BY458TR Equivalent & Substitute Parts

Part Overview

The BY458TR is an avalanche diode rated for 1200 V DC reverse voltage and 2 A average rectified current, manufactured by Vishay General Semiconductor - Diodes Division. The device is packaged in SOD-57 axial configuration for through-hole mounting applications. This part is Active in product status and fully compliant with RoHS3 and REACH regulations. Substitute parts are identified when equivalent electrical performance is required, packaging constraints change, or inventory availability necessitates alternative sourcing while maintaining circuit functionality.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	1200	V
Current - Average Rectified (Io)	2	A
Voltage - Forward (Vf) (Max) @ If	1.6 @ 3	V @ A
Reverse Recovery Time (trr)	2	µs
Current - Reverse Leakage @ Vr	3	µA @ 1200 V
Operating Temperature - Junction (Max)	140	°C
Package / Case	SOD-57, Axial	—
Mounting Type	Through Hole	—
Technology	Avalanche	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitute parts for the BY458TR are selected based on electrical parameter compatibility within the following criteria:

Primary Substitution Logic:

Voltage - DC Reverse (Vr) rating must equal or exceed 1200 V
Current - Average Rectified (Io) must equal or exceed 2 A
Forward voltage (Vf) and reverse recovery time (trr) must be compatible with circuit timing and power dissipation requirements
Mounting type must be Through Hole to maintain PCB assembly compatibility
RoHS3 compliance and REACH status must be maintained

Identified Substitute Parts:

BY448TAP — Avalanche diode with 1500 V rating and 2 A current capacity, same SOD-57 package, higher voltage rating provides design margin
STTH112RL — General purpose diode with 1200 V rating and 1 A current capacity, DO-41 package, lower current rating requires circuit evaluation

Parameter Comparison

Parameter	BY458TR	BY448TAP	STTH112RL
Manufacturer	Vishay General Semiconductor	Vishay General Semiconductor	STMicroelectronics
Voltage - DC Reverse (Vr) (Max)	1200 V	1500 V	1200 V
Current - Average Rectified (Io)	2 A	2 A	1 A
Voltage - Forward (Vf) (Max) @ If	1.6 V @ 3 A	1.6 V @ 3 A	1.9 V @ 1 A
Reverse Recovery Time (trr)	2 µs	2 µs	75 ns
Current - Reverse Leakage @ Vr	3 µA @ 1200 V	3 µA @ 1200 V	5 µA @ 1200 V
Operating Temperature - Junction (Max)	140°C	140°C	175°C
Package / Case	SOD-57, Axial	SOD-57, Axial	DO-41, Axial
Mounting Type	Through Hole	Through Hole	Through Hole
Technology	Avalanche	Avalanche	Standard
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Packaging Format	Tape & Reel (TR)	Cut Tape (CT)	Cut Tape (CT)

Engineering Selection Recommendations

BY448TAP Substitution: The BY448TAP is a direct functional substitute for the BY458TR. Both devices employ avalanche technology, maintain identical forward voltage characteristics, and share the same SOD-57 package footprint. The BY448TAP provides a higher DC reverse voltage rating of 1500 V compared to the 1200 V of the BY458TR, offering increased design margin for overvoltage transient conditions. Both parts are Active in product status, ROHS3 compliant, and REACH unaffected. The BY448TAP is suitable for applications where higher voltage headroom is beneficial or required.

STTH112RL Substitution: The STTH112RL is a partial substitute with significant parameter differences. While it maintains the 1200 V DC reverse voltage rating and Through Hole mounting, the current capacity is reduced to 1 A, compared to the 2 A rating of the BY458TR. The STTH112RL employs standard recovery technology with a 75 ns reverse recovery time, substantially faster than the 2 µs of the BY458TR. The package format differs (DO-41 versus SOD-57), requiring PCB layout modification. This substitute is applicable only in circuits where the 1 A current limit is acceptable and faster switching characteristics are advantageous. The STTH112RL is Active in product status and fully compliant with RoHS3 and REACH requirements.

Frequently Asked Questions (FAQ)

Q: Can BY448TAP directly replace BY458TR without circuit modification? A: Yes. The BY448TAP maintains electrical compatibility with identical forward voltage, reverse recovery time, and current rating. The higher voltage rating (1500 V versus 1200 V) does not require circuit changes. Package footprint is identical (SOD-57 axial). Substitution is direct.

Q: What are the limitations of using STTH112RL as a substitute? A: The STTH112RL has a reduced current rating of 1 A compared to the 2 A of the BY458TR. Applications requiring the full 2 A capacity cannot use this substitute. Additionally, the DO-41 package differs from the SOD-57, requiring PCB layout changes. The faster recovery time (75 ns) may affect circuit timing in applications sensitive to switching speed.

Q: Are all substitute parts RoHS3 compliant? A: Yes. Both BY448TAP and STTH112RL are ROHS3 compliant and REACH unaffected, matching the compliance status of the BY458TR.

Q: What is the primary difference between avalanche and standard recovery technology in these diodes? A: Avalanche diodes (BY458TR and BY448TAP) are designed to conduct in reverse bias under overvoltage conditions, providing transient protection. Standard recovery diodes (STTH112RL) do not provide this avalanche protection function. Technology selection depends on circuit protection requirements.

Q: Can STTH112RL be used in high-current applications originally designed for BY458TR? A: No. The STTH112RL current rating of 1 A is insufficient for applications requiring 2 A. Using an undersized current component creates thermal stress and reliability risk.

Q: Does packaging format affect electrical performance? A: No. Packaging format (Tape & Reel versus Cut Tape) affects supply and handling logistics but not electrical characteristics. However, physical package shape (SOD-57 versus DO-41) requires PCB footprint compatibility verification.

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