LPC662: How to read date code on LPC661IM?

Ken Lambach

Part Number: LPC662

I know the LPC661IM is discontinued but have some with an unknown date of manufacture. The part markings are first line reads MJAB while the second and third lines state the part number (LPC661IM). It looks to me like the MJAB is assembly and wafer locations plus product line. Is there a date code on this part (its not on the underside either). If so, how is it read?

Our vendor has some with 5B06 as the first line. How do I read this? The label on the bag containing their tubes reads 5403547EM5. Does this provide date information?

I have entered the part into the TI date code web page but it does not find it.

I had to specify LPC662 as the part number on this page above but the part in question is actually the LPC661.

Thank you.

over 5 years ago

0 Former Member over 5 years ago

Hi Ken,

This is a pretty interesting case as I've dug around and asked around and haven't been able to match your topside markings with anything in our records.

I'm going to take a deeper dive into it. In the meantime, could you please provide the following:

1. An image of the topside markings so we are 100% on the same page
2. The name of the vendor
3. The year and, if possible, the month when the parts were purchased

Regards,
Daniel

0 Former Member over 5 years ago

Hi Ken,

As it turns out, the first two letters of the first line belong to the date code. "M" stands for 13 and "J" stands for 10. So your parts are dated October of 2013. The second two letters, "AB," refer to a lot code.

Hope this answers your question. Let me know if you need more help.

Regards,
Daniel

0 Ken Lambach44 over 5 years ago in reply to Former Member

Prodigy 20 points

Thanks Daniel. I appreciate your help very much!

0 Ken Lambach44 over 5 years ago in reply to Ken Lambach44

Prodigy 20 points

I have one more followup question on this. Would there be any issue using parts manufactured in 1995 so long as they have been factory sealed since manufacture? What if they have been opened somewhere along the way?

I've read the various documents on the TI web site and they seem to contradict themselves. I've also seen that military contracts now prohibit date code requirements which might imply 24 year old parts are OK?

0 Former Member over 5 years ago in reply to Ken Lambach44

Hi Ken,

Have you considered moisture exposure. If the packing has been unsealed, this is the first thing I would check. If it appears the packing has not been opened and you decide to open it, this is also the first thing I would check.

I recommend you take a look at our article on MSL Ratings and Reflow Profiles. From section 2, "The MSL rating of an IC determines its floor life before board mounting after the drypack packing (MSL2 and higher number ratings) has been opened." Section 2 of this article will have the relevant information.

Let me know if you have any further questions.

Regards,

Daniel

0 Paul Grohe over 5 years ago in reply to Ken Lambach44

TI__Guru 52946 points

Hi Ken,

Also keep in mind that if it is from 1995, it is not likely not RoHS compliant - so you may void any RoHS compliance you have on the end equipment.

The chips themselves do not "go stale", but the packaging may absorb moisture over time if it was opened. There should be a tattle-tale desiccant pack or moisture litmus card in the envelope. If they were in rails outside in-the-open - then they would need baking before wave soldering.

The packages are also designed for the lower temperature Pb reflow profile - so they may popcorn in modern RoHS flows if they have absorbed moisture.

If the soldering and RoHS issues are not a problem, I see no reason not to use them.

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LPC662: How to read date code on LPC661IM?