TEMPERATURE SENSOR LM35

General description of  LM 35

The LM35 is an integrated circuit sensor that can be used to measure temperature with an electrical output proportional to the temperature (in ^oC) The LM35 series 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 Centigrade 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. Low cost is assured by trimming and calibration at the wafer level. The LM35’s low output impedance, linear output, and precise inherent calibration make interfacing to readout or control circuitry especially easy. It can be used with single power supplies, or with plus and minus.

                                                           

LM 35 Temperature Sensor 

                                                      

Features

1.      Calibrated directly in ° Celsius (Centigrade)

2.      Linear + 10.0 mV/°C scale factor

3.      0.5°C accuracy guarantee able (at +25°C)

4.      Rated for full −55° to +150°C range

5.      Suitable for remote applications

6.      Low cost due to wafer-level trimming

7.      Operates from 4 to 30 volts

8.      Less than 60 μA current drain

9.      Low self-heating, 0.08°C in still air

10.  Non linearity only ±1⁄4°C typical

11.  Low impedance output, 0.1 W for 1 mA load

 Advantages of LM35  to Measure Temperature?

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.

Working of LM35:

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. 

It has an output voltage that is proportional to the Celsius temperature.