2SC4081RT1G Equivalent & Substitute Parts

Part Overview

The 2SC4081RT1G is an NPN bipolar junction transistor manufactured by onsemi, rated for 50 V collector-emitter breakdown voltage and 100 mA maximum collector current in a surface mount SC-70 (SOT-323) package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The 200 mW power rating and specified electrical characteristics define the functional requirements for suitable replacements.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	50	V
Current - Collector (Ic) (Max)	100	mA
Power - Max	200	mW
Vce Saturation (Max) @ Ib, Ic	500mV @ 10mA, 100mA	—
Current - Collector Cutoff (Max)	100	nA
DC Current Gain (hFE) (Min) @ Ic, Vce	180 @ 2mA, 6V	—
Operating Temperature (Max)	150	°C
Package / Case	SC-70, SOT-323	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution of the 2SC4081RT1G is determined by the following critical parameters:

Mandatory Matching Parameters:

Transistor Type: NPN
Package / Case: SC-70 or SOT-323 (surface mount, three-terminal configuration)
Mounting Type: Surface Mount
Current - Collector (Ic) (Max): 100 mA or greater
Voltage - Collector Emitter Breakdown (Max): 50 V or greater
Power - Max: 200 mW or greater
Operating Temperature: 150°C or greater

Acceptable Variation Parameters:

DC Current Gain (hFE): May vary within active device specifications
Vce Saturation: May vary within acceptable switching characteristics
Frequency - Transition: May exceed specified value without impact on DC operation
Current - Collector Cutoff (Max): May be lower (improved leakage performance)

Substitute parts are grouped into three categories: Direct Substitutes (identical electrical and package specifications), Similar Substitutes (enhanced performance characteristics), and Upgrade Substitutes (improved reliability or automotive qualification).

Parameter Comparison

Part Number	Manufacturer	Ic (Max) mA	Vce(br) V	Power mW	hFE (Min)	Package	Product Status	Frequency MHz
2SC4081RT1G	onsemi	100	50	200	180 @ 2mA, 6V	SC-70, SOT-323	Obsolete	—
MSC2712GT1G	onsemi	100	50	200	200 @ 2mA, 6V	SC-59, SOT-23-3	Active	50
BC847AW RFG	Taiwan Semiconductor Corporation	100	45	200	110 @ 2mA, 5V	SC-70, SOT-323	Active	100
BC847BW-TP	Micro Commercial Co	100	45	200	200 @ 2mA, 5V	SC-70, SOT-323	Active	100
BC847CW RFG	Taiwan Semiconductor Corporation	100	45	200	420 @ 2mA, 5V	SC-70, SOT-323	Active	100
BC847CW-TP	Micro Commercial Co	100	45	200	420 @ 2mA, 5V	SC-70, SOT-323	Active	100
BC850AW RFG	Taiwan Semiconductor Corporation	100	45	200	110 @ 2mA, 5V	SC-70, SOT-323	Active	100
2PD601ARW,115	Nexperia USA Inc.	100	50	200	210 @ 2mA, 10V	SC-70, SOT-323	Active	100
2PD601ASW,115	NXP USA Inc.	100	50	200	290 @ 2mA, 10V	SC-70, SOT-323	Active	100
2SC4081-A-TP	Micro Commercial Co	150	50	200	120 @ 1mA, 6V	SC-70, SOT-323	Active	180
2SC4081-B-TP	Micro Commercial Co	150	50	200	120 @ 1mA, 6V	SC-70, SOT-323	Active	180

Engineering Selection Recommendations

Direct Substitutes (Identical Electrical and Package Specifications):

BC847BW-TP and BC847CW-TP are direct substitutes in the SC-70/SOT-323 package with 100 mA collector current and 200 mW power rating. Both are manufactured by Micro Commercial Co and carry Active product status with RoHS3 compliance. BC847BW-TP provides hFE of 200 at 2 mA, 5 V, while BC847CW-TP provides hFE of 420 at 2 mA, 5 V. Both support 100 MHz transition frequency and operate to 150°C junction temperature.

Voltage-Rated Equivalents (50 V Breakdown):

2PD601ARW,115 and 2PD601ASW,115 maintain the 50 V collector-emitter breakdown voltage specification of the original device. Both are manufactured by Nexperia/NXP USA Inc. and carry Active product status with AEC-Q101 automotive qualification. These devices feature improved saturation voltage characteristics (250 mV @ 10 mA, 100 mA) and lower collector cutoff current (10 nA). 2PD601ASW,115 provides higher hFE (290 @ 2 mA, 10 V) and is available in bulk packaging with significantly higher inventory.

Enhanced Performance Variants (Same Base Number):

2SC4081-A-TP and 2SC4081-B-TP share the 2SC4081 base product number and maintain 50 V breakdown voltage with 200 mW power rating in SC-70/SOT-323 packaging. Both are manufactured by Micro Commercial Co with Active product status. These variants support higher collector current (150 mA maximum) and transition frequency (180 MHz), providing performance headroom for applications requiring enhanced switching speed or current capacity.

