TPS65251-3: The load transient test condition clarify (the slope rate of the load change us/A)

Part Number: TPS65251-3

Tool/software:

Hi team,

Could you clarify the slope rate of the load change in datasheet? 

TPS65251-x 4.5-V to 18-V Input, High Current, Synchronous Step Down datasheet (Rev. B) (ti.com)