美国Dallas半导体公司的数字化温度传感器DS18B20是世界上第一片支持 “单总线”接口的温度传感器，在其内部使用了在板（ON-B0ARD）

专利技术。全部传感元件及转换电路集成在形如一只三极管的集成电路内。“单总线”独特而且经济的特点，使用户可轻松地组建传感器网络，

为测量系统的构建引入全新概念。现场温度直接以“一线总线”的数字方式传输，大大提高了系统的抗干扰性。适合于恶劣环境的现场温度测量，

如：环境控制、设备或过程控制、测温类消费电子产品等。

1. DS18B20的特性 

（1）适应电压范围更宽，电压范围：3.0～5.5V，寄生电源方式下可由数据线供。

（2）独特的单线接口方式，DS18B20在与微处理器连接时仅需要一条口线即可实现微处理器与DS18B20的双向通讯。

（3）DS18B20支持多点组网功能，多个DS18B20可以并联在唯一的三线上，实现组网多点测温。

（4）DS18B20在使用中不需要任何外围元件，全部传感元件及转换电路集成在形如一只三极管的集成电路内。

（5）温范围－55℃～＋125℃，在-10～+85℃时精度为±0.5℃。

（6）可编程的分辨率为9～12位，对应的可分辨温度分别为0.5℃、0.25℃、0.125℃和0.0625℃，可实现高精度测温。

（7）在9位分辨率时最多在93.75ms内把温度转换为数字，12位分辨率时最多在750ms内把温度值转换为数字，速度更快。

（8）测量结果直接输出数字温度信号，以“一线总线”串行传送给CPU，同时可传送CRC校验码，具有极强的抗干扰纠错能力。

（9）负压特性：电源极性接反时，芯片不会因发热而烧毁，但不能正常工作。

2. DS18B20内部结构及DS18B20的管脚排列

64位光刻ROM是出厂前被光刻好的，它可以看作是该DS18B20的地址序列号。不同的器件地址序列号不同。DS18B20内部结构主要由四部分组成：

64位光刻ROM,温度传感器,非挥发的温度报警触发器TH和TL,高速暂存器。 

DS18B20的引脚定义：

(1)DQ为数字信号输入/输出端

(2)GND为电源地

(3)VDD为外接供电电源输入端（在寄生电源接线方式时接地）

LM35集成温度传感器

AD590测量热力学温度、摄氏温度、两点温度差、多点最低温度、多点平均温度的具体电路，广泛应用于不同的温度控制场合。由于AD590精度高、价格低、不需辅助电源、线性好，常用于测温和热电偶的冷端补偿。

FEATURES
Linear current output: 1 μA/K
Wide temperature range: −55°C to +150°C
Probe-compatible ceramic sensor package
2-terminal device: voltage in/current out
Laser trimmed to ±0.5°C calibration accuracy (AD590M)
Excellent linearity: ±0.3°C over full range (AD590M)
Wide power supply range: 4 V to 30 V
Sensor isolation from case
Low cost
GENERAL DESCRIPTION
The AD590 is a 2-terminal integrated circuit temperature transducer that produces an output current proportional to absolute temperature. For supply voltages between 4 V and 30 V, the device acts as a high impedance, constant current regulator passing 1 μA/K. Laser trimming of the chip’s thin-film resistors is used to calibrate the device to 298.2 μA output at 298.2 K (25°C).
The AD590 should be used in any temperature-sensing application below 150°C in which conventional electrical temperature sensors are currently employed. The inherent low cost of a monolithic integrated circuit combined with the elimination of support circuitry makes the AD590 an attractive alternative for many temperature measurement situations. Linearization circuitry, precision voltage amplifiers, resistance measuring circuitry, and cold junction compensation are not needed in applying the AD590.
In addition to temperature measurement, applications include temperature compensation or correction of discrete components, biasing proportional to absolute temperature, flow rate measurement, level detection of fluids and anemometry. The AD590 is available in chip form, making it suitable for hybrid circuits and fast temperature measurements in protected environments.
The AD590 is particularly useful in remote sensing applications. The device is insensitive to voltage drops over long lines due to its high impedance current output. Any well-insulated twisted pair is sufficient for operation at hundreds of feet from the receiving circuitry. The output characteristics also make the AD590 easy to multiplex: the current can be switched by a CMOS multiplexer, or the supply voltage can be switched by a logic gate output.