BC550B Equivalent & Substitute Parts

Part Overview

The BC550B 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 BC550B is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	BC550B Value
Transistor Type	NPN
Current - Collector (Ic) Max	100 mA
Voltage - Collector Emitter Breakdown (Max)	45 V
Vce Saturation (Max) @ Ib, Ic	600 mV @ 5 mA, 100 mA
Current - Collector Cutoff (Max)	15 nA
DC Current Gain (hFE) Min @ Ic, Vce	200 @ 2 mA, 5 V
Power - Max	500 mW
Frequency - Transition	300 MHz
Mounting Type	Through Hole
Package / Case	TO-92-3
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitute parts for the BC550B are classified into two categories based on allowed electrical and mechanical parameters:

Parametric Equivalents maintain identical or equivalent electrical specifications and package form factor:

BC547B and BC547BBU: Identical collector current (100 mA), collector-emitter breakdown voltage (45 V), saturation voltage (600 mV @ 5 mA, 100 mA), current gain (200 @ 2 mA, 5 V), power rating (500 mW), and transition frequency (300 MHz). Both use through-hole TO-92-3 packaging. BC547B is manufactured by Diotec Semiconductor with active product status. BC547BBU is manufactured by onsemi with active product status and RoHS3 compliance.

Similar Substitutes share core electrical characteristics but differ in specific parameters or package type:

MMBT100: Maintains NPN type, 45 V collector-emitter breakdown voltage, and 250 MHz transition frequency. Differs in collector current (500 mA vs. 100 mA), power rating (350 mW vs. 500 mW), and mounting type (surface mount SOT-23-3 vs. through-hole TO-92-3). Suitable for applications where higher current capability and surface-mount integration are acceptable.
2N5232A PBFREE: Maintains NPN type and 100 mA collector current. Differs in collector-emitter breakdown voltage (50 V vs. 45 V), saturation voltage (125 mV vs. 600 mV), power rating (625 mW vs. 500 mW), and lacks specified transition frequency. Uses through-hole TO-92-3 packaging. Suitable for applications requiring higher voltage rating and lower saturation voltage.

Parameter Comparison

Parameter	BC550B	BC547B	BC547BBU	MMBT100	2N5232A PBFREE
Transistor Type	NPN	NPN	NPN	NPN	NPN
Current - Collector (Ic) Max	100 mA	100 mA	100 mA	500 mA	100 mA
Voltage - Collector Emitter Breakdown (Max)	45 V	45 V	45 V	45 V	50 V
Vce Saturation (Max) @ Ib, Ic	600 mV @ 5 mA, 100 mA	600 mV @ 5 mA, 100 mA	600 mV @ 5 mA, 100 mA	400 mV @ 20 mA, 200 mA	125 mV @ 1 mA, 10 mA
Current - Collector Cutoff (Max)	15 nA	15 nA	15 nA	50 nA	30 nA
DC Current Gain (hFE) Min @ Ic, Vce	200 @ 2 mA, 5 V	200 @ 2 mA, 5 V	200 @ 2 mA, 5 V	100 @ 150 mA, 5 V	250 @ 2 mA, 5 V
Power - Max	500 mW	500 mW	500 mW	350 mW	625 mW
Frequency - Transition	300 MHz	300 MHz	300 MHz	250 MHz	Not specified
Mounting Type	Through Hole	Through Hole	Through Hole	Surface Mount	Through Hole
Package / Case	TO-92-3	TO-92-3	TO-92-3	SOT-23-3	TO-92-3
Product Status	Obsolete	Active	Active	Active	Active

Engineering Selection Recommendations

For Direct Replacement (Parametric Equivalents):

BC547B and BC547BBU are the primary substitutes for BC550B applications. Both maintain identical electrical specifications across all critical parameters: collector current (100 mA), collector-emitter breakdown voltage (45 V), saturation voltage (600 mV @ 5 mA, 100 mA), current gain (200 @ 2 mA, 5 V), power rating (500 mW), and transition frequency (300 MHz). Both use through-hole TO-92-3 packaging, ensuring mechanical compatibility with existing PCB layouts.

