onsemi MUR1620CT Ultrafast Rectifier: Datasheet, Pinout, and Application Circuits

The MUR1620CT from onsemi is a high-efficiency, ultra-fast recovery rectifier designed for high-frequency power conversion applications. Housed in a compact and industry-standard TO-220AB package, this rectifier is a common choice for engineers seeking to improve the performance and reliability of switch-mode power supplies (SMPS), inverters, and other circuits where rapid switching and low reverse recovery loss are critical.

Datasheet Overview and Key Specifications

The MUR1620CT is characterized by its very fast recovery time, which minimizes switching losses and reduces noise generation. Key absolute maximum ratings and electrical characteristics from its datasheet include:

Repetitive Peak Reverse Voltage (VRRM): 200 V

Average Forward Output Current (IF(AV)): 8.0 A per leg (16 A total for common-cathode configuration)

Peak Forward Surge Current (IFSM): 150 A

Forward Voltage Drop (VF): Typically 0.975 V at 8.0 A (per leg)

Reverse Recovery Time (trr): A maximum of 60 ns, which qualifies it as an ultrafast recovery rectifier.

A crucial feature of this component is its common-cathode configuration. The "CT" suffix indicates that the package contains two separate diodes connected internally with their cathodes tied together to a single pin. This design is highly beneficial for use in full-wave rectifier circuits, simplifying board layout and improving thermal performance.

Pinout Configuration

The MUR1620CT is supplied in a TO-220AB package with three pins. The standard pinout is as follows:

Pin 1 (Left): Anode of Diode 1

Pin 2 (Center): Common Cathode (connected to both diodes)

Pin 3 (Right): Anode of Diode 2

Correctly identifying the pinout is essential to avoid damaging the device and to ensure the circuit functions as intended.

Application Circuits

The common-cathode design of the MUR1620CT makes it exceptionally suitable for specific rectifier topologies.

1. Center-Tapped Full-Wave Rectifier: This is the most classic application for a common-cathode dual diode. It is used in power supplies with a center-tapped transformer secondary. The common cathode pin becomes the positive DC output terminal, while the two anode pins are connected to each end of the transformer's secondary winding. This circuit efficiently converts the entire AC input waveform into a pulsating DC output.

2. Output Rectification in SMPS: The MUR1620CT is frequently employed in the output stage of switch-mode power supplies, particularly in freewheeling or flyback diode applications within buck, boost, and flyback converters. Its ultrafast recovery characteristic is vital here to prevent reverse recovery current from interfering with the main switching element (like a MOSFET), thereby enhancing overall efficiency and reducing electromagnetic interference (EMI).

3. Polarity Protection and Clamping Circuits: The diodes can be used in circuits to protect sensitive electronic equipment from reverse polarity connection of the power supply. They are also effective in voltage clamping and snubber circuits to suppress voltage spikes and protect switching transistors.

Thermal Management

Due to its ability to handle significant power, proper thermal management is crucial. The TO-220 package is designed to be mounted on a heatsink to dissipate heat effectively. Ensuring a good thermal connection between the device and the heatsink will maximize performance and long-term reliability.

ICGOODFIND Summary

The onsemi MUR1620CT stands out as a robust and highly efficient solution for high-frequency rectification. Its common-cathode configuration and ultrafast recovery time make it an ideal component for simplifying design and boosting performance in power conversion applications like SMPS and inverters. When implementing this rectifier, careful attention to its pinout and adequate thermal management via a heatsink are key to unlocking its full potential.

Keywords:

Ultrafast Rectifier

Common-Cathode

MUR1620CT

Switching Losses

Recovery Time