Equivalent & Substitute Parts for 6A4-T General Purpose Rectifier Diode

Part Overview

The 6A4-T is a general purpose rectifier diode manufactured by Diodes Incorporated, rated for 400 V DC reverse voltage and 6 A average rectified current in an R-6 axial through-hole package. The part is classified as obsolete, necessitating identification of active equivalent and substitute components for ongoing applications. Substitute parts must maintain electrical compatibility across voltage, current, and thermal specifications while accommodating variations in package configuration and recovery characteristics.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	400	V
Current - Average Rectified (Io)	6	A
Voltage - Forward (Vf) (Max) @ If	900 mV @ 6 A	mV
Speed	Standard Recovery >500ns, > 200mA (Io)	-
Current - Reverse Leakage @ Vr	10	µA @ 400 V
Mounting Type	Through Hole	-
Package / Case	R-6, Axial	-
Operating Temperature - Junction	-65°C ~ 175°C	°C
RoHS Status	ROHS3 Compliant	-

Substitute Part Grouping Explanation

Substitution of the 6A4-T is determined by the following critical parameters:

Mandatory Electrical Compatibility:

Voltage - DC Reverse (Vr) (Max): 400 V minimum
Current - Average Rectified (Io): 6 A minimum
Speed classification: Standard or Fast Recovery acceptable
Operating Temperature - Junction: Must accommodate -65°C minimum

Package Compatibility:

Through-hole mounting required
R-6 axial package preferred for direct mechanical replacement
P600 axial package acceptable with mechanical adaptation
DO-201AD axial package acceptable with mechanical adaptation

Compliance Requirements:

RoHS3 compliance preferred for new designs
REACH compliance status documented

Substitute parts are grouped into three categories based on package configuration: R-6 direct replacements, P600 alternatives, and DO-201AD alternatives. Within each category, parts are further differentiated by recovery speed (Standard vs. Fast Recovery) and forward voltage characteristics.

Parameter Comparison

Part Number	Manufacturer	Vr (Max) [V]	Io [A]	Vf (Max) @ If [mV]	Speed	Package	Tj (°C)	Product Status	RoHS
6A4-T	Diodes Incorporated	400	6	900 @ 6A	Standard >500ns	R-6	-65 ~ 175	Obsolete	ROHS3
1N5551	Microchip Technology	400	3	1200 @ 9A	Standard >500ns	B, Axial	-65 ~ 175	Active	Non-compliant
6A04-G	Comchip Technology	400	6	1100 @ 6A	Standard >500ns	P600	-55 ~ 125	Active	ROHS3
6A04B-G	Comchip Technology	400	6	1000 @ 6A	Standard >500ns	R-6	-55 ~ 125	Active	ROHS3
6A4-TP	Micro Commercial Co	400	6	950 @ 6A	Standard >500ns	R-6	-55 ~ 125	Not For New Designs	ROHS3
6A40G B0G	Taiwan Semiconductor Corporation	400	6	1000 @ 6A	Standard >500ns	R-6	-55 ~ 150	Active	ROHS3
FR604GP-AP	Micro Commercial Co	400	6	1300 @ 6A	Fast ≤500ns	R-6	-55 ~ 150	Active	ROHS3
FR604GP-TP	Micro Commercial Co	400	6	1300 @ 6A	Fast ≤500ns	R-6	-55 ~ 150	Active	ROHS3
GI754-E3/54	Vishay General Semiconductor - Diodes Division	400	6	900 @ 6A	Standard >500ns	P600	-50 ~ 150	Active	ROHS3
HER505GP-AP	Micro Commercial Co	400	5	1300 @ 5A	Fast ≤500ns	DO-201AD	-65 ~ 150	Active	-
HER505GP-TP	Micro Commercial Co	400	5	1300 @ 5A	Fast ≤500ns	DO-201AD	-65 ~ 150	Active	-

Engineering Selection Recommendations

Primary Substitutes (R-6 Package, Standard Recovery, Active Status):

6A04B-G and 6A40G B0G are the preferred direct replacements for the 6A4-T. Both parts maintain the R-6 axial package configuration, support 6 A average rectified current at 400 V reverse voltage, and are classified as active products with ROHS3 compliance. 6A04B-G exhibits forward voltage of 1000 mV at 6 A with operating temperature range of -55°C to 125°C. 6A40G B0G provides forward voltage of 1000 mV at 6 A with extended operating temperature range of -55°C to 150°C.

