HER604-T Equivalent & Substitute Parts

Part Overview

The HER604-T is a general-purpose rectifier diode manufactured by Diodes Incorporated, rated for 300 V DC reverse voltage and 6 A average rectified current. The device features fast recovery characteristics with a reverse recovery time of 60 ns and is housed in an R-6 axial package for through-hole mounting applications. The HER604-T is classified as obsolete, necessitating identification of active equivalent components for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility while accommodating potential package and current rating variations.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	300	V
Current - Average Rectified (Io)	6	A
Voltage - Forward (Vf) (Max) @ If	1.2 @ 6	V @ A
Speed Classification	Fast Recovery ≤ 500ns, > 200mA (Io)	—
Reverse Recovery Time (trr)	60	ns
Current - Reverse Leakage @ Vr	10	µA @ 300 V
Mounting Type	Through Hole	—
Package / Case	R-6, Axial	—
Operating Temperature - Junction	-65 to 150	°C
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the HER604-T is determined by the following critical electrical parameters: voltage rating (300 V DC reverse), fast recovery speed classification (≤ 500ns), reverse recovery time (≤ 60 ns), and through-hole axial mounting configuration. The substitute parts identified—HER304GA-G, HER304GT-G, UF3004-G, and UF3004-HF—all maintain the 300 V voltage rating and fast recovery characteristics required for functional equivalence.

A key consideration is the current rating differential. The HER604-T is rated for 6 A average rectified current, while all identified substitutes are rated for 3 A. This represents a current derating of 50%. Substitution is valid only in applications where the actual circuit current demand does not exceed 3 A. The substitute parts are manufactured by Comchip Technology and are classified as active products, ensuring ongoing availability and supply chain continuity.

All substitute parts comply with RoHS3 and REACH requirements, matching the environmental and regulatory status of the original component. Package variations exist among substitutes: HER304GA-G and HER304GT-G utilize DO-27 packaging with different tape configurations (Tape & Box versus Tape & Reel), while UF3004-G and UF3004-HF are supplied in bulk packaging. All maintain the DO-201AA / DO-27 axial through-hole form factor compatible with R-6 footprints.

Parameter Comparison

Parameter	HER604-T	HER304GA-G	HER304GT-G	UF3004-G	UF3004-HF
Manufacturer	Diodes Incorporated	Comchip Technology	Comchip Technology	Comchip Technology	Comchip Technology
Product Status	Obsolete	Active	Active	Active	Active
Voltage - DC Reverse (Vr) (Max)	300 V	300 V	300 V	300 V	300 V
Current - Average Rectified (Io)	6 A	3 A	3 A	3 A	3 A
Voltage - Forward (Vf) (Max) @ If	1.2 V @ 6 A	1 V @ 3 A	1 V @ 3 A	1.3 V @ 3 A	1.3 V @ 3 A
Speed Classification	Fast Recovery ≤ 500ns, > 200mA	Fast Recovery ≤ 500ns, > 200mA	Fast Recovery ≤ 500ns, > 200mA	Fast Recovery ≤ 500ns, > 200mA	Fast Recovery ≤ 500ns, > 200mA
Reverse Recovery Time (trr)	60 ns	50 ns	50 ns	50 ns	50 ns
Current - Reverse Leakage @ Vr	10 µA @ 300 V	5 µA @ 300 V	5 µA @ 300 V	5 µA @ 300 V	5 µA @ 300 V
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	R-6, Axial	DO-201AA, DO-27, Axial	DO-201AA, DO-27, Axial	DO-201AA, DO-27, Axial	DO-201AA, DO-27, Axial
Operating Temperature - Junction	-65 to 150 °C	-55 to 150 °C	-55 to 150 °C	-55 to 125 °C	-55 to 125 °C
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

Selection among the four active substitute parts depends on application current requirements and packaging specifications.

For applications with circuit current ≤ 3 A:

All four substitute parts are electrically compatible with the HER604-T at reduced current ratings. HER304GA-G and HER304GT-G are functionally identical, differing only in packaging format: HER304GA-G is supplied in Tape & Box configuration, while HER304GT-G is supplied in Tape & Reel format. Selection between these two is determined by procurement and assembly process requirements.

