LM35 Temperature Sensor

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LM35 is a three-terminal linear temperature sensor from National semiconductors, whose output voltage varies according to the temperature around it. The temperature it can measure should be anywhere between -55°C to 150°C. It is a low-cost sensor that is easily available in the market. We can also interface it with any Microcontroller that has an analog to digital conversion function.

The voltage output of the LM35 increases by 10mV per degree Celsius rise in temperature. It provides an output voltage in Centigrade (Celsius), so it has an advantage over linear temperature sensors calibrated in Kelvin as it does not require any external calibration circuitry. The temperature output of LM35 is also more precise than the thermistor output.

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Pin Description

Pin Name	Description
VCC	+5 V input voltage is applied at this Pin.
Out	We get the output voltage at this Pin.
GND	Connect this Pin, to the Ground of the circuit

Features of LM35

The current Drain is less than 60-µA
It typically operates at 5V but maximum and minimum input voltages are 30 V and 4 V respectively.
It is available in TO-220, TO-CAN, TO-92 and SO IC packages.
The temperature range it can measure is −55°C to 150°C.
It is a Low-Cost temperature sensor due to Wafer-Level Trimming.
Reading is directly calibrated directly in Celsius (Centigrade).
It is suitable for remote applications.
Linear + 10-mV/°C Scale Factor
Output impedance is low, 0.1 Ω for 1-mA Load.
0.5°C Ensured Accuracy (at 24°C)

Applications

It can be used to measure the temperature of a particular environment.
It can be used in circuits to monitor the temperature of the battery or HVAC system.