SMC Diode Solutions MBR745

Overview

MBR745 from Diodes Incorporated is a 45 V, 7.5 A surface-mount Schottky barrier rectifier in TO-220AC package, featuring low forward voltage drop (0.72 V @ 7.5 A, 25°C), high surge capability (150 A), and guard ring die construction for transient protection. It is used in low-voltage, high-frequency inverters, freewheeling diode circuits, and polarity protection in DC power supplies.

For engineers reviewing the MBR745 datasheet, MBR745 pinout, MBR745 application, or MBR745 equivalent, key selection criteria include its 45 V reverse voltage rating, thermal resistance (3.5°C/W junction-to-case), peak reverse current (0.5 mA @ 25°C), typical capacitance (400 pF), and RoHS-compliant tin-plated terminals.

Technical Context

This Schottky rectifier uses a planar guard ring die structure to enhance transient robustness and reduce leakage under reverse bias. Its low forward voltage minimizes conduction losses in high-current DC/DC and AC/DC secondary-side rectification, while its 150 A non-repetitive surge rating supports inductive load switching.

The device operates across –55°C to +150°C junction temperature range and exhibits 400 pF typical junction capacitance at 4 V reverse bias and 1 MHz - critical for EMI-sensitive high-frequency converter designs where parasitic capacitance affects switching node ringing.

Key Specifications

Pinout & Package

TO-220AC package with insulated tab; molded plastic case (UL 94V-0), tin-plated copper terminals, and 2.3 g mass. Mounting requires mechanical isolation from heatsink unless cathode connection is referenced to ground.

Key Features

Applications

Availability

MBR745 is available at Aetrix Electronics and suitable for DC power supply rectification, motor drive freewheeling, solar charge controller polarity protection, and LED driver output protection requiring stable component supply and legacy-compatible replacement support.

Supply support for MBR745 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-efficiency power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.

The MBR7xx series belongs to Diodes' high-current Schottky rectifier product line, engineered for low-loss secondary-side rectification and transient-tolerant freewheeling in high-reliability power conversion systems.

FAQ

Is MBR745 still in active production?

No - MBR745 is marked obsolete per Diodes Incorporated's DS23007 Rev. 11 (July 2015). It is discontinued and no longer manufactured, though limited legacy stock may be available through authorized channels. Engineering redesign to active alternatives is recommended for new designs.

What is the thermal performance difference between MBR745 and MBR745G?

MBR745G is the green (halogen- and antimony-free) variant of MBR745, with identical electrical and thermal specifications including RθJC = 3.5°C/W. The only difference is the terminal finish composition and compliance with stricter environmental directives - no thermal or electrical derating is required when substituting.

Can MBR745 replace MBR740 in an existing design?

Yes - MBR745 has identical package, pinout, and thermal characteristics as MBR740, with only a 5 V higher VRRM (45 V vs. 40 V). All other parameters - IO, VFM, IFSM, RθJC - are unchanged. No layout or thermal redesign is needed for direct substitution where higher reverse margin is beneficial.

Does MBR745 require a heatsink in 7.5 A continuous operation?

Yes - at 7.5 A continuous current and 25°C ambient, junction temperature exceeds 150°C without heatsinking. With RθJC = 3.5°C/W and typical RθCA ≈ 20°C/W for a modest heatsink, total thermal resistance (~23.5°C/W) limits junction rise to ~176°C at full load - thus a properly sized heatsink maintaining TC ≤ 125°C is mandatory for reliable operation.