Maxim的DS28EA00的單總線測溫系統(tǒng)

基本特點(diǎn)：

DS28EA00數(shù)字溫度傳感器是具有9位(0.5℃)至12位(1/16℃)分辨率和用戶可編程非易失性(NV)上、下觸發(fā)點(diǎn)報警功能的數(shù)字溫度計。每個DS28EA00都具工廠編程的唯一64位序列號。通信時只需一根數(shù)據(jù)線和地線，就可通過1-Wire?協(xié)議串行傳輸數(shù)據(jù)。改進(jìn)型1-Wire接口具有滯回和干擾濾波功能，使得DS28EA00能夠在大的1-Wire網(wǎng)絡(luò)中可靠工作。與其他1-Wire溫度計不同，DS28EA00具有兩個額外的引腳用以執(zhí)行順序檢測功能。該特性允許用戶將器件在鏈路中的物理位置與序列號對應(yīng)，例如，用來測量儲存塔不同高度處的溫度。如果無需順序檢測功能，這些引腳可作為通用輸入或輸出。DS28EA00能夠直接從數(shù)據(jù)線獲取電源進(jìn)行工作(寄生供電)，因此無需外部電源。

·數(shù)字溫度計測量范圍：-40℃至+85℃

·用戶可選擇的9至12位溫度分辨率

·獨(dú)特的1-Wire接口，僅需單個引腳即可進(jìn)行通信

·每個器件都具有在工廠激光刻蝕的唯一64位序列號

·ROM多節(jié)點(diǎn)能力簡化分布式溫度檢測應(yīng)用

·具有滯回和干擾濾波器的改進(jìn)型1-Wire接口

·用戶可定義的非易失性(NV)報警溫度設(shè)置/用戶字節(jié)

·報警搜索命令能夠快速確定溫度超出設(shè)定范圍的器件

·標(biāo)準(zhǔn)和高速1-Wire通信模式

·2個通用可編程IO (PIO)引腳

·級聯(lián)功能使用PIO引腳檢測器件在網(wǎng)絡(luò)中的物理順序

·工作范圍：3.0V至5.5V，-40℃至+85℃

·可由數(shù)據(jù)線供電

方案特點(diǎn)

The DS28EA00 evaluation system (EV system) consists of a single evaluation kit (EV kit) that includes an evaluation board (EV board) made up of three subsections that can be broken/snapped off into three independently exercisable boards. Since one of the major features of the DS28EA00 is detection of physical sequence, a block of dip switches are provided on each subsection of the EV board to re-order the physical connection between the chips. Optionally, the customer can break off the subsections of the eval board, connect them together with the provided cables, and re-order the physical sequence of the DS28EA00s that way.

Easy Setup

Stand-Alone EV Board

Contains Three Separate, Breakable Subsections with a DS28EA00 Per Subsection

The Dipswitch Block on Each EV Board Subsection Routes Physical Chain-Mode

Connections Between Chips When Used as a Stand-Alone Board

EV Board’s Subsections are Breakable Into Three Separate Boards Each of Which Evaluates a Single DS28EA00 or, When Cabled Together, Evaluate Chain-Mode Searching

LEDs Give Visual Indicators of PIO Activity

6-Pin Terminal Strip Allows PIO Testing Outside of Chain Mode

PC Connectivity Included

RoHS Compliant

Free Downloadable Evaluation Software Available

參考原理圖

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圖2 參考layout top

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圖4： 參考layout composite