Acceleration Factor Calculators
Calculate acceleration factors using industry-standard reliability models. Toggle to CSV Profile mode to compute combined acceleration factors from distributional field and test stress profiles (Zhang & Sun, 2018).
Arrhenius Model
Used for temperature acceleration in reliability testing. Models the relationship between temperature and chemical reaction rates, which are indicative of some common temperature-driven material failures and degradation.
Formula:
AF = exp[(Ea/k) × (1/T_field - 1/T_test)]Ranges from -1.0 to 1.5 eV depending on failure mechanism
Acceleration Factor:
N/A
Coffin-Manson Model
Used for thermal cycling fatigue. Models the relationship between cyclic temperature range and fatigue life.
Formula:
AF = (ΔT_test/ΔT_field)^CTypical in range of 2 to 5 for materials / bonds used in electronics, utilize journal research to verify your application's specific coefficient value
Acceleration Factor:
N/A
Norris-Landzberg Model
Plastic strain range model accounting for thermal cycling frequency, temperature range, and maximum temperature effects. Used for solder joint fatigue analysis.
Formula:
AF = (f_field / f_test)^m × (ΔT_field / ΔT_test)^-n × e^(E_a / k × (1 / T_max,field - 1 / T_max,test))Ranges from 0.077 to 0.33 for SAC-305 depending on package type (Lall et al., 2012).
Ranges from 1.07 to 2.86 for SAC-305 depending on package type (Lall et al., 2012).
Ranges from 0.122 eV to 0.393 eV for SAC-305 depending on package type (Lall et al., 2012).
Frequency Factors
Thermal cycling frequency in field conditions
Thermal cycling frequency in test conditions
Temperature Range Factors
Temperature range in field conditions
Temperature range in test conditions
Maximum Temperature Factors
Maximum temperature in field conditions
Maximum temperature in test conditions
Acceleration Factor:
N/A
Peck's Model
A form of Eyring model accounting for relative humidity and temperature effects. Combines an inverse power law for humidity with the Arrhenius equation for temperature.
Formula:
AF = (RH_field / RH_test)^-n × exp[(E_a / k) × (1/T_field - 1/T_test)]Peck and Hallberg suggest to use a value of 3.0 for corrosion in epoxy packages (Hallberg & Peck, 1991)
Peck and Hallberg suggest to use a value of 0.9 for corrosion in epoxy packages (Hallberg & Peck, 1991)
Humidity Factors
Relative humidity under field conditions
Relative humidity under test conditions
Temperature Factors
Temperature under field conditions
Temperature under test conditions
Acceleration Factor:
N/A
About Acceleration Factors
Acceleration factors are used to relate failure rates or lifetimes under test conditions to what would be found in field conditions.
They help to:
- Reduce test time by using accelerated stress conditions
- Predict product reliability under normal operating conditions
- Compare different stress conditions and their effects
- Design appropriate test plans for reliability validation
CSV Profile Mode
When field or test conditions involve distributional (non-constant) stress levels, use CSV Profile mode to upload stress profiles. The combined acceleration factor is computed using the method described by Zhang & Sun (2018), which converts distributional field and test stress levels to their equivalent constant stress levels via a reference-independent formulation.
CSV files should have a header row followed by data rows. The last column is the weight (hours, cycles, or probability at each stress level). Model constants (Ea, coefficients, exponents) are entered separately and do not need to be in the CSV.