Diodes Incorporated MBRD1040-T

Overview

MBRD1040-T from Diodes Incorporated is a 10A, 40V low-forward-voltage Schottky barrier rectifier in DPAK package, designed for high-efficiency DC output rectification and freewheeling in low-voltage, high-frequency power supplies. It features 0.47V typical V_F at 8A/25°C, 100A non-repetitive surge rating, and junction-to-case thermal resistance of 6.0°C/W - enabling compact thermal design in SMPS and OR-ing circuits.

For engineers reviewing the MBRD1040-T datasheet, MBRD1040-T pinout, MBRD1040-T application, or MBRD1040-T equivalent, key selection criteria include forward voltage drop at operating current, thermal resistance under PCB copper layout constraints, reverse leakage at elevated temperature, and mandatory PCB-level connection between pins 1 and 3 for current sharing and thermal path integrity.

Technical Context

This device implements a single-phase, half-wave Schottky rectifier structure with guard-ring die construction for transient robustness. Its 40V V_RRM rating and 0.41–0.51V V_FM range (depending on current and junction temperature) target 5V–12V output rails where conduction loss minimization is critical.

Thermal performance is defined by R_JC = 6.0°C/W and R_JA = 80°C/W (standard FR-4), requiring external PCB copper to serve as heatsink via pins 1 & 3 tie-down and bottom-side thermal pad (pin 4). The 700pF junction capacitance supports operation up to several MHz in switching converters.

Key Specifications

Pinout & Package

Package: DPAK (TO-252AA), surface-mount, with exposed thermal pad on underside (pin 4). Pins 1 and 3 are electrically identical anode terminals and must be connected together on the PCB to ensure current sharing and optimal thermal transfer.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Schottky rectifier applications.

Compared with SS1040-T and MBRD1045G, MBRD1040-T delivers optimal balance of low V_F, DPAK thermal performance, and 40V rating for cost-sensitive 12V-output power stages - making it preferred for high-density, thermally constrained designs where 40V margin suffices.

Availability

MBRD1040-T is available at Aetrix Electronics and suitable for server VRMs, industrial DC/DC converters, automotive infotainment power supplies, and redundant OR-ing circuits requiring stable component supply across production lifecycles.

Supply support for MBRD1040-T 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 automotive markets.

The MBRD1040-T belongs to Diodes' low-V_F Schottky rectifier product line, engineered specifically for high-efficiency, high-current DC/DC conversion in space-constrained power supplies where thermal management and conduction loss dominate design trade-offs.

FAQ

Why must pins 1 and 3 be connected on the PCB?

Pins 1 and 3 are internally connected anode terminals. Connecting them externally ensures balanced current distribution and maximizes thermal conduction through both leads and the exposed pad (pin 4). Omitting this connection risks localized overheating, current crowding, and premature failure at rated 10A load.

What is the maximum ambient temperature for continuous 10A operation?

Per Figure 4, continuous 10A operation is only supported up to ~25°C ambient on standard FR-4. At 75°C ambient, derated current is ~6.5A; at 100°C, it drops to ~4.5A. Achieving full 10A at higher temperatures requires enhanced PCB copper area and thermal vias per AP02001 layout guidelines.

Can MBRD1040-T replace a standard PN rectifier like 1N5408?

Yes - but only in low-voltage, high-frequency applications where its 40V V_RRM and Schottky advantages apply. It cannot replace 1N5408 in 400V AC/DC front-ends due to lower blocking voltage. In 12V SMPS, MBRD1040-T reduces losses by >50% versus 1N5408, but requires careful thermal layout not needed for the slower, higher-V_F PN device.

Is the bottom-side thermal pad (pin 4) electrically isolated?

No - the exposed pad is internally connected to the anode (same potential as pins 1 and 3). It must be routed to the anode net on the PCB and cannot be grounded or left floating. Solder mask openings and thermal vias to inner-layer copper planes are required to realize the specified 6.0°C/W R_JC.