Mobile Phone IC For SM5705 Original
The SM5705 is a highly specialized Power Management Integrated Circuit (PMIC), specifically classified as a USB Charging Control IC. Manufactured for Samsung’s high-to-mid-range smartphones and tablets from the late 2010s, it is the primary controller for the device’s power intake and battery charging cycles.
Technicians often refer to it as the “USB Charging IC” because it handles the critical 5V power handshake between the charging port and the internal motherboard circuitry.
Technical Specifications: SM5705 IC
| Feature | Specification Detail |
| Model Number | SM5705 / SM5705Q / SM5705R |
| Component Type | Secondary PMIC / USB Charging Controller |
| Input Voltage ($V_{BUS}$) | 5V (Standard USB Charging Support) |
| Output Type | Regulated DC for Battery Charging & Logic Rails |
| Package Type | High-Precision BGA (Ball Grid Array) |
| Pin Count | 94 Pins (Back-side configuration) |
| Communication Interface | $I^2C$ / SMBus Control |
| Key Protections | Thermal Shutdown, Over-Voltage (OVP), Over-Current (OCP) |
| Mounting Technology | Surface Mount (SMT) |
| Dimensions | Approx. $4\text{mm} \times 4\text{mm}$ (Typical for this class) |
Core Functional Roles
The SM5705 serves as an intelligent gatekeeper for power distribution. Its architecture is divided into several operational blocks:
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USB Power Routing: It detects when a charger is plugged in and determines whether the power should be routed to the battery (charging) or directly to the system (powering the phone while plugged in).
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Voltage Regulation: It converts the incoming 5V from the USB port into a stable charging voltage (typically $4.2\text{V}$ to $4.4\text{V}$) for Lithium-Ion cells.
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Thermal Monitoring: The IC constantly monitors its own temperature and the battery’s thermistor. If it detects a surge or overheating, it triggers an emergency shutdown to prevent battery swelling or fire.
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OTG (On-The-Go) Support: It facilitates the 5V output required for the phone to act as a host for USB drives, keyboards, and other peripherals.
Compatibility List
The SM5705 family is widely used across various Samsung Galaxy series. While the “Q” and “R” suffixes denote slight revisions for specific regional boards, they are often interchangeable depending on the specific model.
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Galaxy A Series: A5 (2016), A7 (2016), A3 (2016), A9, A156, A5100.
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Galaxy J Series: J5, J500F, J7.
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Galaxy C Series: C5, C5000, C7, C7000, C900F/C9000.
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Galaxy Note Series: Note 4, Note 5 (Select regional variants).
Common Symptoms of Failure
Because the SM5705 is directly exposed to the external power source, it is the most common point of failure for electrical surges.
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“No Charging” / No Logo: The phone does not react to the charger at all, and there is no current draw on a USB ammeter.
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Fake Charging: The lightning bolt icon appears on the screen, but the battery percentage stays stagnant or drops.
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Dead Phone (No Power): A short circuit in the SM5705 can pull the main system rail to ground, preventing the device from booting entirely.
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Slow Charging: The phone takes 6+ hours to reach a full charge because the IC’s high-current buck converter has degraded.
Repair & Installation Guide
The SM5705 is a BGA-94 chip, which requires advanced micro-soldering skills.
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Heat Settings: Use a hot air station at $340\degree\text{C}$ to $355\degree\text{C}$ with low airflow (30-40%) to avoid blowing nearby SMD resistors.
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Orientation: Note the Pin 1 marker (a small dot on the chip surface). Installing the chip backwards will permanently short the main power rail.
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Reflow: Ensure the chip “dances” slightly when nudged with tweezers to confirm all 94 balls have melted and bonded to the motherboard pads.
