BUH50G Equivalent & Substitute Parts

Part Overview

The BUH50G is an NPN bipolar junction transistor manufactured by onsemi, rated for 500 V collector-emitter breakdown voltage and 4 A maximum collector current. Housed in a TO-220-3 through-hole package, this device is part of the SWITCHMODE™ series and is classified as obsolete. The BUH50G is designed for high-voltage switching applications requiring moderate current handling and power dissipation up to 50 W.

Due to its obsolete product status, equivalent and substitute parts are necessary for ongoing design support, production continuity, and component sourcing. Substitute devices must maintain electrical compatibility within the specified voltage, current, and thermal operating ranges while accommodating available packaging options.

Key Parameters

Parameter	BUH50G Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	500	V
Current - Collector (Ic) (Max)	4	A
Power - Max	50	W
Frequency - Transition	4	MHz
Operating Temperature (TJ)	-65 to 150	°C
Mounting Type	Through Hole	—
Package / Case	TO-220-3	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution eligibility for the BUH50G is determined by the following electrical and mechanical parameters:

Primary Substitution Criteria:

Transistor Type: NPN (required match)
Voltage - Collector Emitter Breakdown (Max): minimum 500 V (equal or greater)
Current - Collector (Ic) (Max): minimum 4 A (equal or greater)
Mounting Type: Through Hole (required match)
Package / Case: TO-220-3 or compatible TO-220 variants (required match)

Secondary Compatibility Factors:

Operating Temperature Range: must support minimum -65°C to 150°C or subset thereof
Power Dissipation: must support minimum 50 W
Vce Saturation characteristics at specified base and collector currents

Substitute parts are grouped into two categories:

Category A - Direct Voltage & Current Equivalents (500 V, ≥4 A): Parts maintaining the 500 V breakdown voltage specification with equal or greater current ratings. These provide the closest electrical match to the BUH50G.

Category B - Reduced Voltage Alternatives (450 V, ≥4 A): Parts with 450 V breakdown voltage (50 V reduction) but equal or greater current ratings. These are suitable for applications where the full 500 V rating is not required, provided circuit design margins accommodate the lower voltage specification.

Parameter Comparison

Part Number	Manufacturer	Ic (Max) [A]	Vce Breakdown (Max) [V]	Power (Max) [W]	Frequency [MHz]	Package	Product Status	RoHS Status
BUH50G	onsemi	4	500	50	4	TO-220-3	Obsolete	—
FJPF5021OTU	onsemi	5	500	40	15	TO-220F-3	Active	ROHS3 Compliant
BUJ303A,127	WeEn Semiconductors	5	500	100	—	TO-220AB	Active	ROHS3 Compliant
MJE18004G	onsemi	5	450	75	13	TO-220-3	Active	ROHS3 Compliant
BUT11A	STMicroelectronics	5	450	83	—	TO-220-3	Obsolete	ROHS3 Compliant
BUL38D	STMicroelectronics	5	450	80	—	TO-220-3	Active	ROHS3 Compliant
BUL58D	STMicroelectronics	8	450	85	—	TO-220-3	Active	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (500 V Specification Required):

FJPF5021OTU and BUJ303A,127 maintain the 500 V collector-emitter breakdown voltage of the BUH50G. FJPF5021OTU is manufactured by onsemi (original BUH50G manufacturer) and carries active product status with ROHS3 compliance. BUJ303A,127 is manufactured by WeEn Semiconductors with active status and ROHS3 compliance, offering the highest power rating (100 W) among 500 V alternatives.

For Reduced Voltage Applications (450 V Acceptable):

MJE18004G, BUL38D, and BUL58D are rated at 450 V and are suitable for applications where the full 500 V specification is not required. MJE18004G is manufactured by onsemi with active status, SWITCHMODE™ series designation, and extended temperature range (-65°C to 150°C). BUL38D and BUL58D are manufactured by STMicroelectronics with active status and ROHS3 compliance. BUL58D provides the highest current rating (8 A) among all substitutes.

Compliance Considerations:

All substitute parts listed carry ROHS3 compliance and REACH Unaffected status, matching the regulatory profile of the BUH50G. Parts with active product status (FJPF5021OTU, BUJ303A,127, MJE18004G, BUL38D, BUL58D) are preferred for new designs and ongoing production support.

Frequently Asked Questions (FAQ)

Q: Can FJPF5021OTU directly replace BUH50G in all applications?

A: FJPF5021OTU maintains the 500 V breakdown voltage and exceeds the 4 A current requirement with 5 A rating. However, the package variant differs (TO-220F-3 versus TO-220-3). Verify PCB footprint compatibility before substitution. The lower power rating (40 W versus 50 W) requires thermal design review for applications operating near maximum power dissipation.

Q: What is the difference between 500 V and 450 V rated devices?

A: The 50 V difference represents the maximum collector-emitter breakdown voltage specification. Devices rated at 450 V are suitable for applications with circuit design margins that do not require the full 500 V rating. Applications operating at or near 500 V require parts with 500 V or higher ratings.

Q: Are TO-220-3 and TO-220F-3 packages interchangeable?

A: Both are through-hole TO-220 variants with three leads. TO-220F-3 includes a full pack configuration. Physical dimensions and PCB footprints are compatible for most applications, but mechanical mounting and thermal interface characteristics may differ. Consult package datasheets for specific mounting requirements.

Q: Why is BUH50G listed as obsolete?

A: Obsolete status indicates the manufacturer has discontinued production. Substitute parts with active status are recommended for new designs and long-term production continuity.

Q: Which substitute offers the best thermal performance?

A: BUJ303A,127 provides the highest power dissipation rating (100 W), followed by BUL58D (85 W) and BUT11A (83 W). Higher power ratings indicate improved thermal capability under identical operating conditions.

Q: Can I use BUL58D (8 A) in place of BUH50G (4 A)?

A: Yes, BUL58D exceeds the current requirement and is electrically compatible at 450 V. The higher current rating provides design margin. Verify that the 450 V breakdown voltage is acceptable for your application circuit.

Q: What is the significance of DC Current Gain (hFE) differences?

A: DC Current Gain variations affect base drive requirements and switching characteristics. Substitutes with higher hFE values (e.g., FJPF5021OTU at 20 versus BUH50G at 5) require lower base current for equivalent collector current, potentially improving circuit efficiency.

Q: Are all listed substitutes ROHS3 compliant?

A: All active substitute parts listed (FJPF5021OTU, BUJ303A,127, MJE18004G, BUL38D, BUL58D) carry ROHS3 compliance certification. Obsolete substitutes (BUT11A) also carry ROHS3 compliance but are not recommended for new designs.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message