LM75 is a chip that integrates temperature sensor, Delta-Sigma analog-to-digital converter and digital over-temperature detector, and is equipped with I2C interface. The host can query the LM75 at any time to read temperature. When the temperature exceeds a programmable limit, the open-drain over-temperature shut-down (O.S.) output becomes active. This pin can operate in either “Comparator” or “Interrupt” mode. The host can program both the temperature alarm threshold (TOS) and the temperature at which the alarm condition goes away (THYST). In addition, the host can read back the con- tents of the LM75’s TOS and THYST registers. Three pins (A0, A1, A2) are available for address selection. The sensor powers up in Comparator mode with default thresholds of 80˚C TOS and 75˚C THYST. The LM75’s 3.0V to 5.5V supply voltage range, low supply current and I2C interface make it ideal for a wide range of applications. These include thermal management and pro- tection applications in personal computers, electronic test equipment, and office electronics.
The LM75 digital temperature sensor and thermal watchdog integrates a band‑gap temperature sensor, a 9‑bit Delta‑Sigma ADC, and a programmable comparator. It operates over a 3.0 V to 5.5 V supply range and can be addressed via the I²C bus, allowing up to eight devices on a single bus. The device powers up in Comparator mode with default alarm thresholds of 80 °C (high) and 75 °C (low).
Typical applications include thermal management in personal computers, electronic test equipment, and office electronics. The datasheet provides ordering information, pin descriptions, electrical characteristics, and mechanical dimensions for both SOP‑8 and MSOP‑8 packages.
| Supply Voltage Range | 3.0 V to 5.5 V |
|---|---|
| Temperature Accuracy (‑25 °C to 100 °C) | ±2 °C (max) |
| Temperature Accuracy (‑55 °C to 125 °C) | ±3 °C (max) |
| Resolution | 9 bits |
| Conversion Time | 100 ms to 300 ms (max) |
| Quiescent Current (typical) | 0.25 mA to 0.5 mA (max) |
| Shutdown Mode Current (3 V supply) | 4 pA |
| Maximum Devices on I²C Bus | 8 |
The LM75 operates from 3.0 V up to 5.5 V.
Up to eight LM75 devices can be connected to a single I²C bus.
The temperature conversion time is typically between 100 ms and 300 ms.