Charging faults on the iPhone 6 series and the first-generation iPhone SE almost always trace back to one of two places: the charging port flex or the U2 Tristar IC sitting on the logic board. When you've already ruled out the flex cable and the battery, and the phone still won't pull current from the charger, the 1610A3 IC is where you go next. This chip carries the board marking 1610A3 and the reference designator U4500 on iPhone SE, 6S, and 6S Plus boards, while the closely related 1610A2 (U1700) covers the iPhone 6 and 6 Plus. It's compatible with the Apple iPhone SE first generation, iPhone 6S, and iPhone 6S Plus. Some technicians in the field also refer to it under the fuller part number CBTL1610A3UK when cross-referencing datasheets or forum threads, though the manufacturer treats this as a custom part and doesn't publish full specifications publicly. On the board, this IC sits directly in the charging path. It negotiates USB power delivery between the lightning connector and the PMU, manages charge current to the battery, and talks to iOS software during the handshake that happens the moment you plug in a cable. When this IC gets damaged from a liquid spill, a drop, or a bad charger that sent voltage spikes through the port, you'll see classic dead-after-flash or no-charging symptoms: the phone shows the charging bolt but percentage never rises, it charges only at certain cable angles, or it simply doesn't respond to any charger at all, including a known-good one. This is a 36-pin component, so reflow and reballing calls for a proper hot air station, a BGA stencil sized for 36-pin Tristar-family ICs, and flux suited to fine-pitch work. Before you commit to the IC swap, check the charging port flex for damage or corrosion first — swapping the flex is faster and cheaper, and a good technician always eliminates the easy fix before pulling an IC. If the port checks out clean and you're still not getting a charge signal on the multimeter at the battery connector, that's your confirmation to move to IC-level work. For your repair bench, keep in mind this IC is board-specific: the 1610A3 marking fits SE, 6S, and 6S Plus boards, while 6 and 6 Plus boards use the 1610A2 variant. Installing the wrong marking on the wrong board won't damage anything immediately, but it won't restore charging either, so double-check the board revision before you start reflow. Once you're changing this IC, this is standard jumper-and-reflow work you're already doing daily on Samsung, Oppo, and Vivo boards — the same hot air control and pad-cleaning discipline applies here. Pakistani repair shops running high volume on used and refurbished 6-series stock keep a few of these on hand at all times, since charging complaints are one of the most common walk-in issues technicians see across Lahore, Karachi, and Islamabad repair markets. Stocking this IC alongside your reballing stencils and flux keeps your charging-fault turnaround time short instead of waiting days for imported parts.
