PCB Copy Engineering Suppression of noise sources
1, PCB Copy Engineering carefully selected devices
Selection should pay attention to the aging of components, and select the thermal temperature coefficient of small device copy board. For high-frequency circuits, should be appropriate to use the film to reduce the circuit radiation. In the choice of logic devices, to fully consider its noise margin indicators, it is best to use HTL, if both power consumption, the use of VDD ≥ 15V CMOS is appropriate. The following are the same as the "
2, PCB Copy Engineering using multi-layer printed circuit board
This can be obtained from the structure of the ideal shielding effect: the middle layer for the power line or ground, the power supply sealed in the board, both sides of the insulation treatment, can flow through the lower and lower disturbances do not affect each other; The inner layer made of a large area of the conductive area, the wires have a large electrostatic capacitance between the formation of very low impedance power supply circuit copy board, which can effectively prevent the circuit board radiation and receive noise.
3, PCB Copy Engineering printed circuit board "full ground"
When drawing high-frequency circuit boards, in addition to as thick as the ground printed wire, the circuit board should not be occupied by all the area as a ground wire, so that the device closer to the ground. This can effectively reduce the parasitic inductance, while a large area of the ground can effectively reduce the noise radiation. 4, in the printed circuit board with one or both sides of the ground plate
That is, with a piece of aluminum or iron attached to the printed circuit board on the back (welding surface), or the printed board caught in two aluminum or iron plate. The grounding plate is installed as close as possible to the printed circuit board and must be connected to the (SG) optimum ground point of the system signal. This structure is simple and easy to do multi-layer printed circuit board copy board. If you want to pursue a better suppression effect, the printed circuit board can be installed in a completely shielded metal box, so that it does not produce, do not respond to noise.