What kind of PCB is a good PCB
One aspect to satisfy at least the following
1. Low power interference is small, the key left line and the bottom line is reasonable, stable performance all aspects (premise is circuit without defects).
2. Good for EMC, low radiation, the loop is reasonable.
3. To meet the safety, the safety distance meet the requirements.
4. Meet the process, production can be productive, and reduce the cost of production.
5. Beautiful, orderly layout rules (device not stagger), linear beautiful beautiful, not seven curved around eight.
How to do the above, to share my experience of cloth plate
1. Layout before, know the specifications of the power supply, power supply specifications, have special requirements, as well as to the safety standard.
Confirm the structure of input conditions is not accurate, and air duct, input and output ports, as well as the main power flow.
Process route selection, according to the density of the device, and presence of special devices, choose corresponding process route.
2. Layout, pay attention to the layout reasonable, ensure the four loop as small as possible, early anticipation subsequent line is easy. Transformer put basic determines the overall layout, must be careful, in the best position. EMI the layout of the part to clear, a clear separation and other main power part. To reduce the interference of main power switch device. The absorption loop area is as small as possible, and reasonable position to the length of the radiator, no wind.
Part 3. Go line, input the walk line of EMI circuit meet the safety, the former vice edge distance, input and output to meet the safety distance of the earth.
Walk line thickness meets enough current size, key signals (such as the driving signal, sampling signal, ground wire is reasonable), drive signals do not interfere with sensitive (high frequency signal); Is the sampling signal sampling accurately and will interference; Reasonable ground wire is pulled, sometimes need a single point grounding, sometimes need a multipoint grounding has to do with actual needs), the main power and the signal to distinguish strictly, the original edge chip from the sampling resistor, don’t draw on the large electrolytic (especially sampling resistance and large electrolytic ground distance), ground level ground before back to big electrolytic VCC, secondary capacitor to connect chips, feedback signal and a single point of IC, IC to single point. Radiator must connect the main power, can’t pick up the signal and so on a lot of the details of the requirements.