CIS PCB Design & Fabrication Standards Flashcards
6 cards from real CIS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CIS PCB Design & Fabrication Standards flashcards as text
What IPC class designation applies to high-reliability electronic products such as life-support equipment?
Answer: Class 3
IPC Class 3 applies to high-reliability products where continued performance is critical, such as medical life-support and military hardware.
What is the purpose of a 'via-in-pad' design in PCBs?
Answer: To place a via directly within a surface mount pad to save space
Via-in-pad places the via directly inside the SMT land pad, saving board real estate and improving electrical performance for dense designs.
The glass transition temperature (Tg) of a PCB laminate is important because:
Answer: It indicates the temperature at which the laminate transitions from rigid to soft
Tg is the temperature at which the PCB laminate transitions from a rigid, glassy state to a softer, rubbery state, affecting reliability during thermal excursions.
What is the function of a 'thermal relief' in PCB design?
Answer: It connects a through-hole pad to a copper plane with spoke connections to ease soldering
A thermal relief connects a pad to a copper plane through spoke-shaped connections, reducing heat dissipation during soldering to allow proper solder wetting.
According to IPC-6012 Class 3, what is the minimum acceptable annular ring for supported holes in internal layers?
Answer: 0.050 mm
IPC-6012 Class 3 requires a minimum 0.050 mm (50 µm) annular ring for supported holes in internal layers.
What does 'DFM' stand for in PCB fabrication?
Answer: Design for Manufacturing
DFM stands for Design for Manufacturing, the process of designing PCBs to be easily and reliably fabricated with minimal defects.