SFFS125 June   2021 SN74HCS74-Q1

 

  1.   Trademarks
  2. 1Overview
  3. 2Functional Safety Failure In Time (FIT) Rates
  4. 3Failure Mode Distribution (FMD)
  5. 4Pin Failure Mode Analysis (Pin FMA)

Functional Safety Failure In Time (FIT) Rates

This section provides Functional Safety Failure In Time (FIT) rates for SN74HCS74-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 for SOIC (D) FIT for TSSOP (PW) FIT for WQFN (BQA)
Total Component FIT Rate 20 13 8
Die FIT Rate 4 4 3
Package FIT Rate 16 9 5

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
  • Power dissipation: 175 mW
  • Climate type: World-wide Table 8
  • Package factor (lambda 3): Table 17b
  • Substrate Material: FR4
  • EOS FIT rate assumed: 0 FIT
Table 2-2 Component Failure Rates per Siemens Norm SN 29500-2
TableCategoryReference FIT RateReference Virtual TJ
5 CMOS Logic FCT, HC, LV, LVC, ALVC, VHC, and so forth 5 FIT 45°C

The Reference FIT Rate and Reference Virtual TJ (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.