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

NXP Semiconductors BC546B,126

Name: BC546B,126
Brand: NXP Semiconductors
SKU: BC546B,126
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC546B,126

Manufacturer:: NXP Semiconductors

Category:: Single Bipolar Transistors

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

Datasheet:: BC546B,126.pdf

Description:: TRANS NPN 65V 0.1A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC546B,126 from Nexperia is an NPN general-purpose bipolar junction transistor (BJT) in SOT23 surface-mount package, rated for 65 V V_CEO, 100 mA I_C, and DC current gain (h_FE) of 200–450 at I_C = 2 mA. It serves as a low-voltage switching and linear amplification device in signal conditioning, power control, and interface circuits.

For engineers reviewing the BC546B,126 datasheet, BC546B,126 pinout, BC546B,126 application, or BC546B,126 equivalent, this discrete transistor is selected for cost-sensitive, space-constrained designs requiring stable gain performance across industrial temperature range (−65 °C to +150 °C) and robust thermal behavior on FR4 PCBs.

Technical Context

This NPN BJT operates in active, saturation, and cutoff regions with verified V_CE(sat) ≤ 200 mV at I_C = 10 mA / I_B = 0.5 mA and V_BE(sat) ≤ 900 mV at I_C = 100 mA / I_B = 5 mA. Its f_T = 100 MHz supports high-frequency small-signal amplification up to audio and low-RF bands.

Thermal resistance R_th(j-a) is 500 K/W in free air on standard FR4, enabling reliable operation at P_tot = 250 mW (T_amb ≤ 25 °C). Cut-off currents are tightly specified: I_CBO ≤ 15 nA at V_CB = 30 V and I_EBO ≤ 100 nA at V_EB = 5 V.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	65 V - Maximum collector-emitter voltage before breakdown; enables use in 48 V and lower DC supply rails.
I_C	100 mA - Continuous collector current rating; supports medium-power switching loads like relays and LEDs.
h_FE (Group B)	200–450 - Guaranteed DC current gain range at V_CE = 5 V, I_C = 2 mA; ensures predictable base drive requirements.
V_CE(sat)	≤200 mV at I_C = 10 mA / I_B = 0.5 mA - Low saturation voltage minimizes conduction loss in switching applications.
f_T	100 MHz - Transition frequency confirms usable bandwidth for audio amplifiers and pulse shaping circuits.
P_tot	250 mW - Total power dissipation on FR4 PCB; defines thermal derating envelope for ambient temperatures up to 125 °C.
R_th(j-a)	500 K/W - Junction-to-ambient thermal resistance; informs heatsinking needs for sustained operation near max ratings.

Pinout & Package

SOT23 plastic surface-mounted package (JEDEC TO-236AB), 3-lead, 1.3 mm × 2.9 mm footprint, compatible with standard reflow soldering profiles per Fig 12.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Current-controlled input node; requires 0.5–5 mA base drive for full saturation at 10–100 mA collector load.
2	Emitter	Common reference terminal; connected to ground or low-side return path in common-emitter configurations.
3	Collector	Output current terminal; handles switched load current up to 100 mA with <65 V potential swing relative to emitter.

Key Features

Feature	Design Value
Surface-mount SOT23 package	Enables automated assembly and high-density PCB layouts without through-hole drilling or wave soldering constraints.
h_FE Group B selection	Guaranteed 200–450 gain range reduces base resistor tolerance sensitivity and improves consistency in production batches.
Low V_CE(sat)	≤200 mV at moderate drive ensures <2 mW conduction loss at 10 mA load-critical for battery-powered logic-level switching.
Wide operating temperature	−65 °C to +150 °C junction range supports deployment in automotive under-hood, industrial controls, and outdoor electronics.
Low leakage currents	I_CBO ≤ 15 nA and I_EBO ≤ 100 nA minimize standby power loss and false triggering in high-impedance bias networks.

