onsemi MUR120RLG Ultrafast Rectifier: Datasheet, Pinout, and Application Circuits
The onsemi MUR120RLG is a prominent member of the ultrafast rectifier family, designed to deliver high-efficiency power conversion in a wide array of switching power supplies and other high-frequency circuits. Its excellent switching characteristics and rugged construction make it a preferred choice for engineers seeking reliability and performance.
Datasheet Overview: Key Specifications
A thorough review of the MUR120RLG datasheet reveals its core electrical characteristics. This rectifier is rated for a repetitive peak reverse voltage (VRRM) of 200V and an average forward output current (IF(AV)) of 1A. Its most critical feature is its ultrafast recovery time, typically 35ns. This swift recovery minimizes switching losses and reduces noise, which is crucial for high-frequency operation. The device also features a low forward voltage drop (typically 0.925V at 1A), enhancing its efficiency. The datasheet also provides essential details on its non-repetitive peak surge current (IFSM), operating junction temperature range (-65°C to +175°C), and its plastic package that carries UL Flammability Classification 94V-0.
Pinout and Package
The MUR120RLG is offered in the compact and ubiquitous DO-41 axial lead package. The pinout is straightforward: the cathode is identified by a grey band marked on the body of the diode. The opposite end is the anode. This simple two-pin configuration makes it easy to integrate into both through-hole prototype boards and automated production assemblies.
Application Circuits
The primary application for the MUR120RLG is in freewheeling, clamping, and reverse battery protection circuits, especially in switch-mode power supplies (SMPS), inverters, and motor drives.
1. SMPS Freewheeling Diode: In a flyback or boost converter, the MUR120RLG is commonly used as the freewheeling diode. It provides a path for the inductor current when the main power switch (e.g., a MOSFET) turns off, preventing voltage spikes that could damage components. Its fast recovery is vital here to ensure smooth current commutation and high efficiency.
2. Clamping Circuit: The diode can be used in clamping networks to limit voltage levels to a desired maximum, protecting sensitive ICs from transient overvoltage events.
3. Reverse Polarity Protection: A simple circuit to protect a device from damage if the battery is connected backwards can be implemented by placing the MUR120RLG in series with the positive supply line. This ensures current only flows when the polarity is correct.
In summary, the onsemi MUR120RLG stands out as a highly reliable and efficient ultrafast rectifier. Its robust specifications, including a 200V voltage rating and 35ns recovery time, make it exceptionally suited for high-frequency power conversion applications like freewheeling and clamping in SMPS designs. Its simple DO-41 package ensures easy implementation, solidifying its position as a fundamental component in modern electronic power systems.
Keywords:
Ultrafast Rectifier, Switching Power Supply, Freewheeling Diode, Recovery Time, DO-41 Package
