一种具有静电防护功能RS_485接口电路的设计方案.pdf

2009 仪 表 技 术 与 传 感 器 2009 11 Instrument Technique and Sensor No11 RS- 485 1 2 3 4 郑英兰 ,付 强 , 李文昌, 张 帅 ( 1. , 110045; 2. , 110026; 3. , 610054) : 文中设计一个通讯高效使用可靠的 S- 485接口芯片, 它可以安 地使用在工业场合, 确保计算机和工业产 品之间的通信畅通地进行该芯片完 符合 S- 485通讯协议, 由单一 5 V 电源供电, 采用 06 mBCD工艺芯片主要 由驱动器和接收器2部分构成其中, 驱动器的摆率不受限制, 可以实现最高 2. 5M bit/s的传输速率;接收器输入具有失 效保护特性, 当输入开路时, 可确保逻辑高电平输出 : S- 485; 收发器;驱动器; 接收器 : TM 76 : A : 1002- 1841( 2009) 11- 0068- 03 Design of RS485 Interface Chip w ith Abilit of E lectrostatic Protection 1 2 3 2 ZHENG Y inglan, FU Q iang, LIW enchang, ZHANG Shuai ( 1. Shen ang Pol technic Co llege, Shen ang 110045, China; 2. L iaoning Universit , Shen ang 10036, China; 3. Universit of E lectronics Science and Techno log of China, Chengdu 610054, China) Abstract: This paper designed a S485 interface chipwhich is high efficiency of communication, reliable of use. It can be safely used in industrial occasions to ensure that the communication between computers and industrialproducts is fluent. This chip was fully consistentw ith S485 communication protoco.l It used a single 5 V power supply and could be fabricated in 0. 6 m BCD process. This chipwasmainly composed of a driver and a receiver. The driver slew rates is not lmi ited and could transmit up to 2. 5M bps. The receiver input has a failsafe feature that guarantees a logichigh output if the input is open circuit. K e words: S485; transceiver; driver; receiver 0 ( 1)R IN 12 k; S- 485 EIA( ) T IA( ( 2)- 7~ 12V ; ) 2EIA 1983 ( 3) 50 pF; S-