Diodes Incorporated SBR40U120CT

Overview

SBR40U120CT from Diodes Incorporated is a 40A dual common-cathode Super Barrier Rectifier with 120V peak reverse voltage, ultra-low 0.71V forward voltage at 20A/125°C, 150°C junction rating, and TO-220AB package - used in high-efficiency AC/DC front-end rectification for industrial power supplies and server PSUs.

For engineers reviewing the SBR40U120CT datasheet, SBR40U120CT pinout, SBR40U120CT application, or SBR40U120CT equivalent, key selection criteria include forward voltage at elevated temperature, surge current capability (300A), thermal resistance (2.0°C/W), and RoHS-compliant lead-free construction.

Technical Context

This dual-leg rectifier integrates two independent 20A-rated super barrier diodes in a single TO-220AB package with common cathode configuration, enabling synchronous half-wave or full-wave center-tapped rectification. Its patented super barrier structure replaces traditional PN junctions to reduce forward conduction loss while maintaining soft reverse recovery.

Designed for operation up to 150°C junction temperature, it delivers stable VF performance across -65°C to +150°C ambient range and exhibits <40mA leakage at 120V/125°C - critical for high-reliability offline power conversion where thermal management and leakage-induced standby loss are design constraints.

Key Specifications

Pinout & Package

TO-220AB package: 3-terminal molded plastic case with isolated tab (cathode-connected), matte tin-plated copper leadframe, UL 94V-0 rated, 1.85g weight. Mounting hole centered on tab for mechanical fixation and thermal transfer.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-current super barrier rectifier applications.

Compared with VS-40CPH12 and MUR40120CT, SBR40U120CT uniquely combines ultra-low VF at 125°C, 150°C rating, and soft switching - making it optimal for thermally constrained, high-efficiency AC/DC rectification where both conduction loss and EMI matter.

Availability

SBR40U120CT is available at Aetrix Electronics and suitable for industrial power supplies, telecom rectifier modules, and LED driver systems requiring stable component supply, long-lifecycle support, and RoHS-compliant manufacturing.

Supply support for SBR40U120CT 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, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.

The SBR® Super Barrier Rectifier product line targets high-efficiency power conversion in computing, industrial, and telecom infrastructure - engineered to replace Schottky and fast recovery diodes where low VF, high-temperature stability, and soft switching are critical.

FAQ

Is SBR40U120CT pin-compatible with standard TO-220AB dual diodes like MUR40120CT?

Yes - SBR40U120CT uses the industry-standard TO-220AB outline with identical mechanical dimensions and 3-pin common-cathode pinout (Anode1–Anode2–Cathode/Tab). It mounts identically and interfaces with existing PCB footprints and heatsinks designed for dual-diode TO-220AB packages.

What is the maximum recommended heatsink thermal resistance for continuous 40A operation?

With RθJC = 2.0°C/W and max TJ = 150°C, assuming 70°C ambient and 0.5°C/W interface resistance, the heatsink must provide ≤1.0°C/W RθSA to maintain safe junction temperature. Derating curves in Figure 3 confirm 40A is sustainable only with adequate heatsinking below 60°C ambient.

Does SBR40U120CT require a thermal pad or insulator when mounted to a grounded heatsink?

Yes - the metal tab is internally connected to the common cathode, so electrical isolation is required if the heatsink is grounded. Use UL-rated mica or ceramic washers with thermal grease, or silicone-based insulating pads rated ≥3kV dielectric strength to prevent short circuits and ensure safety compliance.

Can SBR40U120CT be used in synchronous rectification topologies?

No - it is a passive super barrier rectifier, not a MOSFET-based synchronous rectifier controller or driver. While its soft switching and low VF benefit quasi-resonant and LLC topologies, it cannot replace actively controlled SR FETs; it functions only as a unidirectional, voltage-controlled conduction device.