FXLN83xx Datasheet Clarification

[Heckenj]

In looking at the datasheet for the FXLN83xxq, what is meant by this:

1)      calibrated sensitivity ?

2)      calibrated sensitivity error ? Why is it only listed for the +/- 2 & 4 G range only?

3)      What is the % error for the 8371 in the +/- 8G mode and the 8372 +/- 4G mode ?

The datasheet shows the 'Calibrated Sensitivity' with an equation in V/g, but that's the same as 'Nominal Sensitivity' but different units.  (Using Vbyp of 1.5Volts in that equation works out fine).  So, what does that mean - if anything?

Then for 2 and 3, there is no data for those listed, is this somewhere else?

[TomasVaverka]

Hi Jeff,

I am working with our apps/design team to answer these questions. We will get back to you soon.

Best regards,

Tomas

[TomasVaverka]

Hi Jeff,

Sorry for such a long delay in getting back to you. We have been trying to get some CZ data to frame a response to the customer and I will definitely get back to you once I have an update from key people who worked on this project.

Best regards,

Tomas

[TomasVaverka]

Hi Jeff,

Please find below the answers I received today from our apps team.

1. There are two measurement topologies:

• Host MCU/ADC does not digitize Vbyp voltage (Vbyp not measured for every part).
• Host MCU/ADC digitizes the Vbyp voltage (Vbyp is measured for every part).

If the customer uses the second topology, the sensitivity will be independent of Vbyp variation, as they can calculate the «exact» sensitivity to use in their firmware by the equation for calibrated sensitivity. The part is "auto trimmed" internally, meaning the sensitivity is trimmed in order to achieve the target "VBYP/(3.276*gRange)" formula using whatever value Vbyp is on that particular device.

If the customer uses the first topology, they also have to include the Vbyp variation effect on the device sensitivity, which is ~ +/-3% according to the datasheet.

2&3. The FXLN83xx has 2 variants, namely the 2g/8g version and the 4g/16g version. I was able to confirm that the ‘calibrated sensitivity error’ listed for 2g and 4g in the data sheet also applies for the corresponding 8g and 16g configurations. The one item I am waiting for is to get test data to confirm whether it should be 6% for 4g ( &16g) case or if it is still 5% irrespective of g-range cases. Hopefully I can get back soon on this.

Best regards,

Tomas