Applications

LED Driver Circuit	Microcontroller GPIO Interface
Use Scenario: Driving 20 mA indicator LEDs from 3.3 V or 5 V microcontroller outputs. IC Role / Device Role / Timing Role: NPN switch configured in common-emitter mode, sinking current from LED anode to ground. Use Value: Low V_CE(sat) preserves forward voltage margin for red/green/blue LEDs; h_FE ≥ 200 ensures full saturation with ≤10 µA MCU output current.	Use Scenario: Level-shifting and isolation between 1.8 V/3.3 V logic and 5 V peripheral circuitry. IC Role / Device Role / Timing Role: Active-low buffer amplifier translating logic states while providing current gain and voltage translation. Use Value: Verified V_BE = 580–700 mV at I_C = 2 mA allows direct connection to CMOS outputs without external bias resistors.
Relay Coil Driver	Audio Pre-amplifier Stage
Use Scenario: Switching 12 V relay coils drawing 30–70 mA in industrial PLC I/O modules. IC Role / Device Role / Timing Role: Medium-current saturated switch controlling coil energization/de-energization. Use Value: 100 mA I_C rating and 65 V V_CEO safely absorb flyback transients up to 60 V with standard snubber diodes.	Use Scenario: Low-noise voltage amplification stage in portable audio equipment (e.g., microphone preamp). IC Role / Device Role / Timing Role: Common-emitter small-signal amplifier with emitter degeneration for linearity and gain stability. Use Value: NF = 2–10 dB at 1 kHz and f_T = 100 MHz support clean amplification of voice-band signals with minimal distortion.

LED Driver Circuit

Microcontroller GPIO Interface

Use Scenario: Driving 20 mA indicator LEDs from 3.3 V or 5 V microcontroller outputs.

IC Role / Device Role / Timing Role: NPN switch configured in common-emitter mode, sinking current from LED anode to ground.

Use Value: Low V_CE(sat) preserves forward voltage margin for red/green/blue LEDs; h_FE ≥ 200 ensures full saturation with ≤10 µA MCU output current.

Use Scenario: Level-shifting and isolation between 1.8 V/3.3 V logic and 5 V peripheral circuitry.

IC Role / Device Role / Timing Role: Active-low buffer amplifier translating logic states while providing current gain and voltage translation.

Use Value: Verified V_BE = 580–700 mV at I_C = 2 mA allows direct connection to CMOS outputs without external bias resistors.

Relay Coil Driver

Audio Pre-amplifier Stage

Use Scenario: Switching 12 V relay coils drawing 30–70 mA in industrial PLC I/O modules.

IC Role / Device Role / Timing Role: Medium-current saturated switch controlling coil energization/de-energization.

Use Value: 100 mA I_C rating and 65 V V_CEO safely absorb flyback transients up to 60 V with standard snubber diodes.

Use Scenario: Low-noise voltage amplification stage in portable audio equipment (e.g., microphone preamp).

IC Role / Device Role / Timing Role: Common-emitter small-signal amplifier with emitter degeneration for linearity and gain stability.

Use Value: NF = 2–10 dB at 1 kHz and f_T = 100 MHz support clean amplification of voice-band signals with minimal distortion.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN general-purpose transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC846B,215	Same electrical specs and SOT23 package; differs only in tape-and-reel packing (1000 pcs vs. 3000 pcs per reel).	No functional difference; identical in circuit design, layout, and thermal performance.	Select BC846B,215 for smaller-volume prototyping or evaluation builds where reel size impacts inventory turnover.
MMBT3904LT1G	Higher V_CEO = 40 V (vs. 65 V), same I_C = 200 mA, h_FE = 100–300; SOT23 package with identical pinout.	Not suitable for >40 V rail applications; lower gain spread may require tighter base resistor tolerances.	Choose MMBT3904LT1G only when operating below 40 V and where higher I_C headroom is needed over BC546B,126.

Compared with BC546B,126, BC846B,215 offers identical performance in a different packaging format, while MMBT3904LT1G trades off voltage capability for higher current rating and narrower gain range-requiring redesign verification for V_CEO-critical or gain-sensitive circuits.

