SNIS197 August   2017 LM60-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  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 Electrical Characteristics
    6. 7.6 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 LM60 Transfer Function
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Capacitive Loads
    2. 9.2 Typical Applications
      1. 9.2.1 Full-Range Centigrade Temperature Sensor
        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 Centigrade Thermostat Application
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curve
    3. 9.3 System Examples
      1. 9.3.1 Conserving Power Dissipation With Shutdown
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

11 Layout

11.1 Layout Guidelines

The LM60-Q1 can be applied easily in the same way as other integrated-circuit temperature sensors. It can be glued or cemented to a surface. The temperature that the LM60-Q1 is sensing will be within about +0.1°C of the surface temperature that the leads of th LM60-Q1 are attached to.

This presumes that the ambient air temperature is almost the same as the surface temperature. If the air temperature were much higher or lower than the surface temperature, the actual temperature of the device die would be at an intermediate temperature between the surface temperature and the air temperature.

To ensure good thermal conductivity the backside of the device die is directly attached to the GND pin. The lands and traces to the device will, of course, be part of the printed-circuit board, which is the object whose temperature is being measured. These printed-circuit board lands and traces do not cause the temperature of the device to deviate from the desired temperature.

Alternatively, the device can be mounted inside a sealed-end metal tube, and can then be dipped into a bath or screwed into a threaded hole in a tank. As with any IC, the device and accompanying wiring and circuits must be kept insulated and dry to avoid leakage and corrosion. Specifically when the device operates at cold temperatures where condensation can occur. Printed-circuit coatings and varnishes such as a conformal coating and epoxy paints or dips are often used to ensure that moisture cannot corrode the device or connections.

11.2 Layout Example

LM60-Q1 Layout_Config_SNIS177.gif
1/2-inch square printed circuit board with 2-oz. copper foil or similar.
Figure 19. PCB Layout

11.3 Thermal Considerations

The thermal resistance junction to ambient (RθJA) is the parameter used to calculate the rise of a device junction temperature due to the device power dissipation. Use Equation 4 to calculate the rise in the die temperature of the device.

Equation 4. TJ = TA + RθJA [(+VS IQ) + (+VS − VO) IL]

where

  • IQ is the quiescent current
  • IL is the load current on the output

Table 2 summarizes the rise in die temperature of the LM60-Q1 without any loading, and the thermal resistance for different conditions. The values in Table 2 were actually measured where as the values shown in where calculated using modeling methods as described in the Semiconductor and IC Package Thermal Metrics (SPRA953) application report.

Table 2. Temperature Rise of LM60-Q1 Due to Self-Heating and Thermal Resistance (RθJA)

SOT-23(1)
NO HEAT SINK		 SOT-23(2)
SMALL HEAT FIN		 TO-92(1)
NO HEAT FIN		 TO-92(3)
SMALL HEAT FIN
RθJA TJ − TA RθJA TJ − TA RθJA TJ − TA RθJA TJ − TA
(°C/W) (°C) (°C/W) (°C) (°C/W) (°C) (°C/W) (°C)
Still air 450 0.17 260 0.1 180 0.07 140 0.05
Moving air — — 180 0.07 90 0.034 70 0.026
(1) Part soldered to 30 gauge wire.
(2) Heat sink used is 1/2-in square printed-circuit board with 2-oz. foil with part attached as shown in Figure 20.
(3) Part glued or leads soldered to 1-in square of 1/16-in printed-circuit board with 2-oz. foil or similar.
LM60-Q1 sva1268114_nis119.gif
1/2-in Square Printed-Circuit Board with 2-oz. Copper Foil or Similar.
Figure 20. Printed-Circuit Board Used for Heat Sink to Generate Thermal Response Curves