338S00942 Power iC

Every iPhone motherboard runs on a power hierarchy, and on the 14 Pro series, the 338S00942 sits right at the top of it. Apple labels it internally as APL109A, and on board-level schematics you'll usually see it referenced simply as the big power IC. It works alongside the A16 Bionic processor, taking input from the battery and charging circuit and stepping it down into the multiple regulated voltage rails the CPU, RAM, and surrounding chips need to boot and stay stable.When this IC develops a fault, the symptoms are rarely subtle. You get a phone that pulls current on the bench power supply but never boots past the Apple logo, or one that shows zero current draw at all, meaning the board isn't waking up. Some units short internally after water exposure and pull the whole rail down, which is why board-level techs test this chip early in any dead phone diagnosis on the 14 Pro platform, especially after ruling out charging port and battery connector faults.This is a BGA component, so replacing it is a reflow job, not a plug-and-play swap. You'll need a hot air rework station with tight temperature control, a decent microscope for BGA alignment, and either a laser stencil or a compatible reballing kit to reball the chip before reinstalling. Board-level shops working on iPhone 14 Pro boards typically keep this IC stocked alongside the neighboring Dialog 338S00839 and 338S00819 power chips, since a single motherboard fault can sometimes affect more than one of these rails at once, particularly after liquid damage where corrosion spreads across the board.Because it sits this close to the processor, incorrect handling during removal or reflow can easily damage adjacent components or lift pads on the board, so this replacement is recommended for technicians already comfortable with fine-pitch BGA work rather than beginners. Get your reflow temperature profile right, keep your hot air nozzle centered, and inspect under the microscope before and after reflow to confirm there's no bridging or tombstoning on the pads.Fitted correctly, this IC restores normal power sequencing to the board, letting the A16 chip boot and the device power on and charge normally again. It's a targeted fix for a specific class of dead-board faults on the 14 Pro and 14 Pro Max, not a general-purpose part, so confirming the fault actually traces to this rail before ordering saves you time and avoids an unnecessary reflow on a board that didn't need one.