LM35 is an integrated analog temperature sensor whose electrical output is proportional to degrees centigrade. LM35 Sensor does not require any external calibration or trimming to provide typical accuracies. The LM35’s low output impedance, linear output, and precise inherent calibration make interfacing to readout or control circuitry especially easy.

As such no extra components are required to interface LM35 to ADC as the output of LM35 is linear with a 10mv/degree scale. It can be directly interfaced with any 10 or 12-bit ADC. But if you are using an 8-bit ADC like ADC0808 or ADC0804 an amplifier section will be needed if you require to measure 1°C change. The LM35 device is rated to operate over a −55°C to 150°C temperature range, while the LM35C device is rated for a −40°C to 110°C range.

LM35 can also be directly connected to Arduino. The output of the LM35 temperature can also be given to a comparator circuit and can be used for over-temperature indication or by using a simple relay that can be used as a temperature controller.

Features:

• 0.5°C accuracy guarantee-able (at a25°C)
• Calibrated directly in Degree Celsius 
• Linear at 10.0 mV/°C scale factor
• Operates from 4 to 30 volts
• Non-linearity only 0.25°C typical
• Low self-heating, 0.08°C in still air
• Suitable for remote applications
• Low cost due to wafer-level trimming
• Less than 60 mA current drain
• Low impedance output, 0.1?for 1 mA load