PCB Risk Assessment & Management 4

Question 1

What risk does insufficient clearance between high-voltage traces on a PCB introduce?

Accepted Answer

Dielectric breakdown and arcing between conductors

Answer

Insufficient high-voltage clearance can cause dielectric breakdown through air or substrate, resulting in arcing and catastrophic failure.

Question 2

A PCB design uses a star ground topology for a mixed-signal board. What risk does this topology help mitigate?

Accepted Answer

Ground loops that allow noise currents to couple between analog and digital sections

Answer

Star grounding ensures that ground return currents from digital and analog circuits share no common impedance, preventing noise coupling.

Question 3

Which manufacturing risk is introduced by specifying a minimum annular ring that is too small for the fabrication process capability?

Accepted Answer

Drill breakout that disconnects the via pad from the drilled hole, causing open circuits

Answer

If annular rings are smaller than fabrication tolerances, drill registration error can break out of the pad, creating open vias.

Question 4

What is the primary risk of using Ball Grid Array (BGA) components without performing X-ray inspection after soldering?

Accepted Answer

Hidden solder joint defects such as bridges, opens, or insufficient reflow cannot be detected visually

Answer

BGA solder joints are hidden under the package body, making X-ray inspection the only reliable method to detect joint defects.

Question 5

What risk is created by routing a high-speed clock signal without a continuous ground reference plane beneath it?

Accepted Answer

Discontinuous return path increases loop area, worsening EMI and signal integrity

Answer

Clock signals need a low-impedance return path directly below; gaps in the reference plane force return currents to take longer paths, increasing EMI.

PCB - Design Practice Test

PCB - Design Practice Test

PCB Risk Assessment & Management 4