SFFSAY1 Functional safety information

SFFSAY1 October 2025 LM51261A-Q1 , LM5126A-Q1

2.1 VQFN Package

This section provides functional safety failure in time (FIT) rates for the VQFN package of the LM5126A-Q1 and LM51261A-Q1 based on two different industry-wide used reliability standards:

Table 2-1 provides FIT rates based on IEC TR 62380 / ISO 26262 part 11
Table 2-2 provides FIT rates based on the Siemens Norm SN 29500-2

Table 2-1 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	21
Die FIT rate	4
Package FIT rate	17

The failure rate and mission profile information in Table 2-1 comes from the reliability data handbook IEC TR 62380 / ISO 26262 part 11:

Mission profile: Motor control from table 11 or figure 16
Power dissipation: 500mW
Climate type: World-wide table 8 or figure 13
Package factor (lambda 3): From table 17b or figure 15
Substrate material: FR4
EOS FIT rate assumed: 0 FIT

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

Table	Category	Reference FIT Rate	Reference Virtual T_J
5	CMOS, BICMOS ASICs analog and mixed HV >50V supply	N/A	75°C

The reference FIT rate and reference virtual T_J (junction temperature) in Table 2-2 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.