For modules, the FIT is calculated differently.
This is a module assembly made of up individual components (unlike solid state silicon). As such this reliability prediction is based on TR-NWT-332 Reliability prediction model that uses a parts count methodology rather than Burn-in data used for silicon. The inherent reliability of each component is based on data in the TR332 model and then factored assuming a 50% electrical stress of rated maximum and also as at 40C operating environment. The failure rate of each component is then summed to give the failure rate of the module.
The way to calculate FIT rate for modules is to use the MTBF given in the datasheet.
FIT = (1/MTBF)*10^9 = 1/26600000 * 10^9 = 37.59
FIT = 37.6
