SNIS202A October   2017  – June 2022 LMT87-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Accuracy Characteristics
    6. 7.6 Electrical Characteristics
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 LMT87-Q1 Transfer Function
    4. 8.4 Device Functional Modes
      1. 8.4.1 Mounting and Thermal Conductivity
      2. 8.4.2 Output Noise Considerations
      3. 8.4.3 Capacitive Loads
      4. 8.4.4 Output Voltage Shift
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Connection to ADC
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curve
      2. 9.2.2 Conserving Power Dissipation With Shutdown
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Support Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

8.3.1 LMT87-Q1 Transfer Function

Table 8-1 shows the output voltage of the LMT87-Q1 across the complete operating temperature range. This table is the reference from which the LMT87-Q1 accuracy specifications (listed in the Accuracy Characteristics table) are determined. This table can be used, for example, in a host processor look-up table. A file containing this data is available for download at the LMT87-Q1 product folder under Tools and Software Models.

Table 8-1 LMT87-Q1 Transfer Table
TEMP
(°C)		VOUT
(mV)		TEMP
(°C)		VOUT
(mV)		TEMP
(°C)		VOUT
(mV)		TEMP
(°C)		VOUT
(mV)		TEMP
(°C)		VOUT
(mV)
–503277–1027673022317016791101115
–493266–927543122177116651111101
–483254–827403222047216511121087
–473243–727273321907316371131073
–463232–627143421767416231141058
–453221–527003521637516091151044
–443210–426873621497615951161030
–433199–326743721367715811171015
–423186–226603821227815671181001
–413173–12647392108791553119987
–40316002633402095801539120973
–39314712620412081811525121958
–38313422607422067821511122944
–37312132593432054831497123929
–36310842580442040841483124915
–35309552567452026851469125901
–34308262553462012861455126886
–33306972540471999871441127872
–32305682527481985881427128858
–31304392513491971891413129843
–303030102500501958901399130829
–293017112486511944911385131814
–283004122473521930921371132800
–272991132459531916931356133786
–262978142446541902941342134771
–252965152433551888951328135757
–242952162419561875961314136742
–232938172406571861971300137728
–222925182392581847981286138713
–212912192379591833991272139699
–2028992023656018191001257140684
–1928862123526118051011243141670
–1828732223386217911021229142655
–1728592323256317771031215143640
–1628462423116417631041201144626
–1528332522986517491051186145611
–1428202622856617351061172146597
–1328072722716717211071158147582
–1227932822586817071081144148568
–1127802922446916931091130149553
150538

Although the LMT87-Q1 is very linear, the response does have a slight umbrella parabolic shape. Table 8-1 very accurately reflects this shape. The transfer table can be calculated by using the parabolic equation (Equation 1).

Equation 1. GUID-8C68B125-1975-431A-AAE3-18900372D2EA-low.gif

The parabolic equation is an approximation of the transfer table and the accuracy of the equation degrades slightly at the temperature range extremes. Equation 1 can be solved for T resulting in:

Equation 2. GUID-41FC3019-4D85-4323-BB98-83289A30A3FA-low.gif

For an even less accurate linear transfer function approximation, a line can easily be calculated over the desired temperature range from Table 8-1 using the two-point equation (Equation 3):

Equation 3. GUID-73FBC20F-0276-4AC5-A12C-DAB1ECA6866C-low.gif

where

  • V is in mV,
  • T is in °C,
  • T1 and V1 are the coordinates of the lowest temperature,
  • and T2 and V2 are the coordinates of the highest temperature.

For example, if the user wanted to resolve this equation, over a temperature range of 20°C to 50°C, they would proceed as follows:

Equation 4. GUID-43688D1D-D8FF-47DB-A42D-E4A033914C73-low.gif
Equation 5. GUID-13F6DF00-2D3D-429A-B690-0D8DCDB25808-low.gif
Equation 6. GUID-AEB41FE8-DA4C-4FF7-B775-19852400798D-low.gif

Using this method of linear approximation, the transfer function can be approximated for one or more temperature ranges of interest.