Secondary Substitutes (P600 Package, Standard Recovery, Active Status):

6A04-G and GI754-E3/54 provide electrical equivalence with P600 axial package configuration. Both support 6 A average rectified current at 400 V reverse voltage and are ROHS3 compliant. 6A04-G exhibits forward voltage of 1100 mV at 6 A with operating temperature range of -55°C to 125°C. GI754-E3/54 exhibits forward voltage of 900 mV at 6 A with operating temperature range of -50°C to 150°C. Mechanical adaptation is required for P600 package integration into R-6 footprints.

Fast Recovery Alternatives (R-6 Package, Active Status):

FR604GP-AP and FR604GP-TP provide fast recovery characteristics (≤500 ns) with 6 A current rating and 400 V reverse voltage in R-6 package. Both are ROHS3 compliant with operating temperature range of -55°C to 150°C. Forward voltage is 1300 mV at 6 A. These parts are suitable for applications requiring reduced reverse recovery time.

Current-Limited Alternative (DO-201AD Package, Fast Recovery, Active Status):

HER505GP-AP and HER505GP-TP support 5 A average rectified current at 400 V reverse voltage with fast recovery characteristics (50 ns reverse recovery time) in DO-201AD axial package. Operating temperature range is -65°C to 150°C. These parts are suitable only for applications where 5 A current rating is acceptable.

Not Recommended for New Designs:

6A4-TP is classified as "Not For New Designs" and should not be selected for new circuit implementations despite electrical compatibility.

Frequently Asked Questions (FAQ)

Q: Can 6A04B-G directly replace 6A4-T without circuit modification?

A: Yes. 6A04B-G maintains identical electrical specifications for voltage (400 V), current (6 A), and package (R-6 axial). Forward voltage is 1000 mV at 6 A compared to 900 mV for the original part. Operating temperature range is -55°C to 125°C versus -65°C to 175°C for the original. Verify application temperature requirements before selection.

Q: What is the difference between Standard Recovery and Fast Recovery diodes in this product line?

A: Standard Recovery diodes exhibit recovery time greater than 500 ns, while Fast Recovery diodes exhibit recovery time of 150 ns or less. Fast Recovery diodes reduce switching losses in high-frequency applications but exhibit higher forward voltage. The 6A4-T specifies Standard Recovery. FR604GP-AP and FR604GP-TP provide Fast Recovery alternatives with 1300 mV forward voltage at 6 A.

Q: Can P600 package diodes be used in R-6 footprints?

A: P600 and R-6 are both axial through-hole packages with different physical dimensions. Mechanical adaptation is required. Verify PCB layout and component spacing before substitution. 6A04-G and GI754-E3/54 are P600 alternatives.

Q: Why is 1N5551 listed as a substitute if it only supports 3 A?

A: 1N5551 is included in the substitute list based on the provided input data. However, the 3 A current rating is below the 6 A requirement of the 6A4-T. This part is suitable only for applications where current demand does not exceed 3 A.

Q: What is the significance of RoHS3 compliance for this diode?

A: RoHS3 compliance indicates the part meets Restriction of Hazardous Substances requirements. 6A04B-G, 6A40G B0G, FR604GP-AP, FR604GP-TP, and GI754-E3/54 are ROHS3 compliant. 1N5551 is RoHS non-compliant. HER505GP-AP and HER505GP-TP do not specify RoHS status.

Q: Are there temperature limitations when substituting the 6A4-T?

A: Yes. The 6A4-T operates from -65°C to 175°C. Most active substitutes operate from -55°C to 125°C or -55°C to 150°C, representing reduced low-temperature capability. Applications requiring operation below -55°C require verification of substitute part suitability. HER505GP-AP and HER505GP-TP support -65°C minimum temperature.

Q: What packaging options are available for 6 A, 400 V diodes?

A: Three axial through-hole packages are represented: R-6 (6A04B-G, 6A40G B0G, FR604GP-AP, FR604GP-TP), P600 (6A04-G, GI754-E3/54), and DO-201AD (HER505GP-AP, HER505GP-TP at 5 A rating). R-6 package provides direct mechanical compatibility with the original 6A4-T footprint.

Q: How does forward voltage affect circuit performance?

A: Forward voltage determines voltage drop across the diode during conduction. The 6A4-T specifies 900 mV at 6 A. Substitutes range from 900 mV to 1300 mV at rated current. Higher forward voltage increases power dissipation and heat generation. Verify thermal design and voltage regulation requirements before selecting substitutes with elevated forward voltage specifications.

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