SNOAA48 Functional safety information

SNOAA48A December 2019 – November 2024 LM4040-N-Q1

2.2 Functional Safety Failure In Time (FIT) Rates for 8.192V Voltage Option

This section provides functional safety failure in time (FIT) rates for the LM4040-N-Q1 (8.192V voltage option) based on two different industry-wide used reliability standards:

Table 2-5 provides FIT rates based on IEC TR 62380 / ISO 26262 part 11
Table 2-6 provides FIT rates based on the Siemens Norm SN 29500-2

Table 2-3 Component Failure Rates per IEC TR 62380 / ISO 26262 Part 11

FIT IEC TR 62380 / ISO 26262	FIT (Failures Per 10⁹ Hours)
Total component FIT rate	7
Die FIT rate	6
Package FIT rate	1

The failure rate and mission profile information in Table 2-5 comes from the reliability data handbook IEC TR 62380 / ISO 26262 part 11:

Mission profile: Motor control from table 11
Power dissipation: 123mW
Climate type: World-wide table 8
Package factor (lambda 3): Table 17b
Substrate material: FR4
EOS FIT rate assumed: 0 FIT

Table 2-4 Component Failure Rates per Siemens Norm SN 29500-2

Table	Category	Reference FIT Rate	Reference Virtual T_J
5	CMOS, BICMOS Digital, analog, or mixed	20 FIT	55°C

The reference FIT rate and reference virtual T_J (junction temperature) in Table 2-6 come from the Siemens Norm SN 29500-2 tables 1 through 5. Failure rates under operating conditions are calculated from the reference failure rate and virtual junction temperature using conversion information in SN 29500-2 section 4.