You need the 65W adapter, but the 90W unit will work fine as well.  
Hello, I own a Dell Latitude 5480, but I lost the AC adapter in a move. Now I don't know which one I should get, because the manual lists 2 possible specifications: Input current (maximum): 65 W 1.7 A          90 W 1.6 A Output current: 65 W 3.34 A            90 W 4.62 A Which one should I get for 5480 with: i5 7440HQ, 8GB RAM, no dedicated graphics, NVME drive? And if I need 65W, but get the 90W variant instead would it still work?  
Dell Latitude 5480 which AC adapter?