IIS3DHHC. MSL3 preconditioning.

[Pawel Piwowarski]

What exactly "MSL3 preconditioning" means?

Does it mean the same as "baking"?

This preconditioning corresponds with soldering, or all the time?

How accuracy are affected by moisture?

I understand that omitting the baking before soldering, will cause cracks in MEMS structure and degrade the accuracy.

So baking guarantee that accuracy will be as the datasheet, just before baking and soldering.

But what about later?

Moisture will continue to degrade accuracy even far after soldering? (I mean only moisture, without temperature cycling)

And baking will recovers accuracy?

[Eleon BORLINI]

Hi @Pawel Piwowarski​ , with (MSL3) preconditioning is intended 8 hours of THS (temperature-humidity storage) at 85°C/85%.

Most of datasheet parameters are guaranteed after reliability aging tests (168h, 500h, 1000h), but if you put the device in an high-humidity environment you will risk a degradation in accuracy performances. Btw a successive baking will solve the degradation. Regards

[Pawel Piwowarski]

So preconditioning is something completely different than baking?

How degradation should be expected when device is used in 25°C/60% environment?

BTW. How is "cross axis sensitivity" of IIS3DHHC? It is not mentioned in datasheet.

[Eleon BORLINI]

​While standard baking is typically performed at 85°C but without specification of the relative humidity, the preconditioning basically specifies also the fact that humidity relative level is 85%.

Consider that the 1000h THS (storage in T and H) and THB (biased) is done at stressful conditions that simulate a long stay in a standard ambient environment (close to the 25°C/60% condition you mentioned), and no particular degradation is detected after these reliability tests.

About cross axis, the spec is maximum +-5% for all the 6 axis combinations (X to Y, X to Z, Y to X, Y to Z, Z to X, Z to Y).

Regards