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On Semi公司的A5191HRT是用于可尋址遠程傳感器高速通道(HART)現場儀表的單片CMOS調制解調器,只需外接幾個元件就可組成HART物理層所需的所有功能,包括調制,解調,接收濾波,載波檢測和發送信號整形.工作電壓3.0V-5.5V,每秒FSK調制解調器半雙工1200比特, Bell 202移頻1200Hz和2200Hz,主要用在HART復接器,HART調制解調器接口和4-20mA回路發送器.本文介紹了A5191HRT主要特性,方框圖, 應用框圖以及評估板A5191HRTNGEVB主要特性,電路圖,材料清單,PCB布局圖和接收器濾波器電路圖及其元件數值. The A5191HRT is a single−chip, CMOS modem for use in highway addressable remote transducer (HART) field instruments and masters. The modem and a few external passive components provide all of the functions needed to satisfy HART physical layer requirements including modulation, demodulation, receive filtering, carrier detect, and transmit−signal shaping. The A5191HRT uses phase continuous frequency shift keying (FSK) at 1200 bits per second. To conserve power the receive circuits are disabled during transmit operations and vice versa. This provides the half−duplex operation used in HART communications. A5191HRT主要特性: • Single−chip, Half−duplex 1200 Bits per Second FSK Modem • Bell 202 Shift Frequencies of 1200 Hz and 2200 Hz • 3.0 V − 5.5 V Power Supply • Transmit−signal Wave Shaping • Receive Band−pass Filter • Low Power: Optimal for Intrinsically Safe Applications • Compatible with 3.3 V or 5 V Microcontroller • Internal Oscillator Requires 460.8 kHz Crystal or Ceramic Resonator • Meets HART Physical Layer Requirements • Industrial Temperature Range of −40℃ to +85℃ • Available in 28−pin PLCC, 32−pin QFN and 32−pin LQFP Packages • These are Pb−Free Devices A5191HRT 應用: • HART Multiplexers • HART Modem Interfaces • 4 − 20 mA Loop Powered Transmitters 
圖1. A5191HRT方框圖
圖2. A5191HRT應用框圖 評估板A5191HRTNGEVB The A5191HRTNGEVB evaluation board includes all external components needed for operating the A5191HRT IC and demonstrates the small PCB surface area such an implementation requires. The EVB allows easy design of HART implementations using A5191HRT.
圖3. 評估板A5191HRTNGEVB外形圖
圖4. 評估板A5191HRTNGEVB電路圖
圖5.A5191HRT接收器濾波器電路圖 接收器濾波器元件數值:
評估板A5191HRTNGEVB材料清單:
圖6. 評估板A5191HRTNGEVB元件布局圖
圖7. 評估板A5191HRTNGEVB PCB布局圖:頂層
圖8. 評估板A5191HRTNGEVB PCB布局圖:底層 詳情： 
A5191HRT-D.pdf
(192.93 KB)
A5191HRTNGEVB_MANUAL.pdf
(2.52 MB)
來源：網絡 |
