BC547BU Equivalent & Substitute Parts

Part Overview

The BC547BU is an NPN bipolar junction transistor manufactured by onsemi, designed for general-purpose switching and amplification applications. It features a maximum collector current of 100 mA, collector-emitter breakdown voltage of 45 V, and maximum power dissipation of 500 mW in a Through Hole TO-92-3 package. The BC547BU is classified as obsolete, making identification of equivalent substitute parts essential for ongoing design support and procurement continuity.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Current - Collector (Ic) Max	100	mA
Voltage - Collector Emitter Breakdown (Max)	45	V
Vce Saturation (Max)	600	mV @ 5mA, 100mA
Current - Collector Cutoff (Max)	15	nA
DC Current Gain (hFE) Min	110	@ 2mA, 5V
Power - Max	500	mW
Frequency - Transition	300	MHz
Operating Temperature (TJ)	150	°C
Mounting Type	Through Hole	—
Package / Case	TO-92-3	—

Substitute Part Grouping Explanation

Substitution of the BC547BU is determined by strict equivalence across the following electrical and mechanical parameters:

Critical Matching Parameters:

Transistor Type: NPN
Maximum Collector Current (Ic): 100 mA
Collector-Emitter Breakdown Voltage: 45 V
Maximum Power Dissipation: 500 mW
Transition Frequency: 300 MHz
Package Type: TO-92-3 Through Hole

Acceptable Variation Parameters:

DC Current Gain (hFE): Minimum 110 @ 2mA, 5V (higher values acceptable)
Vce Saturation: 600 mV @ 5mA, 100mA (matching specification)
Collector Cutoff Current (ICBO): 15 nA (matching specification)
Operating Temperature Range: Up to 150°C maximum junction temperature

The BC547B from Diotec Semiconductor meets all critical electrical parameters and package requirements, qualifying as a direct substitute for the obsolete BC547BU.

Parameter Comparison

Parameter	BC547BU (onsemi)	BC547B (Diotec)	Match Status
Transistor Type	NPN	NPN	Equivalent
Current - Collector (Ic) Max	100 mA	100 mA	Equivalent
Voltage - Collector Emitter Breakdown (Max)	45 V	45 V	Equivalent
Vce Saturation (Max)	600 mV @ 5mA, 100mA	600 mV @ 5mA, 100mA	Equivalent
Current - Collector Cutoff (Max)	15 nA	15 nA	Equivalent
DC Current Gain (hFE) Min	110 @ 2mA, 5V	200 @ 2mA, 5V	Compatible (higher gain)
Power - Max	500 mW	500 mW	Equivalent
Frequency - Transition	300 MHz	300 MHz	Equivalent
Operating Temperature (TJ)	150°C	-55°C ~ 150°C	Compatible (wider range)
Mounting Type	Through Hole	Through Hole	Equivalent
Package / Case	TO-92-3	TO-92-3	Equivalent

Engineering Selection Recommendations

The BC547B manufactured by Diotec Semiconductor is a direct electrical and mechanical substitute for the obsolete BC547BU. Selection of the BC547B is supported by the following factors:

Product Status: The BC547B is classified as Active, ensuring ongoing availability and manufacturing support, whereas the BC547BU is obsolete.

Electrical Compatibility: All critical electrical parameters match or exceed the BC547BU specification. The BC547B exhibits a higher minimum DC current gain (200 vs. 110 @ 2mA, 5V), which is compatible with applications designed for the BC547BU and does not introduce functional degradation.

Thermal Performance: The BC547B supports an extended operating temperature range (-55°C to 150°C) compared to the BC547BU (150°C maximum), providing enhanced thermal margin for industrial and extended-temperature applications.

Package Compatibility: Both devices utilize the TO-92-3 Through Hole package with formed leads, ensuring direct mechanical and electrical compatibility in existing PCB layouts.

Compliance: Both parts carry identical ECCN (EAR99) and HTSUS (8541.21.0075) classifications, maintaining regulatory consistency.

Frequently Asked Questions (FAQ)

Q: Can the BC547B be used as a direct replacement for the BC547BU without circuit modification?

A: Yes. The BC547B meets all electrical specifications of the BC547BU. The higher DC current gain (200 vs. 110) is compatible with existing circuit designs and does not require modification.

Q: Are there package differences between the BC547BU and BC547B?

A: Both devices are supplied in the TO-92-3 Through Hole package. The BC547B features formed leads, which is standard for active production parts. This does not affect PCB compatibility or electrical performance.

Q: What is the significance of the higher DC current gain in the BC547B?

A: The BC547B minimum DC current gain of 200 @ 2mA, 5V exceeds the BC547BU specification of 110 @ 2mA, 5V. This represents improved transistor efficiency and is fully compatible with circuits designed for the BC547BU. No circuit redesign is required.

Q: Why is the BC547BU classified as obsolete?

A: The BC547BU is no longer in active production. The BC547B from Diotec Semiconductor represents the current production equivalent, offering identical electrical performance with enhanced availability.

Q: Are there any compliance or certification differences between these parts?

A: Both parts carry identical ECCN and HTSUS classifications. The BC547B is not subject to RoHS requirements (Not applicable), consistent with Through Hole component classification. Moisture sensitivity level is Not Applicable for both parts.

Q: What is the inventory status of these parts?

A: The BC547BU has 878 pieces in stock (obsolete status). The BC547B has 19,651 pieces in stock (active status), providing superior long-term procurement availability.

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