CN3903

The CN3903 is a single-cell lithium-ion battery charging IC designed for portable applications. It integrates a PWM controller, power MOSFET, and charge management functions, supporting 4.2V/4.35V/4.4V battery configurations.
Key features:
- Input voltage range: 4.5V–9V (max 12V).
- Programmable charging current (up to 2A).
- Automatic charge termination with trickle/pre-charge/constant-current/constant-voltage modes.
- Thermal regulation and reverse polarity protection.
- Low standby current (<50μA).
Applications include smartphones, tablets, Bluetooth devices, and portable electronics. Its compact ESOP-8 package makes it suitable for space-constrained designs.
The CN3903 simplifies charging circuits while ensuring safe, efficient power management.

The CN3903 is a 5V USB charger controller. Equivalent products include:
- TP4056 (Lithium charge controller, similar but not identical)
- MCP73831 (Single-cell Li-Ion charger)
- BQ24075 (USB-compatible charger IC)
- LTC4054 (Linear Li-Ion charger)
These alternatives vary in features but serve similar charging purposes. Check datasheets for exact compatibility.

The CN3903 is a 3.7V lithium battery charging IC with the following key features:
- Input Voltage Range: 4.5V to 6.5V (USB or adapter compatible).
- Charging Current: Adjustable up to 1A (default 500mA).
- Charging Modes: CC (Constant Current), CV (Constant Voltage), and trickle charge for deeply discharged batteries.
- Battery Protection: Auto-cutoff at full charge (4.2V ±1%) and thermal regulation.
- Low Quiescent Current: ~3μA in standby mode.
- Indication LEDs: Supports charging (red) and full-charge (green) status.
- Compact Package: SOT23-6, suitable for portable devices.
Ideal for single-cell Li-ion/LiPo battery applications like Bluetooth devices, wearables, and small gadgets.

The CN3903 is a lithium-ion battery charge management IC, primarily used in:
1. Portable Electronics – Smartphones, tablets, and Bluetooth devices.
2. Wearable Devices – Smartwatches and fitness trackers.
3. IoT & Embedded Systems – Sensors and low-power wireless modules.
4. Power Banks – Compact charging solutions.
5. Medical Devices – Portable health monitors.
It supports 1A charging, integrates overvoltage/current protection, and operates with USB or adapter inputs, making it ideal for space-constrained, battery-powered applications.

The CN3903 is typically available in a TO-252-3 (DPAK) surface-mount package. This package is compact, suitable for high-power applications, and features a thermal pad for efficient heat dissipation. It is commonly used in DC-DC converters and battery charging circuits. Other variants may include TO-263 (D2PAK) for enhanced thermal performance. Check datasheets for specific options.