Part Number: SN74LVC1G175
This app note describes the process of calculating MTBF, for when D changes state within the setup/hold timing window of the CLK edge; which creates a metastable condition.
From the app note, it shows calculations will be considerably easier if τ and t0 data is already characterized...this data doesn't have to be precise, but is it available somewhere for the LVC logic series? Specifically any data on these values for SN74LVC1G175DCKR?
The data doesn't have to be "official"; just a guideline to get a rough idea if MTBF will be several minutes or several hundred years, etc for a given application.
There's a physical failure MTBF listed on the quality page for the device: https://www.ti.com/quality/docs/estimator.tsp
For the SN74LVC1G175 the MTBF is listed as 2.14 x 10^9 hours.
We are glad that we were able to resolve this issue, and will now proceed to close this thread.
If you have further questions related to this thread, you may click "Ask a related question" below. The newly created question will be automatically linked to this question.
In reply to Emrys Maier:
I appreciate the quality page link, but I already visited the page...:(The qualification doesn't list the CLK and D signal frequencies during the test though, right?
These values seem pretty important, as a failure for the D-type Flip Flop occurs when there is a metastable state; aka the D input has a transition within the setup/hold time around the CLK input signal edge.
From the above literature I attached, it looks like I should be able to calculate τ and t0 given the MTBF time from the quality page, as long as I know what the frequencies were during the test.
MTBF is highly dependent upon these clocks.
Can you see if that information is available? If so you could send it to me offline (I am in the Directory Services)?
In reply to Darren (FAE):
Referring back to our previous discussion - I think you're referring to a bit error type of failure rather than a physical device failure.
MTBF for my products is related to the physical failure of the device -- ie an internal trace wears out, or hot carrier injection produces too much of a shift in threshold.
It's unrelated to the digital operation and possible errors therein.
I see...yes, I have been trying to discuss bit error failures, which require device characterization data to calculate.Does this mean we don't have any characterization data that could be used to calculate τ and t0 for this device?
From the app note, the author seems to have suggested this characterization exists...at least for some devices; as he gives a simple method of testing for it.
That is correct -- this device is a relatively simple analog circuit. If you provide the correct setup and hold times, the output will be correct. If you don't, we can't guarantee anything (and that's the main area the app note discusses - metastable states).
In other words, if you violate the datasheet spec, we don't guarantee functionality.
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.