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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi BC549C_J35Z

Name: BC549C_J35Z
Brand: onsemi
SKU: BC549C_J35Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC549C_J35Z

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: BC549C_J35Z.pdf

Description:: TRANS NPN 30V 0.1A TO-92-3

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Product details

Overview

BC549C_J35Z from ON Semiconductor is an NPN epitaxial silicon transistor optimized for low-noise amplification and general-purpose switching in analog signal paths, with h_FE = 420–800 at I_C = 2 mA, V_CEO = 30 V, and noise figure of 1.4–4.0 dB (f = 30–15 kHz, R_G = 2 kΩ). It is widely used in audio preamplifiers, sensor interface stages, and low-power linear regulators.

For engineers reviewing the BC549C_J35Z datasheet, pinout, applications, or equivalent options, key selection criteria include its low-noise performance, TO-92 package compatibility, DC current gain classification (Class C), and V_CEO/V_CBO ratings suitable for ≤30 V rail applications.

Technical Context

This device belongs to the legacy BC54x family originally developed by Fairchild and now maintained by ON Semiconductor. It operates as a discrete bipolar junction transistor with fixed emitter-base and collector-base junction geometry, requiring external biasing networks for stable DC operating points.

Its low-noise design targets small-signal amplification where thermal and flicker noise must be minimized - confirmed by specified noise figure (1.4–4.0 dB) and typical f_T of 300 MHz at I_C = 10 mA, enabling use up to mid-VHF frequencies in tuned amplifier stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	30 V - Maximum safe collector-emitter voltage before breakdown; defines upper rail limit in common-emitter amplifier designs.
h_FE (I_C = 2 mA)	420–800 - High DC current gain enables high-input-impedance amplifier stages with minimal base drive current.
Noise Figure	1.4–4.0 dB (f = 30–15 kHz, R_G = 2 kΩ) - Confirmed low-noise performance critical for microphone preamps and sensor front-ends.
f_T	300 MHz - Unity-gain bandwidth supports stable small-signal amplification up to ~50 MHz with proper compensation.
V_BE(sat)	700–900 mV (I_C = 10–100 mA) - Predictable saturation voltage simplifies switch-mode driver design and loss estimation.
P_C	500 mW - Power dissipation limit at T_A = 25°C; requires derating above 25°C ambient per thermal resistance spec.

Pinout & Package

BC549C_J35Z is housed in a standard through-hole TO-92 package (JEDEC TO-92 compliant), with straight leads and molded plastic body. Pin 1 is Collector, Pin 2 is Base, Pin 3 is Emitter - verified per Fairchild/ON Semiconductor mechanical drawings and ordering information.

Pin/Terminal	Circuit Role	Design Meaning
1 (Collector)	Output current sink node	Connected to load or next stage; voltage swing limited by V_CEO = 30 V and power dissipation.
2 (Base)	Control input terminal	Receives bias current to modulate collector current; requires series resistor to limit I_B and prevent thermal runaway.
3 (Emitter)	Reference/output return path	Typically grounded or connected to emitter degeneration resistor; sets DC operating point and AC impedance.

Key Features

Feature	Design Value
Low-noise amplification	Verified noise figure of 1.4–4.0 dB enables high-fidelity audio and precision sensor signal conditioning without added op-amp stages.
High h_FE Class C	DC current gain range 420–800 reduces required base drive and improves input impedance in CE amplifier configurations.
TO-92 mechanical compatibility	Standard 3-lead through-hole footprint allows drop-in replacement in legacy designs using BC546–BC550 family footprints.
Complementary PNP pairing	Designed as NPN counterpart to BC559 (PMPN), enabling matched push-pull output stages and differential pairs.

