BC549B A1G Equivalent & Substitute Parts

Part Overview

The BC549B A1G is a bipolar NPN transistor manufactured by Taiwan Semiconductor Corporation, designed for general-purpose switching and amplification applications. This device operates at a maximum collector voltage of 30 V with a collector current rating of 100 mA and dissipates up to 500 mW. The BC549B A1G is classified as obsolete, which necessitates identification of active equivalent components for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility across voltage, current, and power ratings while accommodating packaging and thermal specifications.

Substiute Parts

BC549B A1G

Taiwan Semiconductor CorporationIn Stock: 1051BC549B A1G Datasheet

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BC549CTA

onsemiIn Stock: 35783BC549CTA Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the BC549B A1G is determined by strict equivalence across the following electrical and mechanical parameters:

Electrical Compatibility Criteria:

• Transistor type must be NPN
• Maximum collector current (Ic) must equal or exceed 100 mA
• Maximum collector-emitter breakdown voltage (VCEO) must equal or exceed 30 V
• Maximum power dissipation must equal or exceed 500 mW
• Collector cutoff current (ICBO) must not exceed 15 nA
• DC current gain (hFE) minimum must support the specified operating point

Mechanical Compatibility Criteria:

• Package type must be TO-92-3 (TO-226-3)
• Mounting configuration must be Through Hole
• Physical form factor must accommodate existing PCB layouts

Compliance Requirements:

• RoHS3 compliance required
• REACH unaffected status required
• ECCN classification must be EAR99

The BC549CTA manufactured by onsemi satisfies all substitution criteria and is classified as an active product, providing long-term availability and supply chain continuity.

Parameter Comparison

Engineering Selection Recommendations

The BC549CTA is a direct electrical and mechanical substitute for the BC549B A1G. Selection of the BC549CTA is supported by the following factors:

Product Status: The BC549CTA maintains active manufacturing status, ensuring continued availability and supply chain reliability. The BC549B A1G is classified as obsolete, creating supply constraints for new production and long-term support.

Electrical Equivalence: The BC549CTA meets or exceeds all maximum electrical ratings specified for the BC549B A1G. The collector current, breakdown voltage, power dissipation, and cutoff current parameters are identical. The DC current gain of the BC549CTA (420 @ 2mA, 5V) exceeds the BC549B A1G minimum specification (200 @ 2mA, 5V), providing improved performance margin.

Mechanical Compatibility: Both devices utilize the TO-92-3 package with through-hole mounting, ensuring direct PCB layout compatibility without redesign.

Regulatory Compliance: The BC549CTA maintains RoHS3 compliance, REACH unaffected status, and EAR99 export classification, matching the compliance profile of the BC549B A1G.

Thermal Performance: The BC549CTA supports the upper operating temperature limit of 150°C, accommodating the thermal requirements of the BC549B A1G.

Frequently Asked Questions (FAQ)

Q: Can the BC549CTA be used as a direct replacement for the BC549B A1G in existing designs?

A: Yes. The BC549CTA is electrically and mechanically equivalent to the BC549B A1G. Both devices share identical maximum ratings for collector current (100 mA), collector-emitter breakdown voltage (30 V), and power dissipation (500 mW). The TO-92-3 package pinout and through-hole mounting configuration are identical, permitting direct substitution without circuit modification or PCB redesign.

Q: What is the primary reason for substituting the BC549B A1G?

A: The BC549B A1G is classified as obsolete, indicating discontinued manufacturing and declining inventory availability. The BC549CTA is an active product manufactured by onsemi, providing assured long-term supply and production continuity.

Q: Are there any performance differences between the BC549B A1G and BC549CTA?

A: The BC549CTA exhibits a higher DC current gain (hFE) of 420 @ 2mA, 5V compared to the BC549B A1G minimum of 200 @ 2mA, 5V. This represents improved amplification performance. The BC549CTA also specifies a transition frequency of 300 MHz, which is not documented for the BC549B A1G. These differences represent performance enhancements that do not compromise backward compatibility.

Q: Do both devices meet the same regulatory and compliance standards?

A: Yes. Both the BC549B A1G and BC549CTA are RoHS3 compliant, REACH unaffected, and classified as EAR99 for export purposes. Compliance profiles are identical.

Q: Is the TO-92-3 package identical between both devices?

A: Yes. Both devices utilize the TO-92-3 package (also designated TO-226-3 or TO-226AA with formed leads). The physical dimensions, pin configuration, and through-hole mounting specifications are identical, ensuring direct PCB compatibility.

Q: What is the operating temperature range for the BC549CTA?

A: The BC549CTA supports an upper junction temperature (TJ) of 150°C. This accommodates the upper operating limit specified for the BC549B A1G (-65°C to 150°C).

Q: Are there any packaging format differences between the BC549B A1G and BC549CTA?

A: The BC549B A1G is supplied in standard packaging format. The BC549CTA is supplied in Cut Tape (CT) format. Both devices are identical in component form and electrical specification; packaging format differences relate only to supply and handling methods and do not affect component performance or compatibility.