5.4.2.1 Maximum Allowable Deflection Of ICs

The maximum allowable PWB deflection (_{max}) for an
IC can be calculated using equation 5-6. This value is the largest PWB
deflection that the IC can withstand before lead damage or fatigue occurs.
This calculation is then used in Section
5.4.2.4 to determine the maximum allowable input PSD level which
for the tested IC. The PSD level is calculated using the smallest expected
deflection as determined in Equation
5-3.

where: _{max} =** **Endurance limit (Se) of the IC lead
material, psi.