Hi,
Failed production module replicated on the Production floor by Engineering
Engineer considered the temperature variable to be a possible cause
MOD temperature taken down to 10degrees C in the oven and power on test attempted. MOD failed to power on.
Repeatable results from the same batch allowed Engineering to identify a replicate of the failure mode consistently.
Engineering have determined a contributing component to be PWM chip TEA1751 (ACP100326) found in multiple 3A and 5A Litone MODs.
PWM Chip alone is not the only cause – this was proved by swapping the chip from a failed MOD with a MOD that passed:
1.Swapping chip between a PASSING and FAILING PCA above and applied direct cooling of chip and 10°C oven test
Swapped the TEA1751T PWM chip from a “PASSING” G2405N,Sept 2019, board to a “FAILING” G2403N April 2020 the results were:
–Managed to induce a fail on the G2405N with G2403N TEA1751T but this was much more difficult and appeared to only pass through a failure temperature when warming-up from being cooled
–G2405N PASSED with the swapped TEA1751T from FAILED G2403N
And
G2403N PASSED with the swapped TEA1751T from PASSED G2405N
When testing at board level it was confirmed that the PWM chip TEA1751T (ACP100326) was sensitive to cold and could be cooled directly to FAIL on the G2403N April 2020
The G2405N PCA could not be made to fail cooling the chip directly
What has changed? Is the chip performing as per its specification? If not, what has changed? What else has changed to make this issue become more apparent now?
Could NXP support us in creating a screening method for the chip or improve their screening? Have they seen this issue with other customers?