Applications

Audio Preamp Stage	Sensor Signal Amplifier
Use Scenario: Low-level microphone or piezoelectric sensor output amplification prior to ADC sampling. IC Role / Device Role / Timing Role: Discrete NPN transconductance amplifier providing first-stage gain with minimal added noise. Use Value: 1.4–4.0 dB noise figure ensures signal integrity preservation; h_FE ≥ 420 enables high input impedance without loading source.	Use Scenario: Amplifying millivolt-level outputs from thermistors, strain gauges, or photodiodes in industrial monitoring systems. IC Role / Device Role / Timing Role: Single-transistor non-inverting amplifier with emitter-degeneration for linearity and temperature stability. Use Value: Low V_BE(on) (580–700 mV) and tight h_FE tolerance support predictable DC biasing across temperature.
Linear Voltage Regulator Pass Element	General-Purpose Switch Driver
Use Scenario: Series pass transistor in adjustable 3–24 V linear regulators (e.g., with LM317 error amplifier). IC Role / Device Role / Timing Role: Current-controlled active pass element regulating output voltage via base bias modulation. Use Value: V_CEO = 30 V and P_C = 500 mW allow safe operation at ≤200 mA load currents with adequate heatsinking.	Use Scenario: Driving LEDs, relays, or small solenoids from microcontroller GPIO pins. IC Role / Device Role / Timing Role: Saturated switch controlling load current with low V_CE(sat) (90–600 mV) to minimize conduction loss. Use Value: Verified V_CE(sat) ≤ 250 mV at I_C = 10 mA / I_B = 0.5 mA ensures efficient switching with <1% voltage drop.

Audio Preamp Stage

Sensor Signal Amplifier

Use Scenario: Low-level microphone or piezoelectric sensor output amplification prior to ADC sampling.

IC Role / Device Role / Timing Role: Discrete NPN transconductance amplifier providing first-stage gain with minimal added noise.

Use Value: 1.4–4.0 dB noise figure ensures signal integrity preservation; h_FE ≥ 420 enables high input impedance without loading source.

Use Scenario: Amplifying millivolt-level outputs from thermistors, strain gauges, or photodiodes in industrial monitoring systems.

IC Role / Device Role / Timing Role: Single-transistor non-inverting amplifier with emitter-degeneration for linearity and temperature stability.

Use Value: Low V_BE(on) (580–700 mV) and tight h_FE tolerance support predictable DC biasing across temperature.

Linear Voltage Regulator Pass Element

General-Purpose Switch Driver

Use Scenario: Series pass transistor in adjustable 3–24 V linear regulators (e.g., with LM317 error amplifier).

IC Role / Device Role / Timing Role: Current-controlled active pass element regulating output voltage via base bias modulation.

Use Value: V_CEO = 30 V and P_C = 500 mW allow safe operation at ≤200 mA load currents with adequate heatsinking.

Use Scenario: Driving LEDs, relays, or small solenoids from microcontroller GPIO pins.

IC Role / Device Role / Timing Role: Saturated switch controlling load current with low V_CE(sat) (90–600 mV) to minimize conduction loss.

Use Value: Verified V_CE(sat) ≤ 250 mV at I_C = 10 mA / I_B = 0.5 mA ensures efficient switching with <1% voltage drop.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN low-noise transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC549B_J35Z	Lower h_FE range (200–450) and identical noise figure (1.4–4.0 dB); same V_CEO, package, and pinout.	Suitable where moderate gain suffices and tighter h_FE tolerance is acceptable; lower gain reduces risk of oscillation in high-Z layouts.	Select BC549B_J35Z when gain stability and reduced sensitivity to layout parasitics outweigh need for maximum h_FE.
2N3904	V_CEO = 40 V (higher), h_FE = 100–300 (lower), noise figure ≈ 5 dB (higher), f_T = 300 MHz (same).	Better for higher-voltage switching; less suitable for ultra-low-noise analog gain due to higher noise and lower h_FE.	Choose 2N3904 only if V_CEO > 30 V is required and noise performance is secondary to voltage rating.

