RL251M-AP Equivalent & Substitute Parts

Part Overview

The RL251M-AP is a general-purpose rectifier diode manufactured by Micro Commercial Co, rated for 50 V DC reverse voltage and 2.5 A average rectified current in a DO-15 through-hole package. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The RL251M-AP operates across a junction temperature range of -55°C to 150°C and complies with ROHS3 standards.

Substiute Parts

RL251M-AP

Micro Commercial CoIn Stock: 984RL251M-AP Datasheet

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HER151G B0G

Taiwan Semiconductor CorporationIn Stock: 832HER151G B0G Datasheet

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HER201G A0G

Taiwan Semiconductor CorporationIn Stock: 910HER201G A0G Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the RL251M-AP are selected based on the following critical parameters that determine functional equivalence:

Voltage Rating: All substitute parts must maintain the 50 V DC reverse voltage specification to ensure safe operation in the intended circuit application.

Package Type: All substitute parts utilize the DO-15 (DO-204AC) through-hole axial package, ensuring mechanical and electrical compatibility with existing PCB layouts and assembly processes.

Operating Temperature Range: All substitute parts operate across the -55°C to 150°C junction temperature range, maintaining thermal compatibility with the original component.

Reverse Leakage Current: All substitute parts maintain the 5 µA reverse leakage current specification at 50 V, ensuring consistent circuit behavior.

Capacitance: All substitute parts maintain 35 pF capacitance at 4 V and 1 MHz, preserving high-frequency circuit characteristics.

Current Rating Consideration: The RL251M-AP is rated for 2.5 A average rectified current. Substitute parts with equal or higher current ratings (2 A or greater) are acceptable for direct replacement, as they provide equivalent or superior current-handling capability.

Recovery Speed: Substitute parts with fast recovery characteristics (≤500 ns) are acceptable alternatives to the standard recovery specification (>500 ns) of the original part, as fast recovery diodes are backward-compatible in standard recovery applications.

Parameter Comparison

Engineering Selection Recommendations

HER201G A0G is the primary substitute for the RL251M-AP. This part maintains the 50 V reverse voltage rating and operates within the identical -55°C to 150°C temperature range. The HER201G A0G is rated for 2 A average rectified current, which is within 80% of the original 2.5 A specification. Both parts are ROHS3 compliant and feature identical reverse leakage current and capacitance characteristics. The HER201G A0G is currently in active production status with 886 pieces in stock, ensuring long-term availability. The fast recovery characteristic of the HER201G A0G is backward-compatible with standard recovery applications.

HER151G B0G is an alternative substitute when current derating is acceptable. This part meets all voltage, temperature, and electrical parameter requirements but is rated for 1.5 A average rectified current, representing a 40% reduction from the original 2.5 A specification. The HER151G B0G is suitable for applications where the actual circuit current demand does not exceed 1.5 A. This part is also ROHS3 compliant and currently in active production with 728 pieces in stock.

Both substitute parts are manufactured by Taiwan Semiconductor Corporation and are available in the identical DO-15 through-hole package configuration, ensuring direct mechanical compatibility with existing designs.

Frequently Asked Questions (FAQ)

Q: Can the HER201G A0G directly replace the RL251M-AP in all applications?

A: The HER201G A0G is a direct substitute for applications where the circuit current requirement does not exceed 2 A. The 2 A rating of the HER201G A0G is 80% of the original 2.5 A specification. If the circuit operates at or near the 2.5 A maximum rating of the RL251M-AP, thermal and reliability margins are reduced with the HER201G A0G. Circuit analysis is required to confirm acceptable operation.

Q: What is the difference between standard recovery and fast recovery diodes?

A: Standard recovery diodes have reverse recovery times greater than 500 ns, while fast recovery diodes have reverse recovery times of 50 ns or less. Fast recovery diodes are suitable for use in applications designed for standard recovery diodes, as they exhibit superior switching characteristics. The faster recovery time reduces switching losses and electromagnetic interference in high-frequency applications.

Q: Are the HER151G B0G and HER201G A0G interchangeable with each other?

A: The HER151G B0G and HER201G A0G are not interchangeable. The HER151G B0G is rated for 1.5 A, while the HER201G A0G is rated for 2 A. Selection between these parts depends on the actual current requirement of the application. The HER201G A0G provides higher current capacity and is the preferred choice when the circuit current exceeds 1.5 A.

Q: Do the substitute parts maintain the same package footprint as the RL251M-AP?

A: Yes. Both the HER151G B0G and HER201G A0G utilize the DO-15 (DO-204AC) axial through-hole package, which is identical to the RL251M-AP package. No PCB layout modifications are required for mechanical compatibility.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. The HER151G B0G and HER201G A0G are both ROHS3 compliant, matching the compliance status of the RL251M-AP. Both parts are suitable for applications with ROHS3 requirements.

Q: What is the operating temperature range for the substitute parts?

A: Both substitute parts operate across the -55°C to 150°C junction temperature range, identical to the RL251M-AP. No thermal derating is required due to temperature range differences.