UF3004-G and UF3004-HF are supplied in bulk packaging and feature identical electrical specifications. Both are suitable for applications where tape-and-reel or tape-and-box packaging is not required.

For applications with circuit current > 3 A and ≤ 6 A:

No direct substitute exists among the provided parts. The current derating from 6 A to 3 A represents a fundamental limitation of the available alternatives. Circuit redesign or identification of additional substitute sources is required.

Compliance and Supply Continuity:

All substitute parts maintain RoHS3 compliance and REACH unaffected status, ensuring regulatory alignment with the original HER604-T. All substitutes are classified as active products with confirmed inventory availability, providing supply chain assurance for production and design transitions.

Temperature Operating Range:

The HER604-T operates from -65°C to 150°C. HER304GA-G and HER304GT-G operate from -55°C to 150°C, representing a 10°C reduction in minimum operating temperature. UF3004-G and UF3004-HF operate from -55°C to 125°C, representing both a 10°C reduction in minimum temperature and a 25°C reduction in maximum temperature. Applications requiring operation below -55°C or above 125°C must account for these thermal limitations.

Frequently Asked Questions (FAQ)

Q: Can the HER304GA-G, HER304GT-G, UF3004-G, or UF3004-HF be used as direct replacements for the HER604-T in all applications?

A: Direct replacement is valid only in applications where the circuit current does not exceed 3 A. The substitute parts are rated for 3 A average rectified current, compared to the HER604-T's 6 A rating. If the application requires 6 A operation, these substitutes are not suitable without circuit modification.

Q: What is the difference between HER304GA-G and HER304GT-G?

A: Both parts are electrically identical, rated for 300 V, 3 A, with 50 ns reverse recovery time. The difference is packaging: HER304GA-G is supplied in Tape & Box format, while HER304GT-G is supplied in Tape & Reel format. Selection depends on assembly line requirements and procurement preferences.

Q: How do UF3004-G and UF3004-HF differ from the HER304 series?

A: UF3004-G and UF3004-HF are electrically equivalent to HER304GA-G and HER304GT-G, maintaining 300 V, 3 A ratings and 50 ns reverse recovery time. The primary differences are packaging (bulk versus tape formats) and maximum operating temperature (125°C versus 150°C for HER304 parts). Forward voltage at 3 A is 1.3 V for UF3004 parts compared to 1.0 V for HER304 parts.

Q: Are all substitute parts compatible with the R-6 axial package footprint?

A: Yes. All substitute parts utilize DO-201AA / DO-27 axial through-hole packaging, which is mechanically compatible with R-6 footprints. Physical dimensions and lead spacing are equivalent, allowing direct board-level substitution without PCB redesign.

Q: What is the impact of the lower reverse recovery time (50 ns) in substitute parts compared to the HER604-T (60 ns)?

A: Lower reverse recovery time indicates faster switching characteristics. This is a performance improvement, not a limitation. Substitute parts with 50 ns recovery time will exhibit faster switching behavior than the original 60 ns specification, which is beneficial for high-frequency applications.

Q: Do the substitute parts meet the same environmental and regulatory standards as the HER604-T?

A: Yes. All substitute parts are RoHS3 compliant and REACH unaffected, matching the environmental compliance status of the HER604-T. All parts are classified as standard technology rectifier diodes with identical regulatory certifications.

Q: What is the significance of the reduced reverse leakage current in substitute parts (5 µA versus 10 µA)?

A: Lower reverse leakage current indicates improved leakage performance. This is a performance enhancement, not a limitation. Substitute parts with 5 µA leakage will exhibit lower standby current consumption than the original 10 µA specification.

Q: Can UF3004-G or UF3004-HF be used in applications requiring operation above 125°C?

A: No. UF3004-G and UF3004-HF are rated for maximum junction temperature of 125°C. Applications requiring operation above 125°C must use HER304GA-G or HER304GT-G, which are rated to 150°C, or identify alternative substitute sources.

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