Mobile Phone IC For 358S-2122 Original
The 358S-2122 is a specialized power management and charging control integrated circuit (IC) widely used in the mobile repair industry. It is a critical “gatekeeper” component found in various mid-range smartphones and tablets, particularly those from Asus (Zenfone series), Oppo, and Samsung.
This IC is primarily responsible for managing the power flow from the USB port to the battery, ensuring safe and efficient charging while protecting the motherboard from electrical surges.
Technical Specifications: 358S-2122
| Feature | Specification Detail |
| Model Number | 358S-2122 (often marked as SM358S 2122) |
| Component Type | Secondary PMIC / USB Charging Controller |
| Package Type | 30-Pin BGA (Ball Grid Array) |
| Compatible Brands | Asus, Samsung, Oppo, Meizu, Xiaomi |
| Input Voltage ($V_{BUS}$) | 5.0V (Standard USB Voltage) |
| Output Type | Regulated DC for Battery Charging and System Rails |
| Primary Functions | Battery Charging, USB Data Switching, Over-Voltage Protection |
| Logic Interface | $I^2C$ / SMBus Control |
| Mounting Tech | SMT (Surface Mount Technology) |
| Operating Temp | -40°C to +125°C |
Core Functional Roles
The 358S-2122 is more than just a charging chip; it is a multi-purpose interface controller designed to handle high-current power paths.
1. Charging Logic & Regulation
The IC manages the Constant Current (CC) and Constant Voltage (CV) phases required for Lithium-Ion batteries. It communicates with the processor to determine the safe charging speed, preventing the battery from swelling or overheating.
2. USB Interface Management
This chip acts as a high-speed switch for the USB D+ and D- lines. It identifies whether the connected cable is a standard wall charger, a computer USB port, or a USB-OTG accessory (like a flash drive), routing the signals to the correct logic blocks.
3. System Power Path (NVDC)
Many devices using this IC employ a “Narrow VDC” architecture. This means the 358S-2122 can power the phone’s internal systems directly from the charger even if the battery is completely dead or missing, allowing for “Instant-On” functionality.
Common Symptoms of a Defective 358S-2122
Because this IC is the first major component connected to the external charging port, it is highly susceptible to damage from faulty cables or liquid ingress.
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“Fake Charging”: The phone shows a charging icon (the lightning bolt), but the battery percentage never increases or actually drops while plugged in.
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Dead Phone (No Power): A short circuit inside the 358S-2122 can ground the main system rail, preventing the device from booting even with a charged battery.
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No USB Data Connection: The phone charges fine but is not recognized by a PC for file transfers or software flashing.
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Overheating: The area of the motherboard near the charging port becomes extremely hot to the touch as soon as a charger is connected.
Repair & Installation Guide
The 358S-2122 is a 30-pin BGA chip, making it a high-difficulty repair that requires professional micro-soldering tools.
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Pin 1 Orientation: Note the small Pin 1 dot on the corner of the chip. Installing the IC in the wrong orientation will cause a permanent short circuit on the battery line.
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Heat Settings: Use a hot air station set to $340\degree\text{C}$ to $350\degree\text{C}$. Because it is a 30-pin grid, ensure even heat distribution to prevent “popcorning” the silicon.
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Flux & Wicking: Before installing a new chip, ensure the motherboard pads are perfectly flat using a soldering wick and high-quality no-clean flux to prevent bridges between the tiny solder balls.
