RU 4B Equivalent & Substitute Parts – Engineering Reference

Part Overview

RU 4B, manufactured by Sanken Electric USA Inc., is an axial, through-hole general-purpose rectifier diode rated at 800 V and 1.5 A. The device operates with fast recovery (trr = 400 ns) and is RoHS compliant. The part has reached an obsolete status, necessitating identification of compatible substitute diodes. Selecting suitable alternates is essential to maintain system reliability and compliance in electronic assemblies.

Key Parameters

Parameter	Value (RU 4B)
Manufacturer	Sanken Electric USA Inc.
Category	Diodes, Rectifiers
Voltage - DC Reverse (Vr) (Max)	800 V
Current - Average Rectified (Io)	1.5A
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 3 A
Speed / Reverse Recovery Time (trr)	Fast Recovery = 400 ns
Current - Reverse Leakage @ Vr	10 µA @ 800 V
Mounting Type	Through Hole
Package / Case	Axial
Operating Temperature - Junction	-40°C ~ 150°C
RoHS Status	RoHS Compliant

Substitute Part Grouping Explanation

Substitutes for RU 4B in the Diodes, Rectifiers category are determined on the basis of critical electrical and mechanical compatibility:

Maximum DC Reverse Voltage (Vr)
Average Rectified Current (Io)
Forward Voltage (Vf) at specified current
Reverse Recovery Time (trr) or Speed, within the category's allowed range
Reverse Leakage Current at Vr
Mounting Type and Package / Case: through-hole, axial configuration
RoHS and moisture sensitivity compliance

All candidate substitute parts strictly meet or exceed the RU 4B’s parameters according to the provided input data.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Voltage - DC Reverse (Vr) (Max)	Current - Average Rectified (Io)	Voltage - Forward (Vf) (Max) @ If	Speed / Reverse Recovery Time (trr)	Current - Reverse Leakage @ Vr	Mounting Type	Package / Case	Operating Temperature - Junction	RoHS Status
RU 4B	Sanken Electric USA Inc.	800 V	1.5A	1.5 V @ 3 A	400 ns (Fast Recovery)	10 µA @ 800 V	Through Hole	Axial	-40°C ~ 150°C	RoHS Compliant
RGP30K-E3/54	Vishay	800 V	3A	1.3 V @ 3 A	500 ns (Fast Recovery)	5 µA @ 800 V	Through Hole	DO-201AD, Axial	-65°C ~ 175°C	ROHS3 Compliant
UF5407-E3/54	Vishay	800 V	3A	1.7 V @ 3 A	75 ns (Fast Recovery)	10 µA @ 800 V	Through Hole	DO-201AD, Axial	-55°C ~ 150°C	ROHS3 Compliant
GP30K-E3/54	Vishay	800 V	3A	1.1 V @ 3 A	5 µs (Standard Recovery)	5 µA @ 800 V	Through Hole	DO-201AD, Axial	-65°C ~ 175°C	ROHS3 Compliant
1N5407G	Taiwan Semiconductor	800 V	3A	1 V @ 3 A	Standard Recovery >500ns	5 µA @ 800 V	Through Hole	DO-201AD, Axial	-55°C ~ 150°C	ROHS3 Compliant
1N5407G-T	Diodes Incorporated	800 V	3A	1.1 V @ 3 A	2 µs (Standard Recovery)	5 µA @ 800 V	Through Hole	DO-201AD, Axial	-65°C ~ 150°C	ROHS3 Compliant
1N5408G	Taiwan Semiconductor	1000 V	3A	1 V @ 3 A	Standard Recovery >500ns	5 µA @ 1000 V	Through Hole	DO-201AD, Axial	-55°C ~ 150°C	ROHS3 Compliant
1N5627-TR	Vishay	800 V	3A	1 V @ 3 A	7.5 µs (Standard Recovery)	1 µA @ 800 V	Through Hole	SOD-64, Axial	-55°C ~ 175°C	ROHS3 Compliant
STTH208	STMicroelectronics	800 V	2A	1.65 V @ 2 A	75 ns (Fast Recovery)	5 µA @ 800 V	Through Hole	DO-204AC, DO-15, Axial	175°C (Max)	ROHS3 Compliant

Engineering Selection Recommendations

RU 4B has reached obsolete status and is no longer in active production. All substitute parts listed are RoHS compliant and have Moisture Sensitivity Level (MSL) 1. The substitutes maintain active product status and match or exceed compliance specifications as indicated by their respective certifications. When selecting an alternate, ensure that documentation and compliance standards are met according to the requirements enforced in your specific application or region.

Frequently Asked Questions (FAQ)

Q1: What are the mandatory parameters for substituting a diode in the Diodes, Rectifiers category?
A1: Substitution must be based on: maximum DC reverse voltage (Vr), average rectified current (Io), forward voltage (Vf) at rated current, reverse recovery time (trr), reverse leakage current at Vr, mounting type, package/case compatibility, and RoHS status.

Q2: Is package type critical in diode substitution?
A2: Yes. Only through-hole, axial package/case types as listed in the input are allowed for direct substitution, maintaining form-factor and compatibility for PCB and mechanical assembly.

Q3: Do all listed substitute diodes meet the compliance and reliability criteria?
A3: Yes. All listed substitutes are RoHS compliant, have MSL 1, and are in active product status based on their provided specifications.

Q4: Can substitute parts have higher voltage or current ratings than the original RU 4B?
A4: Substitutes may exceed but must not fall below the original’s specified maximum DC reverse voltage (Vr) and average rectified current (Io) as per input requirements.

Q5: How should reverse recovery time (trr) be considered?
A5: Only substitute diodes with reverse recovery times specified in the input parameter set are included. Fast recovery characteristics are matched as defined.

Q6: Is RoHS compliance mandatory for substitutes?
A6: Yes. Only substitute parts documented as RoHS or ROHS3 compliant are included for full environmental and regulatory equivalence.

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