onsemi MURD620CTG Rectifier: Datasheet, Pinout, and Application Circuits
The MURD620CTG from onsemi is a highly efficient dual common cathode ultra-fast rectifier designed for high-frequency power conversion applications. Housed in a compact TO-252 (DPAK) surface-mount package, this component is engineered to deliver superior performance in demanding environments, making it a popular choice for switch-mode power supplies (SMPS), freewheeling diodes, and reverse battery protection circuits.
Datasheet Overview and Key Specifications
The datasheet for the MURD620CTG reveals its core electrical characteristics, which are critical for circuit design. Key specifications include:
Repetitive Peak Reverse Voltage (VRRM): 200 V
Average Forward Rectified Current (IO): 3.0 A per diode (at TC = 130°C)
Peak Forward Surge Current (IFSM): 150 A
Forward Voltage Drop (VF): Typically 0.95 V at 3.0 A (per diode), ensuring low conduction losses.
Reverse Recovery Time (trr): An ultra-fast 35 ns (typical), which is crucial for minimizing switching losses and reducing noise in high-frequency operation.
Operating Junction Temperature (TJ): -55°C to +150°C
These specifications highlight the device's capability to handle significant power levels with high efficiency and speed.
Pinout and Package Configuration
The MURD620CTG is a dual common cathode rectifier in a 3-pin DPAK package. This configuration means it contains two separate ultra-fast diodes integrated into a single package with their cathodes tied together internally. The pinout is as follows:
Pin 1 (Tab): Common Cathode. The tab is electrically connected to this pin and must be considered in the PCB layout for both electrical connection and heatsinking.
Pin 2: Anode of Diode 1
Pin 3: Anode of Diode 2
This common cathode design is particularly useful for constructing center-tapped full-wave rectifier circuits, as it simplifies the board layout and reduces component count.
Application Circuits
The primary application for the MURD620CTG is in high-frequency power rectification.
1. Switch-Mode Power Supply (SMPS) Output Rectification:
In an SMPS, especially flyback and forward converters, the ultra-fast reverse recovery time (trr) of the MURD620CTG is essential. It quickly blocks reverse voltage after switching, preventing large current spikes and significantly improving efficiency. Its dual-diode design is perfect for center-tapped transformer outputs in higher-power designs.
2. Freewheeling / Flyback Diode:
In inductive load circuits, such as those driven by motor controllers or relay drivers, the MURD620CTG acts as a freewheeling diode. It provides a safe path for the current to decay when the driving switch (like a MOSFET) turns off, protecting the switch from voltage spikes caused by the collapse of the magnetic field in the inductor.
3. Reverse Battery Protection:
The device can be used in series with a power rail to prevent damage from accidental reverse connection of a battery. When installed correctly, it blocks current flow if the polarity is reversed, safeguarding sensitive electronics downstream.
The onsemi MURD620CTG stands out as a robust and highly efficient solution for modern power electronics. Its ultra-fast recovery特性, low forward voltage drop, and convenient dual common cathode configuration in a surface-mount package make it an excellent choice for designers looking to optimize performance, reduce board space, and enhance the reliability of their power conversion stages. Its suitability for high-frequency applications like SMPS output rectification and freewheeling duties makes it a versatile component in any power designer's toolkit.
Keywords:
Ultra-Fast Rectifier, Switch-Mode Power Supply (SMPS), Common Cathode, Reverse Recovery Time, Freewheeling Diode
