FXAS21002C gyro does not pass self-test

[adamheinrich]

Dear colleagues,

in our current project we are planning to use the FXAS21002C gyro. The PCB has been designed with respect to layout recommendations and we have manufactured several prototypes.

However it looks like all of them are dead as they fail the self-test for both X and Y axes (value is outside the specified range) and it reads angular movement although the board does not move during test. The Z axis is OK and the code works well on older prototypes build around NXP's breakouts.

What could be possibly wrong?

Moreover, the errata document FXAS21002CER states that there should be new chip revision with SPI issue fixed. How do we identify the new revision? Our chips' traceability date code reads FCSA.

Thank you,

Adam Heinrich

[TomasVaverka]

Dear Adam,

Could you please post here the values you are getting during the self-test? Are they outside of the specified range shown below?

The gyro offset is temperature, orientation and acceleration dependent and its typical value is ±50 LSBs @ ±2000 dps range:

The "CS" in the part marking denotes the 19th week of 2015, so you have old parts with SPI issue described in the

FXAS21002CER.

Best regards,

Tomas

[adamheinrich]

Dobrý den,

thank you for your fast response. Yes, they are outside the range. Exact self-test output values are 489 for X and 635 for Y (Z is 16952 and stays within specified range).

How can we order the fixed chip from distributors? Does the new FXAS21002 have some special P/N?

Díky,

Adam

[TomasVaverka]

Dobrý den Adame,

Regarding the self-test, I am asking our device group to comment on this.

You or your distributors can place an order requesting fixed parts. There is no special P/N for them, but the data code corresponding to WW32’2015 is “DF” (xDFx). WW33’2015 is “DG”, WW34 “DH” etc. WW1’2016 is then “EA”. If you just need a few samples, please let me know, I can provide them directly.

S pozdravem,

Tomáš