## 3 Defining Physics of Failure for Power Electronics
### The Test Plan
#### 3.3.2 Defining Performance Metrics
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Analysis** & **Test Overview** & **Test Standard(s)** & **Test Parameters** \\ \hline \multirow{7}{*}{Thermal} & Cycle: This test is conducted to determine the ability of components and solder interconnects to withstand mechanical stresses induced by alternating high and low temperature extremes & Mil-Std-810G Method 503.5 Procedure I-B & 1 cycle, 30 min low and 30 min high, transfer rate 1 min max. \\  & & & 503.5 Procedure I-B & Low temperature \(-\)33 \({}^{\circ}\)C \\  & & & & High temperature 63 \({}^{\circ}\)C \\ \cline{2-4}  & Event: These tests are used to determine the effects of bias conditions and temperature on solid state devices over time. It simulates the devices’ operating condition in an accelerated way and is primarily for device qualification and reliability monitoring. & & Three 24 h cycles, 30–63 \({}^{\circ}\)C, Ambient Air Conditions \\ \hline \multirow{7}{*}{Natural Frequency} & The test evaluates the circuit board and components against resonant affects. This is carried out by sweeping through a range of frequencies and evaluating where resonance occurs the greatest. & In-house & 10–2000 Hz sweep to determine the boards natural frequencies @ 0.1–10 g for 1 h. \\ \hline \multirow{7}{*}{Harmonic \& Random Frequency} & This test deals with broadband random vibration, looking at equipment and products that may undergo vibrations that are random in nature. Random vibrations occur in shipping transportation and operational environments such as aircraft, space vehicles and land vehicles & & Non-operational test, Minimum integrity test 20–2000 Hz 20–1000 Hz at 0.04 G\({}^{2}\)/Hz, 1000–2000 Hz at 6 dB, overall 7.7 G RMS; Test duration: 1 h \(\times\) 3 axis. Unit is non-operational \\ \hline \multirow{7}{*}{Mechanical Shock} & This test evaluates the structural integrity and the satisfactory performance of products that would experience steady or constant acceleration forces. & & Method 516.5, Procedure I, Environment Functional shock 15 G, \(\pm\) x,yz, 3 shocks in each direction, 18 shocks in total. General handling. Half sine wave 6 ms, 10 g, 6 number of shocks, 3 pulses per direction \\ \hline \multirow{7}{*}{Component Failure} & Predicts time to failure for aluminum liquid electrolytic and ceramic capacitors. & EIA IS-749 & 5000 h 105 \({}^{\circ}\)C with charge 20\% of initial value based upon working voltage, ripple, temp and current. \\ \hline \multirow{2}{*}{Thermal De-rating} & Flags devices being used outside of the specified operation or storage temperature range. & In-house & \(-\)55 \({}^{\circ}\)C to 105 \({}^{\circ}\)C 80\% of Value \\ \hline \multirow{2}{*}{Plated Through Hole} & Predicts fatigue of plated through holes/vias in circuit boards using IPC TR-579 calculations. & SAE J3168 & IPC TR-579 calculations \\ \hline \multirow{7}{*}{Solder Fatigue} & Predicts solder fatigue reliability under thermo-mechanical environments for all electronic parts (die attach, ball grid array (BGA), quad flat no-leads (QFN), thin small outline package (TSOP), chip resistor, through-hole, etc.). & IPC-JEDEC J-STD-020D-01 & 3 reflow cycles, peak temperature = 4260 \({}^{\circ}\)C \\ \cline{1-1} \cline{2-4}  & Predicts failure rate and end of life of integrated circuits using degradation algorithms for electro-migration, time electrode-migration, time dependent dielectric breakdown, hot carrier injection, and negative bias temperature instability. & SAE ARP 6338 & SAE ARP 6338 for electro-migration, time independent dielectric breakdown, hot carrier injection, and negative bias temperature instability. \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Hypothetical test plan for PCB under test. For each set of results from the test plan above, a metric for pass/failure needs to be set for the board. Because the board is a commercial, off-the-shelf evaluation board for use in a laboratory environment, it cannot be expected to endure the stringent outcomes of aerospace and automotive applications.