BC548B A1G Equivalent & Substitute Parts

Part Overview

The BC548B A1G is a Bipolar (BJT) NPN transistor manufactured by Taiwan Semiconductor Corporation, rated for 30 V collector-emitter breakdown voltage and 100 mA maximum collector current in a Through Hole TO-92 package. This device is classified as Obsolete, which necessitates identification of active equivalent components for ongoing design support and procurement continuity. Substitute parts must maintain electrical and mechanical compatibility while meeting current manufacturing and compliance standards.

Substiute Parts

BC548B A1G

Taiwan Semiconductor CorporationIn Stock: 1121BC548B A1G Datasheet

Current PartRFQ

BC549BTA

onsemiIn Stock: 2028BC549BTA Datasheet

SimilarRFQ

BC549CTA

onsemiIn Stock: 35783BC549CTA Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BC548B A1G is based on strict electrical and mechanical parameter matching within the NPN Bipolar (BJT) transistor category. The following parameters establish substitution validity:

Critical Matching Parameters:

• Transistor Type: NPN (required match)
• Current - Collector (Ic) (Max): 100 mA (required match)
• Voltage - Collector Emitter Breakdown (Max): 30 V (required match)
• Current - Collector Cutoff (Max): 15 nA (ICBO) (required match)
• Power - Max: 500 mW (required match)
• Mounting Type: Through Hole (required match)
• Package / Case: TO-92-3 (required match)
• RoHS Status: ROHS3 Compliant (required match)

Acceptable Parameter Variations:

• DC Current Gain (hFE) (Min): Substitute parts may exceed the minimum specification of 200 @ 2 mA, 5 V
• Frequency - Transition: Substitute parts may include specified transition frequency where the main part does not
• Operating Temperature (Upper Limit): Substitute parts may match or exceed the upper limit of 150°C
• Product Status: Active substitute parts are acceptable for Obsolete main parts

The BC549BTA and BC549CTA manufactured by onsemi satisfy all critical matching parameters and are classified as Active products, providing design continuity and procurement availability.

Parameter Comparison

Engineering Selection Recommendations

BC549BTA Selection Criteria: The BC549BTA is suitable for applications requiring the BC548B A1G electrical specifications with Active product status and current manufacturing support. This part maintains the minimum DC Current Gain specification of 200 @ 2 mA, 5 V and includes specified transition frequency of 300 MHz. The BC549BTA is ROHS3 Compliant and REACH Unaffected, meeting regulatory requirements equivalent to the main part.

BC549CTA Selection Criteria: The BC549CTA provides identical electrical ratings to the BC549BTA with an elevated DC Current Gain minimum of 420 @ 2 mA, 5 V. This higher gain specification may be advantageous in applications where increased amplification is beneficial or where design margins require higher current gain performance. The BC549CTA is ROHS3 Compliant and REACH Unaffected. Inventory availability for BC549CTA is significantly higher (35,685 Pcs) compared to BC549BTA (2,000 Pcs), supporting procurement continuity.

Compliance and Certification: Both substitute parts maintain ROHS3 Compliance and REACH Unaffected status, ensuring regulatory alignment with the original BC548B A1G specification. Both parts are manufactured by onsemi, an established semiconductor manufacturer with active product support.

Frequently Asked Questions (FAQ)

Q: Can BC549BTA and BC549CTA be used interchangeably with BC548B A1G?

A: Yes. Both BC549BTA and BC549CTA meet all critical electrical and mechanical parameters required for BC548B A1G substitution. The primary difference is DC Current Gain specification: BC549BTA maintains the 200 minimum, while BC549CTA specifies 420 minimum. Both are electrically compatible in circuits designed for the BC548B A1G.

Q: What is the difference between BC549BTA and BC549CTA?

A: The BC549BTA and BC549CTA are identical except for DC Current Gain (hFE) specification. BC549BTA specifies 200 @ 2 mA, 5 V (matching BC548B A1G), while BC549CTA specifies 420 @ 2 mA, 5 V. Both parts share identical maximum ratings, frequency response (300 MHz), and package specifications.

Q: Are the TO-92 and TO-92-3 packages physically compatible?

A: Yes. The TO-92-3 designation used by onsemi for BC549BTA and BC549CTA refers to the same physical package as the TO-92 used by Taiwan Semiconductor Corporation for BC548B A1G. Both are TO-226-3 (TO-226AA) Formed Leads packages with identical pin configuration and through-hole mounting compatibility.

Q: Does the higher DC Current Gain of BC549CTA affect circuit operation?

A: The higher DC Current Gain of BC549CTA (420 vs. 200) does not negatively affect circuits designed for BC548B A1G. Circuits designed with the minimum gain specification of 200 will operate with improved performance margins when using BC549CTA. Applications requiring specific gain matching should account for this specification difference during design validation.

Q: Are BC549BTA and BC549CTA RoHS compliant?

A: Yes. Both BC549BTA and BC549CTA are ROHS3 Compliant and REACH Unaffected, matching the compliance status of BC548B A1G.

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

A: The BC549BTA and BC549CTA specify a maximum junction temperature (TJ) of 150°C. The BC548B A1G specifies -65°C ~ 150°C. For applications requiring the full -65°C lower temperature limit, design validation is required to confirm substitute part performance at minimum operating temperature.

Q: Why is BC548B A1G classified as Obsolete?

A: The Obsolete classification indicates that Taiwan Semiconductor Corporation has discontinued manufacturing this part. BC549BTA and BC549CTA provide equivalent electrical and mechanical functionality with Active product status from onsemi, ensuring ongoing availability and manufacturing support.