## FST2045: Low Voltage Trench MOS Barrier Schottky Rectifier The **FST2045** is a common electronic component used primarily for power management and rectification. It is typically a **Dual Schottky Barrier Rectifier** designed to provide high efficiency and high-speed switching. ### 1. General Specifications The part number "2045" usually denotes its primary ratings: a 20-Ampere current capacity and a 45-Volt reverse voltage limit. | Parameter | Value | Unit | | :--- | :--- | :--- | | **Max Average Forward Current ($I_{F(AV)}$)** | 20 (10A per leg) | Amperes | | **Peak Repetitive Reverse Voltage ($V_{RRM}$)** | 45 | Volts | | **Max Forward Voltage Drop ($V_F$)** | ~0.50 - 0.58 | Volts | | **Operating Junction Temperature ($T_J$)** | -55 to +150 | °C | | **Package Types** | TO-220AB, ITO-220AB, D2PAK | - | --- ### 2. Key Electronic Features * **Schottky Barrier Construction:** Unlike standard PN junction diodes, Schottky diodes use a metal-to-semiconductor junction. This results in a much lower forward voltage drop ($V_F$), leading to less power loss as heat. * **High Frequency Operation:** Because it is a majority carrier device, the reverse recovery time is negligible, making it ideal for high-speed switching. * **Common Cathode Configuration:** Most FST2045 units come in a 3-pin package where the two outer pins are anodes and the center pin (connected to the tab) is the common cathode. * **Guard Ring Protection:** Many versions include a guard ring for transient protection and high $dv/dt$ capability. --- ### 3. Common Applications The FST2045 is frequently found in the secondary stage of power conversion circuits. 1. **Switching Power Supplies (SMPS):** Used for output rectification to convert high-frequency AC from a transformer into DC. 2. **Freewheeling Diodes:** Used in motor control circuits to protect components from voltage spikes. 3. **OR-ing Diodes:** In redundant power systems, they prevent current from flowing back into a failed power supply. 4. **Battery Chargers:** Due to low power dissipation, they help in maintaining high efficiency during high-current charging. --- ### 4. Typical Pinout (TO-220 Package) | Pin Number | Designation | Description | | :--- | :--- | :--- | | 1 | Anode 1 | Input 1 | | 2 | Cathode | Common Output (Connected to tab) | | 3 | Anode 2 | Input 2 |