onsemi MBRAF2H100T3G 100V Schottky Barrier Rectifier: Datasheet, Pinout, and Application Circuit Design
The onsemi MBRAF2H100T3G is a state-of-the-art Schottky barrier rectifier engineered for high-efficiency power conversion applications. This device is part of a family of rectifiers renowned for their low forward voltage drop and fast switching capabilities, making them ideal for use as output rectifiers in switched-mode power supplies (SMPS), freewheeling diodes, and polarity protection circuits. This article delves into its key specifications, pin configuration, and a practical application circuit design.
Datasheet Overview and Key Specifications
The MBRAF2H100T3G is housed in a compact D2PAK (TO-263) surface-mount package, which offers excellent thermal performance. Its core electrical characteristics are what set it apart:
Repetitive Peak Reverse Voltage (VRRM): 100 V
Average Forward Current (IF(AV)): 2 x 30 A (per diode in a common cathode configuration)
Low Forward Voltage Drop (VF): Typically 0.70 V at IF = 15 A, TJ = 25°C. This low VF is critical for minimizing power loss and improving overall system efficiency.
Excellent Switching Performance: The Schottky barrier design inherently provides extremely fast switching with no reverse recovery time (trr) in the conventional sense, significantly reducing switching noise and losses in high-frequency circuits.
These specifications make it exceptionally suitable for modern power supplies operating at frequencies beyond 100 kHz, where efficiency and thermal management are paramount.
Pinout and Package Information
The MBRAF2H100T3G is a dual common-cathode Schottky rectifier. The D2PAK package has three pins:
1. Pin 1 (Anode 1): Anode terminal for the first diode.
2. Pin 2 (Anode 2): Anode terminal for the second diode.
3. Pin 3 (Cathode): Common cathode terminal for both diodes. This pin is also electrically connected to the large metal tab, which is designed to be soldered to the PCB's copper area to act as the primary thermal pad for heat dissipation.
Proper PCB layout is crucial. The cathode tab must be connected to a sufficiently large copper pour to act as a heat sink, ensuring the junction temperature (TJ) remains within safe operating limits.
Application Circuit Design: A Synchronous Buck Converter Example
A prime application for the MBRAF2H100T3G is in a high-current synchronous buck converter, which steps down a higher DC voltage (e.g., 48V) to a lower one (e.g., 12V). While often used as the secondary-side rectifier, its dual common-cathode configuration is perfect for a synchronous rectifier stage in non-isolated converters.
In a typical circuit:
The input voltage (VIN) is switched by a high-side MOSFET controller.
The MBRAF2H100T3G can be used in place of the low-side synchronous MOSFET in simpler designs or for cost reduction. Its common-cathode pins (Anode 1 and Anode 2) can be connected to the switching node (SW), and the cathode is connected to ground.
The intrinsic fast switching speed of the Schottky diode ensures that it conducts immediately when the high-side switch turns off, minimizing the body diode conduction period of a MOSFET and improving efficiency.
A large ceramic capacitor is placed at the output (VOUT) to filter ripple current.
The critical design consideration is thermal management. The power dissipated (PD) in the diode is calculated as PD = IF(AV) VF. This loss must be managed by an appropriately sized PCB heatsink connected to the cathode tab to prevent thermal runaway.
ICGOOODFIND: The onsemi MBRAF2H100T3G stands out as a robust and highly efficient solution for demanding power management tasks. Its combination of a high 100V rating, very low forward voltage, and dual common-cathode design in a thermally efficient package makes it an exceptional choice for designers aiming to maximize efficiency and power density in contemporary high-frequency power converters, from server PSUs to industrial equipment.
Keywords:
Schottky Barrier Rectifier
Low Forward Voltage
Fast Switching
Common Cathode
Thermal Management
