LED display module board PCB design rules 2
(4) the requirements of ground
Digital part of the ground lines width> = 50mil.
Column driver should be part of the ground the power line width than the line of drives is recommended for the power line width of 1.5 times.
Cell board into the ground shall be chessboard-shaped cloth, the connectivity between the various branches.
Drive part of the copper shop, the digital part of the grid to shop. To and from other parts of the set more than 20mil. The line width of the grid to 25mil, center spacing of 40mil.
Paving should be no loop to avoid dead ends. Paving is completed, will be separated by hand to spread to all parts connected.
Simulation to put in the entrance test to the power pin.
Figures in the input pin, output pin and place the test in the middle of 9702 pins.
(5) capacitance requirements
Part and digital part in driving the power inlet, put 100u electrolytic capacitors and capacitor 104.
In the power cord entrance and the end of the local branch, put the 100u electrolytic capacitors.
Recommended to stay close to the line driver chip 100u electrolytic capacitor.
Series switch and driver IC's power pin and capacitor 104 between the left position.
(6) chip pins power outlet
Series switch and the chip, the power line driver chip and pin pad pin qualify at least as wide.
(7) column lines and signal lines:
Room shielding plate lights, the column line and signal line width> = 12mil. In the PCB size is large, the proposed signal line width 15mil.
Other occasions, recommended the column line and signal line width of 12mil, at least 10mil.
Line spacing is not less than the minimum line width.
Room shielding of the light board, through a hole 50 mil, 28 mil.
Other occasions advised of a hole 50 mil, 28 mil. At least 40 mil, 24mil.
Vias and line spacing is not less than the minimum line width.
Power lines over the hole diameter <power line width, power lines through-hole diameter> = width * supply 1 / 3. The proposed through-hole diameter: 28mil, 40mil.
Large power and ground to increase the number of vias.
In order to ensure welding, do not put the pad over the hole. From the pad at least 5mil.
(9) plug weld pad devices:
Insert the device pad solder through-hole plug device to ensure there is no problem.
Ordinary row of pinhole diameter 40mil, power seat pad hole 60mil.
(10) mounting holes:
For LED module unit boards, avoid mounting holes located at the junction of two modules, can not have copper around the hole to prevent the mounting holes with the cell plate is connected to the DC ground (for the customer's last resort, have the customer's signature .)
General components should be placed away from the center of 3.5mm mounting holes outside, relatively high components (such as capacitors, plug-in chips) should be placed away from the fixed center of the hole more than 5mm place.
The user does not explicitly demand, level with pin and power away from the seat to be placed in the hole if they had fixed the connection outside of 2cm.
Specifically designed for customers in the PCB, to clear the customer's location and mounting holes to determine the pin fixed structure, power seat, and other devices placed.