MJF18008 Equivalent & Substitute Parts

Part Overview

The MJF18008 is an NPN bipolar junction transistor (BJT) manufactured by onsemi, designed for high-voltage switching applications. This device operates at 450 V collector-emitter breakdown voltage with a maximum collector current of 8 A and 45 W power dissipation capability. The MJF18008 is classified as obsolete, necessitating identification of equivalent and substitute components for new designs and ongoing production requirements. Active alternatives with identical or comparable electrical characteristics are available to ensure design continuity and supply chain reliability.

Substiute Parts

MJF18008

onsemiIn Stock: 1509MJF18008 Datasheet

Current PartRFQ

MJF18008G

onsemiIn Stock: 1345MJF18008G Datasheet

DirectRFQ

BUT11AFTU

onsemiIn Stock: 2203BUT11AFTU Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the MJF18008 is determined by strict equivalence across the following critical electrical and mechanical parameters:

Direct Equivalent Criteria:

• Transistor type (NPN)
• Voltage - Collector Emitter Breakdown (450 V minimum)
• Current - Collector (Ic) rating (8 A or higher)
• Power dissipation capability (45 W or higher)
• Mounting type (Through Hole)
• Package type (TO-220-3 Full Pack)

Similar Substitute Criteria:

• Transistor type (NPN)
• Voltage - Collector Emitter Breakdown (450 V minimum)
• Current - Collector (Ic) rating (5 A or higher, with derating consideration)
• Power dissipation capability (40 W or higher, with derating consideration)
• Mounting type (Through Hole)
• Package type (TO-220 variant)

The MJF18008G qualifies as a direct equivalent, maintaining identical electrical specifications while offering active product status and improved compliance. The BUT11AFTU qualifies as a similar substitute with reduced current and power ratings, suitable for applications with lower current demands.

Parameter Comparison

Engineering Selection Recommendations

MJF18008G (Direct Equivalent): The MJF18008G is the primary substitute for the obsolete MJF18008. This part maintains identical electrical specifications across all critical parameters: 450 V breakdown voltage, 8 A maximum collector current, 45 W power dissipation, and 13 MHz transition frequency. The MJF18008G carries active product status, ensuring long-term availability and supply chain stability. The part is ROHS3 compliant, addressing regulatory requirements that the original MJF18008 does not meet. Mechanical compatibility is confirmed through identical TO-220-3 Full Pack packaging. Direct substitution is appropriate for all applications currently using the MJF18008 without circuit modification.

BUT11AFTU (Similar Substitute): The BUT11AFTU is a similar substitute suitable for applications where collector current requirements do not exceed 5 A and power dissipation remains below 40 W. This part maintains the 450 V breakdown voltage and through-hole TO-220 mounting configuration. The BUT11AFTU is ROHS3 compliant and carries active product status. Differences in saturation voltage (1.5 V versus 700 mV), collector cutoff current (1 mA versus 100µA), and unspecified transition frequency require circuit evaluation before substitution. This part is appropriate for lower-current switching applications or as a secondary option when the MJF18008G is unavailable.

Frequently Asked Questions (FAQ)

Q: Can the MJF18008G be used as a direct replacement for the MJF18008?

A: Yes. The MJF18008G maintains identical electrical specifications for voltage, current, power, and frequency parameters. Mechanical compatibility is confirmed through identical TO-220-3 Full Pack packaging. No circuit modifications are required.

Q: What is the primary advantage of using MJF18008G over the original MJF18008?

A: The MJF18008G carries active product status and is ROHS3 compliant, whereas the MJF18008 is obsolete and RoHS non-compliant. This ensures long-term supply availability and regulatory compliance for new designs.

Q: Can the BUT11AFTU replace the MJF18008 in all applications?

A: No. The BUT11AFTU has reduced maximum collector current (5 A versus 8 A) and power dissipation (40 W versus 45 W). Substitution is limited to applications where these reduced ratings are acceptable. Circuit evaluation is required before substitution.

Q: What are the key differences between MJF18008G and BUT11AFTU?

A: The MJF18008G provides full electrical equivalence with 8 A current and 45 W power capability. The BUT11AFTU offers reduced ratings at 5 A and 40 W, with higher saturation voltage (1.5 V versus 700 mV) and higher collector cutoff current (1 mA versus 100µA). Both maintain 450 V breakdown voltage and through-hole mounting.

Q: Are there packaging differences between these parts?

A: All three parts use TO-220-3 Full Pack through-hole mounting. The MJF18008 and MJF18008G use TO-220FP supplier packaging, while the BUT11AFTU uses TO-220F-3 supplier packaging. Physical compatibility with PCB layouts is maintained across all variants.

Q: What compliance certifications apply to these substitutes?

A: Both MJF18008G and BUT11AFTU are ROHS3 compliant and REACH unaffected. The original MJF18008 is RoHS non-compliant, making the active alternatives preferable for regulatory compliance.

Q: Is the MJF18008G available in the same packaging options as the MJF18008?

A: The MJF18008G is supplied in tube packaging, while the original MJF18008 packaging is not specified. Both maintain identical TO-220-3 Full Pack case configuration suitable for through-hole PCB assembly.