BUT11A Equivalent & Substitute Parts

Part Overview

The BUT11A is an NPN bipolar junction transistor manufactured by STMicroelectronics, rated for 450 V collector-emitter breakdown voltage and 5 A maximum collector current in a TO-220 through-hole package. This device is designed for high-voltage switching applications requiring 83 W power dissipation capability. The BUT11A is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Direct replacements and functionally equivalent alternatives are available from active manufacturers.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	450	V
Current - Collector (Ic) (Max)	5	A
Power - Max	83	W
Vce Saturation (Max) @ Ib, Ic	1.5V @ 500mA, 2.5A	—
DC Current Gain (hFE) (Min) @ Ic, Vce	10 @ 500mA, 5V	—
Current - Collector Cutoff (Max)	1	mA
Operating Temperature (TJ)	150	°C
Mounting Type	Through Hole	—
Package / Case	TO-220-3	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the BUT11A is determined by matching critical electrical parameters within specified tolerances and maintaining compatible package configurations. The primary substitution criteria are:

Critical Parameters for Direct Substitution:

Transistor Type: NPN (required match)
Voltage - Collector Emitter Breakdown (Max): 450 V minimum
Current - Collector (Ic) (Max): 5 A minimum
Package / Case: TO-220-3 (mechanical compatibility)
Mounting Type: Through Hole (required match)

Secondary Parameters for Functional Equivalence:

Power - Max: 75 W or greater
Vce Saturation characteristics
DC Current Gain (hFE)
Operating Temperature range
RoHS and REACH compliance status

Parts are classified as Direct Substitutes when all critical parameters match or exceed the BUT11A specifications. Parts are classified as Similar Alternatives when one or more electrical parameters fall below the main part specifications but remain suitable for applications with reduced performance requirements.

Parameter Comparison

Part Number	Manufacturer	Ic (Max) [A]	Vce Breakdown (Max) [V]	Power (Max) [W]	Vce Sat @ Ib, Ic	hFE (Min) @ Ic, Vce	Package	Status
BUT11A	STMicroelectronics	5	450	83	1.5V @ 500mA, 2.5A	10 @ 500mA, 5V	TO-220-3	Obsolete
KSC5338DTU	onsemi	5	450	75	500mV @ 200mA, 1A	6 @ 2A, 1V	TO-220-3	Last Time Buy
MJE18004G	onsemi	5	450	75	750mV @ 500mA, 2.5A	14 @ 300mA, 5V	TO-220-3	Active
BUJ103A,127	WeEn Semiconductors	4	400	80	1V @ 600mA, 3A	13 @ 500mA, 5V	TO-220-3	Active
BUJ302A,127	WeEn Semiconductors	4	400	80	1.5V @ 1A, 3.5A	25 @ 800mA, 3V	TO-220-3	Active
BUX85G	onsemi	2	450	50	1V @ 200mA, 1A	30 @ 100mA, 5V	TO-220-3	Active
FJP5555TU	Fairchild Semiconductor	5	400	75	1.5V @ 1A, 3.5A	20 @ 800mA, 3V	TO-220-3	Active
PHD13005,127	WeEn Semiconductors	4	400	75	1V @ 1A, 4A	10 @ 2A, 5V	TO-220-3	Active
TSC742CZ C0G	Taiwan Semiconductor Corporation	5	420	70	1.5V @ 1A, 3.5A	48 @ 100mA, 5V	TO-220-3	Active

Engineering Selection Recommendations

Direct Substitutes (Full Parameter Match):

The MJE18004G (onsemi) is the primary direct substitute for the BUT11A. This device maintains 5 A collector current and 450 V breakdown voltage ratings in an identical TO-220-3 package. The MJE18004G is classified as Active product status, ensuring long-term availability and supply chain stability. It carries ROHS3 compliance and REACH Unaffected status, matching the regulatory profile of the original part. The 75 W power rating is slightly reduced from 83 W but remains suitable for most applications within the BUT11A's operational envelope.