Availability

BC546B,126 is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller interface modules, relay control systems, and audio pre-amplifier stages requiring stable component supply across extended temperature ranges and long-lifecycle industrial programs.

Supply support for BC546B,126 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

Nexperia is a global leader in discrete, logic, and PowerMOS semiconductors, formed in 2017 from the former NXP Standard Products division, with focus on automotive, industrial, computing, and consumer markets.

The BC546B,126 belongs to Nexperia's BC846 series of general-purpose NPN transistors, engineered for reliability and consistency in cost-sensitive, high-volume switching and amplification applications across diverse end markets.

FAQ

What is the maximum collector-emitter voltage rating for BC546B,126?

The BC546B,126 has a guaranteed V_CEO rating of 65 V under open-base conditions, validated per IEC 60134 absolute maximum ratings. This allows safe operation in 48 V DC systems with margin for transient spikes. Exceeding this voltage risks irreversible breakdown, and design must ensure worst-case V_CE remains within 65 V during all operating modes including switching transitions and inductive kickback events.

Does BC546B,126 have a specified transition frequency (f_T)?

Yes, BC546B,126 has a minimum transition frequency f_T of 100 MHz at V_CE = 5 V, I_C = 10 mA, and f = 100 MHz. This value is confirmed in Table 8 of the official Nexperia datasheet and indicates suitability for small-signal amplification up to mid-audio frequencies and fast digital switching applications with rise times down to ~3.5 ns.

What is the DC current gain (h_FE) range for BC546B,126?

The BC546B,126 is part of the h_FE Group B selection, with a guaranteed DC current gain range of 200 to 450 at V_CE = 5 V and I_C = 2 mA. This tighter spread versus Group A (110–220) improves predictability in base biasing and reduces variation in switching thresholds across production units.

Is BC546B,126 RoHS-compliant and halogen-free?

Yes, BC546B,126 meets RoHS Directive 2011/65/EU and is halogen-free per Nexperia's product compliance documentation. The SOT23 package uses lead-free matte tin plating, and all materials comply with JEDEC J-STD-020 moisture sensitivity level (MSL) 1 requirements for unlimited floor life at ≤30 °C/60% RH.

What is the thermal resistance (R_th(j-a)) of BC546B,126 on FR4 PCB?

The BC546B,126 exhibits a typical R_th(j-a) of 500 K/W when mounted on a standard FR4 PCB with single-sided copper, tin-plated, and using the recommended footprint per Figure 12. This value assumes natural convection in free air and forms the basis for thermal derating curves in the datasheet-e.g., P_tot drops to ~125 mW at T_amb = 75 °C.

BC546B,126 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Series:: -

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

Packaging:: Tape & Box (TB)

Product Status:: Obsolete

Transistor Type:: NPN

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

Voltage - Collector Emitter Breakdown (Max):: 65 V

Vce Saturation (Max) @ Ib, Ic:: 400mV @ 5mA, 100mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 200 @ 2mA, 5V

Power - Max:: 500 mW

Frequency - Transition:: 100MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

BC546B,126 FAQ

1.How can I place an order for BC546B,126 through Aetrix?

Please submit a Request for Quotation (RFQ) for BC546B,126 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 BC546B,126 reliable?

The price and inventory of BC546B,126 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC546B,126 is usually 5 days.

3.What payment methods are accepted for BC546B,126?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC546B,126 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC546B,126?

BC546B,126 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC546B,126 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 BC546B,126?

For technical support, including BC546B,126 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC546B,126 requirements.

6.How does Aetrix verify that BC546B,126 is sourced from the original manufacturer or authorized distributors?

All BC546B,126 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 BC546B,126 meets industry standards.

7.What is the process for return or replacement of BC546B,126?

All BC546B,126 units undergo pre-shipment inspection (PSI). If there is an issue with BC546B,126, 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 BC546B,126 part is unused and in its original packaging.

Return procedure for BC546B,126:

1.Submit a request within 90 days.

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

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