Temperature Sensor

The LM35 series are precision integrated-circuit temperature devices with an output voltage linearly-proportional to the Centigrade temperature. The LM35 device has an advantage over linear temperature sensors calibrated in Kelvin, as the user is not required to subtract a large constant voltage from the output to obtain convenient Centigrade scaling. The LM35 device does not require any external calibration or trimming to provide typical accuracies

The LM35 datasheet specifies that this ICs are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature.
The LM35 thus has an advantage over linear temperature sensors calibrated in ? Kelvin, as the user is not required to subtract a large constant voltage from its output to obtain convenient Centi-grade scaling. The LM35 does not require any external calibration or trimming to provide typical accuracies of ±1⁄4?C at room temperature and ±3⁄4?C over a full −55 to +150?C temperature range.

• You can measure temperature more accurately than a using a thermistor.
• The sensor circuitry is sealed and not subject to oxidation, etc.
• The LM35 generates a higher output voltage than thermocouples and may not require that the output voltage be amplified.
  • It has an output voltage that is proportional to the Celsius temperature.
  • The scale factor is .01V/^oC
  • The LM35 does not require any external calibration or trimming and maintains an accuracy of  +/-0.4 ^oC at room temperature and +/- 0.8 ^oC over a range of 0 ^oC to +100 ^oC.
  • Another important characteristic of the LM35DZ is that it draws only 60 micro amps from its supply and possesses a low self-heating capability. The sensor self-heating causes less than 0.1 ^oC temperature rise in still air.

        The LM35 comes in many different packages, including the following.

• TO-92 plastic transistor-like package,
• T0-46 metal can transistor-like package
• 8-lead surface mount SO-8 small outline package

Features

• Calibrated directly in ^o Celsius (Centigrade)
• Linear + 10.0 mV/^oC scale factor
• 0.5^oC accuracy guaranteeable (at +25^oC)
• Rated for full −55^o to +150^oC range
• Suitable for remote applications
• Low cost due to wafer-level trimming
• Operates from 4 to 30 volts
• Less than 60 µA current drain
• Low self-heating, 0.08^oC in still air
• Nonlinearity only ±1⁄4^oC typical
• Low impedance output, 0.1 Ω for 1 mA load