PCB DESIGN

Printed circuit board (PCB) is a component made of one or more layers of insulating material with electrical conductors. The insulator is made of various materials that are normally based on fiberglass, ceramics, or plastic. During manufacturing the portions of conductors that are not needed are etched off, leaving printed circuits that connect electronic components. Currently the main generic standard for printed circuit board design, regardless of materials is IPC-2221A. Whether PCB board is single-sided, double-sided or multilayer, this standard provides rules for manufacturability and quality such as requirements for material properties, criteria for surface plating, conductor thickness, component placement, dimensioning and tolerance rules, and more. For a specific technology the designer can then choose the appropriate sectional standard from the IPC-2220 series. Additional parameters for Power Conversion Devices are standardized by the draft of IPC-9592.The width of the circuit conductors should be chosen based on maximum temperature rise at rated current and acceptable impedance. The spacing between the PC traces is determined by peak working voltage, the type of the circuit and application. Depending on application, other standards may also apply. For example, for mains-powered or battery-powered information technology equipment, UL 60950-1 set additional requirements for creepage and clearance between various circuits. The minimum possible width of the traces and spacing between them are limited by the manufacturing capabilities of your vendor. The width and spacing should never be less then 2 mils. Typical minimum values are 6/6 mils.