HER302-T Equivalent & Substitute Parts

Part Overview

The HER302-T is a general-purpose rectifier diode manufactured by Diodes Incorporated, rated for 100 V DC reverse voltage and 3 A average rectified current in a DO-201AD through-hole axial package. The device features fast recovery characteristics with a reverse recovery time of 50 ns and operates across a junction temperature range of -65°C to 150°C.

The HER302-T is classified as obsolete. Equivalent and substitute parts are necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this rectifier specification.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	100	V
Current - Average Rectified (Io)	3	A
Voltage - Forward (Vf) (Max) @ If	1.1 V @ 3 A	V
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	—
Reverse Recovery Time (trr)	50	ns
Current - Reverse Leakage @ Vr	10	µA @ 100 V
Mounting Type	Through Hole	—
Package / Case	DO-201AD, Axial	—
Operating Temperature - Junction	-65 to 150	°C
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the HER302-T is determined by the following critical parameters:

Electrical Equivalence Criteria:

Voltage - DC Reverse (Vr) (Max): 100 V minimum
Current - Average Rectified (Io): 3 A minimum
Forward voltage drop characteristics within acceptable operating range
Reverse recovery time and speed classification

Mechanical Compatibility Criteria:

Mounting Type: Through Hole
Package / Case: DO-201AD or equivalent axial package geometry

Environmental & Compliance Criteria:

Operating Temperature - Junction: -65°C to 150°C minimum range
RoHS3 Compliance status
REACH Unaffected status

Substitute parts are grouped into two categories:

Category A - Direct Package Match (DO-201AD): Parts with identical DO-201AD package geometry, enabling direct mechanical and electrical substitution with no layout modifications.

Category B - Equivalent Axial Package (B, DO-27, DO-201AA): Parts with alternative axial package geometries that maintain electrical equivalence and through-hole mounting but may require footprint verification.

Parameter Comparison

Part Number	Manufacturer	Vr (Max) [V]	Io [A]	Vf (Max) [V]	Speed	trr [ns]	Ir @ Vr [µA]	Package	Temp Range [°C]	Product Status	RoHS
HER302-T	Diodes Incorporated	100	3	1.1 @ 3A	Fast Recovery ≤ 500ns	50	10 @ 100V	DO-201AD	-65 to 150	Obsolete	ROHS3
1N5401-E3/54	Vishay General Semiconductor	100	3	1.2 @ 3A	Standard Recovery >500ns	—	5 @ 100V	DO-201AD	-50 to 150	Active	ROHS3
1N5401G	Good-Ark Semiconductor	100	3	1.1 @ 3A	Standard Recovery >500ns	—	5 @ 100V	DO-201AD	-55 to 150	Active	ROHS3
1N5401RLG	onsemi	100	3	1.0 @ 3A	Standard Recovery >500ns	—	10 @ 100V	DO-201AA, DO-27, Axial	-65 to 150	Not For New Designs	ROHS3
1N5186	Microchip Technology	100	3	1.5 @ 9A	Fast Recovery ≤ 500ns	150	2 @ 100V	B, Axial	-65 to 175	Active	Non-compliant
1N5416	Microchip Technology	100	3	1.5 @ 9A	Fast Recovery ≤ 500ns	150	1 @ 100V	B, Axial	-65 to 175	Active	Non-compliant
1N5804	Solid State Inc.	100	2.5	0.875 @ 1A	Fast Recovery ≤ 500ns	25	1 @ 100V	DO-204AP	-65 to 175	Active	ROHS3
GI501-E3/73	Vishay General Semiconductor	100	3	1.1 @ 9.4A	Standard Recovery >500ns	2000	5 @ 100V	DO-201AD	-50 to 150	Active	ROHS3
HER302G A0G	Taiwan Semiconductor Corporation	100	3	1.0 @ 3A	Fast Recovery ≤ 500ns	50	10 @ 100V	DO-201AD	-55 to 150	Active	ROHS3
MR851G	onsemi	100	3	1.25 @ 3A	Fast Recovery ≤ 500ns	300	10 @ 100V	DO-201AA, DO-27, Axial	-65 to 125	Active	ROHS3
MR851RLG	onsemi	100	3	1.25 @ 3A	Fast Recovery ≤ 500ns	300	10 @ 100V	DO-201AA, DO-27, Axial	-65 to 125	Active	ROHS3

Engineering Selection Recommendations

Primary Substitutes (Direct DO-201AD Package Match):

1N5401-E3/54, 1N5401G, GI501-E3/73, and HER302G A0G are direct mechanical and electrical substitutes for the HER302-T. All maintain the DO-201AD package geometry, 100 V / 3 A electrical rating, and ROHS3 compliance. These parts are classified as Active products, ensuring long-term supply availability.

