Mobile Phone IC For SM5708 Original
The SM5708 is a specialized high-performance power management and battery charging integrated circuit (IC). It is a staple in modern mobile repair, primarily serving as the “Charging IC” for several popular mid-range smartphones released between 2018 and 2020.
In mobile architecture, the SM5708 is categorized as a Sub-PMIC. Its primary responsibility is to bridge the gap between the USB charging port and the battery, managing high-current power paths that would generate too much heat for the main PMIC to handle alone.
Technical Specifications: SM5708 IC
| Feature | Specification Detail |
| Model Number | SM5708 |
| Component Type | Single-Cell Li-ion/Li-Polymer Battery Charger |
| Package Type | QFN-24 (RoHS compliant) / Micro-BGA |
| Input Voltage ($V_{IN}$) | $3.0\text{V} \text{ to } 13.5\text{V}$ (Supports Fast Charging) |
| Max Charging Current | Up to $3.0\text{A}$ (Programmable) |
| USB Support | Integrated USB On-The-Go (OTG) boost support |
| Power Management | Dynamic Power Path Management (DPPM) |
| Interface | $I^2C$ Controlled / Hardware-Level Logic |
| Protections | Thermal regulation, OVP (Over-Voltage), Safety Timers |
| Operating Temp | $0\degree\text{C} \text{ to } 45\degree\text{C}$ (Standard mobile range) |
Key Functional Roles
The SM5708 is designed to handle the “heavy lifting” of energy intake for the device.
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Dynamic Power Path Management (DPPM): This allows the device to power the system simultaneously while charging the battery. If the adapter cannot provide enough current for both, the IC automatically prioritizes system power and draws the remainder from the battery.
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High-Voltage Input Support: With an input range reaching $13.5\text{V}$, the SM5708 is compatible with various quick-charging protocols (such as Samsung’s Adaptive Fast Charging or QC 2.0/3.0), allowing it to pull more power through the USB cable without increasing current-related heat.
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Integrated USB OTG: It includes a built-in boost regulator that converts battery voltage to a steady $5\text{V}$ output. This allows the phone to power external USB devices like flash drives, keyboards, or mice.
Device Compatibility
The SM5708 is most famously utilized in the following Samsung Galaxy models:
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Galaxy J8 (J810G/DS)
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Galaxy A6 Plus (A605F, A605G, A605FN)
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Galaxy Tab S10 Lite (Select variants)
Common Failure Symptoms
Because it sits directly on the line between the wall charger and the internal motherboard, the SM5708 is highly susceptible to damage from surges or non-original cables.
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“Fake Charging”: The phone displays the lightning bolt icon, but the battery percentage never increases or actually decreases during use.
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No Power (Dead): A short inside the SM5708 can ground the main power rail ($V_{BUS}$), preventing the phone from booting or even showing a charging logo.
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No OTG Function: The phone charges and transfers data to a PC but fails to recognize any USB accessories plugged into the port.
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Excessive Heat: The top area of the motherboard near the CPU becomes dangerously hot as soon as a charger is connected.
Professional Repair & Handling
The SM5708 is a QFN-24 or Micro-BGA package, requiring advanced micro-soldering techniques.
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Heat Profile: Recommended removal temperature is $340\degree\text{C}$ to $350\degree\text{C}$. Technicians should use a controlled ramp-up to avoid thermal shock.
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Underfill Removal: Some OEM boards apply a hard black epoxy around the chip. This must be picked away at $150\degree\text{C}$ before attempting to lift the IC, or the motherboard pads may be torn off.
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Handshake Protocol: Unlike simpler charging chips, the SM5708 uses an ADC (Analog-to-Digital Converter) to monitor cell temperature. If the battery’s thermistor is faulty, the IC will refuse to charge, even if the chip itself is new.
