This is the power management chip, aka PMIC for iPhone 8 and 8 plus. This chip needs to be replaced when it gets physical damage---look for a tiny crack in the chip and heat coming from the chip. Do not be fooled by short circuits elsewhere that create heat on this chip. Always look for the physical damage before attempting to change this chip.
Replacing this chip is technically challenging due to underfill and proximity to the CPU on the opposite side of the board. If you are not experienced, consider sending this job out.
We offer mail-in repair service, start here: https://www.ipadrehab.com/index.cfm?Page=Start-a-Repair