SNIS187A March   2015  – July 2015 LMT70 , LMT70A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Wide-Range Precision Active RTD or NTC Replacement (−55°C to 150°C)
  5. 5 Revision History
  6. 6 Device Comparison Table
  7. 7 Pin Configuration and Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Electrical Characteristics Temperature Lookup Table (LUT)
    7. 8.7 Switching Characteristics
    8. 8.8 Typical Performance Characteristics
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Temperature Analog Output (TAO)
        1. 9.3.1.1 LMT70 Output Transfer Function
          1. 9.3.1.1.1 First Order Transfer Function
          2. 9.3.1.1.2 Second Order Transfer Function
          3. 9.3.1.1.3 Third Order Transfer Function
        2. 9.3.1.2 LMT70A TAO Matching
        3. 9.3.1.3 TAO Noise Considerations
        4. 9.3.1.4 TAO Capacitive Loads
      2. 9.3.2 TON Digital Input
      3. 9.3.3 Light Sensitivity
    4. 9.4 Device Functional Modes
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Temperature Algorithm Selection
        2. 10.2.2.2 ADC Requirements
      3. 10.2.3 Finer Resolution LUT
      4. 10.2.4 Application Curves
    3. 10.3 System Examples
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 Mounting and Temperature Conductivity
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Related Links
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Community Resources
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

1 Features

  • Accuracy:
    • ±0.05°C (typ) or ±0.13°C (max) from 20°C to 42°C
    • ±0.2°C (max) from -20°C to 90°C
    • ±0.23°C (max) from 90°C to 110°C
    • ±0.36°C (max) from -55°C to 150°C
  • Wide Temperature Range: −55°C to 150°C
  • Matching of Two Adjacent LMT70A on Tape and Reel: 0.1°C (max) at 30°C
  • Very Linear Analog Temperature Sensor with Output Enable Pin
  • NTC Output Slope: -5.19 mV/°C
  • Output On/Off Switch with RDS on < 80 Ω
  • Wide Power Supply Range: 2.0 V to 5.5 V
  • Low Power Supply Current: 9.2 µA (typ)12 µA (max)
  • Ultra Small 0.88 mm by 0.88 mm 4-bump WLCSP (DSBGA) Package

2 Applications

  • Internet of Things (IoT) Sensor Nodes
  • Industrial RTD (Class AA) or Precision NTC/PTC Thermistor Replacement
  • Medical/Fitness Equipment
  • Medical Thermometer
  • Human Body temperature monitor
  • Metering Temperature Compensation

3 Description

The LMT70 is an ultra-small, high-precision, low-power CMOS analog temperature sensor with an output enable pin. Applications for the LMT70 include virtually any type of temperature sensing where cost-effective, high precision and low-power are required, such as Internet of Things (IoT) sensor nodes, medical thermometers, high-precision instrumentation and battery powered devices. The LMT70 is also a great replacement for RTD and precision NTC/PTC thermistors.

Its output enable pin allows multiple LMT70s to share one ADC channel, thus simplifying ADC calibration and reducing the overall system cost for precision temperature sensing. The LMT70 also has a linear and low impedance output allowing seamless interface to an off-the-shelf MCU/ADC. Dissipating less than 36µW, the LMT70 has ultra-low self-heating supporting its high-precision over a wide temperature range.

The LMT70A provides unparalleled temperature matching performance of 0.1°C (max) for two adjacent LMT70A's picked from the same tape and reel. Therefore, the LMT70A is an ideal solution for energy metering applications requiring heat transfer calculations.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
LMT70 DSBGA - WLCSP (4) YFQ 0.88 mm x 0.88 mm
(1) For all available packages, see the orderable addendum at the end of the data sheet.

4 Wide-Range Precision Active RTD or NTC Replacement (−55°C to 150°C)

LMT70 LMT70A Schem_05_SNIS187.gif

4.0.0.1 LMT70 Accuracy vs Temperature

LMT70 LMT70A C001_SNIS187.png