Currently I'm using a buck switching regulator AOZ1284PI of Alpha & Omega Semiconductor to generate a 5V supply from a 12V input of a lead-acid sealed battery, and I plan to use AOZ1284PI again on the project below.
I plan to design some vehicle tracker that can be used in cars and bus/truck, so my input voltage range to be considered is from 10 to 30V (maybe 32?) steady. Of course I will use a schottky diode at the input to prevent reverse connection of the supply input (battery power of the vehicle). And I plan to use a TVS diode SMAJ30CA right at the supply input (it is bidirectional TVS diode), before the protection diode.
According to the datasheet of AOZ1284PI, the maximum supply voltage recommended is 36V, and absolute maximum is 40V. According to specs of TVS diode SMAJ30CA, Voltage Clamping (Max) @ Ipp = 48.4V.
Then, considerer voltage spikes are occuring at the battery and the TVS diode is clamping them at the input of my circuit. Clamping voltage would be 48.4V, and this is greater than the maximum of 40V of AOZ1284PI. Of course such voltage peaks will probably have a very short time duration in practice.
I would like to know what are your observations for that situation.
Would the AOZ1284PI be prone to be easily damaged in such situations? In a vehicle environment? That's my main question.
Or in this case we have to consider the ESD rating of the IC?
Datasheet of AOZ1284PI: http://aosmd.com/res/data_sheets/AOZ1284PI.pdf SMAJ30CA specs on Digikey: https://www.digikey.com/product-detail/en/littelfuse-inc/SMAJ30CA/SMAJ30CALFCT-ND/762507