The **MIC79110YML** is a high-efficiency, simple-to-use linear battery charger designed specifically for single-cell Lithium-Ion (Li-Ion) batteries. It is produced by Microchip Technology (formerly Micrel) and is known for its tiny footprint and minimal requirement for external components. --- ## 1. Core Technical Specifications The following table summarizes the key electrical characteristics of the MIC79110YML: | Parameter | Specification | | :--- | :--- | | **Input Voltage Range** | 4.5V to 16V | | **Charge Current** | Fixed at 1.2A (typical) | | **Output Regulation Voltage** | 4.2V | | **Package Type** | 10-pin 3mm x 3mm MLF® (QFN) | | **Operating Temperature** | -40°C to +125°C | | **Battery Type** | Single-cell Li-Ion / Li-Polymer | --- ## 2. Functional Description The device operates as a linear charger, meaning it regulates the voltage and current without the need for an inductor. It follows the standard Li-Ion charging profile: 1. **Pre-conditioning (Trickle Charge):** If the battery voltage is below a certain threshold, the device applies a small current to safely recover the cell. 2. **Constant Current (CC) Mode:** The charger provides a steady 1.2A current to the battery. 3. **Constant Voltage (CV) Mode:** As the battery nears full charge (4.2V), the current begins to taper off while the voltage is held constant. --- ## 3. Key Features and Protections ### Safety Mechanisms * **Thermal Regulation:** The device limits the charge current if the internal die temperature exceeds a specific threshold to prevent overheating. * **Current Limiting:** Built-in protection against excessive current draw. * **Reverse Current Protection:** Prevents the battery from discharging back into the power source when the input is removed. ### Control and Status Pins * **EN (Enable):** Logic high enables the device; logic low puts it in a low-power standby mode. * **STBY (Standby Indicator):** An open-drain output that indicates the charging status (High-Z when charging, active low when complete). --- ## 4. Typical Application Circuit Because the MIC79110 is a "simple" charger, the external component count is extremely low. ```mermaid graph LR Vin[Input Voltage 5V-16V] --> Cin(Input Cap 2.2uF) Cin --> MIC79110[MIC79110 IC] MIC79110 --> Cout(Output Cap 2.2uF) Cout --> Battery(Single Cell Li-Ion) MIC79110 --- GND(Ground) ``` --- ## 5. Summary Table: Pros and Cons | Pros | Cons | | :--- | :--- | | High input voltage capability (up to 16V). | Fixed charge current (cannot be adjusted via resistor). | | Extremely small MLF package saves PCB space. | Linear topology generates heat at high voltage drops ($P = (V_{in} - V_{bat}) \times I$). | | No external sense resistor or diode required. | Limited to 4.2V termination (not for 4.35V cells). |