## SSL21084T: Overview and Technical Specifications The **SSL21084T** is a high-voltage Integrated Circuit (IC) designed by NXP Semiconductors. It is specifically engineered to drive LED lamps in non-isolated, high-efficiency lighting applications. It belongs to the GreenChip™ family, which focuses on energy efficiency and low component count. --- ### 1. Key Features and Functions The SSL21084T is a **Buck Converter** controller with an integrated high-voltage power switch. Its primary role is to convert AC mains voltage into a regulated constant current to drive LED strings. | Feature | Description | | :--- | :--- | | **Topology** | Non-isolated Buck converter | | **Integrated Switch** | Internal 600V MOSFET | | **Regulation Type** | Constant Current (CC) | | **Efficiency** | High efficiency (up to 95%) | | **Dimming** | Primarily non-dimmable (though some basic versions exist) | | **Protection** | Short-circuit, Over-temperature, and Brown-out protection | --- ### 2. Pin Configuration and Functions The device is typically housed in an **SO8 (Small Outline)** package. Below are the functional descriptions of the pins: | Pin Number | Name | Function | | :--- | :--- | :--- | | 1 | **VCC** | Supply voltage for the internal logic. | | 2 | **GND** | Ground reference for the IC. | | 3 | **NC** | Not connected. | | 4 | **DVDT** | Controls the dV/dt of the internal power switch to reduce EMI. | | 5 | **SOURCE** | Source of the internal MOSFET; connects to the sense resistor. | | 6, 7, 8 | **DRAIN** | Drain of the internal 600V power MOSFET. | --- ### 3. Technical Specifications (Electrical Data) | Parameter | Value | Unit | | :--- | :--- | :--- | | **Input Voltage Range** | 100 to 230 (Universal Mains) | V (AC) | | **Maximum Drain-Source Voltage** | 600 | V | | **Maximum Output Power** | Up to 15 (depending on cooling) | W | | **Internal Oscillator Frequency** | ~100 | kHz | | **Operating Temperature** | -40 to +125 | °C | --- ### 4. Circuit Implementation Details * **Internal MOSFET:** Because the 600V MOSFET is built into the chip, the PCB design is simplified, requiring fewer external components. * **Current Sensing:** The IC monitors the current through an external resistor connected to the `SOURCE` pin. Once the peak current is reached, the internal switch turns off. * **EMI Reduction:** The `DVDT` pin allows designers to slow down the switching speed, which helps the lamp meet electromagnetic interference (EMI) standards without bulky filters. ### 5. Common Applications * LED retrofit lamps (e.g., A19, GU10 bulbs). * LED T8 tubes. * Small LED luminaires. ---