Diodes Incorporated HER104-T

Overview

HER104-T from Diodes Incorporated is a 1.0A high-efficiency axial-lead rectifier diode in DO-41 package, rated for 300V maximum recurrent peak reverse voltage (V_RRM), 1.1V max forward voltage at 1.0A DC, and 50ns reverse recovery time (t_rr). It delivers low leakage (5.0µA @ 300V), high-speed switching, and operates from –65°C to +150°C - used in offline AC/DC power supplies and auxiliary rail rectification.

For engineers reviewing the HER104-T datasheet, HER104-T pinout, HER104-T application, or HER104-T equivalent, key selection criteria include V_RRM margin for surge tolerance, t_rr impact on EMI in flyback snubbers, VF trade-off vs. thermal rise under 1A continuous load, and DO-41 lead-form compatibility with through-hole PCB layouts.

Technical Context

This device is a silicon planar epitaxial high-efficiency rectifier optimized for fast recovery (50ns) and low forward conduction loss. Its junction capacitance is 20pF at 4.0V reverse bias, and it sustains 30A non-repetitive surge current (8.3ms half-sine) - enabling robust operation in capacitor-input filter stages and low-noise secondary-side rectification.

The cathode is marked by a color band on the DO-41 body; polarity must be observed during board assembly. Thermal derating begins above 50°C ambient, with I_AV dropping to ~0.7A at 100°C - requiring heatsinking only in high-duty-cycle or enclosed environments.

Key Specifications

Pinout & Package

DO-41 molded plastic package with axial plated leads; cathode identified by single color band. Lead length 9.5mm standard; weight ≈0.35g. Compliant with UL 94V-0 flammability rating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-efficiency rectifier applications.

Compared with UF1004-T, HER104-T trades 15ns slower recovery for broader thermal stability and lower price; versus 1N4004, it enables efficient high-frequency operation but requires tighter layout control for EMI mitigation.

Availability

HER104-T is available at Aetrix Electronics and suitable for AC/DC adapters, industrial control power supplies, LED driver auxiliary rails, and offline flyback snubber networks requiring stable component supply and long-term manufacturability.

Supply support for HER104-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, headquartered in Plano, Texas, with design and manufacturing operations across Asia and the Americas.

HER101–HER106 is part of Diodes' high-efficiency rectifier product line, engineered for improved switching speed and thermal performance over standard 1N400x devices in compact, cost-sensitive power conversion systems.

FAQ

Is HER104-T RoHS compliant and halogen-free?

Yes. HER104-T meets RoHS Directive 2011/65/EU and is halogen-free per IEC 61249-2-21. The DO-41 package uses lead-free matte tin-plated axial leads and UL 94V-0 compliant molding compound - verified in Diodes Incorporated's material declarations DS25001 Rev.6 and compliance certificates.

Can HER104-T replace HER103 in an existing design?

Yes, with voltage margin benefit. HER104-T has 300V V_RRM versus HER103's 200V - allowing direct substitution where system transients exceed 200V. All other parameters (I_AV, t_rr, V_F) are identical, and DO-41 mechanical fit is unchanged.

What is the maximum allowable PCB trace width for 1.0A continuous current?

For 1.0A steady-state current with ≤10°C temperature rise, IPC-2221 recommends ≥10 mil (0.25 mm) trace width on 1 oz copper internal layer. With DO-41 axial leads soldered to 15–20 mil pads, thermal relief spokes should be minimized to maximize heat transfer to copper pour.

Does HER104-T require derating when mounted horizontally on a PCB?

Yes. Horizontal mounting reduces natural convection cooling. At 50°C ambient, I_AV remains 1.0A per datasheet; however, at 70°C ambient, derated I_AV drops to ~0.85A. For horizontal orientation above 60°C, add local copper pour or airflow per Figure 1 derating curve.