What Is the LM35? Analog Temperature Sensor: Pinout and Uses
The LM35 is an analog-output temperature sensor; its output scales at 10 mV/°C (25 °C = 250 mV) and needs no calibration. It connects to an MCU ADC to read (°C = mV/10). Pinout TO-92: +Vs, Vout, GND. The basic hookup starts at 0 °C; negatives need extra circuitry. For digital convenience the DS18B20 is preferred.
The LM35 is an analog-output temperature sensor. Its output scales directly in Celsius: 10 mV per °C. It needs no calibration and is very easy to read. For the concept, see what is a temperature sensor.
What is the LM35 used for?
Ambient temperature measurement, thermostats, fan control and simple logging. Its analog output goes to an MCU's ADC: e.g. at 25 °C the output is 250 mV (°C = mV/10). Unlike the DS18B20 it is not digital and needs an ADC.
LM35 pinout (TO-92)
Flat face front, left to right: +Vs – Vout – GND.
| Lead | Function |
|---|---|
| 1 | +Vs (supply, 4–30 V) |
| 2 | Vout (10 mV/°C) |
| 3 | GND |
Specifications
| Parameter | Value |
|---|---|
| Output | 10 mV/°C (linear, analog) |
| Range | 0–100 °C (−55…+150 °C with extra circuitry) |
| Accuracy | ~±0.5 °C |
| Supply | 4–30 V |
Limitations
- Negative temperatures need extra circuitry (the basic hookup starts at 0 °C).
- It is analog; on long cables noise and ADC resolution matter → for digital use the DS18B20.
Equivalents
- TMP36: offset analog (also measures negatives).
- LM335: Kelvin output.
- DS18B20: a digital (1-Wire) alternative.
Find it in our catalog
Use the LM35 search.