2340648_en-US

[#1]

[MCU0/1/3] PMHF Value (in FIT)

Could you please share the PMHF value for each MCU?

PMHF (in FIT) value

MCU0 (S32K324)

MCU1 (S32K388) (ASIL B) 

MCU1 (S32K388) (ASIL D)

MCU3 (S32N55)

PMHF value was not stated clearly in Safety report of MCU1, for example.

It does demonstrate the SPFM & LFM, but not PMHF.

In the safety report of MCU1 (S32K388), there is a guideline, below the summary table from Medini, mentioning that SoC level result to be used to calculate PMHF.

(Note: Medini does not calculate PMHF automatically, you need to place additional script within Medini)

Re: [MCU0/1/3] PMHF Value (in FIT)

Hello @90insu,

It is not possible for NXP to provide a PMHF value to customers because the PMHF calculation depends on the system topology and the specific use case, which are not known to us. NXP supplies the necessary residual failure rates and latent failure rates for its components so that customers can incorporate them into their own PMHF calculations. ISO 26262:2018 Part 10 provides examples and guidance on how PMHF can be calculated, which customers may use as a reference.

Regards,

Daniel

Re: [MCU0/1/3] PMHF Value (in FIT)

Could you confirm the consolidated total hardware failure rate (λ_total) per MCU (in FIT) ?

Re: [MCU0/1/3] PMHF Value (in FIT)

Hello @90insu,

For any functional safety–related questions, please contact your assigned NXP FAE, if your company has one, or reach out through your local distributor. Both channels have direct access to NXP’s safety teams and can coordinate the appropriate support.
Thank you for your understanding.

Regards,

Daniel

Re: [MCU0/1/3] PMHF Value (in FIT)

Feedback from Animesh.

Next step:

1. Animesh to confirm MCU1 ASIL B FIT number
For MCU1, I am observing different FIT values for ASIL‑B MCU1 compared to those documented in the following version of the safety analysis report:

rp1035202 – S32K388 Safety Analysis Report, Rev. 0.2
To ensure alignment, could you please share the latest released version of the safety analysis report for MCU1?
I have calculated PMHF values for the following devices -

 2. Judy to share the lastest safety analysis report for MCU3

Hi Inso,

I have calculated PMHF values for the following devices -

PMHF = SPF+RF+MPF Contribution 

MPF contribution = MPF (latent) × MPF (detected) × T

MPF (detected) = Total safety‑related − SPF -  LF (FIT)

1.MCU0 (S32K324- 172 package) –

MPF (det) = 3985.34 – 3.540646 – 0.06819649 = 3981.73115751

MPF  contribution = 3981.73115751 x 0.06819649 x 10000 x 10^-9 = 0.0027154008

PMHF = 3.540646 + 0.0027154008 = 3.5433614008 FIT

2. MCU0 (S32K324 – 257 package)-

MPF (det) = 3978.34 – 10.44137-0.05368173 = 3967.84494827

MPF contribution =  3967.84494827 x 0.05368173 x 10000 x 10^-9 = 0.0021300078

PMHF = 10.44137 + 0.0021300078 = 10.443500078 FIT

3. MCU1 (S32K388- ASIL D)-

MPF(det) = 9368.623 – 5.14307- 0.07702615 = 9363.4029

MPF contribution = 9363.4029 x 0.07702615 x 10000 x 10^-9 =  0.007212268

PMHF = 5.14307 + 0.007212268 = 5.150282268 FIT

4.MCU1(S32K388- ASIL B)-

MPF(det) = 9368.159 – 7.107391 – 0.07625516 = 9360.97535384

MPF contribution = 9360.97535384 x 0.07625516 x 10000 x 10^-9 = 0.00713541

PMHF = 7.107391 + 0.00713541 = 7.11452641 FIT

5.MCU 3 (S32N55) : Adding @Judy Ren to look into the PMHF value for this device.