topic Re: Shelf Life Of device in 8-bit Microcontrollers

Shelf Life Of device - MC68HC908JK8

Deepak1 — Sat, 29 Mar 2008 18:17:25 GMT

Dear Sir,

I am using MC68HC908JK8.I would like to know What is the Shelf Life of the device MC68HC908JK8 OR any 8 bit device.

Added part number to subject

Message Edited by NLFSJ on 2008-03-29 10:47 AM

Re: Shelf Life Of device

JimDon — Sat, 29 Mar 2008 21:09:33 GMT

1000 Years at room temperature.
Now that I have said that, lets be more conservative and say 100 years.
At room temperature the Flash is specified by Freescale to remember it's data for 100 years, so I would guess that would mean the part is good for a least 100 years.

Re: Shelf Life Of device

bigmac — Sat, 29 Mar 2008 22:02:35 GMT

Hello,

The "shelf life" is likely to depend on whether the device is already mounted to the circuit board, or not, and the conditions under which the storage takes place.

If the storage takes place prior to being mounted, maintaining solderability of the pins is likely to be the main issue. Storage in a damp "tropical" climate is likely to be a problem, especially if fungal growth can occur.

It is possible for the device package to absorb moisture over time. With SM devices, this can give reliability problems during the reflow soldering process, unless baked for a lengthy period prior to use.

These considerations would dictate that, for long term storage, sealed packing should be used, that incorporates a desiccant.

Regards,

Mac

Re: Shelf Life Of device

JimDon — Sat, 29 Mar 2008 22:51:40 GMT

Agreed, but I would take shelf life to mean stored as per some specification.
If the part is mounted in a board, you have an entirely different set of parameters.

The expiration on a carton of milk assumes a set of storage conditions, not after you pour it in a glass (i.e. remove it from its "factory" container). And that of course it is at a certain temperature.

Note to that ROHS could add a whole new dimension to this.

You should read this.

Re: Shelf Life Of device

Deepak1 — Sun, 30 Mar 2008 12:48:54 GMT

Thank for reply,

Without Opening factory Package how long we can keep the device as it is & what precaution should we take before usage.