BY399 Fast Recovery Diode Equivalent & Substitute Parts

Part Overview

The BY399 is a fast recovery rectifier diode manufactured by Diotec Semiconductor, rated for 800 V DC reverse voltage with 3 A average rectified current. This component is designed for through-hole mounting in the DO-201AA axial package configuration. The device features a fast recovery time of 500 ns, making it suitable for applications requiring rapid switching characteristics.

The BY399 maintains Active product status. Identification of equivalent and substitute parts becomes necessary when addressing supply chain requirements, inventory constraints, or when design specifications permit operation within the electrical and mechanical parameters of alternative qualified components.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	800	V
Current - Average Rectified (Io)	3	A
Voltage - Forward (Vf) (Max) @ If	1.2 @ 3	V @ A
Reverse Recovery Time (trr)	500	ns
Current - Reverse Leakage @ Vr	5	µA @ 800 V
Operating Temperature - Junction	-50 to 150	°C
Mounting Type	Through Hole	-
Package / Case	DO-201AA, DO-27, Axial	-

Substitute Part Grouping Explanation

Substitution of the BY399 is determined by equivalence across the following critical electrical and mechanical parameters:

Electrical Equivalence Criteria:

Voltage - DC Reverse (Vr) (Max): 800 V minimum
Current - Average Rectified (Io): 3 A minimum
Mounting Type: Through Hole
Package / Case: DO-201AA, DO-27, or Axial configuration

Recovery Characteristics: The BY399 specifies fast recovery operation with reverse recovery time (trr) of 500 ns. Substitute parts may operate at standard recovery speeds (>500 ns) provided all voltage and current ratings are met or exceeded.

Temperature Range: The BY399 operates across -50°C to 150°C junction temperature. Substitute parts with equal or extended temperature ranges maintain functional compatibility.

The 1N5407RLG, manufactured by onsemi, satisfies all electrical and mechanical substitution criteria for the BY399 within the specified parameter envelope.

Parameter Comparison

Parameter	BY399 (Diotec)	1N5407RLG (onsemi)	Unit
Voltage - DC Reverse (Vr) (Max)	800	800	V
Current - Average Rectified (Io)	3	3	A
Voltage - Forward (Vf) (Max) @ If	1.2 @ 3	1.0 @ 3	V @ A
Reverse Recovery Time (trr)	500	>500	ns
Current - Reverse Leakage @ Vr	5	10	µA @ 800 V
Operating Temperature - Junction	-50 to 150	-65 to 150	°C
Mounting Type	Through Hole	Through Hole	-
Package / Case	DO-201AA, DO-27, Axial	DO-201AA, DO-27, Axial	-
Product Status	Active	Not For New Designs	-

Engineering Selection Recommendations

BY399 (Diotec Semiconductor): The BY399 maintains Active product status and is suitable for new design implementations. This component is the primary selection for applications requiring ongoing supply chain support and long-term availability assurance.

1N5407RLG (onsemi): The 1N5407RLG carries a "Not For New Designs" product status designation. This substitute part meets all electrical and mechanical equivalence requirements and is suitable for legacy system maintenance, repair operations, or applications where design refresh cycles are not planned. The 1N5407RLG provides extended lower temperature operation (-65°C minimum versus -50°C) and demonstrates ROHS3 compliance with REACH Unaffected status.

Selection between these components should be based on design phase requirements and supply availability. Both components operate within identical voltage and current specifications and share compatible through-hole axial packaging.

Frequently Asked Questions (FAQ)

Q: Can the 1N5407RLG directly replace the BY399 in existing circuit designs?

A: Yes. Both components share identical voltage ratings (800 V), current ratings (3 A), and through-hole axial package configurations (DO-201AA, DO-27). Physical dimensions and pin configurations are compatible. The 1N5407RLG forward voltage drop is lower (1.0 V versus 1.2 V at 3 A), which may reduce power dissipation in the application.

Q: What is the significance of the "Not For New Designs" status on the 1N5407RLG?

A: This designation indicates that onsemi does not recommend the 1N5407RLG for new product development. The component remains available for existing applications and maintenance purposes. For new designs, the BY399 (Active status) is the preferred selection to ensure long-term supply chain continuity.

Q: Are there differences in recovery speed between these components?

A: Yes. The BY399 specifies fast recovery operation with 500 ns reverse recovery time. The 1N5407RLG operates at standard recovery speeds (>500 ns). In applications where fast switching transitions are critical, the BY399 characteristics should be verified against circuit requirements. Both components meet the >200 mA threshold for speed classification.

Q: Do these components require different mounting techniques?

A: No. Both the BY399 and 1N5407RLG use identical through-hole axial mounting in the DO-201AA package. Printed circuit board layouts, lead spacing, and soldering procedures remain unchanged between components.

Q: What compliance differences exist between these parts?

A: The 1N5407RLG is ROHS3 compliant with REACH Unaffected status. The BY399 RoHS status is listed as "Not applicable." Both components carry EAR99 ECCN classification. Compliance requirements should be verified against specific application and regional regulations.

Q: How do reverse leakage currents compare?

A: The BY399 specifies 5 µA reverse leakage at 800 V, while the 1N5407RLG specifies 10 µA at the same voltage. In high-impedance or precision analog applications, this difference may be significant and should be evaluated against circuit design tolerances.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message