BSP51 Equivalent & Substitute Parts

Part Overview

The BSP51 is an NPN Darlington bipolar junction transistor manufactured by onsemi, designed for surface mount applications in the SOT-223-4 package. This component operates at a maximum collector voltage of 80 V with a collector current rating of 500 mA and maximum power dissipation of 1 W. The BSP51 is classified as obsolete, necessitating identification of equivalent and substitute components for new designs and ongoing production requirements. Substitute parts must maintain functional compatibility while meeting the electrical and mechanical specifications required for the application.

Key Parameters

Parameter	BSP51 Value
Transistor Type	NPN - Darlington
Current - Collector (Ic) (Max)	500 mA
Voltage - Collector Emitter Breakdown (Max)	80 V
Vce Saturation (Max) @ Ib, Ic	1.3V @ 500µA, 500mA
Current - Collector Cutoff (Max)	10µA
DC Current Gain (hFE) (Min) @ Ic, Vce	1000 @ 150mA, 10V
Power - Max	1 W
Operating Temperature	-55°C ~ 150°C (TJ)
Mounting Type	Surface Mount
Package / Case	TO-261-4, TO-261AA
Supplier Device Package	SOT-223-4
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the BSP51 is determined by the following critical parameters: transistor type (NPN - Darlington), package compatibility (SOT-223 surface mount variants), collector voltage rating (80 V minimum), and collector current capability. Substitute parts must maintain the same transistor topology and surface mount package family to ensure mechanical and electrical compatibility with existing PCB layouts and circuit designs.

The following parameters establish substitution validity:

Transistor Type: NPN - Darlington configuration
Package Family: SOT-223 surface mount (TO-261-4, TO-261AA)
Voltage Rating: Minimum 80 V collector-emitter breakdown voltage
Current Rating: Minimum 500 mA collector current capability
Saturation Voltage: Compatible with 1.3 V specification at rated conditions
Operating Temperature Range: Minimum -55°C to 150°C

Parameter Comparison

Parameter	BSP51	BSP52T1G	BSP51,115	FZT603TA
Manufacturer	onsemi	onsemi	Nexperia USA Inc.	Diodes Incorporated
Transistor Type	NPN - Darlington	NPN - Darlington	NPN - Darlington	NPN - Darlington
Current - Collector (Ic) (Max)	500 mA	1 A	1 A	2 A
Voltage - Collector Emitter Breakdown (Max)	80 V	80 V	60 V	80 V
Vce Saturation (Max) @ Ib, Ic	1.3V @ 500µA, 500mA	1.3V @ 500µA, 500mA	1.3V @ 500µA, 500mA	1.13V @ 20mA, 2A
Current - Collector Cutoff (Max)	10µA	10µA	50nA	10µA
DC Current Gain (hFE) (Min) @ Ic, Vce	1000 @ 150mA, 10V	2000 @ 500mA, 10V	2000 @ 500mA, 10V	5000 @ 500mA, 5V
Power - Max	1 W	800 mW	1.25 W	2 W
Operating Temperature	-55°C ~ 150°C (TJ)	-65°C ~ 150°C (TJ)	150°C (TJ)	-55°C ~ 150°C (TJ)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA
Supplier Device Package	SOT-223-4	SOT-223 (TO-261)	SOT-223	SOT-223-3
Product Status	Obsolete	Active	Active	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

BSP52T1G (onsemi) serves as a direct substitute for applications requiring up to 1 A collector current at 80 V. This part maintains the same manufacturer lineage and package family as the BSP51, with active product status and ROHS3 compliance. The BSP52T1G provides enhanced current capability (1 A versus 500 mA) while maintaining saturation voltage characteristics. Power dissipation is rated at 800 mW, which is lower than the BSP51's 1 W rating; applications requiring the full 1 W dissipation should verify thermal requirements.

BSP51,115 (Nexperia USA Inc.) is suitable for applications operating at 60 V or lower collector-emitter voltage. This variant offers 1 A collector current capability, 1.25 W power dissipation, and includes automotive qualification (AEC-Q101) with ROHS3 compliance. The reduced voltage rating (60 V versus 80 V) limits its use to lower-voltage applications. The transition frequency specification of 200 MHz indicates suitability for higher-frequency switching applications.

FZT603TA (Diodes Incorporated) provides the highest current capability at 2 A with 80 V voltage rating and 2 W power dissipation. This part is suitable for applications requiring higher current handling or thermal margin. The FZT603TA features a transition frequency of 150 MHz and ROHS3 compliance. The SOT-223-3 package variant differs from the SOT-223-4 configuration; pin compatibility must be verified for direct PCB substitution.

All substitute parts maintain NPN Darlington topology, surface mount SOT-223 package family compatibility, and MSL 1 (Unlimited) moisture sensitivity rating. Selection should be based on specific application requirements for collector current, voltage rating, power dissipation, and operating temperature range.

Frequently Asked Questions (FAQ)

Q: Can the BSP52T1G directly replace the BSP51 in existing designs?

A: The BSP52T1G is mechanically and electrically compatible with the BSP51 for applications requiring up to 1 A collector current. Both parts use the SOT-223 surface mount package family and maintain identical saturation voltage characteristics. PCB layout compatibility is maintained. However, the BSP52T1G has a lower maximum power rating (800 mW versus 1 W); applications operating near the 1 W thermal limit should be re-evaluated.

Q: What is the primary difference between BSP51,115 and the original BSP51?

A: The BSP51,115 is manufactured by Nexperia USA Inc. and features a reduced maximum collector-emitter breakdown voltage of 60 V compared to the BSP51's 80 V. The BSP51,115 offers higher current capability (1 A versus 500 mA) and includes automotive qualification (AEC-Q101). This part is suitable only for applications operating at 60 V or lower.

Q: Is the FZT603TA package compatible with the BSP51 PCB layout?

A: The FZT603TA uses the SOT-223-3 package variant, while the BSP51 uses SOT-223-4. Both are surface mount packages within the SOT-223 family with compatible TO-261-4 and TO-261AA case designations. Pin configuration differences must be verified against the specific PCB layout before substitution.

Q: Which substitute part is recommended for new designs?

A: Selection depends on application requirements. For applications requiring 500 mA or less at 80 V, the BSP52T1G (onsemi) is recommended due to active product status, ROHS3 compliance, and manufacturer continuity. For automotive applications at 60 V or lower, the BSP51,115 (Nexperia) with AEC-Q101 qualification is appropriate. For applications requiring 2 A capability, the FZT603TA (Diodes Incorporated) is suitable.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. The BSP52T1G, BSP51,115, and FZT603TA are all ROHS3 compliant. The original BSP51 does not specify RoHS status due to its obsolete classification.

Q: What is the operating temperature range for each substitute?

A: The BSP52T1G operates from -65°C to 150°C (TJ), providing the widest temperature range. The BSP51,115 specifies 150°C (TJ) maximum without a minimum temperature specification. The FZT603TA operates from -55°C to 150°C (TJ), matching the original BSP51 range.

Q: Can the BSP51,115 be used in applications requiring 80 V operation?

A: No. The BSP51,115 has a maximum collector-emitter breakdown voltage of 60 V and is not suitable for 80 V applications. The BSP52T1G or FZT603TA must be used for 80 V operation.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message