A3B U2 610A3B Charging Power IC iPhone 7, 7+

The Tristar U2 chip sits at the center of every iPhone 7 and iPhone 7 Plus charging circuit, and the 610A3B is the exact NXP-manufactured version Apple used on these boards. You already know the symptom before you even open the phone: customer says charging stopped, you swap the battery, you swap the charging port flex, and the phone still won't take a charge. That's the moment this IC becomes the suspect, not the accessory.U2, labeled U4001 on the schematic, does more than pass power through. It negotiates charging current with the adapter, talks to the PMU about battery state, and routes USB data lines for computer detection. When this chip degrades — usually from moisture, a bad charger, or a static discharge through the lightning port — you'll see a mix of symptoms: no charging at all, charging only in a specific position, charging port shows connected but current stays at 0, or the phone charges but doesn't show up in iTunes or Finder. Some boards even show a "dead after flash" pattern where liquid damage under U2 corrupted the charging path months before the software issue showed up.This chip ships in the same 36-pin BGA footprint as the original, so your reflow profile and stencil don't change. Drop it onto your hot air station at your usual iPhone 7 profile, use flux the way you already do for tristar-class ICs, and reball with your standard 0.3mm balls if you're not using a pre-balled part. Board prep matters more here than heat — clean the pads fully before reflow, because leftover flux residue under U2 is one of the most common reasons technicians reball twice on the same board.Diagnosis before replacement saves you time. Check the PP5V0_USB and charge current lines on your board view first. If you're getting voltage at the connector but nothing downstream of U2, or your multimeter shows a short on the charging rail when you probe near this IC's pads, that confirms the fault sits here rather than at the tristar power management IC or the battery gauge. Don't skip this check — swapping U2 on a board where the real fault is a shorted PMU wastes your part and your bench time.This IC covers both iPhone 7 and iPhone 7 Plus boards since Apple used the identical charging architecture across both models that generation. If your workshop handles volume iPhone 7 repairs, keeping a few of these on hand alongside your battery and charging port stock cuts your turnaround time on the "won't charge" jobs that come in every week — this fault pattern is one of the most common walk-in complaints for this device generation.Handle this component with standard ESD precautions since it's a sensitive board-level part, not a plug-and-play module. Store it in an anti-static bag until you're ready to reflow, and avoid touching the ball contacts directly. Once installed correctly with a clean reflow, charging behavior returns to normal immediately — no further calibration or software step is needed on the charging side.For workshops running higher volume, pair this IC with a good hot air rework station and a board holder rated for iPhone-size logic boards, since precision placement on a 36-pin BGA package leaves very little room for misalignment.