BUL59 Equivalent & Substitute Parts

Part Overview

The BUL59 is an NPN bipolar junction transistor manufactured by STMicroelectronics, rated for 400 V collector-emitter breakdown voltage and 8 A maximum collector current in a TO-220 through-hole package. This device is classified as obsolete, necessitating identification of equivalent and substitute components for ongoing design requirements and production continuity. Substitute parts are selected based on matching or exceeding the electrical and mechanical specifications of the original BUL59.

Key Parameters

Parameter	BUL59 Value
Transistor Type	NPN
Current - Collector (Ic) (Max)	8 A
Voltage - Collector Emitter Breakdown (Max)	400 V
Power - Max	90 W
Mounting Type	Through Hole
Package / Case	TO-220-3
Operating Temperature (TJ)	150°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the BUL59 is determined by the following critical parameters:

Primary Matching Criteria:

Transistor Type: NPN configuration required
Voltage - Collector Emitter Breakdown (Max): Minimum 400 V
Current - Collector (Ic) (Max): Minimum 8 A
Mounting Type: Through Hole
Package / Case: TO-220-3 or compatible TO-220 variant

Secondary Considerations:

Power dissipation capability (90 W minimum preferred)
Operating temperature range (150°C maximum junction temperature)
RoHS3 compliance for regulatory alignment

Substitute parts are grouped into two categories: direct electrical equivalents (matching 400 V / 8 A specifications) and enhanced-performance alternatives (exceeding voltage or current ratings while maintaining package compatibility).

Parameter Comparison

Part Number	Manufacturer	Ic (Max)	Vce Breakdown (Max)	Power (Max)	Package	Product Status	RoHS Status
BUL59	STMicroelectronics	8 A	400 V	90 W	TO-220-3	Obsolete	ROHS3 Compliant
BUL743	STMicroelectronics	12 A	500 V	100 W	TO-220-3	Active	ROHS3 Compliant
BUJ105A,127	WeEn Semiconductors	8 A	400 V	80 W	TO-220-3	Active	RoHS Compliant
FJP13007H2TU	onsemi	8 A	400 V	80 W	TO-220-3	Last Time Buy	ROHS3 Compliant
FJP13009TU	onsemi	12 A	400 V	100 W	TO-220-3	Active	ROHS3 Compliant
MJE13007G	onsemi	8 A	400 V	80 W	TO-220-3	Active	ROHS3 Compliant
MJE18008G	onsemi	8 A	450 V	125 W	TO-220-3	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Electrical Equivalents (Recommended for Pin-Compatible Replacement):

The BUJ105A,127 (WeEn Semiconductors), FJP13007H2TU (onsemi), and MJE13007G (onsemi) provide direct electrical equivalence to the BUL59, matching the 400 V / 8 A specification envelope. All three are active products with current manufacturing status and ROHS3 compliance. The BUJ105A,127 and MJE13007G are preferred for new designs due to active product status and established supply availability.

Enhanced-Performance Alternatives:

The BUL743 (STMicroelectronics), FJP13009TU (onsemi), and MJE18008G (onsemi) exceed the BUL59 specifications in voltage and/or current ratings. These parts are suitable for applications requiring design margin or upgraded performance. The BUL743 and FJP13009TU provide 12 A current capability, while the MJE18008G offers 450 V breakdown voltage and 125 W power dissipation. All three maintain TO-220-3 package compatibility and active product status.

Compliance Considerations:

All substitute parts listed are ROHS3 compliant or RoHS compliant, aligning with regulatory requirements. The BUL59 is classified as obsolete; therefore, transition to an active product status part is recommended for long-term supply chain stability.

Frequently Asked Questions (FAQ)

Q: Can the BUL59 be directly replaced with any of the listed substitutes?

A: Direct pin-compatible replacement is possible with BUJ105A,127, FJP13007H2TU, and MJE13007G, which maintain identical TO-220-3 package configuration and 400 V / 8 A electrical specifications. Enhanced-performance alternatives (BUL743, FJP13009TU, MJE18008G) are also pin-compatible but provide higher current or voltage ratings.

Q: What is the primary difference between direct equivalents and enhanced alternatives?

A: Direct equivalents match the BUL59 at 400 V / 8 A ratings. Enhanced alternatives exceed these specifications: BUL743 and FJP13009TU provide 12 A current capability; MJE18008G provides 450 V breakdown voltage and 125 W power dissipation. All maintain through-hole TO-220 package compatibility.

Q: Are there package compatibility concerns when substituting?

A: All listed substitute parts use TO-220-3 or compatible TO-220 package variants, ensuring mechanical and thermal compatibility with existing PCB layouts and heat sink mounting arrangements.

Q: Why is the BUL59 listed as obsolete?

A: The BUL59 is no longer in active production. Substitute parts with active product status (BUL743, BUJ105A,127, FJP13009TU, MJE13007G, MJE18008G) are recommended for new designs and ongoing production requirements.

Q: Which substitute offers the best long-term supply availability?

A: MJE13007G and MJE18008G (onsemi SWITCHMODE™ series) and FJP13009TU (onsemi) are active products with established market presence. BUL743 (STMicroelectronics) is also active. FJP13007H2TU is classified as Last Time Buy and should be avoided for new designs.

Q: Are all substitutes RoHS compliant?

A: Yes. All listed substitute parts are either ROHS3 compliant or RoHS compliant, meeting regulatory requirements for hazardous substance restrictions.

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