure (ƒC) 150 2 3 4 5 VP - VN (V) C019 Using Temp = (PC/4096 × 256°C ) – 50°C VP – VN = 5.5V 6 C004 TA = 30°C Figure 16. Accuracy Using Linear Transfer Function Figure 17. Output Current vs VP-VN Voltage 150 Percent of (Final - Initial) Value (%) 110 125 Output Current (µA) ±25 C020 High Level Current 100 75 Low Level Current 50 25 0 100 90 80 70 60 50 40 30 20 10 0 ±50 ±25 0 25 50 75 100 125 LMT01 Juntion Temperature (ƒC) 150 0 120 240 360 480 600 720 840 960 1080 1200 Time (seconds) C003 VP – VN = 3.3 V TINITIAL = 23°C, VP – VN = 3.3 V Figure 18. Output Current vs Temperature C033 TFINAL = 70°C Figure 19. Thermal Response in Still Air (TO92S/LPG Package) Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 11 LMT01 SNIS189D – JUNE 2015 – REVISED JUNE 2018 www.ti.com 110 110 100 100 Percent of (Final - Initial) Value (%) Percent of (Final - Initial) Value (%) Typical Characteristics (continued) 90 80 70 60 50 40 30 20 10 0 80 70 60 50 40 30 20 10 0 0 20 40 60 80 100 120 140 160 180 200 Time (seconds) VP – VN = 3.3 V TINITIAL = 23°C, TFINAL = 70°C 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Time (seconds) C032 Air Flow = 2.34 meters/sec Figure 20. Thermal Response in Moving Air (TO92S/LPG Package) 12 90 VP – VN = 3.3 V TINITIAL = 23°C, C031 TFINAL = 70°C Figure 21. Thermal Response in Stirred Oil (TO92S/LPG Package) Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 LMT01 www.ti.com SNIS189D – JUNE 2015 – REVISED JUNE 2018 7 Detailed Description 7.1 Overview The LMT01 temperature output is transmitted over a single wire using a train of current pulses that typically change from 34 µA to 125 µA. A simple resistor can then be used to convert the current pulses to a voltage. With a 10-kΩ resistor, the output voltage levels range from 340 mV to 1.25 V, typically. A simple microcontroller comparator or external transistor can be used convert this signal to valid logic levels the microcontroller can process properly through a GPIO pin. The temperature can be determined by gating a simple counter on for a specific time interval to count the total number of output pulses. After power is first applied to the device the current level will remain below 34 µA for at most 54 ms while the LMT01 is determining the temperature. When the temperature is determined, the pulse train begins. The individual pulse frequency is typically 88 kHz. The LMT01 will continuously convert and transmit data when the power is applied approximately every 104 ms (maximum). The LMT01 uses thermal diode analog circuitry to detect the temperature. The temperature signal is then amplified and applied to the input of a ΣΔ ADC that is driven by an internal reference voltage. The ΣΔ ADC output is then processed through the interface circuitry into a digital pulse train. The digital pulse train is then converted to a current pulse train by the output signal conditioning circuitry that includes high and low current regulators. The voltage applied across the pins of the LMT01 is regulated by an internal voltage regulator to provide a consistent Chip VDD that is used by the ADC and its associated circuitry. 7.2 Functional Block Diagram VP Chip VDD Chip VSS Thermal Diode Analog Circuitry Data ADC Interface Voltage Regulator and Output Signal Conditioning VREF LMT01 VN 7.3 Feature Description 7.3.1 Output Interface The LMT01 provides a digital output in the form of a pulse count that is transmitted by a train of current pulses. After the LMT01 is powered up, it transmits a very low current of 34 µA for less than 54 ms while the part executes a temperature to digital conversion, as shown in Figure 22. When the temperature-to-digital conversion is complete, the LMT01 starts to transmit a pulse train that toggles from the low current of 34 µA to a high current level of 125 µA. The pulse train total time interval is at maximum 50 ms. The LMT01 transmits a series of pulses equivalent to the pulse count at a given temperature as described in Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT. After the pulse count has been transmitted the LMT01 current level will remain low for the remainder of the 50 ms. The total time for the temperature to digital conversion and the pulse train time interval is 104 ms (maximum). If power is continuously applied, the pulse train output will repeat start every 104 ms (maximum). Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 13 LMT01 SNIS189D – JUNE 2015 – REVISED JUNE 2018 www.ti.com Feature Description (continued) Start of data transmission Power ON End of data 54ms max Start of next conversion result data End of data 104ms max Power 50ms max 50ms max Power Off Pulse Train Figure 22. Temperature to Digital Pulse Train Timing Cycle The LMT01 can be powered down at any time to conserve system power. Take care to ensure that a minimum power-down wait time of 50 ms is used before the device is turned on again. 7.3.2 Output Transfer Function TheLMT01 outputs at minimum 1 pulse and a theoretical maximum 4095 pulses. Each pulse has a weight of 0.0625°C. One pulse corresponds to a temperature less than –50°C while a pulse count of 4096 corresponds to a temperature greater than 200°C. Note that the LMT01 is only ensured to operate up to 150°C. Exceeding this temperature by more than 5°C may damage the device. The accuracy of the device degrades as well when 150°C is exceeded. Two different methods of converting the pulse count to a temperature value are discussed in this section. The first method is the least accurate and uses a first order equation, and the second method is the most accurate and uses linear interpolation of the values found in the look-up table (LUT) as described in Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT. The output transfer function appears to be linear and can be approximated by Equation 1: § PC · Temp ¨ u 256qC ¸ 50qC © 4096 ¹ where • • PC is the Pulse Count Temp is the temperature reading (1) Table 1 shows some sample calculations using Equation 1. Table 1. Sample Calculations Using Equation 1 14 TEMPERATURE (°C) NUMBER OF PULSES –49.9375 1 –49.875 2 –40 160 –20 480 0 800 30 1280 50 1600 100 2400 150 3200 Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 LMT01 www.ti.com SNIS189D – JUNE 2015 – REVISED JUNE 2018 The curve shown in Figure 23 shows the output transfer function using equation Equation 1 (blue line) and the look-up table (LUT) found in Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT (red line). The LMT01 output transfer function as described by the LUT appears to be linear, but upon close inspection, it can be seen as truly not linear. To actually see the difference, the accuracy obtained by the two methods must be compared. 4096 3584 Pulse Count 3072 2560 2048 1536 1024 512 0 ±50 ±25 0 25 50 75 100 125 150 175 200 225 LMT01 Junction Temperature (ƒC) C002 Figure 23. LMT01 Output Transfer Function For more exact temperature readings the output pulse count can be converted to temperature using linear interpolation of the values found in Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT. 3.0 1.0 2.5 0.8 Temperature Accuracy (ƒC) Temperature Accuracy (ƒC) The curves in Figure 24 and Figure 25, show the accuracy of typical units when using the Equation 1 and linear interpolation using Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT, respectively. When compared, the improved performance when using the LUT linear interpolation method can clearly be seen. For a limited temperature range of 25°C to 80°C, the error shown in Figure 24 is flat, so the linear equation will provide good results. For a wide temperature range, TI recommends that linear interpolation and the LUT be used. 2.0 1.5 1.0 0.5 0.0 -0.5 Max Limit 0.6 0.4 0.2 0.0 -0.2 -0.4 -0.6 Min Limit -0.8 -1.0 -1.0 ±50 ±25 0 25 50 75 100 125 LMT01 