The KSC5338DTU (onsemi) provides equivalent electrical performance with 5 A and 450 V ratings. This part is classified as Last Time Buy, indicating limited future availability. Selection of KSC5338DTU is appropriate for applications requiring immediate substitution with known long-term supply constraints.

Functional Alternatives (Reduced Current Rating):

The BUJ103A,127, BUJ302A,127, and PHD13005,127 (WeEn Semiconductors) are functionally equivalent alternatives with 4 A maximum collector current and 400 V breakdown voltage. These parts are suitable for applications where the full 5 A rating is not required. All three maintain Active product status and ROHS3 compliance. The reduced voltage and current ratings necessitate circuit-level verification before implementation.

The FJP5555TU (Fairchild Semiconductor) offers 5 A collector current with 400 V breakdown voltage in Active status. This part is appropriate for applications operating below 450 V system voltages.

The TSC742CZ C0G (Taiwan Semiconductor Corporation) provides 5 A current capability with 420 V breakdown voltage. This part is Active and ROHS3 compliant, suitable for applications with voltage margins below 450 V.

Limited Substitution (Reduced Current Rating):

The BUX85G (onsemi) is rated for only 2 A maximum collector current, making it unsuitable for applications requiring the full 5 A capability of the BUT11A. This part is listed only for reference in applications with significantly reduced current demands.

Frequently Asked Questions (FAQ)

Q: Can the MJE18004G directly replace the BUT11A without circuit modifications?

A: The MJE18004G maintains the critical electrical parameters of 5 A collector current, 450 V breakdown voltage, and TO-220-3 package configuration. Direct substitution is permissible in applications where the 75 W power rating (versus 83 W original) does not exceed thermal design margins. Verify thermal management and saturation voltage characteristics for the specific application circuit.

Q: What is the difference between Direct Substitutes and Similar Alternatives?

A: Direct Substitutes match or exceed all critical electrical parameters of the BUT11A: 5 A collector current, 450 V breakdown voltage, and TO-220-3 package. Similar Alternatives have one or more reduced parameters, such as 4 A current or 400 V voltage rating, and require circuit-level evaluation before implementation.

Q: Why is the BUT11A listed as Obsolete?

A: The BUT11A is no longer manufactured by STMicroelectronics. Existing inventory remains available, but new production is not available. Equivalent parts from active manufacturers (MJE18004G, KSC5338DTU) are recommended for new designs and long-term production planning.

Q: Are all substitute parts RoHS3 compliant?

A: All listed substitute parts carry ROHS3 compliance certification, matching the regulatory status of the original BUT11A. REACH Unaffected status is maintained across all direct and functional alternatives.

Q: Can I use a 4 A rated part in a 5 A application?

A: Parts rated for 4 A maximum collector current (BUJ103A,127, BUJ302A,127, PHD13005,127) are not suitable for applications requiring sustained 5 A operation. Circuit redesign or thermal derating is required if these parts are considered. Verify actual application current requirements before substitution.

Q: What is the significance of the TO-220-3 package specification?

A: The TO-220-3 package is a three-lead through-hole configuration with standardized pin spacing and mounting geometry. All listed substitute parts use identical TO-220-3 packaging, ensuring mechanical compatibility with existing PCB layouts and heat sink mounting arrangements. No mechanical redesign is required for package-compatible substitutes.

Q: How do Vce Saturation characteristics affect substitution?

A: Vce Saturation determines the voltage drop across the transistor in the saturated (fully conducting) state. Variations in Vce Saturation between the BUT11A and substitute parts affect power dissipation and circuit performance. Applications with tight voltage margin requirements must verify saturation characteristics against circuit specifications.

Q: Is the KSC5338DTU suitable for new production designs?

A: The KSC5338DTU is classified as Last Time Buy, indicating that onsemi will discontinue production after existing inventory is exhausted. For new production designs with extended lifecycle requirements, the MJE18004G (Active status) is the recommended choice to ensure long-term supply availability.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message