BUL310 Equivalent & Substitute Parts

Part Overview

The BUL310 is an NPN bipolar junction transistor manufactured by STMicroelectronics, rated for 500 V collector-emitter breakdown voltage and 5 A maximum collector current in a TO-220 through-hole package. This device is classified as obsolete, necessitating identification of equivalent substitute components for ongoing design support and procurement continuity. Substitute parts must maintain electrical compatibility across critical parameters including voltage rating, current capacity, and power dissipation while accommodating available packaging options.

Substiute Parts

BUL310

STMicroelectronicsIn Stock: 3904BUL310 Datasheet

Current PartRFQ

BUJ303A,127

WeEn SemiconductorsIn Stock: 6631BUJ303A,127 Datasheet

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KSC5338D

onsemiIn Stock: 2042KSC5338D Datasheet

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KSC5338DTU

onsemiIn Stock: 2349KSC5338DTU Datasheet

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MJE18004G

onsemiIn Stock: 1405MJE18004G Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the BUL310 are selected based on the following critical electrical and mechanical parameters:

Primary Compatibility Criteria:

• Transistor Type: NPN configuration
• Collector-Emitter Breakdown Voltage: 500 V or higher
• Maximum Collector Current: 5 A or higher
• Power Dissipation: 75 W or higher
• Mounting Type: Through Hole
• Package: TO-220 or TO-220-3 variants
• Operating Temperature Range: 150°C (TJ) or higher

Substitution Logic: Parts meeting all primary criteria are classified as direct substitutes. Parts with collector-emitter breakdown voltage below 500 V (such as 450 V rated devices) are classified as functional substitutes with voltage derating considerations. All substitute candidates maintain NPN polarity, through-hole mounting, and TO-220 package family compatibility.

Parameter Comparison

Engineering Selection Recommendations

Direct Substitutes (500 V Rating):

The BUJ303A,127 manufactured by WeEn Semiconductors is a direct electrical substitute with matching 500 V collector-emitter breakdown voltage and 5 A collector current rating. This part carries Active product status and is available in TO-220-3 packaging. The BUJ303A,127 provides enhanced power dissipation capability at 100 W compared to the 75 W rating of the BUL310, offering additional thermal margin. Both parts maintain ROHS3 compliance and REACH Unaffected status.

Functional Substitutes (450 V Rating):

The KSC5338D, KSC5338DTU, and MJE18004G are functional substitutes with 450 V collector-emitter breakdown voltage ratings. These parts maintain 5 A collector current and 75 W power dissipation specifications. The KSC5338D carries Active product status with bulk packaging, while KSC5338DTU is designated Last Time Buy with tube packaging. The MJE18004G is Active status with tube packaging and includes transition frequency specification of 13 MHz. All three parts are ROHS3 compliant and REACH Unaffected. Application circuits operating below 450 V can utilize these substitutes without electrical derating.

Compliance and Regulatory Alignment:

All substitute parts maintain ROHS3 compliance and REACH Unaffected status, ensuring regulatory continuity with the original BUL310 specification. Moisture sensitivity level is either 1 (Unlimited) or Not Applicable across all candidates, indicating no special handling requirements beyond standard component storage practices.

Frequently Asked Questions (FAQ)

Q: Can the BUJ303A,127 directly replace the BUL310 in all applications?

A: The BUJ303A,127 is a direct electrical substitute with identical 500 V breakdown voltage and 5 A current ratings. Both parts use TO-220-3 packaging and maintain 150°C maximum junction temperature. Pin configuration compatibility must be verified against the specific circuit board layout, as TO-220-3 packages have standardized pin assignments.

Q: What is the voltage derating consideration for KSC5338D and KSC5338DTU substitutes?

A: The KSC5338D and KSC5338DTU are rated for 450 V collector-emitter breakdown voltage compared to the BUL310's 500 V rating. These parts are suitable for applications with maximum operating voltages at or below 450 V. Applications requiring the full 500 V rating must use the BUJ303A,127 substitute.

Q: Are there packaging differences between substitute options?

A: All substitute parts use TO-220-3 through-hole packaging, maintaining mechanical and thermal interface compatibility with the BUL310. Packaging variants include tube (BUJ303A,127, KSC5338DTU, MJE18004G) and bulk (KSC5338D) options, which affect procurement and handling but not electrical performance or board-level installation.

Q: What is the product status significance for long-term procurement?

A: The BUL310 is classified Obsolete, indicating discontinued manufacturing. The BUJ303A,127 and MJE18004G carry Active status, ensuring ongoing availability. The KSC5338DTU is designated Last Time Buy, indicating limited future availability. For new designs or long-term production requirements, Active status parts are preferred.

Q: Do all substitutes maintain the same thermal characteristics?

A: All substitute parts are rated for 150°C maximum junction temperature, matching the BUL310. The BUJ303A,127 provides 100 W power dissipation compared to 75 W for other substitutes, offering enhanced thermal headroom. Thermal interface requirements (heat sink coupling, mounting torque) remain consistent across all TO-220-3 packages.

Q: Are there DC current gain differences between substitutes?

A: DC current gain (hFE) specifications vary across substitutes at different measurement conditions. The BUL310 specifies 6 @ 3A, 2.5V; BUJ303A,127 specifies 14 @ 500mA, 5V; and KSC5338D/DTU specify 6 @ 2A, 1V. Circuit designs dependent on specific hFE values must account for these variations in bias network calculations.

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

A: The BUJ303A,127 (WeEn Semiconductors, Active status) and MJE18004G (onsemi, Active status) both carry Active product status, indicating ongoing manufacturing and availability. The KSC5338D (Active) and KSC5338DTU (Last Time Buy) from onsemi provide near-term alternatives, with KSC5338DTU availability limited to existing inventory.