LP8867-Q1: What should we consider when we use this device with -30℃ to 90℃?

Hi

Because it's a qualified device so we can ensure the device feature within the temp spec in datasheet.

I think "-30℃ to 100℃" means ambient temp, the key point for customer is to consider the consumption of device. 

You should make sure the device work in the condition that the junction temp is below 150 ℃.