PCB Risk Assessment & Management 3

Question 1

What risk is associated with using tin-lead (SnPb) solder on a board required to meet RoHS compliance?

Accepted Answer

Regulatory non-compliance and potential market access restrictions

Answer

RoHS restricts hazardous substances including lead; using SnPb solder violates compliance and can block product sales in regulated markets.

Question 2

During PCB fabrication, what risk does excessive copper etching (over-etching) introduce?

Accepted Answer

Trace width reduction leading to higher resistance and potential open circuits

Answer

Over-etching removes more copper than intended, narrowing traces, increasing resistance, and risking open circuits on fine-pitch designs.

Question 3

What failure risk is increased by placing bypass capacitors far from the IC power pins they are intended to decouple?

Accepted Answer

Increased inductance in the decoupling path reduces high-frequency effectiveness

Answer

Longer paths to bypass capacitors add parasitic inductance, reducing their ability to suppress high-frequency noise at the IC power pins.

Question 4

A designer skips Design Rule Check (DRC) before submitting a PCB for fabrication. What is the most likely risk?

Accepted Answer

Fabrication errors such as shorts, opens, or clearance violations that could have been caught automatically

Answer

DRC automates the detection of design errors like clearance violations and short circuits; skipping it allows preventable defects to reach fabrication.

Question 5

What risk does a missing solder mask dam between fine-pitch SMD pads create?

Accepted Answer

Solder bridging between adjacent pads during reflow

Answer

Without a solder mask dam, molten solder can flow between closely spaced pads, creating unintended electrical bridges.

PCB - Design Practice Test

PCB - Design Practice Test

PCB Risk Assessment & Management 3