2N3771 Equivalent & Substitute Parts

Part Overview

The 2N3771 is an NPN bipolar junction transistor (BJT) rated for 40 V collector-emitter breakdown voltage and 30 A maximum collector current. Manufactured by STMicroelectronics, this device is housed in a TO-3 package and rated for 150 W maximum power dissipation with a transition frequency of 200 kHz. The part is classified as obsolete, making identification of equivalent and substitute components necessary for ongoing design support and procurement continuity.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	40	V
Current - Collector (Ic) (Max)	30	A
Power - Max	150	W
Frequency - Transition	200	kHz
Vce Saturation (Max) @ Ib, Ic	4 V @ 6 A, 30 A	—
Current - Collector Cutoff (Max)	10	mA
DC Current Gain (hFE) (Min) @ Ic, Vce	15 @ 15 A, 4 V	—
Package / Case	TO-204AA, TO-3	—
Mounting Type	Chassis Mount	—

Substitute Part Grouping Explanation

Substitution of the 2N3771 is determined by strict equivalence across the following electrical and mechanical parameters:

Transistor Type: NPN configuration required
Voltage Rating: Collector-emitter breakdown voltage of 40 V minimum
Current Rating: Maximum collector current of 30 A minimum
Power Dissipation: Maximum power rating of 150 W or greater
Frequency Response: Transition frequency of 200 kHz or greater
Saturation Characteristics: Vce saturation of 4 V at specified base and collector currents
Package Compatibility: TO-3 package format

Two substitute parts meet these criteria: the 2N3771 from Solid State Inc. and the 2N5301 PBFREE from Central Semiconductor Corp. Both devices maintain the required electrical specifications and package format, though with variations in product status, mounting configuration, and power rating.

Parameter Comparison

Parameter	2N3771 (STMicroelectronics)	2N3771 (Solid State Inc.)	2N5301 PBFREE (Central Semiconductor)
Transistor Type	NPN	NPN	NPN
Voltage - Collector Emitter Breakdown (Max)	40 V	40 V	40 V
Current - Collector (Ic) (Max)	30 A	30 A	30 A
Power - Max	150 W	150 W	200 W
Frequency - Transition	200 kHz	200 kHz	4 MHz
Vce Saturation (Max) @ Ib, Ic	4 V @ 6 A, 30 A	4 V @ 6 A, 30 A	Not Specified
Current - Collector Cutoff (Max)	10 mA	10 mA	Not Specified
DC Current Gain (hFE) (Min) @ Ic, Vce	15 @ 15 A, 4 V	15 @ 15 A, 4 V	Not Specified
Package / Case	TO-204AA, TO-3	TO-204AA, TO-3	TO-204AA, TO-3
Mounting Type	Chassis Mount	Through Hole	Through Hole
Product Status	Obsolete	Active	Obsolete
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

2N3771 (Solid State Inc.) is the primary substitute for the STMicroelectronics 2N3771. This part maintains identical electrical specifications across all critical parameters: 40 V breakdown voltage, 30 A collector current, 150 W power rating, and 200 kHz transition frequency. The device is currently in active production status, ensuring long-term availability. Both parts are ROHS3 compliant. The primary difference is mounting configuration: the Solid State Inc. variant uses through-hole mounting versus the chassis mount of the original part. This difference requires mechanical design verification for board-level integration.

2N5301 PBFREE (Central Semiconductor Corp) serves as a secondary substitute. This device meets the core voltage and current requirements (40 V, 30 A) and exceeds the power rating (200 W versus 150 W) and transition frequency (4 MHz versus 200 kHz). However, critical saturation and cutoff specifications are not provided for this part. The 2N5301 PBFREE is also classified as obsolete. Selection of this part requires confirmation that unspecified parameters are acceptable for the intended application.

Frequently Asked Questions (FAQ)

Q: Can the 2N3771 from Solid State Inc. directly replace the STMicroelectronics 2N3771?

A: Electrical substitution is valid. Both parts share identical voltage, current, power, and frequency specifications. Mechanical integration requires verification due to mounting type differences: chassis mount (original) versus through-hole (substitute).

Q: What is the significance of the 2N5301 PBFREE having a higher power rating and transition frequency?

A: The 2N5301 PBFREE exceeds the minimum electrical requirements for voltage and current. The higher power rating (200 W) and transition frequency (4 MHz) indicate enhanced performance capability. However, saturation and cutoff specifications are not provided, requiring application-specific validation.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. The 2N3771 (STMicroelectronics), 2N3771 (Solid State Inc.), and 2N5301 PBFREE (Central Semiconductor Corp) are all ROHS3 compliant.

Q: What is the difference between chassis mount and through-hole mounting for the TO-3 package?

A: Chassis mount and through-hole are mechanical mounting configurations. Chassis mount typically uses a stud or bolt for direct mounting to a heat sink or chassis. Through-hole configuration uses leads for insertion into a printed circuit board. Design verification is required to confirm compatibility with the target assembly method.

Q: Why are some electrical parameters not specified for the 2N5301 PBFREE?

A: Saturation voltage, cutoff current, and DC current gain are not provided in the available data for the 2N5301 PBFREE. These parameters must be obtained from the manufacturer datasheet if application requirements depend on these specifications.

Q: Is product status (active versus obsolete) a factor in substitution selection?

A: Product status indicates availability and long-term support. The 2N3771 from Solid State Inc. is active, ensuring continued procurement availability. The 2N5301 PBFREE is obsolete, which may limit future sourcing. Selection should consider supply chain requirements and design lifecycle.

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