# LM35

**Texas Instruments** · Analog temperature sensor · TO-92

A precision analog temperature sensor in a TO-92 that outputs a voltage directly proportional to Celsius temperature: 10 mV per degree C, so 250 mV means 25 C. Unlike a thermistor it is linear and needs no calibration or linearization, and unlike the digital DS18B20 it feeds an ADC directly with three pins (+VS, VOUT, GND). It reads -55 to +150 C (the full range needs a small negative-bias resistor) with about plus/minus 0.5 C accuracy, drawing only 60 uA so self-heating is negligible. Runs from 4 to 30 V.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | +VS | power_in | Positive supply pin. Recommended operating range 4 V to 30 V; absolute max 35 V. Quiescent current is typ. 60 µA (LM35A at 5 V, 25°C). |
| 2 | VOUT | output | Analog temperature output. Linear scale factor +10 mV/°C referenced to GND (0 V at 0°C). Low-impedance output (~0.1 Ω at 1 mA load); rated output current 10 mA; output voltage range −1 V to +6 V (absolute max). |
| 3 | GND | power_in | Device ground pin; connect to power-supply negative terminal (or to the −VS rail in a full-range dual-supply configuration). |

## Key specifications

| Parameter | Value |
|---|---|
| Type | Analog temperature sensor |
| Output | 10 mV/°C (linear, direct Celsius) |
| Range | -55 to +150 °C |
| Accuracy | ±0.5 °C (typical) |
| Calibration | none required |
| Supply current | ~60 µA |
| Supply voltage | 4-30 V |
| Package | TO-92 (3-lead) |

## Ordering variants

Same part, different packaging or reel option.

- `LM35DZ (TO-92, 0 to 100 °C)`
- `LM35CZ (TO-92, -40 to 110 °C)`

## CAD (KiCad official)

- Symbol: `Sensor_Temperature:LM35-LP`
- Footprint: `Package_TO_SOT_THT:TO-92_Inline`
- 3D model: TO-92 (KiCad packages3D)
- 3D model files: `lm35-etched.step` / `lm35-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `lm35.step` / `lm35.glb` are the bare package body.

## Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/lit/ds/symlink/lm35.pdf) (38 pp, sha256 `1884601dffcbe160`, retrieved 2026-08-17, tier: manufacturer)
- **Extractor:** `ds2sf` (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/lm35-datasheet.pdf)