Maxim 公司的LM75是带Delta-Sigma ADC和数字超温检测器的温度传感器，I²C总线接口，漏极开路输出，工作电压3.0V到5.5V，典型工作电流200uA，关断电流4uA，广泛应用于热系统管理，热保护，测试设备，计算机和办公设备。本文介绍了LM75的主要特性，功能方框图，以及风扇控制电路，I²C 控制的温度传感器应用电路和带声音告警的温度传感器应用电路。

The LM75 temperature sensor includes a delta-sigma analog-to-digital converter, and a digital overtemperature detector. The host can query the LM75 through its I2C interface to read temperature at any time. The open-drain overtemperature output (OS) sinks current when the programmable temperature limit is exceeded.

The OS output operates in either of two modes, comparator or interrupt. The host controls the temperature at which the alarm is asserted (TOS) and the hysteresis temperature below which the alarm condition is not valid (THYST). Also, the LM75’s TOS and THYST registers can be read by the host. The address of the LM75 is set with three pins to allow multiple devices to work on the same bus. Power-up is in comparator mode, with defaults of TOS = +80°C and THYST = +75°C. The 3.0V to 5.5V supply voltage range, low supply current, and I2C interface make the LM75 ideal for many applications in thermal management and protection.

LM75主要特性：

_ SO (SOP) and μMAX (μSOP) Packages
_ I2C Bus Interface
_ Separate Open-Drain OS Output Operates as Interrupt or Comparator/Thermostat Input
_ Register Readback Capability
_ Power-Up Defaults Permit Stand-Alone Operation as a Thermostat
_ 3.0V to 5.5V Supply Voltage
_ Low Operating Supply Current 250μA (typ), 1mA (max)
_ 4μA (typ) Shutdown Mode Minimizes Power Consumption
_ Up to Eight LM75s Can Be Connected to a Single Bus
_ Pin- and/or Register-Compatible with Improved-Performance Maxim Sensors Including MAX7500, MAX6625, MAX6626, DS75LV, and DS7505

LM75应用：

Thermal System Management
Thermal Protection
Test Equipment
Computers and Office Electronics

图1 LM75功能方框图

图2  采用LM75的风扇控制

图3  I²C 控制的温度传感器

详情请见：http://datasheets.maxim-ic.com/en/ds/LM75.pdf