CIS CIS PCB Design & Fabrication Standards 2

Question 1

What IPC class designation applies to high-reliability electronic products such as life-support equipment?

Accepted Answer

Class 3

Answer

IPC Class 3 applies to high-reliability products where continued performance is critical, such as medical life-support and military hardware.

Question 2

What is the purpose of a 'via-in-pad' design in PCBs?

Accepted Answer

To place a via directly within a surface mount pad to save space

Answer

Via-in-pad places the via directly inside the SMT land pad, saving board real estate and improving electrical performance for dense designs.

Question 3

The glass transition temperature (Tg) of a PCB laminate is important because:

Accepted Answer

It indicates the temperature at which the laminate transitions from rigid to soft

Answer

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.

Question 4

What is the function of a 'thermal relief' in PCB design?

Accepted Answer

It connects a through-hole pad to a copper plane with spoke connections to ease soldering

Answer

A thermal relief connects a pad to a copper plane through spoke-shaped connections, reducing heat dissipation during soldering to allow proper solder wetting.

Question 5

According to IPC-6012 Class 3, what is the minimum acceptable annular ring for supported holes in internal layers?

Accepted Answer

0.050 mm

Answer

IPC-6012 Class 3 requires a minimum 0.050 mm (50 µm) annular ring for supported holes in internal layers.

(CIS) Certified IPC Specialist Practice Test

(CIS) Certified IPC Specialist Practice Test

CIS CIS PCB Design & Fabrication Standards 2