The LM35 is an analog temperature sensor calibrated directly in degrees Celsius, with a linear output of +10 mV/°C, 0.5 °C ensured accuracy at 25 °C and a 4 V to 30 V supply. You read it with an ADC and need no calibration. It is the older, higher-voltage alternative to the TMP235. Figures are from the Texas Instruments LM35 datasheet SNIS159H.
Key specifications
| Output | +10 mV/°C |
|---|---|
| Accuracy | 0.5 °C ensured at 25 °C |
| Range | −55 to 150 °C (LM35) |
| Supply | 4–30 V |
| Current | under 60 µA |
| Self-heating | 0.08 °C in still air |
| Output impedance | 0.1 Ω at 1 mA |
What the datasheet promises
| Item | Datasheet value |
|---|---|
| Scale factor | Linear +10 mV/°C, calibrated directly in Celsius |
| Accuracy | 0.5 °C ensured at 25 °C |
| Temperature range | LM35: −55 to 150 °C; LM35C: −40 to 110 °C |
| Supply voltage | 4 V to 30 V |
| Supply current | Less than 60 µA |
| Self-heating | 0.08 °C in still air |
| Output impedance | 0.1 Ω for a 1 mA load |
| Packages | TO-CAN, TO-92, SOIC-8 and TO-220, depending on the variant |
Because the supply is at least 4 V, it will not run from a 3.3 V rail; for that use a part with a lower supply such as the TMP235. With a 5 V ADC, the output at 25 °C is 250 mV, and as a calculation 10 mV per degree means a 10-bit ADC at 5 V resolves about 0.5 °C per step.
Using it on a robot
- Measure motor, battery or enclosure temperature with one ADC pin.
- Run a long cable to a remote sensor, which the datasheet lists as a suitable use, keeping the lead away from motor wiring.
- Check the full-range circuit in the datasheet if you need to read below 2 °C.
Sources and further reading
- Texas Instruments LM35 datasheet (SNIS159H) — scale factor, accuracy, range, supply, current, self-heating and packages above.
Last reviewed: November 2026. Limits are from the Texas Instruments datasheet; breakout boards and modules vary. No price is quoted because it has not been checked.
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