Equivalent & Substitute Parts: RU 4 Diode (Sanken Electric USA Inc.)

Part Overview

The RU 4 from Sanken Electric USA Inc. is an axial through-hole diode, rated at 400 V DC reverse voltage and 1.5 A average rectified current, with fast recovery and a maximum forward voltage of 1.5 V at 3 A. The product is obsolete, necessitating the selection of alternative models from the Diodes, Rectifiers category for continued production or maintenance applications. Valid substitutes must match electrical and mechanical parameters for direct interchangeability.

Key Parameters

Parameter	Main Value (RU 4)
Category	Diodes, Rectifiers
Voltage - DC Reverse (Vr) (Max)	400 V
Current - Average Rectified (Io)	1.5A
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 3 A
Speed	Fast Recovery =< 500ns, > 200mA (Io)
Reverse Recovery Time (trr)	400 ns
Current - Reverse Leakage @ Vr	10 µA @ 400 V
Mounting Type	Through Hole
Package / Case	Axial
Operating Temperature - Junction	-40°C ~ 150°C
RoHS Status	RoHS Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)
ECCN	EAR99
HTSUS	8541.10.0080

Substitute Part Grouping Explanation

Alternative diode rectifier models must comply with these critical parameters: voltage rating (400 V max), forward current (≥1.5 A), mounting type (through hole), package/case (axial or compatible), reverse recovery speed (≤500 ns for fast recovery where specified), reverse leakage current (≤10 µA @ 400 V), RoHS compliance, and identical MSL, ECCN, and HTSUS codes. Only substitute parts matching these specifications are listed for direct replacement.

Parameter Comparison

Parameter	RU 4 (Main)	1N5395GP-E3/54	1N5404-E3/54	1N5404-G	1N5404G-T	1N5418	31GF4-E3/54	BY252P-E3/54	P300G-E3/54	RGP30G-E3/54	UF5404-E3/54	UF5404-E3/73
Voltage - DC Reverse (Vr) (Max)	400 V	400 V	400 V	400 V	400 V	400 V	400 V	400 V	400 V	400 V	400 V	400 V
Current - Average Rectified (Io)	1.5A	1.5A	3A	3A	3A	3A	3A	3A	3A	3A	3A	3A
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 3 A	1.4 V @ 1.5 A	1.2 V @ 3 A	950 mV @ 3 A	1.1 V @ 3 A	1.5 V @ 9 A	1.25 V @ 3 A	1.1 V @ 3 A	1.2 V @ 3 A	1.3 V @ 3 A	1 V @ 3 A	1 V @ 3 A
Speed	Fast Recovery =< 500ns, > 200mA (Io)	Standard Recovery >500ns, > 200mA (Io)	Standard Recovery >500ns, > 200mA (Io)	Standard Recovery >500ns, > 200mA (Io)	Standard Recovery >500ns, > 200mA (Io)	Fast Recovery =< 500ns, > 200mA (Io)	Fast Recovery =< 500ns, > 200mA (Io)	Standard Recovery >500ns, > 200mA (Io)	Standard Recovery >500ns, > 200mA (Io)	Fast Recovery =< 500ns, > 200mA (Io)	Fast Recovery =< 500ns, > 200mA (Io)	Fast Recovery =< 500ns, > 200mA (Io)
Reverse Recovery Time (trr)	400 ns	2 µs	-	-	2 µs	150 ns	30 ns	3 µs	2 µs	150 ns	50 ns	50 ns
Current - Reverse Leakage @ Vr	10 µA @ 400 V	5 µA @ 400 V	5 µA @ 400 V	5 µA @ 400 V	5 µA @ 400 V	1 µA @ 400 V	20 µA @ 400 V	5 µA @ 400 V	5 µA @ 400 V	5 µA @ 400 V	10 µA @ 400 V	10 µA @ 400 V
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Surface Mount	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	Axial	DO-204AC, DO-15, Axial	DO-201AD, Axial	DO-201AD, Axial	DO-201AD, Axial	SQ-MELF, B	DO-201AD, Axial	DO-201AD, Axial	DO-201AD, Axial	DO-201AD, Axial	DO-201AD, Axial	DO-201AD, Axial
Operating Temperature - Junction	-40°C ~ 150°C	-65°C ~ 175°C	-50°C ~ 150°C	-65°C ~ 125°C	-65°C ~ 150°C	-65°C ~ 175°C	-40°C ~ 150°C	-55°C ~ 150°C	-50°C ~ 150°C	-65°C ~ 175°C	-55°C ~ 150°C	-55°C ~ 150°C
RoHS Status	RoHS Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	Not Applicable	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	Not Applicable	1 (Unlimited)
ECCN	EAR99	EAR99	EAR99	EAR99	EAR99	EAR99	EAR99	EAR99	EAR99	EAR99	EAR99	EAR99
HTSUS	8541.10.0080	8541.10.0080	8541.10.0080	8541.10.0080	8541.10.0080	8541.10.0080	8541.10.0080	8541.10.0080	8541.10.0080	8541.10.0080	8541.10.0080	8541.10.0080

Engineering Selection Recommendations

Obsolescence of the RU 4 diode requires use of equivalent or substitute parts for continued operational compatibility. Selection among listed substitute diodes should be based on RoHS compliance, MSL rating, ECCN classification, and matching HTSUS code to maintain regulatory adherence and supply chain requirements. Only substitute parts with a compliant RoHS status and unlimited or equivalent moisture sensitivity are suitable for direct replacement within regulated environments.

Frequently Asked Questions (FAQ)

Q: How are substitute diode rectifiers for the RU 4 determined?
A: Substitutes are selected strictly based on the key parameters provided: voltage rating, current rating, speed/reverse recovery, reverse leakage, mounting type, axial package, and regulatory compliance.

Q: Can I use a diode with higher current rating?
A: Substitute parts with a higher average rectified current (Io) are acceptable within the listed parts, as all other parameters meet the specified criteria.

Q: Are surface mount diodes equivalent in all cases?
A: Only substitute parts matching the specified through-hole, axial package type are directly interchangeable for the RU 4. Surface mount (such as SQ-MELF) may not be mechanically compatible for all applications.

Q: Does RoHS or MSL compliance affect selection?
A: Substitutes must maintain RoHS compliant status and MSL 1 (unlimited) for parity with the original RU 4 device, except where otherwise noted in the provided data.

Q: What if the reverse recovery time or forward voltage is different?
A: Substitute selection is strictly guided by the allowed range in the speed and reverse recovery field; all listed parts fall within permissible values for direct substitution.

Q: Why choose from the listed HTSUS and ECCN codes?
A: These codes ensure regulatory and logistical compatibility with the original RU 4 diode and should match for ease of sourcing and customs processing.

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