Customer use self test feature and setting high and low threshold for 3-axis. They test 55 pcs and happen 5 pcs fail due to under threshold. But they take fail unit. and re-heating ADXL345. After this action, the fail unit become good unit due to 3-axis results are between high/low threshold.
Why self-test results of Z axis will become pass results between HIgh/Low threshold after re-heating chip? Has any comments for this issue root cause and how to verify it? Thank you.
Failed z self-test! z_sum = 107 (under 110.25 so it is fail)
Threshold: z_min = 110.25 z_max = 1286.25
Others axis pass setting threshold.