Junction Temperaure (ƒC) 150 ±50 Figure 24. LMT01 Typical Accuracy When Using First Order Equation Equation 1 – 92 Typical Units Plotted at (VP – VN) = 2.15 V ±25 0 25 50 75 100 LMT01 Junction Temperaure (ƒC) C018 125 150 C017 Figure 25. LMT01 Accuracy Using Linear Interpolation of LUT Found In Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT – 92 typical units plotted at (VP – VN) = 2.15 V 7.3.3 Current Output Conversion to Voltage The minimum voltage drop across the LMT01 must be maintained at 2.15 V during the conversion cycle. After the conversion cycle, the minimum voltage drop can decrease to 2.0 V. Thus the LMT01 can be used for low voltage applications. See Application Information for more information on low voltage operation and other information on picking the actual resistor value for different applications conditions. The resistor value is dependent on the power supply level and the variation and the threshold level requirements of the circuitry the resistor is driving (that is, MCU, GPIO, or Comparator). Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 15 LMT01 SNIS189D – JUNE 2015 – REVISED JUNE 2018 www.ti.com Stray capacitance can be introduced when connecting the LMT01 through a long wire. This stray capacitance influences the signal rise and fall times. The wire inductance has negligible effect on the AC signal integrity. A simple RC time constant model as shown in Figure 26 can be used to determine the rise and fall times. POWER tHL LMT01 VF VHL OUTPUT C 100pF 34 and 125 µA R 10k VS Figure 26. Simple RC Model for Rise and Fall Times § V VS · Ru Cu In ¨ F ¸ © VF VHL ¹ tHL where • • • • RC as shown in Figure 26 VHL is the target high level the final voltage VF = 125 µA × R the start voltage VS = 34 µA × R (2) For the 10% to 90% level rise time (tr), Equation 2 simplifies to: tr = R×C×2.197 (3) Take care to ensure that the LMT01 voltage drop does not exceed 300 mV under reverse bias conditions, as given in the Absolute Maximum Ratings. 7.4 Device Functional Modes The only functional mode the LMT01 has is that it provides a pulse count output that is directly proportional to temperature. 16 Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 LMT01 www.ti.com SNIS189D – JUNE 2015 – REVISED JUNE 2018 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 8.1 Application Information 8.1.1 Mounting, Temperature Conductivity, and Self-Heating The LMT01 can be applied easily in the same way as other integrated-circuit temperature sensors. It can be glued or cemented to a surface to ensure good temperature conductivity. The temperatures of the lands and traces to the leads of the LMT01 also affect the temperature reading, so they must be a thin as possible. Alternatively, the LMT01 can be mounted inside a sealed-end metal tube, and then can be dipped into a bath or screwed into a threaded hole in a tank. As with any IC, the LMT01 and accompanying wiring and circuits must be kept insulated and dry to avoid excessive leakage and corrosion. Printed-circuit coatings are often used to ensure that moisture cannot corrode the leads or circuit traces. The junction temperature of the LMT01 is the actual temperature being measured by the device. The thermal resistance junction-to-ambient (RθJA) is the parameter (from Thermal Information) used to calculate the rise of a device junction temperature (self-heating) due to its average power dissipation. The average power dissipation of the LMT01 is dependent on the temperature it is transmitting as it effects the output pulse count and the voltage across the device. Equation 4 is used to calculate the self-heating in the die temperature of the LMT01 (TSH). ª§ tCONV · u VCONV ¸ «¨IOL u tCONV tDATA ¹ ¬«© TSH § ª§ PC tDATA ·º I I · § 4096 PC u OL OH ¸ ¨ u IOL ¸» u ¨ «¨ ¨ © 4096 2 ¹ © 4096 ¹¼ t CONV tDATA ©¬ º · ¸ u VDATA » u RTJA ¸ ¹ ¼» where • • • • • • • • TSH is the ambient