Lower Voltage Alternatives (45 V Breakdown):

BC847AW RFG, BC847CW RFG, and BC850AW RFG are manufactured by Taiwan Semiconductor Corporation with 45 V collector-emitter breakdown voltage. These devices are suitable for applications where the 50 V specification is not a hard requirement. All three maintain 100 mA collector current, 200 mW power rating, and SC-70/SOT-323 packaging with 100 MHz transition frequency and Active product status with RoHS3 compliance.

Package Consideration:

MSC2712GT1G is an onsemi device with identical electrical specifications (50 V, 100 mA, 200 mW) but uses SC-59/SOT-23-3 packaging instead of SC-70/SOT-323. This substitute is suitable only if the application PCB layout accommodates the different package footprint.

Frequently Asked Questions (FAQ)

Q: Can BC847BW-TP or BC847CW-TP replace 2SC4081RT1G in all applications?

A: BC847BW-TP and BC847CW-TP are direct substitutes in terms of electrical performance and SC-70/SOT-323 package compatibility. However, the 45 V collector-emitter breakdown voltage is lower than the original 50 V specification. These substitutes are suitable for applications where the maximum supply voltage does not exceed 45 V. For applications requiring the full 50 V rating, use 2PD601ARW,115, 2PD601ASW,115, 2SC4081-A-TP, or 2SC4081-B-TP.

Q: What is the difference between BC847AW RFG, BC847BW-TP, and BC847CW RFG?

A: All three are NPN transistors in SC-70/SOT-323 packaging with 45 V breakdown voltage and 100 mA collector current. The primary difference is DC current gain (hFE): BC847AW RFG provides 110 @ 2 mA, 5 V; BC847BW-TP provides 200 @ 2 mA, 5 V; BC847CW RFG provides 420 @ 2 mA, 5 V. Higher hFE values reduce base drive requirements in switching applications. BC847AW RFG and BC847CW RFG are manufactured by Taiwan Semiconductor Corporation, while BC847BW-TP is manufactured by Micro Commercial Co.

Q: Why is MSC2712GT1G listed as a substitute if it uses a different package?

A: MSC2712GT1G maintains identical electrical specifications (50 V, 100 mA, 200 mW) and is manufactured by onsemi with Active product status. The SC-59/SOT-23-3 package is a different footprint than SC-70/SOT-323. This substitute is listed for applications where PCB layout can accommodate the alternative package geometry, providing an onsemi-sourced alternative to the obsolete 2SC4081RT1G.

Q: Are 2PD601ARW,115 and 2PD601ASW,115 interchangeable?

A: Both devices maintain 50 V breakdown voltage, 100 mA collector current, 200 mW power rating, and SC-70/SOT-323 packaging. The primary difference is DC current gain: 2PD601ARW,115 provides 210 @ 2 mA, 10 V, while 2PD601ASW,115 provides 290 @ 2 mA, 10 V. Both carry AEC-Q101 automotive qualification and Active product status. 2PD601ASW,115 is available in significantly higher inventory (705,135 pcs) compared to 2PD601ARW,115 (862 pcs).

Q: Can 2SC4081-A-TP or 2SC4081-B-TP be used as direct replacements?

A: 2SC4081-A-TP and 2SC4081-B-TP share the 2SC4081 base product number and maintain 50 V breakdown voltage with SC-70/SOT-323 packaging. These variants support higher collector current (150 mA) and transition frequency (180 MHz) compared to the original 100 mA and unspecified frequency. They are suitable as direct replacements with enhanced performance capability. Both are manufactured by Micro Commercial Co with Active product status.

Q: What is the significance of the 50 V versus 45 V breakdown voltage difference?

A: The collector-emitter breakdown voltage (Vce(br)) defines the maximum voltage that can be applied between collector and emitter without device failure. The 2SC4081RT1G is rated for 50 V, while BC847 and BC850 series devices are rated for 45 V. For applications with maximum supply voltages at or below 45 V, the lower-rated devices are acceptable. For applications requiring operation at voltages between 45 V and 50 V, only 50 V-rated devices (2PD601ARW,115, 2PD601ASW,115, 2SC4081-A-TP, 2SC4081-B-TP) are suitable.

Q: Are all listed substitutes RoHS3 compliant?

A: All Active product status devices listed (BC847AW RFG, BC847BW-TP, BC847CW RFG, BC847CW-TP, BC850AW RFG, 2PD601ARW,115, 2PD601ASW,115, 2SC4081-A-TP, 2SC4081-B-TP, MSC2712GT1G) carry RoHS3 compliance. The original 2SC4081RT1G is classified as Obsolete and does not have RoHS status specified. All devices maintain Moisture Sensitivity Level 1 (Unlimited) and REACH Unaffected status.

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