BC547BBU, manufactured by onsemi, carries RoHS3 compliance and active product status, making it the preferred choice for new designs and applications requiring regulatory compliance documentation.

BC547B, manufactured by Diotec Semiconductor, also maintains active product status and provides equivalent electrical performance. Selection between BC547B and BC547BBU depends on supply chain availability and manufacturer preference.

For Applications Requiring Higher Current Capability:

MMBT100 is suitable when collector current requirements exceed 100 mA. It maintains the 45 V collector-emitter breakdown voltage and provides 500 mA maximum collector current. The transition frequency is reduced to 250 MHz, and power dissipation is limited to 350 mW. MMBT100 uses surface-mount SOT-23-3 packaging, requiring PCB redesign for integration. RoHS3 compliance is confirmed.

For Applications Requiring Higher Voltage Rating:

2N5232A PBFREE is suitable when collector-emitter breakdown voltage must exceed 45 V. It provides 50 V maximum breakdown voltage and maintains 100 mA collector current. The saturation voltage is significantly lower (125 mV @ 1 mA, 10 mA), and power dissipation is higher (625 mW). Through-hole TO-92-3 packaging is compatible with existing layouts. RoHS3 compliance is confirmed. Transition frequency is not specified.

Frequently Asked Questions (FAQ)

Q: Can BC547B or BC547BBU be used as direct replacements for BC550B?

A: Yes. BC547B and BC547BBU are parametric equivalents with identical electrical specifications and through-hole TO-92-3 packaging. No circuit modifications are required for direct substitution.

Q: What is the difference between BC547B and BC547BBU?

A: Both parts maintain identical electrical specifications. BC547B is manufactured by Diotec Semiconductor, while BC547BBU is manufactured by onsemi. BC547BBU carries RoHS3 compliance certification. Selection depends on supply availability and manufacturer preference.

Q: When should MMBT100 be used instead of BC547B or BC547BBU?

A: MMBT100 is selected when applications require collector current exceeding 100 mA. It provides 500 mA maximum collector current. However, it uses surface-mount SOT-23-3 packaging, requiring PCB redesign. Transition frequency is reduced to 250 MHz, and power dissipation is limited to 350 mW.

Q: Is MMBT100 compatible with through-hole PCB layouts designed for BC550B?

A: No. MMBT100 uses surface-mount SOT-23-3 packaging, while BC550B uses through-hole TO-92-3 packaging. PCB redesign is required for MMBT100 integration.

Q: When should 2N5232A PBFREE be used?

A: 2N5232A PBFREE is selected when applications require collector-emitter breakdown voltage exceeding 45 V. It provides 50 V maximum breakdown voltage and significantly lower saturation voltage (125 mV vs. 600 mV). Through-hole TO-92-3 packaging is compatible with existing layouts. Transition frequency is not specified.

Q: What are the key electrical differences between BC550B and 2N5232A PBFREE?

A: Collector-emitter breakdown voltage is higher (50 V vs. 45 V), saturation voltage is lower (125 mV vs. 600 mV), and power dissipation is higher (625 mW vs. 500 mW). Collector current (100 mA) and current gain (250 @ 2 mA, 5 V) are comparable or superior.

Q: Are all substitute parts RoHS3 compliant?

A: BC547BBU and 2N5232A PBFREE carry RoHS3 compliance certification. MMBT100 carries RoHS3 compliance. BC547B RoHS status is not applicable per manufacturer documentation.

Q: What is the inventory status of substitute parts?

A: BC547B: 19,651 units. BC547BBU: 21,955 units. MMBT100: 65,400 units. 2N5232A PBFREE: 17,706 units. All substitute parts are available as new original stock.

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