PCB News - LVDS high-speed signal PCB wiring requirements

LVDS high-speed signal PCB wiring requirements:

1. The transceiver should be as close to the connector as possible to reduce the length of the high-speed signal trace on the board.
2. The geometric size of the differential line is determined by the differential impedance. LVDS has built-in 100 ohm matching, the differential line impedance is controlled at about 100 ohms, and the single line impedance is about 50 ohms.
3. Minimize the distance between the differential lines as much as possible to help improve the common-mode rejection ratio.
4. In plane wiring, it is better to isolate the differential wire pairs with ground wires. If there is no ground wire, the distance between the differential wire pairs should be more than 2 times the distance between the differential wires.
5. TTL/CMOS signal lines should be far away from LVDS signal lines, and the distance should be at least 3 times the distance between differential lines.

The above is an introduction to the requirements of LVDS high-speed signal PCB wiring. Ipcb is also provided to PCB manufacturers and PCB manufacturing technology. 6. LVDS differential signal lines should be strictly equal in length.
7. Avoid wiring crossing the ground and power planes.
8. Avoid 90-degree turning.
9. Minimize the number of vias.
10. To maintain the continuity of the trace impedance, the wiring of adjacent layers should be crossed vertically.
11. Each power supply pin of LVDS devices should be strictly decoupled.
Consider the actual situation of each board to determine the wiring strategy. The high-speed transceiver is close to the connector, and the wiring is as short as possible to reduce the attenuation of high-speed signals on the transmission line. The thinner and longer the trace, the greater the attenuation, so the high-speed LVDS trace width is above 8mil. The distance between the differential lines can be 8 mils, and ground wires can be added between the differential line pairs, and some ground vias should be made at a distance on the ground wires. If board routing is difficult, in the case of short high-speed routing, the distance between the differential line pairs can be more than 16 mils to reduce the crosstalk of the routing. The receiving and sending wires should be separated because the backward crosstalk is greater than the forward crosstalk. Veribest's measurement tool is weak, and it is difficult to control the equal length of the differential line when the arc angle of the high-speed line travels, and the line can be routed at an obtuse angle.