1N5401-E3/54 offers the highest inventory availability (62,000 pcs) and is recommended as the primary replacement for new production. HER302G A0G provides the closest electrical match to the original HER302-T, including identical fast recovery characteristics (50 ns trr) and forward voltage drop (1.0 V @ 3 A).

Secondary Substitutes (Alternative Axial Packages):

1N5186, 1N5416, MR851G, and MR851RLG maintain electrical equivalence but utilize alternative axial package geometries (B, DO-27, DO-201AA). These parts are suitable for applications where package footprint flexibility exists. MR851G and MR851RLG are recommended over 1N5186 and 1N5416 due to ROHS3 compliance status.

Not Recommended for New Designs:

1N5401RLG is classified as "Not For New Designs" and should be avoided for new production despite electrical equivalence.

Current-Limited Substitute:

1N5804 is rated for 2.5 A average rectified current, below the 3 A specification of the HER302-T. This part is suitable only for applications with reduced current requirements.

Frequently Asked Questions (FAQ)

Q: Can I directly replace HER302-T with 1N5401-E3/54?

A: Yes. Both parts share identical electrical ratings (100 V, 3 A), the same DO-201AD package geometry, and ROHS3 compliance. No circuit modifications are required. The 1N5401-E3/54 is classified as Active with high inventory availability.

Q: What is the difference between fast recovery and standard recovery diodes?

A: Recovery speed refers to the reverse recovery time (trr), which is the time required for a diode to stop conducting when reverse bias is applied. The HER302-T specifies fast recovery (≤ 500 ns, trr = 50 ns). Standard recovery diodes (trr > 500 ns) exhibit slower switching behavior. For applications sensitive to switching transients or operating at higher frequencies, fast recovery characteristics are preferred.

Q: Can I use 1N5186 or 1N5416 as substitutes?

A: Electrically, yes. Both parts meet the 100 V / 3 A specification and feature fast recovery characteristics. However, they use alternative axial package geometries (B, DO-27) rather than the DO-201AD. Physical footprint verification is required before substitution. Additionally, both parts are RoHS non-compliant, which may conflict with system-level compliance requirements.

Q: Why is 1N5804 listed as a substitute if it is only rated for 2.5 A?

A: The 1N5804 is included for applications where the actual circuit current requirement is 2.5 A or less. It is not a direct substitute for the full 3 A rating but provides an alternative for reduced-current designs. The part offers superior fast recovery characteristics (25 ns trr) and extended temperature range (-65°C to 175°C).

Q: What does ROHS3 compliance mean?

A: ROHS3 (Restriction of Hazardous Substances Directive 3) compliance indicates that the component meets European Union restrictions on hazardous materials, specifically the prohibition of lead, cadmium, mercury, hexavalent chromium, and certain brominated flame retardants. ROHS3-compliant parts are required for most commercial and industrial applications in regulated markets.

Q: Is HER302G A0G a better choice than 1N5401-E3/54?

A: HER302G A0G provides an exact electrical match to the original HER302-T, including identical fast recovery characteristics (50 ns trr) and forward voltage (1.0 V @ 3 A). However, 1N5401-E3/54 offers significantly higher inventory availability (62,000 pcs vs. 811 pcs) and is classified as Active. Selection depends on whether exact electrical matching or supply chain continuity is prioritized.

Q: Can I use MR851G or MR851RLG in place of HER302-T?

A: Electrically, yes, with package considerations. Both parts meet the 100 V / 3 A specification and feature fast recovery characteristics. However, they use DO-201AA / DO-27 axial packages rather than DO-201AD. Physical footprint compatibility must be verified. Additionally, the maximum operating temperature is limited to 125°C, compared to 150°C for the HER302-T.

Q: What is the significance of reverse leakage current (Ir)?

A: Reverse leakage current is the small current that flows through a diode when reverse bias is applied. The HER302-T specifies 10 µA @ 100 V. Lower leakage currents indicate better diode quality and reduced power dissipation in reverse bias conditions. Substitutes with lower leakage (such as 1N5186 at 2 µA or 1N5416 at 1 µA) provide improved performance in this parameter.

Q: Why is 1N5401RLG marked as "Not For New Designs"?

A: This designation indicates that the manufacturer (onsemi) has discontinued active development and support for this part number. While existing inventory may be available, the part is not recommended for new product designs due to uncertain long-term supply and potential obsolescence. Active alternatives such as 1N5401G or HER302G A0G should be selected instead.

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