Compared with BC549B_J35Z and 2N3904, BC549C_J35Z delivers the highest guaranteed h_FE in its family while maintaining best-in-class noise figure - making it optimal for low-level analog amplification where both gain and SNR are critical.

Availability

BC549C_J35Z is available at Aetrix Electronics and suitable for audio preamplifiers, sensor interface circuits, and linear regulator pass elements requiring stable component supply and long-term obsolescence management.

Supply support for BC549C_J35Z includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power management, analog, and discrete devices for automotive, industrial, and consumer applications.

BC549C_J35Z belongs to the BC54x legacy transistor product line, designed for cost-sensitive, high-reliability analog signal conditioning and switching in industrial control, audio, and instrumentation systems.

FAQ

What is the maximum collector-emitter voltage rating for BC549C_J35Z?

The BC549C_J35Z has a maximum collector-emitter voltage (V_CEO) rating of 30 V at T_A = 25°C. This value is absolute maximum and must not be exceeded in operation; derating is required at elevated ambient temperatures per the device's thermal characteristics. The BC549C_J35Z is not rated for 45 V or higher rails like the BC547 variant.

Does BC549C_J35Z have a specified noise figure, and under what conditions?

Yes, BC549C_J35Z has a specified noise figure of 1.4–4.0 dB, measured at V_CE = 5 V, I_C = 200 μA, R_G = 2 kΩ, and frequency range 30–15,000 Hz. This low-noise performance is explicitly documented in the Fairchild/ON Semiconductor datasheet and distinguishes BC549C_J35Z from standard-gain variants like BC547.

What is the h_FE range for BC549C_J35Z, and how is it tested?

The BC549C_J35Z is classified as Class C with a DC current gain (h_FE) range of 420–800, tested at V_CE = 5 V and I_C = 2 mA. This classification is marked on the device body and verified during final test; it ensures consistent gain behavior across production lots for precision analog designs.

Is BC549C_J35Z pin-compatible with other BC54x family members?

Yes, BC549C_J35Z uses the standard TO-92 package with identical pinout (Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter) as all BC546–BC550 variants. Mechanical and electrical pin compatibility is confirmed in the official Fairchild/ON Semiconductor datasheet and physical dimension drawings.

What is the power dissipation limit of BC549C_J35Z, and how does it scale with temperature?

The BC549C_J35Z has a maximum collector power dissipation (P_C) of 500 mW at T_A = 25°C. Above 25°C, dissipation must be linearly derated at 4.55 mW/°C - meaning usable power drops to ~364 mW at 60°C ambient. This derating is defined in the Absolute Maximum Ratings table and applies regardless of PCB copper area unless heatsinking is added.

BC549C_J35Z Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 100 mA

Voltage - Collector Emitter Breakdown (Max):: 30 V

Vce Saturation (Max) @ Ib, Ic:: 600mV @ 5mA, 100mA

Current - Collector Cutoff (Max):: 15nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 420 @ 2mA, 5V

Power - Max:: 500 mW

Frequency - Transition:: 300MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

BC549C_J35Z FAQ

1.How can I place an order for BC549C_J35Z through Aetrix?

Please submit a Request for Quotation (RFQ) for BC549C_J35Z on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BC549C_J35Z reliable?

The price and inventory of BC549C_J35Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC549C_J35Z is usually 5 days.

3.What payment methods are accepted for BC549C_J35Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC549C_J35Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC549C_J35Z?

BC549C_J35Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC549C_J35Z order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BC549C_J35Z?

For technical support, including BC549C_J35Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC549C_J35Z requirements.

6.How does Aetrix verify that BC549C_J35Z is sourced from the original manufacturer or authorized distributors?

All BC549C_J35Z products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BC549C_J35Z meets industry standards.

7.What is the process for return or replacement of BC549C_J35Z?

All BC549C_J35Z units undergo pre-shipment inspection (PSI). If there is an issue with BC549C_J35Z, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BC549C_J35Z part is unused and in its original packaging.

Return procedure for BC549C_J35Z:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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