SNIS161D March   2000  – January  2016 LM34


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  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: LM34A and LM34CA
    6. 6.6 Electrical Characteristics: LM34, LM34C, and LM34D
    7. 6.7 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Capacitive Drive Capability
      2. 7.3.2 LM34 Transfer Function
    4. 7.4 Device Functional Modes
  8. Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Basic Fahrenheit Temperature Sensor Application
        1. Design Requirements
        2. Detailed Design Procedure
        3. Application Curve
    3. 8.3 System Examples
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Trademarks
    2. 11.2 Electrostatic Discharge Caution
    3. 11.3 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8 Application and Implementation


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

The features of the LM34 device make it suitable for many general temperature sensing applications. Multiple package options expand on flexibility of the device.

8.2 Typical Application

8.2.1 Basic Fahrenheit Temperature Sensor Application

LM34 basic_fahrenheit_temp_sensor_snis161.gif Figure 14. Basic Fahrenheit Temperature Sensor (5°F to 300°F) Design Requirements

Table 1. Key Requirements

Accuracy at 77°F ±2°F
Accuracy from –50°F to 300°F ±3°F
Temperature Slope 10 mV/°F Detailed Design Procedure

Because the LM34 is a simple temperature sensor that provides an analog output, design requirements related to layout are more important than electrical requirements (see Layout). Application Curve

LM34 graph_09_snis161.gif Figure 15. Temperature Error

8.3 System Examples

LM34 full_range_fahenheit_temp_sensor_snis161.gif
Figure 16. Full-Range Fahrenheit Temperature Sensor
LM34 two_wire_remote_temp_sensor_grounded_sensor_snis161.gif
VOUT = 10 mV/°F (TA+3°F) from 3°F to 100°F
Figure 18. Two-Wire Remote Temperature Sensor
(Grounded Sensor)
LM34 typ_app_fig_01_snis161.gif
Figure 20. 4- to -20 mA Current Source (0°F to 100°F)
LM34 typ_app_fig_03_snis161.gif
Figure 22. Expanded Scale Thermometer
(50°F to 80°F, for Example Shown)
LM34 graph_12_snis161.gif
Figure 24. LM34 With Voltage-to-Frequency Converter and Isolated Output
(3°F to 300°F; 30 Hz to 3000 Hz)
LM34 typ_app_fig_06_snis161.gif
Figure 26. Temperature-to-Digital Converter
(Parallel TRI-STATE Outputs for Standard Data Bus to µP Interface, 128°F Full Scale)
LM34 typ_app_fig_00_snis161.gif
Figure 17. Full Range Farenheit Sensor (–50 °F to 300 °F)
LM34 two_wire_remote_temp_sensor_output_referred_to_ground_snis161.gif
Figure 19. Two-Wire Remote Temperature Sensor
(Output Referred to Ground)
LM34 typ_app_fig_02_snis161.gif
Figure 21. Fahrenheit Thermometer (Analog Meter)
LM34 typ_app_fig_04_snis161.gif
Figure 23. Temperature-to-Digital Converter
(Serial Output, 128°F Full Scale)
LM34 typ_app_fig_05_snis161.gif
Figure 25. Bar-Graph Temperature Display
(Dot Mode)
LM34 typ_app_fig_07_snis161.gif
Figure 27. Temperature Controller