SMB1355 001-04 Charger IC for Xiaomi MIX3

When a Xiaomi MIX 3 comes into your workshop with a charging issue, the fault isn't always the charging port or the battery. On this model, Qualcomm split the charging load across two ICs — a main PMIC and a parallel charger — and the SMB1355 001-04 is that second IC. It shares the charge current with the primary charger so the phone can pull higher current without overheating a single component. When this IC fails or gets damaged from moisture, a bad reflow, or a power surge, you'll typically see slow charging, charging that stops randomly, or a phone that shows charging on the screen but the percentage never actually climbs.You get a genuine part-level replacement here, not a generic substitute. The SMB1355 sits in the QTI parallel charger family, built specifically to eliminate the redundant circuitry that stand-alone chargers usually carry. That means less board space and a cleaner charge-management setup on Snapdragon 845 devices like the MIX 3. For your repair bench, that translates to a straightforward swap — pull the faulty IC, drop this one in, and the parallel charging path is restored to spec.This IC fits into the broader PCB repair and charging repair workflow you already run daily. Diagnosis starts the same way every time: check the charging port for damage, test the battery connector, then move to board-level testing with your multimeter or power supply to see if the board is pulling current at all. If the port and battery test clean but the phone still won't charge properly or draws unusually low current, the parallel charger circuit is your next stop. A thermal camera or diode mode check around the SMB1355 footprint will usually confirm a dead or shorted IC before you commit to reballing or a full IC change.Because it's built in a WLNSP36 wafer-level chip-scale package, this isn't a drag-solder job — you're working with a small-pitch part that needs a proper reflow station, flux, and a steady hand under the microscope. Reheating without shielding nearby components, using the wrong preheat profile, or skipping flux cleanup are the most common ways technicians damage the board further during this kind of IC change. Take your time on placement; a misaligned IC on a board this dense usually means a bridge short and a repeat visit.Software marna won't fix this fault — no flash tool or box will restore charging if the parallel charger IC itself is dead. This is strictly a hardware fault, and once you confirm it through board-level testing, the fix is physical: remove the damaged IC, clean the pads, and solder in the replacement. Technicians who stock this part avoid the delay of sourcing it mid-repair when a MIX 3 comes in with a charging complaint, since parallel charger faults on this model aren't rare once the phone has some age or history of drop damage.Stocking genuine SMB1355 001-04 units also protects your shop's reputation. A cheap or mismatched substitute can cause charging instability, overheating, or a repeat failure within weeks — and that comes back to your workbench as a complaint, not a repeat customer. This part is sourced and tested to work reliably in the exact charging architecture Xiaomi built into the MIX 3, so your repair holds up under real daily charging cycles, not just on the test bench.