SLCA005 Functional safety information

SLCA005A May 2020 – July 2022 LM2903B-Q1

1.2 Functional Safety Failure In Time (FIT) Rates

This section provides Functional Safety Failure In Time (FIT) rates for LM2903B-Q1 based on two different industry-wide used reliability standards:

Table 1-1 provides FIT rates based on IEC TR 62380 / ISO 26262 part 11
Table 1-3 provides FIT rates based on the Siemens Norm SN 29500-2

Table 1-1 Component Failure Rates per IEC TR 62380 / ISO 26262 Part 11

FIT IEC TR 62380 / ISO 26262	FIT (Failures Per 10⁹ Hours)
Package	VSSOP-8	TSSOP-8	SOIC-8
Total Component FIT Rate	7	9	10
Die FIT Rate	3	3	3
Package FIT Rate	4	6	7

Table 1-2 Component Failure Rates per IEC TR 62380 / ISO 26262 Part 11

FIT IEC TR 62380 / ISO 26262	FIT (Failures Per 10⁹ Hours)
Package	SOT23-8	WSON-8
Total Component FIT Rate	5	5
Die FIT Rate	3	3
Package FIT Rate	2	2

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

Mission Profile: Motor Control from Table 11
Power dissipation: 50 mW
Climate type: World-wide Table 8
Package factor (lambda 3): Table 17b
Substrate Material: FR4
EOS FIT rate assumed: 0 FIT

Table 1-3 Component Failure Rates per Siemens Norm SN 29500-2

Table	Category	Reference FIT Rate	Reference Virtual T_J
4	Bipolar Comparator	6 FIT	55°C

The Reference FIT Rate and Reference Virtual T_J (junction temperature) in Table 1-3 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.