BUL741 Equivalent & Substitute Parts

Part Overview

The BUL741 is an NPN bipolar junction transistor manufactured by STMicroelectronics, designed for high-voltage switching and amplification applications. This through-hole TO-220 package device operates at collector-emitter breakdown voltages up to 400 V with a maximum collector current of 2.5 A and power dissipation of 60 W. The BUL741 maintains Active product status with full RoHS3 compliance and unlimited moisture sensitivity rating. Substitute parts are identified when equivalent electrical performance and mechanical compatibility are required due to component availability, supply chain considerations, or design flexibility within specified parameter tolerances.

Substiute Parts

BUL741

STMicroelectronicsIn Stock: 2028BUL741 Datasheet

Current PartRFQ

BUX85G

onsemiIn Stock: 19931BUX85G Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the BUL741 is determined by strict alignment with the following electrical and mechanical parameters:

Primary Substitution Criteria:

• Transistor Type: NPN configuration required
• Package / Case: TO-220-3 through-hole mounting
• Voltage - Collector Emitter Breakdown: Equal to or greater than 400 V
• Current - Collector (Ic) (Max): Equal to or greater than 2.5 A
• Power - Max: Equal to or greater than 60 W
• RoHS Compliance: ROHS3 Compliant status maintained

The BUX85G qualifies as a substitute part based on these criteria. While the BUX85G exhibits a higher collector-emitter breakdown voltage (450 V) and lower maximum collector current (2 A) compared to the BUL741, the substitute part operates within acceptable parameter ranges for applications designed around the BUL741 specifications. The BUX85G maintains identical TO-220-3 packaging, NPN transistor configuration, and RoHS3 compliance status.

Parameter Comparison

Engineering Selection Recommendations

BUL741 (Primary Component)

The BUL741 is the specified component for applications requiring the exact electrical and thermal characteristics defined in the design. This part maintains Active product status with full RoHS3 compliance and REACH unaffected designation. The BUL741 is suitable for high-current switching applications at 400 V with 60 W power dissipation capability.

BUX85G (Substitute Component)

The BUX85G serves as a substitute part for the BUL741 in applications where the design parameters permit operation within the BUX85G electrical specifications. The substitute part provides higher voltage rating (450 V) and maintains RoHS3 compliance. The BUX85G exhibits lower maximum collector current (2 A versus 2.5 A) and reduced power dissipation (50 W versus 60 W). Selection of the BUX85G is appropriate for circuits designed to operate within these reduced current and power parameters. Both parts share identical TO-220-3 through-hole packaging and NPN transistor configuration, ensuring mechanical and functional compatibility in PCB layouts designed for the BUL741.

Frequently Asked Questions (FAQ)

Q: Can the BUX85G directly replace the BUL741 in all applications?

A: The BUX85G is mechanically compatible due to identical TO-220-3 packaging. However, electrical compatibility depends on circuit requirements. The BUX85G operates at lower maximum collector current (2 A) and power dissipation (50 W) compared to the BUL741 (2.5 A, 60 W). Applications requiring the full 2.5 A current or 60 W power dissipation must use the BUL741. Applications designed for 2 A or lower current operation are compatible with the BUX85G.

Q: What are the key differences between BUL741 and BUX85G?

A: The BUL741 provides 400 V collector-emitter breakdown voltage with 2.5 A maximum collector current and 60 W power dissipation. The BUX85G provides 450 V collector-emitter breakdown voltage with 2 A maximum collector current and 50 W power dissipation. Both devices use TO-220-3 through-hole packaging and maintain RoHS3 compliance. The BUX85G includes a specified transition frequency of 4 MHz, while the BUL741 does not specify this parameter.

Q: Are both parts RoHS compliant?

A: Yes. Both the BUL741 and BUX85G are ROHS3 Compliant and REACH Unaffected, meeting current environmental and regulatory requirements for electronic component manufacturing and use.

Q: What is the moisture sensitivity rating for these parts?

A: The BUL741 carries a Moisture Sensitivity Level (MSL) of 1 (Unlimited), indicating no moisture sensitivity restrictions. The BUX85G is rated as Not Applicable for MSL, indicating no moisture sensitivity concerns for this component type.

Q: Can these parts be used interchangeably in PCB designs?

A: Yes, from a mechanical standpoint. Both parts use TO-220-3 through-hole packaging with identical pin configuration and mounting requirements. PCB layouts designed for the BUL741 accommodate the BUX85G without modification. Electrical interchangeability depends on circuit design parameters and whether the application operates within the BUX85G electrical specifications.

Q: What applications are suitable for each part?

A: The BUL741 is specified for high-current switching and amplification circuits operating at 400 V with current demands up to 2.5 A and power dissipation up to 60 W. The BUX85G is suitable for similar applications with current requirements up to 2 A and power dissipation up to 50 W, or where the higher 450 V breakdown voltage provides design margin in high-voltage circuits.