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EPC120-QFN16 参数 Datasheet PDF下载

EPC120-QFN16图片预览
型号: EPC120-QFN16
PDF下载: 下载PDF文件 查看货源
内容描述: 完全集成的隔光芯片,带有2线总线接口 [Fully integrated Light-Barrier Chips with 2-Wire Bus Interface]
分类和应用:
文件页数/大小: 27 页 / 550 K
品牌: EPC [ ESPROS PHOTONICS CORP ]
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epc120  
Figure 7 shows the different messages with the parity bits. From the interface to the sensor/transmitter device the “normal command” is used  
except for the register write command. In the other direction only the register readout has a different format. Notice the different start bits  
which identify the direction of the transmission: 00 for the direction interface to sensor devices and 01 in the other direction. Between the  
telegrams, an idle time of 2 clock periods are need to detect the start of the transmission.  
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 C0 C1 C2 P0 P1 P2 P3 P4 P5 P6 P7 P8 P9  
Normal Command  
Device Address  
Command  
Parity Bits  
A0 A1 A2 A8 A9 C0 C1 C2 P0 P1 P8 P9 R0 R1 R2 R3 R4 D0 D1 D14 D15 P0 P1 P8 P9  
Device Address Parity Bits Register Data Parity Bits  
Write Command  
Command  
D0 D1 D9 D10 A0 A1 A2 A8 A9 P0 P1 P8 P9  
Data Device Address Parity Bits  
Results  
R0 R1 R2 R3 R4 D0 D1 D14 D15 P0 P1 P8 P9  
Register Data Parity Bits  
Register Readout  
Figure 7: Message Structure  
Bus Wire Considerations  
The electromechanical design of a system using multiple epc10x devices on a twisted pair cable with an impedance of typically 100 Ohms has  
an impact on the overall impedance of the system. Figure 8 shows the change of the cable impedance with smaller element pitch.  
120  
100  
80  
60  
40  
20  
0
1.0 1.8 3.2 5.6 10.0 17.8 31.6 56.2 100.0  
Pitch [cm]  
Figure 8: Line impedance as a function of the element pitch  
on a 100 Ohm twisted pair cable  
It is highly recommended to terminate the bus line on both sides with an AC terminator network (shown in Figure 9) which matches the overall  
impedance of the system according to Figure 8. In order to avoid high DC currents in the termination resistor, a capacitor of 100nF should be  
connected in series to the termination resistor.  
100nF  
RT  
Figure 9: Bus termination network  
© 2011 ESPROS Photonics Corporation  
Characteristics subject to change without notice  
9
Datasheet epc12x - V2.1  
www.espros.ch