Mobile Phone IC For SM5703 Original
The SM5703 is a specialized Power Management Integrated Circuit (PMIC), commonly referred to in the repair industry as a “Small Power IC” or “Charging IC.” Manufactured by Silicon Mitus, this chip is a staple in Samsung’s mid-range and budget smartphone lineups.
Its primary role is to manage the battery charging cycle, regulate power for the display, and provide secondary voltage rails that the main PMIC does not cover.
Technical Specifications: SM5703 IC
| Feature | Specification Detail |
| Model Number | SM5703 / SM5703A |
| Component Type | Secondary PMIC / Battery Charger IC |
| Package Type | 30-Pin BGA (Ball Grid Array) |
| Input Voltage ($V_{BUS}$) | $3.8\text{V} \text{ to } 5.0\text{V}$ (Supports USB 2.0/3.0 Standard) |
| Max Charging Current | $2.0\text{A}$ to $2.5\text{A}$ (Typical) |
| Output Rails | Integrated LDOs and Buck Converters |
| Compatible Brands | Samsung Galaxy (A, J, M, and S series) |
| Operating Temp | $-40\degree\text{C} \text{ to } +125\degree\text{C}$ |
| Safety Features | Over-Voltage (OVP), Thermal Shutdown, Battery Temp Sensing |
Core Functional Overview
The SM5703 is designed to be an efficient “middle-man” between the USB port and the battery.
1. Battery Charging & Management
The SM5703 houses the Switching Charger logic. It converts the $5\text{V}$ input from the wall charger into a precise voltage required to safely charge the Lithium-Ion battery. It also monitors the battery’s thermistor; if the battery gets too hot, the SM5703 will immediately cut off the current to prevent a fire hazard.
2. Display Bias Voltage
One of its most critical tasks is providing the power for the OLED or LCD panel. It generates the specific positive and negative voltage rails (usually around $+4.6\text{V}$ and $-4.4\text{V}$) needed to drive the pixels. If this section of the chip fails, the phone will remain “on” (it can receive calls), but the screen will be completely black.
3. Logic Power Delivery
Beyond charging, the SM5703 provides power to smaller peripheral components, such as the Proximity Sensor, Ambient Light Sensor, and sometimes the Front Camera LDOs.
Common Signs of a Defective SM5703
In the repair industry, the SM5703 is one of the most frequently replaced ICs due to its exposure to external electrical surges from faulty chargers.
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“Fake Charging”: The phone shows the charging lightning bolt icon, but the battery percentage never increases, or it drops even while plugged in.
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Dead Phone (No Power): A short circuit inside the SM5703 can pull the main power rail ($V_{PH\_PWR}$) to ground, preventing the device from booting entirely.
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Temperature Warning: The phone displays a “Charging Paused: Battery temperature too low/high” error even when the phone is at room temperature.
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Black Screen: The phone vibrates and rings, but the display remains dead because the SM5703 is not producing the necessary display bias voltages.
Installation & Repair Notes
The SM5703 is a BGA (Ball Grid Array) chip, which requires professional micro-soldering tools to replace.
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Heat Profile: Use a hot air station at $340\degree\text{C} – 350\degree\text{C}$ for removal. Use low airflow to avoid “blowing” away neighboring resistors.
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Orientation: Note the Pin 1 marker (a small dot on the chip). Installing it backwards will likely cause a permanent short that could destroy the CPU.
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Underfill: Some Samsung models use a hard black epoxy around the chip. This must be carefully picked away at $200\degree\text{C}$ before attempting to lift the IC.
