Onsemi MUR8100 Ultrafast Rectifier: Datasheet, Pinout, and Application Circuits

The Onsemi MUR8100 is a high-efficiency ultrafast rectifier diode designed for high-frequency power conversion applications. Its exceptional switching speed and low forward voltage drop make it a preferred choice for engineers designing switch-mode power supplies (SMPS), freewheeling diodes, and reverse battery protection circuits.

This rectifier belongs to a family of devices renowned for their robustness. It is housed in a industry-standard DO-41 package, making it easy to implement on printed circuit boards (PCBs) and compatible with automated assembly processes.

Datasheet Overview and Key Specifications

The MUR8100 datasheet details its electrical characteristics and absolute maximum ratings, which are critical for reliable circuit design.

Repetitive Peak Reverse Voltage (VRRM): 800 V

Average Forward Rectified Current (IO): 8.0 A at a case temperature of 100°C

Peak Forward Surge Current (IFSM): 150 A (8.3 ms single half-sine wave)

Forward Voltage Drop (VF): 1.25 V maximum at 8.0 A (typical is much lower, ensuring high efficiency)

Reverse Recovery Time (trr): 75 ns maximum (ultrafast characteristic)

Operating Junction Temperature (TJ): -65°C to +175°C

These specifications highlight the diode's ability to handle high voltage and current stresses while minimizing switching losses, a crucial factor in high-frequency operation.

Pinout and Packaging

The MUR8100 features a simple two-pin configuration in an axial-leaded DO-41 package.

Anode (A): This terminal is typically marked by a colored band (usually black) on the diode's body. Conventional current flows into this pin.

Cathode (K): This is the unbanded end of the diode. Conventional current flows out of this pin.

The physical simplicity of its pinout makes it straightforward to integrate into circuits, but attention must be paid to orientation for proper functionality.

Application Circuits

The MUR8100's ultrafast recovery特性 makes it ideal for several key power electronics applications.

1. Switch-Mode Power Supply (SMPS) Output Rectifier: In SMPS designs, particularly flyback and boost converters, the MUR8100 is used as the output rectifier. Its fast recovery time minimizes reverse recovery current, leading to lower switching losses, reduced electromagnetic interference (EMI), and higher overall power supply efficiency.

2. Freewheeling or Flyback Diode: In inductive load circuits, such as those driving motors or relays, the MUR8100 acts as a freewheeling diode. When the driving switch (like a MOSFET) turns off, the diode provides a path for the inductive current to decay safely, protecting the switch from voltage spikes that could otherwise cause damage.

3. Reverse Battery Protection: The diode can be placed in series with the power input line. This ensures current only flows when the power supply polarity is correct, safeguarding sensitive electronic components from damage caused by accidental reverse connection of a battery.

ICGOODFIND: The Onsemi MUR8100 stands out as a highly reliable and efficient ultrafast rectifier. Its robust 800V voltage rating and 8A current handling capability, combined with a fast recovery time, make it an excellent component for demanding applications in power conversion and protection, including SMPS, freewheeling functions, and reverse polarity protection circuits.

Keywords: Ultrafast Rectifier, Switch-Mode Power Supply (SMPS), Freewheeling Diode, Reverse Recovery Time, DO-41 Package.