Diodes Incorporated SBR40U300CTB

Overview

SBR40U300CTB from Diodes Incorporated is a 300V, 40A dual common-cathode Super Barrier Rectifier in D2PAK (TO-263) package, featuring ultra-low forward voltage (0.81V @ 20A, 25°C), soft fast switching (trr ≤ 50 ns), and 175°C maximum junction temperature-designed for high-efficiency AC/DC and DC/DC secondary-side rectification in server power supplies.

For engineers reviewing the SBR40U300CTB datasheet, SBR40U300CTB pinout, SBR40U300CTB application, or SBR40U300CTB equivalent, key selection criteria include per-leg forward voltage at 20A/125°C, reverse leakage at 300V/125°C, thermal resistance (RθJC = 2°C/W), and D2PAK mounting compatibility with FR-4 PCBs using 2 oz. copper.

Technical Context

This dual common-cathode rectifier integrates two independent 300V/20A legs sharing a single cathode terminal, enabling synchronous-like efficiency without gate drive complexity. Its patented Super Barrier structure replaces traditional PN junctions with low-barrier metal-semiconductor interfaces, reducing VF while maintaining low IR and high-temperature stability.

Designed for high-frequency switching topologies (e.g., LLC resonant, active clamp forward), it delivers soft recovery (no hard reverse recovery spikes) and stable performance up to 175°C junction temperature-critical for compact, thermally constrained power modules where thermal resistance (2°C/W) directly impacts derating curves and system reliability.

Key Specifications

Pinout & Package

Package: D2PAK (TO-263), surface-mount, single-piece molded plastic case with matte tin-plated copper leadframe; UL 94V-0 rated, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-efficiency, high-current rectification applications.

Compared with VS-40CPH03-M3 and MBR4030CT, SBR40U300CTB uniquely combines 300V blocking, sub-0.9V VF at 125°C, and <100 μA leakage at 125°C-making it the sole choice for thermally demanding, high-voltage secondary-side rectification where efficiency and reliability are co-constrained.

Availability

SBR40U300CTB is available at Aetrix Electronics and suitable for server power supplies, industrial DC/DC converters, telecom rectifier modules, and renewable energy inverters requiring stable component supply across multi-year production cycles.

Supply support for SBR40U300CTB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-performance power management, signal integrity, and protection solutions for industrial, computing, and communications markets.

SBR40U300CTB belongs to the SBR® Super Barrier Rectifier product line, engineered specifically to replace conventional Schottky and fast recovery diodes in high-efficiency, high-temperature power conversion applications where low VF, soft switching, and thermal robustness are critical.

FAQ

What is the maximum continuous current rating per anode leg?

The SBR40U300CTB is rated for 20 A average forward current per anode leg at 25°C ambient, with total device current capacity of 40 A due to its dual-leg, common-cathode configuration. Derating is required above 25°C per the published forward current derating curve, reaching 10 A per leg at 100°C ambient with R_θJA = 10°C/W.

Does this device require a heatsink in typical applications?

A heatsink is strongly recommended for continuous operation above 10 A per leg. With R_θJC = 2°C/W and typical power dissipation of ~16 W at 20 A/25°C, a heatsink maintaining <70°C case temperature is necessary to stay within the 175°C maximum junction limit-especially in enclosed or high-ambient environments.

How does the soft recovery behavior affect EMI performance?

The soft, low-IRR reverse recovery (trr ≤ 50 ns, IRR ≤ 0.25A) eliminates abrupt current collapse and associated voltage spikes, reducing high-frequency radiated emissions by up to 10 dB compared to fast recovery diodes. This simplifies EMI filter design and improves compliance with EN55022 Class B limits in dense power assemblies.

Is the D2PAK package compatible with standard reflow profiles?

Yes-the D2PAK package uses matte tin-plated copper leads and is qualified for standard Pb-free reflow profiles (JEDEC J-STD-020, peak 260°C). Moisture sensitivity is Level 1, eliminating bake requirements. Recommended pad layout follows Diodes' AP02001 guidelines with 2 oz. copper and thermal vias under the exposed cathode tab.