BC549CTF Equivalent & Substitute Parts

Part Overview

The BC549CTF is an NPN bipolar junction transistor manufactured by onsemi, designed for small-signal switching and amplification applications. This device operates at a maximum collector voltage of 30 V with a collector current rating of 100 mA and a transition frequency of 300 MHz. The BC549CTF is classified as obsolete, necessitating identification of active equivalent parts for continued circuit implementation and procurement.

Key Parameters

Parameter	Value
Transistor Type	NPN
Current - Collector (Ic) (Max)	100 mA
Voltage - Collector Emitter Breakdown (Max)	30 V
Vce Saturation (Max) @ Ib, Ic	600 mV @ 5 mA, 100 mA
Current - Collector Cutoff (Max)	15 nA (ICBO)
DC Current Gain (hFE) (Min) @ Ic, Vce	420 @ 2 mA, 5 V
Power - Max	500 mW
Frequency - Transition	300 MHz
Operating Temperature (TJ)	150°C
Mounting Type	Through Hole
Package / Case	TO-92-3 (TO-226AA) Formed Leads

Substitute Part Grouping Explanation

Substitution of the BC549CTF is determined by electrical and mechanical parameter equivalence. The following criteria establish valid substitutes:

Electrical Parameters (Required Match):

Transistor Type: NPN
Maximum Collector Current: 100 mA
Maximum Collector-Emitter Breakdown Voltage: 30 V
Vce Saturation: 600 mV @ 5 mA, 100 mA
Maximum Collector Cutoff Current: 15 nA (ICBO)
Minimum DC Current Gain (hFE): 420 @ 2 mA, 5 V
Maximum Power Dissipation: 500 mW
Transition Frequency: 300 MHz
Maximum Operating Temperature: 150°C

Mechanical Parameters (Required Match):

Mounting Type: Through Hole
Package: TO-92-3 (TO-226AA) Formed Leads

The identified substitute parts meet all specified electrical and mechanical parameters, enabling direct functional replacement in circuit applications.

Parameter Comparison

Parameter	BC549CTF (Main)	BC549CTA (Substitute)	BC548CTA (Substitute)
Manufacturer	onsemi	onsemi	Fairchild Semiconductor
Product Status	Obsolete	Active	Active
Transistor Type	NPN	NPN	NPN
Current - Collector (Ic) (Max)	100 mA	100 mA	100 mA
Voltage - Collector Emitter Breakdown (Max)	30 V	30 V	30 V
Vce Saturation (Max) @ Ib, Ic	600 mV @ 5 mA, 100 mA	600 mV @ 5 mA, 100 mA	600 mV @ 5 mA, 100 mA
Current - Collector Cutoff (Max)	15 nA (ICBO)	15 nA (ICBO)	15 nA (ICBO)
DC Current Gain (hFE) (Min) @ Ic, Vce	420 @ 2 mA, 5 V	420 @ 2 mA, 5 V	420 @ 2 mA, 5 V
Power - Max	500 mW	500 mW	500 mW
Frequency - Transition	300 MHz	300 MHz	300 MHz
Operating Temperature (TJ)	150°C	150°C	150°C
Mounting Type	Through Hole	Through Hole	Through Hole
Package / Case	TO-92-3 (TO-226AA)	TO-92-3 (TO-226AA)	TO-92-3 (TO-226AA)
ECCN	EAR99	EAR99	EAR99
HTSUS	8541.21.0075	8541.21.0075	8541.21.0075

Engineering Selection Recommendations

BC549CTA (onsemi): This part is the primary substitute for the BC549CTF. It is manufactured by the same original equipment manufacturer (onsemi) and maintains active product status. The BC549CTA is supplied in Cut Tape (CT) packaging and is ROHS3 compliant. With 35,685 units in stock, this part provides immediate availability and supply chain continuity. The BC549CTA is identical in all electrical and mechanical specifications to the BC549CTF.

BC548CTA (Fairchild Semiconductor): This part serves as a secondary substitute manufactured by Fairchild Semiconductor. It maintains active product status and is supplied in Bulk packaging. The BC548CTA is electrically and mechanically equivalent to the BC549CTF across all specified parameters. This option provides an alternative source for procurement and supply chain diversification.

Both substitute parts are classified as REACH Unaffected and carry the same export control classification (EAR99) and tariff code (HTSUS 8541.21.0075) as the original part.

Frequently Asked Questions (FAQ)

Q: Can BC549CTA directly replace BC549CTF in existing circuit designs?

A: Yes. The BC549CTA is electrically and mechanically equivalent to the BC549CTF. All electrical parameters, including collector current, breakdown voltage, saturation voltage, current gain, power dissipation, and transition frequency, are identical. The through-hole TO-92-3 package is identical, enabling direct pin-compatible substitution.

Q: What is the difference between BC549CTA and BC548CTA?

A: Both parts are electrically and mechanically equivalent to the BC549CTF across all specified parameters. The primary differences are manufacturer (onsemi versus Fairchild Semiconductor) and packaging format (Cut Tape versus Bulk). Selection between these parts depends on procurement requirements and supply chain preferences.

Q: Why is the BC549CTF classified as obsolete?

A: The BC549CTF is listed as obsolete by the manufacturer. Active equivalent parts (BC549CTA and BC548CTA) are available for continued circuit implementation and new designs.

Q: Are there packaging differences between the substitute parts?

A: The BC549CTA is supplied in Cut Tape (CT) packaging, while the BC548CTA is supplied in Bulk packaging. Both parts use the identical TO-92-3 (TO-226AA) formed leads package for circuit board mounting. Packaging format affects handling and automated assembly processes but does not affect electrical performance or pin compatibility.

Q: What compliance certifications apply to the substitute parts?

A: The BC549CTA is ROHS3 compliant. Both BC549CTA and BC548CTA are REACH Unaffected and classified under export control code EAR99 with tariff code HTSUS 8541.21.0075.

Q: Is inventory availability a consideration for part selection?

A: The BC549CTA has 35,685 units in stock, providing substantial availability. The BC548CTA has 1,749 units in stock. Both parts are available for immediate procurement.

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