原标题：Maxim DS18B20可编分辨率1线数字温度计解决方案

Maxim公司的DS18B20是可编分辨率1Wire(线)数字温度计,提供9位到12位摄氏温度测量,在非易失可编用户上限和下限时具有告警功能.DS18B20在1Wire(线)总线(由数据线和地)和中央处理器进行通信.此外,器件直接从数据线(寄生电源)驱动电源,而不需要外接电源.每个DS18B20有单独的64位串行代码(存储在板上ROM),使得多个DS18B20可作用在同一的1Wire(线)总线上.这样用一个微处理器就能控制分布在大面积的许多个DS18B20.测量温度范围从 -55℃到 +125℃ (-67°F到 +257°F), -10℃ 到 +85℃时的测量精度为±0.5℃,可编分辨率从9比特到12比特摄氏度.DS18B20不需要任何的外接元件.主要用在热电控制,工业系统,消费类电子产品,热敏感系统和温度计.本文介绍了DS18B20主要特性和优势,框图和评估板DS18B20 EVS主要特性,电路图,材料清单和PCB设计图.

The DS18B20 digital thermometer provides 9-bit to 12-bit Celsius temperature measurements and has an alarm function with nonvolatile user-programmable upper and lower trigger points. The DS18B20 communicates over a 1-Wire bus that by definition requires only one data line (and ground) for communication with a central microprocessor. In addition, the DS18B20 can derive power directly from the data line (“parasite power”),eliminating the need for an external power supply.

Each DS18B20 has a unique 64-bit serial code, which allows multiple DS18B20s to function on the same 1-Wire bus. Thus, it is simple to use one microprocessor to control many DS18B20s distributed over a large area.

Applications that can benefit from this feature include HVAC environmental controls, temperature monitoring systems inside buildings, equipment, or machinery, and process monitoring and control systems.

DS18B20主要特性和优势:

●● Unique 1-Wire® Interface Requires Only One Port Pin for Communication
●● Reduce Component Count with Integrated Temperature Sensor and EEPROM
• Measures Temperatures from -55℃ to +125℃ (-67°F to +257°F)
• ±0.5°C Accuracy from -10°C to +85℃
• Programmable Resolution from 9 Bits to 12 Bits
• No External Components Required
●● Parasitic Power Mode Requires Only 2 Pins for
Operation (DQ and GND)
●● Simplifies Distributed Temperature-Sensing Applications with Multidrop Capability
• Each Device Has a Unique 64-Bit Serial Code Stored in On-Board ROM
●● Flexible User-Definable Nonvolatile (NV) Alarm Settings with Alarm Search Command Identifies Devices with Temperatures Outside Programmed Limits
●● Available in 8-Pin SO (150 mils), 8-Pin μSOP, and 3-Pin TO-92 Packages

DS18B20应用:

●● Thermostatic Controls
●● Industrial Systems
●● Consumer Products
●● Thermometers
●● Thermally Sensitive Systems

图1.DS18B20框图

评估板DS18B20 EVS

The DS18B20 evaluation system (EV system) demonstrates the DS18B20 1-wire thermometer. The DS18B20 EV system consists of the DS18B20 evaluation kit (EV kit) and the USB2PMB2 adapter board. Windows XP® and Windows® 7/8/8.1/10 compatible software provides a user-friendly interface that demonstrates the features of the DS18B20.
The DS18B20 EV system comes with the 8-pin μSOP DS18B20U+ installed.

评估板DS18B20 EVS主要特性:

●● 6-Pin Pmod™-Compatible Connector
●● Proven PCB Layout
●● Fully Assembled and Tested
●● Windows XP, Windows 7/8/8.1/10-Compatible Software

图2.评估板DS18B20 EVS外形图

图3.评估板DS18B20 EVS电路图
评估板DS18B20 EVS材料清单:


图4.评估板DS18B20 EVS PCB设计图:左:顶层丝印;右:顶层布局

图5.评估板DS18B20 EVS PCB设计图:左:底层布局;右:底层丝印