temperature IOL and IOH are the output low and high current level, respectively VCONV is the voltage across the LMT01 during conversion VDATA is the voltage across the LMT01 during data transmission tCONV is the conversion time tDATA is the data transmission time PC is the output pulse count RθJA is the junction to ambient package thermal resistance (4) Plotted in the curve Figure 27 are the typical average supply current (black line using left y axis) and the resulting self-heating (red and violet lines using right y axis) during continuous conversions. A temperature range of –50°C to +150°C, a VCONV of 5 V (red line) and 2.15 V (violet line) were used for the self-heating calculation. As can be seen in the curve, the average power supply current and thus the average self-heating changes linearly over temperature because the number of pulses increases with temperature. A negligible self-heating of about 45m°C is observed at 150°C with continuous conversions. If temperature readings are not required as frequently as every 100 ms, self-heating can be minimized by shutting down power to the part periodically thus lowering the average power dissipation. Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 17 LMT01 SNIS189D – JUNE 2015 – REVISED JUNE 2018 www.ti.com 60 0.06 50 0.05 40 0.04 30 0.03 20 0.02 10 0.01 Average Current Self Heating at VP-VN=5V Self Heating at VP-VN=2.15V 0 -100 -50 0 50 100 150 Self Heating (ƒC) Average Current (µA) Application Information (continued) 0.00 200 Temperature (ƒC) C001 Figure 27. Average Current Draw and Self-Heating Over Temperature 8.2 Typical Application 8.2.1 3.3-V System VDD MSP430 Interface - Using Comparator Input VDD 3.3V MSP430 GPIO Divider VP LMT01 VREF 2.73V or 2.24V TIMER2 VN COMP_B CLOCK + VR IR = 34 and 125 µA R 6.81k 1% Figure 28. MSP430 Comparator Input Implementation 8.2.1.1 Design Requirements The design requirements listed in are used in the detailed design procedure. Table 2. Design Parameters DESIGN PARAMETER EXAMPLE VALUE VDD 3.3 V VDD minimum 3.0 V LMT01 VP – VN minimum during conversion 2.15 V LMT01 VP – VN minimum during data transmission 2.0 V Noise margin 50 mV minimum Comparator input current over temperature range of interest Resistor tolerance 18 < 1 uA 1% Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 LMT01 www.ti.com SNIS189D – JUNE 2015 – REVISED JUNE 2018 8.2.1.2 Detailed Design Procedure First, select the R and determine the maximum logic low voltage and the minimum logic high voltage while ensuring that when the LMT01 is converting, the minimum (VP – VN) requirement of 2.15 V is met. 1. Select R using minimum VP-VN during data transmission (2 V) and maximum output current of the LMT01 (143.75 µA) – R = (3.0 V – 2 V) / 143.75 µA = 6.993 k the closest 1% resistor is 6.980 k – 6.993 k is the maximum resistance so if using 1% tolerance resistor the actual resistor value needs to be 1% less than 6.993 k and 6.98 k is 0.2% less than 6.993 k thus 6.81 k must be used. 2. Check to see if the 2.15-V minimum voltage during conversion requirement for the LMT01 is met with the maximum IOL of 39 µA and maximum R of 6.81 k + 1%: – VLMT01 = 3 V – (6.81 k × 1.01) × 39 µA = 2.73 V 3. Find the maximum low level voltage range using the maximum R of 6.81 k and maximum IOL of 39 µA: – VRLmax = (6.81 k × 1.01) × 39 µA = 268 mV 4. Find the minimum high level voltage using the minimum R of 6.81 k and minimum IOH of 112.5 µA: – VRHmin = (6.81 k × 0.99) × 112.5 µA = 758 mV Now select the MSP430 comparator threshold voltage that enables the LMT01 to communicate to the MSP430 properly. 1. The MSP430 voltage is selected by selecting the internal VREF and then choosing the appropriate 1 of n/32 settings for n of 1 to 31. – VMID= (VRLmax – VRHmin) / 2 + VRHmin = (758 mV – 268 mV) / 2 + 268 mV = 513 mV – n = (VMID / VREF ) × 32 = (0.513 / 2.5) × 32 = 7 2. To prevent oscillation of the comparator, output hysteresis must be implemented. The MSP430 allows this by enabling different n for the rising edge and falling edge of the comparator output. For a falling comparator output transition, N must be set to 6. 