UCC27531: FIT rate for UCC27531QDBVRQ1 (confidence interval 90%)

Kevin Kraxner

Prodigy 30 points

Part Number: UCC27531

Hi all,

can you give me a FIT rate estimation for the UCC27531QDBVRQ1 with a confidence interval of 90% or more, please?

(application temperature with be 75°C)

best regards,

kevin k.

over 3 years ago

0 Kevin Kosta over 3 years ago

TI__Mastermind 18035 points

Hi Kevin,

Thank you for reaching out!

TI provides a MTBF/FIT estimator that can be found at the link I am providing below that can be used for many of our devices. There is also a Functional Safety FIT Rate document available for the UCC27531QDBVRQ. Attached is the estimate from TI for the UCC27531QDBVRQ using the MTBF/FIT estimator. From there you can use the reliability calculators and de-rating tools to get the estimates that you want. I also attached a guide used to calculate those FIT estimates.

MTBF/FIT estimator: https://www.ti.com/quality/docs/estimator.tsp?partType=tiPartNumber&partNumber=UCC27531QDBVRQ1#resultstable

Reliability calculators: https://www.ti.com/support-quality/reliability/calculators.html

Functional Safety: https://www.ti.com/lit/fs/sffs223/sffs223.pdf?ts=1647901537994&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FUCC27531-Q1%253Fqgpn%253Ducc27531-q1

Calculating FIT for a mission Profile: https://www.ti.com/lit/an/spraby3/spraby3.pdf?ts=1647897051826&ref_url=https%253A%252F%252Fwww.ti.com%252Fsitesearch%252Fen-us%252Fdocs%252Funiversalsearch.tsp%253FlangPref%253Den-US%2526searchTerm%253DUCC27531%2Bfit%2526nr%253D30

Thank you,

Kevin

0 Kevin Kraxner over 3 years ago in reply to Kevin Kosta

Prodigy 30 points

hoi kevin,

thanks for the fast response. yes, i am aware of all the documents you mentioned.

i am asking for a higher confidence interval. the FIT estimater only gives values for 60% - i would like to know the FIT for 90%.

best regards,

kevin

0 Kevin Kosta over 3 years ago in reply to Kevin Kraxner

TI__Mastermind 18035 points

Hi Kevin,

Understood thank you for reaching back out. I messaged our team internally and will give you an update when I hear back from them!

Thank you,

Kevin

0 Kevin Kraxner over 3 years ago in reply to Kevin Kosta

Prodigy 30 points

hi kevin,

i wanted to add here something.

in the document
Functional Safety: https://www.ti.com/lit/fs/sffs223/sffs223.pdf?ts=1647901537994&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FUCC27531-Q1%253Fqgpn%253Ducc27531-q1
is a table for failure mode distribution.

i was expecting

33% for OUTH stuck at high & OUTL stuck at low

33% for OUTH stuck at low & OUTL stuck at high

33% open

see in the table below - two times the same failure mode is mentioned.

i guess this is a copy paste failure?

br,

kevin

0 Kevin Kosta over 3 years ago in reply to Kevin Kraxner

TI__Mastermind 18035 points

Hi Kevin,

Thanks for bringing this to my attention. I will also look into this.

Thank you,

Kevin

0 Kevin Kosta over 3 years ago in reply to Kevin Kraxner

TI__Mastermind 18035 points

Hi Kevin,

Thank you for your patience while I was getting an answer for you! I reached out and gathered a calculated process FIT of 0.7 using the following parameters:

Usage temperature = 75C

Confidence level = 90%

Activation energy = 0.7eV

Test temp = 125C

Test duration = 1000hrs

Sample size = 172398

Fails = 0

Please be aware that this is an estimation of the process FIT using generic data containing an aggregate of data for many devices using the same process technology.

Thank you,

Kevin

0 Kevin Kraxner over 3 years ago in reply to Kevin Kosta

Prodigy 30 points

hi Kevin,

sorry but i have to reopen my question because i still have doubts about your FIT rate of 0.7. What does "process FIT" mean?

if i use the FIT calculator for an application temperatur of 75°C

i get MTTF of 1.44e+7. this means FIT = 1/MTTF = 1 / 1.44e+7 = 69.4 FIT. and this for an confidence interval of 60%.

can you tell me how it is possible to get 0.7 FIT then instead?

br,

kevin

0 Kevin Kosta over 3 years ago in reply to Kevin Kraxner

TI__Mastermind 18035 points

Hi Kevin,

Thank you for reaching back for clarification!

When using the derating tool on our site please make sure to edit the FIT at reference temperature of 55C. You are using 16.7 which is what the tool uses as a default value as an example. You must change it to the FIT value provided by the MTBF and FIT Rate Estimator.

Our FIT from the table is 0.1. Using the derate tool we get MTTF of 2.41e+9.

FIT = 1/MTTF

FIT = 1/2.41e+9

FIT = 0.415

This is as you stated earlier at a confidence level of 60%.

Thank you,

Kevin

0 Kevin Kraxner over 3 years ago in reply to Kevin Kosta

Prodigy 30 points

hoi kevin,

i see. thank you very much, now it makes totally sense.

is it possible to adjust the confidence interval in the FIT calculator on my own? I would also like to know the FIT for an application temperatur of 110°C.

with 90% confidence interval.

best regards,

kevin

0 Kevin Kosta over 3 years ago in reply to Kevin Kraxner

TI__Mastermind 18035 points

Hi Kevin,

Glad I could help you there!

Unfortunately we do not have a way of adjusting the confidence interval on our derating tool. As of now you can adjust the application temperature for the FIT calculator at a 60% confidence interval. I will get you a 90% confidence level FIT calculated at an application temperature of 110°C.

Thank you,

Kevin

+1 Kevin Kosta over 3 years ago in reply to Kevin Kraxner

TI__Mastermind 18035 points

Hi Kevin,

Thank you for your patience while I got that new FIT calculated!

For this case I calculated a process FIT of 6.0 with the following parameters:

Usage temp = 110C

Confidence level = 90%

Activation energy = 0.7eV

Test temp = 125C

Test duration = 1000hrs

Sample size = 172398

Fails = 0

Again, please be aware that this is an estimation of the process FIT using generic data containing an aggregate of data for many devices using the same process technology.

Thank you,

Kevin

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UCC27531: FIT rate for UCC27531QDBVRQ1 (confidence interval 90%)