FJP5021 Equivalent & Substitute Parts

Part Overview

The FJP5021 is an NPN bipolar junction transistor manufactured by onsemi, rated for 500 V collector-emitter breakdown voltage and 5 A maximum collector current in a Through Hole TO-220-3 package. This device is classified as obsolete, making identification of equivalent substitute components necessary for ongoing design support and procurement continuity. The FJP5021 is suitable for high-voltage switching and amplification applications requiring moderate current handling in industrial and consumer electronics.

Substiute Parts

FJP5021

onsemiIn Stock: 1044FJP5021 Datasheet

Current PartRFQ

BUJ303A,127

WeEn SemiconductorsIn Stock: 6631BUJ303A,127 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the FJP5021 is determined by electrical and mechanical parameter matching within the NPN bipolar junction transistor category. The critical parameters for substitution are:

• Transistor Type: NPN configuration
• Collector Current Rating: 5 A maximum
• Collector-Emitter Breakdown Voltage: 500 V minimum
• Mounting Type: Through Hole
• Package Type: TO-220-3 or compatible TO-220 variant
• Operating Temperature Range: 150°C maximum junction temperature
• Moisture Sensitivity: MSL 1 (Unlimited)

The BUJ303A,127 meets these core electrical and mechanical requirements, enabling direct substitution in applications where the FJP5021 is specified. Secondary parameters such as power dissipation, saturation voltage, and transition frequency may vary within acceptable design margins but do not preclude functional equivalence.

Parameter Comparison

Engineering Selection Recommendations

The BUJ303A,127 manufactured by WeEn Semiconductors is a direct electrical and mechanical equivalent to the FJP5021. Both devices share identical collector current and breakdown voltage ratings, compatible TO-220-3 Through Hole packaging, and equivalent moisture sensitivity classification.

The BUJ303A,127 offers the following advantages for component selection:

• Active Product Status: The BUJ303A,127 is currently in active production, ensuring long-term availability and supply chain continuity compared to the obsolete FJP5021.
• Regulatory Compliance: Both devices maintain REACH Unaffected status and EAR99 ECCN classification, with the BUJ303A,127 additionally certified as ROHS3 Compliant.
• Enhanced Power Rating: The BUJ303A,127 provides 100 W maximum power dissipation versus 50 W for the FJP5021, offering improved thermal headroom in applications approaching power limits.
• Inventory Availability: The BUJ303A,127 maintains higher stock levels (6581 pcs) compared to the FJP5021 (1009 pcs), supporting procurement reliability.

Selection of the BUJ303A,127 is appropriate for new designs and end-of-life replacement of FJP5021-based applications without circuit modification.

Frequently Asked Questions (FAQ)

Q: Can the BUJ303A,127 be used as a direct replacement for the FJP5021 without circuit changes?

A: Yes. Both devices are NPN transistors with identical 5 A collector current and 500 V breakdown voltage ratings in compatible TO-220-3 Through Hole packages. Pin configuration and electrical characteristics are equivalent for standard switching and amplification applications.

Q: What are the differences between the FJP5021 and BUJ303A,127?

A: The primary differences are product status (FJP5021 is obsolete; BUJ303A,127 is active), maximum power dissipation (50 W versus 100 W), and collector cutoff current (10 µA versus 100 µA). The BUJ303A,127 also carries ROHS3 Compliant certification. These differences do not affect functional substitution in most applications.

Q: Are the TO-220-3 and TO-220AB packages mechanically compatible?

A: Yes. Both designations refer to the same three-lead Through Hole package with identical pin spacing and mounting footprint. The TO-220AB variant designation indicates a specific lead configuration standard but maintains full mechanical and electrical compatibility with TO-220-3 applications.

Q: What is the significance of the higher collector cutoff current in the BUJ303A,127?

A: The BUJ303A,127 specifies 100 µA maximum collector cutoff current compared to 10 µA for the FJP5021. This parameter represents leakage current in the off state. The higher specification does not affect switching performance in typical applications but may require consideration in precision analog circuits requiring extremely low leakage.

Q: Does the higher power rating of the BUJ303A,127 affect thermal management requirements?

A: The BUJ303A,127 100 W rating provides additional thermal margin compared to the FJP5021 50 W rating. Existing thermal management designs for the FJP5021 remain valid for the BUJ303A,127. Applications operating near the 50 W limit may benefit from the increased power rating without additional cooling modifications.

Q: Are both devices suitable for high-voltage switching applications?

A: Yes. Both the FJP5021 and BUJ303A,127 are rated for 500 V collector-emitter breakdown voltage and are suitable for high-voltage switching applications in industrial power supplies, motor control, and similar circuits operating at or below 500 V.