How is creepage measured on a high voltage PCB?
Similar to clearance, creepage measures distance between conductors on for high voltage PCB. However, instead of measuring distance in air, it measures the shortest distance along the surface of the insulation material. Board material and environment also affect creepage requirements.
What are the clearance and creepage requirements for a circuit?
Consider a circuit where the clearance and creepage requirements are defined as 4mm and 7mm, respectively. Now look at the designs in Figures 4 and 5.
What should the spacing be for a high voltage PCB?
Not every PCB design has the same rigorous rules on spacing that a high-voltage PCB design needs. In general, if the normal operating voltage of your product meets or exceeds 30 VAC or 60 VDC, then you should be very diligent about spacing rules in your high voltage PCB design.
What can shorten creepage on a printed circuit board?
Moisture or particulate accumulation on the board can shorten creepage distance the same way they do for clearance. When you have a high density printed circuit board design, creepage can be a difficult requirement to meet.
Which is the standard for PCB breakdown voltage?
There are two standards surrounding PCB breakdown voltage I see referenced most often. The first important high voltage clearance and design standard is IPC-2221, which is the generic standard for guidance on PCB creepage and clearance.
Why is line spacing important in high voltage circuit boards?
In high-density interconnect PCBs, maintaining a minimum line spacing between traces is quite a challenging task. Creepage and clearance distances of the traces become important at high voltages. Designing a high-voltage circuit board requires good knowledge of international safety standards and regulations such as IPC 2221A and UL 60950-1.
Can a high voltage board be used as a separate board?
Earlier, the use of high-voltage boards as a separate board was a common practice in a multi-board system. With miniaturization, it is possible to merge multiple boards, which also allows the designer to utilize mixed technologies, including analog, digital, and RF circuits.