The LM75 is a serially programmable temperature sensor that notifies the host controller when ambient temperature exceeds a user–programmed setpoint. Hysteresis is also programmable. The INT/CMPTR output is programmable as either a simple comparator for thermostat operation or as a temperature event interrupt. Communication with the LM75 is accomplished via a two–wire bus that is compatible with industry standard protocols. This permits reading the current temperature, programming the setpoint and hysteresis, and configuring the device.

The LM75 powers up in Comparator Mode with a default setpoint of 80°C with 5°C hysteresis. Defaults allow independent operation as a stand–alone thermostat. A shutdown command may be sent via the 2–wire bus to activate the low–power standby mode. Address selection inputs allow up to eight LM75’s to share the same 2–wire bus for multi–zone monitoring.

All registers can be read by the host and the INT/CMPTR output’s polarity is user programmable. Both polled and interrupt driven systems are easily accommodated. Small physical size, low installed cost, and ease of use make the LM75 an ideal choice for implementing sophisticated system management schemes.

Features

• Temperature Sensing: 0.5°C Accuracy (Typ.)

• Operates from: 55°C to +125°C

• Operating Range: 2.7V – 5.5V

• Programmable Trip Point and Hysteresis with

Power–up Defaults

• Standard 2–Wire Serial Interface

• Thermal Event Alarm Output Functions as Interrupt or Comparator /

Thermostat Output

• Up to 8 LM75’s May Share the Same Bus

• Shutdown Mode for Low Standby Power Consumption

• 5V Tolerant I/O at VDD = 3V

• Low Power 250µA (Typ.) Operating, 1µA (Typ.)

Shutdown Mode

Typical Applications

• Thermal Protection for High Performance CPUs

• Solid–State Thermometer

• Fire/Heat Alarms

• Thermal Management in Electronic Systems:

Computers

Telecom Racks

Power Supplies / UPS

• Copiers / Office Electronics

• Consumer Electronics / Amplifiers

• Process Control