LTC3891 - Over-temperature Protection?

Hi,

We use the LTC3891 controller in our buck design, 24V to 5V, 1.4W.

We have performed some thermal characterization tests on our design up to 175°C and maybe more, depending on oven calibration (less than 200°C).

The 5V buck has been turned OFF but 5V reference voltage is still there.

We have performed a new test at ambient temperature, and everything works.

Nevertheless, when we try to reproduce the test at 175°C, the controller is turned OFF as described above.

Have we damaged an internal protection threshold? Is there any overtemperature protection in this chip that could explain why the buck in turned OFF?

Kind regards,

Eric