SNIS189D June   2015  – June 2018 LMT01

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     LMT01 Accuracy
  3. 3 Description
    1.     2-Pin IC Temperature Sensor
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics
    6. 6.6  Electrical Characteristics - TO-92/LPG Pulse Count to Temperature LUT
    7. 6.7  Electrical Characteristics - WSON/DQX Pulse Count to Temperature LUT
    8. 6.8  Switching Characteristics
    9. 6.9  Timing Diagram
    10. 6.10 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Output Interface
      2. 7.3.2 Output Transfer Function
      3. 7.3.3 Current Output Conversion to Voltage
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Mounting, Temperature Conductivity, and Self-Heating
    2. 8.2 Typical Application
      1. 8.2.1 3.3-V System VDD MSP430 Interface - Using Comparator Input
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Setting the MSP430 Threshold and Hysteresis
        3. 8.2.1.3 Application Curves
    3. 8.3 System Examples
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

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).

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.

LMT01 Schem08_RiFaTime_SNIS189.gifFigure 26. Simple RC Model for Rise and Fall Times
Equation 2. LMT01 Equation_02_RC_SNIS189.gif

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

For the 10% to 90% level rise time (tr), Equation 2 simplifies to:

Equation 3. LMT01 Equation_2b_RC_SNIS189.gif

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.