3. Determine the noise margin caused by variation in comparator threshold level. Even though the comparator threshold level theoretically is set to VMID, the actual level varies from device to device due to VREF tolerance, resistor divider tolerance, and comparator offset. For proper operation, the COMP_B worst case input threshold levels must be within the minimum high and maximum low voltage levels presented across R, VRHmin and VRLmax, respectively N N_TOL VCHmax VREF u 1 V_REF_TOL u COMP_OFFSET 32 where • • • • • VCLmin VREF is the MSP430 COMP_B reference voltage for this example at 2.5 V V_REF_TOL is the tolerance of the VREF of 1% or 0.01, N is the divisor for the MSP430 or 7 N_TOL is the tolerance of the divisor or 0.5 COMP_OFFSET is the comparator offset specification or 10 mV VREF u 1 V_REF_TOL u N N_TOL 32 (5) COMP_OFFSET where • • • • • VREF is the MSP430 COMP_B reference voltage for this example at 2.5 V, V_REF_TOL is the tolerance of the VREF of 1% or 0.01, N is the divisor for the MSP430 for the hysteresis setting or 6, N_TOL is the tolerance of the divisor or 0.5, COMP_OFFSET is the comparator offset specification or 10 mV (6) The noise margin is the minimum of the two differences: (VRHmin – VCHmax) or (VCHmin – VRLmax) (7) which works out to be 145 mV. Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 19 LMT01 SNIS189D – JUNE 2015 – REVISED JUNE 2018 www.ti.com Comparator Threshold and VR VDD Pulse Count Signal VRHmax VRHmin Noise Margin VCHmax VMID VCHmin Noise Margin VRLmax VRLmin GND Time (µs) Figure 29. Pulse Count Signal Amplitude Variation 8.2.1.2.1 Setting the MSP430 Threshold and Hysteresis The comparator hysteresis determines the noise level that the signal can support without causing the comparator to trip falsely and resulting in an inaccurate pulse count. The comparator hysteresis is set by the precision of the MSP430 and what thresholds it is capable of. For this case, as the input signal transitions high, the comparator threshold is dropped by 77 mV. If the noise on the signal is kept below this level as it transitions, the comparator will not trip falsely. In addition, the MSP430 has a digital filter on the COMP_B output that be used to further filter output transitions that occur too quickly. 8.2.1.3 Application Curves Amplitude = 200 mV/div Time Base = 10 µs/div Δy at cursors = 500 mV Δx at cursors = 11.7 µs Figure 30. MSP430 COMP_B Input Signal No Capacitance Load Amplitude = 200 mV/div Time Base = 10 µs/div Δy at cursors = 484 mV Δx at cursors = 11.7 µs Figure 31. MSP430 COMP_B Input Signal 100-pF Capacitance Load 8.3 System Examples The LMT01 device can be configured in a number of ways. Transistor level shifting can be used so that the output pulse of the device can be read with a GPIO (see Figure 32). An isolation block can be inserted to achieve electrical isolation (see Figure 33). Multiple LMT01 devices can be controlled with GPIOs enabling temperature monitor for multiple zones. Lastly, the LMT01 device can be configured to have a common ground with a high side signal (see Figure 35). 20 Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 LMT01 www.ti.com SNIS189D – JUNE 2015 – REVISED JUNE 2018 System Examples (continued) 3.3V VDD MCU/ FPGA/ ASIC VP LMT01 100k VN GPIO MMBT3904 34 and 125 µA 7.5k Figure 32. Transistor Level Shifting 3V to 5.5V 3V to 5.5V ISO734x VCC1 VCC2 VDD VP ISOLATION LMT01 MCU/FPGA/ ASIC Min 2.0V 100k VN GPIO MMBT3904 34 and 125 µA 7.5k GND2 GND1 Figure 33. Isolation VDD 3V to 5.5V GPIO1 GPIO2 GPIO n Up to 2.0m VP VP VP LMT01 U1 LMT01 U2 LMT01 Un VN VN VN MCU/FPGA/ ASIC Min 2.0V GPIO/ COMP 34 and 125 µA 6.81k (for 3V) Note: to turn off