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ADXL362 Self-Test Results @ 1.8V

Question asked by gilo on Aug 2, 2016
Latest reply on Aug 4, 2016 by neilzhao

Hi,

 

I have a question regarding the self test results. We are getting higher population of the results than appear in the datasheet. Axis Y has significant deviation from the typical value on many devices.

Following ADXL362 rev.D (Table 1), self test typical change is around 550 for X and Z and -550. Fig 20-22 shows quite tight population of the output delta value than what we’ve got in production.

 

Our Self Test Configuration:

  1. TA = 25°C, VS = 1.8V, VDD I/O = 1.8V, 25Hz ODR, HALF_BW = 0, ±2g range, acceleration = 0 g
  2. 300ms delay after asserting self test by setting the ST bit in the SELF_TEST register, Address 0x2E.

 

Tried to evaluate the difference between 1.8V to 2.0V and found that the main difference is in axis Y (about 156 difference in the delta). X and Z have about 50.

 

Some examples of output delta results I'm getting:

X=672    Y=-228  Z=549

X=720    Y=-380  Z=585

X=861    Y=-61     Z=675

 

If I’m compensating the difference from the threshold in Table 1 our devices can pass the self test but still Y axis has higher deviation from the typical value.

 

Your comments are appreciated. We also would like to know if we are missing anything in our consideration.

 

Best Regards,

Gil

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