Failure analysis plays a pivotal role in guaranteeing and enhancing product reliability. It must be incorporated during R & D, manufacturing, and service life to identify weak links early and prevent costly breakdowns.
● Effect of Temperature on Component Failure
1. Effect of Temperature on Semiconductor Device Failure
Ambient temperature is one of the key factors behind device failure. The heart of a semiconductor is the P–N junction, whose characteristics are extremely temperature-sensitive.
When a P–N junction is reverse-biased, the minority-carrier reverse leakage current (ICQ) varies with temperature T as
ICQ = ICQR × 2^{(T – TR)/10 °C}
where ICQR is the leakage current at reference temperature TR.
Every 10 °C rise doubles the leakage current, shifting the amplifier bias point, altering current gain, narrowing the dynamic range, and in severe cases triggering thermal runaway.
The allowable maximum power dissipation (PCM) also drops as temperature rises:
PCM = (TjM – T) / RT
where TjM is the maximum junction temperature and RT is the thermal resistance.
Because the forward voltage of a P–N junction falls with temperature, logic families built on bipolar junctions (e.g., TTL, HTL) see both their logic thresholds and noise margins shift: low-level noise immunity shrinks, high-level immunity grows, leading to level drift, waveform distortion, offset, and possible thermal breakdown.
2. Effect of Temperature on Resistor Failure
Temperature mainly affects resistors in three ways:
Thermal noise increases, pushing resistance away from its nominal value.
The power-dissipation rating falls. For instance, an RXT carbon-film resistor can handle only ≈ 20 % of its rated power at 100 °C.
Designers sometimes exploit this behavior in PTC and NTC thermistors:
PTC (positive-temperature-coefficient) parts surge in resistance after a threshold, limiting fault currents and self-resetting once the circuit returns to normal.
NTC parts do the opposite, their resistance dropping with rising temperature.
3. Capacitors
Temperature fluctuations affect capacitors in several ways: rising temperature increases dielectric loss and thus shortens service life—roughly halving lifetime for every 10 °C rise; it also shifts the RC time constant, and excessive heat can drive dielectric loss high enough to cause thermal breakdown, while simultaneously degrading the insulation of inductors, transformers, and chokes.
● Effect of Humidity on Component Failure
Excessive humidity encourages acidic or alkaline dust to settle on PCBs, corroding solder joints and terminations—eventually causing open circuits. High moisture also promotes leakage coupling, while air that is too dry fosters static-electric discharge. Maintaining a controlled humidity band is therefore essential for reliability.
Gold-Spectrum Lab offers complete MSL (Moisture Sensitivity Level) testing to verify robustness under real-world humidity conditions.
● Effect of Over-Voltage on Component Failure
Stable, within-spec voltage is a prerequisite for dependable operation. Excess voltage can:raise internal temperatures and burn out parts;
cause dielectric breakdown—capacitor failure rate is proportional to the fifth power of applied voltage;
immediately destroy integrated circuits whose absolute-maximum ratings are exceeded.
Both active and passive parts have upper-voltage limits: exceed a transistor’s VCEO or a diode/capacitor’s breakdown voltage and catastrophic failure (thermal or electrical) follows.
● Effect of Vibration and Shock on Component Failure
Mechanical vibration accelerates latent weaknesses, loosens solder or crimp joints, and occasionally forces conductors into unintended contact—producing unpredictable faults.
One common manifestation is Electrical Over-Stress (EOS), where voltage or current surges—often triggered by vibration-induced shorts—generate enough heat to physically damage silicon or metal traces (“burn-out”).
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