an LMT01 set the GPIO pin connected to VP to high impedance state as setting it low would cause the off LMT01 to be reverse biased. Comparator input of MCU must be used. Figure 34. Connecting Multiple Devices to One MCU Input Pin Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 21 LMT01 SNIS189D – JUNE 2015 – REVISED JUNE 2018 www.ti.com System Examples (continued) 3.3V VDD 34 and 125 µA 7.5k MCU/ FPGA/ ASIC MMBT3906 VP LMT01 GPIO VN 100k Note: the VN of the LMT01 must be connected to the MCU GND. Figure 35. Common Ground With High-Side Signal 9 Power Supply Recommendations Because the LMT01 is only a 2-pin device the power pins are common with the signal pins, thus the LMT01 has a floating supply that can vary greatly. The LMT01 has an internal regulator that provides a stable voltage to internal circuitry. Take care to prevent reverse biasing of the LMT01 as exceeding the absolute maximum ratings may cause damage to the device. Power supply ramp rate can effect the accuracy of the first result transmitted by the LMT01. As shown in Figure 36 with a 1-ms rise time, the LMT01 output code is at 1286, which converts to 30.125°C. The scope photo shown in Figure 37 reflects what happens when the rise time is too slow. In Figure 37, the power supply (yellow trace) is still ramping up to final value while the LMT01 (red trace) has already started a conversion. This causes the output pulse count to decrease from the previously shown 1286, to 1282 (or 29.875°C). Thus, for slow ramp rates, TI recommends that the first conversion be discarded. For even slower ramp rates, more than one conversion may have to be discarded as TI recommends that either the power supply be within final value before a conversion is used or that ramp rates be faster than 2.5 ms. Yellow trace = 1 V/div, Red trace = 100 mV/div, Time Base = 20 ms/div TA= 30°C LMT01 Pulse Count = 1286 VP-VN = 3.3 V Rise Time = 1 ms Figure 36. Output Pulse Count With Appropriate Power Supply Rise Time 22 Yellow trace = 1V/div, Red trace = 100 mV/div, Time base = 20 ms/div TA=30°C LMT01 Pulse Count = 1282 VP-VN=3.3 V Rise Time = 100 ms Figure 37. Output Pulse Count With Slow Power Supply Rise Time Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 LMT01 www.ti.com SNIS189D – JUNE 2015 – REVISED JUNE 2018 10 Layout 10.1 Layout Guidelines The LMT01 can be mounted to a PCB as shown in Figure 38 and Figure 39. Take care to make the traces leading to the pads as small as possible to minimize their effect on the temperature the LMT01 is measuring. 10.2 Layout Example VP VN Figure 38. Layout Example (TO92S/LPG Package) VN VP Figure 39. Layout Example for the DQX (WSON) Package Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 23 LMT01 SNIS189D – JUNE 2015 – REVISED JUNE 2018 www.ti.com 11 Device and Documentation Support 11.1 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document. 11.2 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 11.3 Trademarks E2E is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. 11.4 Electrostatic Discharge Caution This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. 11.5 Glossary SLYZ022 — TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. 24 Submit Documentation Feedback Copyright © 2015–2018, Texas Instruments Incorporated Product Folder Links: LMT01 PACKAGE OPTION ADDENDUM www.ti.com 6-Feb-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) LMT01DQXR ACTIVE WSON DQX 2 3000 Green (RoHS & no Sb/Br) SN Level-1-260C-UNLIM -50 to 150 13N LMT01DQXT ACTIVE WSON DQX 2 250 Green (RoHS & no Sb/Br) Call TI Level-1-260C-UNLIM -50 to 150 13N LMT01LPG ACTIVE TO-92 LPG 2 1000 Green (RoHS & no Sb/Br) SN N / A for Pkg Type -50 to 150 LMT01 LMT01LPGM ACTIVE TO-92 LPG 2 3000 Green (RoHS & no Sb/Br) SN N / A for Pkg Type -50 to 150 LMT01 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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