BN35 Charging iC

Open any repair bench log from a busy shop and "dead after flash," slow charging, or charger-not-detected complaints on Tecno and Infinix phones show up almost daily. The BN35 IC sits right in the middle of that fault chain. Marked "BN35" on top but built on the AW32257FCR die, this chip manages how power moves from the USB port into the battery and the rest of the board.Its job breaks down into three parts: reading what the charger is sending, regulating that power so it doesn't spike into sensitive components, and driving the charging circuit itself. When a customer brings in a phone that shows "charging" on screen but the percentage never climbs, or a phone that gets warm near the charging port and then shuts off, the fault often traces back to this IC misreading voltage or failing to drive the circuit correctly.You'll run into this chip most on Infinix Smart 6, Smart 7, and Smart 8 boards, along with Tecno Spark Go 2024 and other Spark series units. These are high-volume, entry-level phones in Pakistan, which is exactly why charging faults on them are so common — the boards see heavy daily use, cheap chargers, and rough handling, all of which stress the power path first.Before swapping the IC, confirm the fault isn't sitting elsewhere. Check the charging port for damage, test the battery separately if possible, and inspect the board for any burnt traces near the connector. If those check out clean and the phone still won't detect the charger or draws current without charging the battery, reflow or replace the BN35. A hot air station with a fine nozzle and a stencil sized for QFN-20L packages makes the swap far more reliable than a straight iron job — this package has fine pitch pins, so alignment matters. After placement, always retest under load rather than just checking for a "charging" icon, since a poorly seated IC can show a false positive for a few minutes before dropping the connection again.This IC also comes up in "dead after flash" cases where a bad flash left the power management sequence unstable. Not every dead-after-flash board needs an IC change — always rule out software first — but when the board draws no current at all from a known-good charger and cable, and voltage checks confirm nothing is reaching the battery line, the charging IC becomes the next real suspect.Stock this one in pairs, not singles. Charging IC jobs rarely come one at a time on Infinix and Tecno boards; once one unit in a batch shows the fault, you'll usually see a second and third within the week from the same model range. Keeping a small buffer stock saves a return trip to the parts counter mid-repair, which matters when a customer is standing at the counter waiting on their phone.Handle the IC with anti-static precautions during storage and installation. Power management ICs like this one are sensitive to static discharge, and a damaged unit will fail testing even though it looks physically fine — a wasted reflow that costs you both the part and the bench time.