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

onsemi BUL146F

Name: BUL146F
Brand: onsemi
SKU: BUL146F
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BUL146F

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3 Full Pack

Datasheet:: BUL146F.pdf

Description:: TRANS NPN 400V 6A TO-220FP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BUL146F from onsemi is an NPN bipolar power transistor designed for high-voltage switching applications in fluorescent lamp ballasts up to 130 W and switchmode power supplies. It features a 400 V_CEO, 700 V_CES, 6 A continuous collector current, 40 W total device dissipation at T_C = 25°C, and UL recognition to 3500 V_RMS (File # E69369) in Case 221D package.

For engineers reviewing the BUL146F datasheet, pinout, applications, or equivalent options, this device is selected for high-reliability, isolated high-voltage switching where low base drive requirements, fast turn-off without tail current, and consistent lot-to-lot parametric distribution are critical in ballast and SMPS designs.

Technical Context

The BUL146F employs a state-of-the-art die optimized for inductive switching in fluorescent lamp ballasts and offline SMPS topologies. Its design emphasizes high DC current gain (h_FE ≥ 12 at I_C = 3.0 A, T_J = 125°C), fast switching (t_off ≤ 2.5 µs at T_J = 125°C), and robust safe operating area under clamped inductive loads.

It operates with no base coil required for turn-off - eliminating current tail - and delivers stable performance across −65°C to +150°C junction temperature range. Full characterization at 125°C ensures reliability in thermally demanding environments such as enclosed ballast housings and compact power adapters.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	400 V - Sustains 400 V collector-emitter voltage during switching transitions, enabling use in 230 VAC input SMPS with margin.
I_C (continuous)	6.0 A - Supports output power levels up to ~130 W in lamp ballasts and medium-power SMPS stages.
V_CE(sat)	0.20–0.30 V (I_C = 3.0 A, I_B = 0.6 A, T_J = 125°C) - Low saturation voltage minimizes conduction loss and thermal stress.
t_off	1.7–2.5 µs (I_C = 3.0 A, T_J = 125°C) - Fast turn-off enables high-frequency operation while maintaining SOA integrity.
R_JC	3.125 °C/W - Thermal resistance from junction to case defines heatsink sizing requirement for 40 W dissipation at T_C = 25°C.
V_ISOL	3500 V_RMS (1 sec, RH < 30%, T_C = 25°C) - UL-recognized isolation supports reinforced insulation in Class II ballast and adapter designs.
h_FE	8.0–20 (I_C = 3.0 A, V_CE = 1.0 V, T_J = 125°C) - High and flat DC gain reduces base drive circuit complexity and improves efficiency.

Pinout & Package

Package: TO-220 Fullpak (Case 221D), fully isolated, UL Recognized (File # E69369). Mounting requires screw or clip with torque ≤ 10 in·lbs to preserve isolation integrity.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Low-impedance control input; accepts 0.6 A peak base current; no external turn-off coil needed due to optimized minority carrier lifetime.
2	Collector	Main high-voltage power terminal; connected internally to metal tab for thermal and electrical path; rated for 700 V_CES.
3	Emitter	Power return node; referenced to ground in common-emitter configurations; supports 6 A continuous current with low forward drop.

Key Features

Feature	Design Value
High and flat DC current gain	h_FE ≥ 12 at I_C = 3.0 A and T_J = 125°C - Enables simplified, low-loss base drive with minimal heat generation in driver stage.
No current tail during turn-off	Eliminates need for base coil - reduces component count, PCB area, and EMI from inductive kickback in ballast circuits.
Full 125°C characterization	All max ratings and switching parameters validated at T_J = 125°C - Ensures predictable performance in sealed, high-ambient lamp enclosures.
Tight parametric distributions	Lot-to-lot consistency in V_CE(sat), h_FE, and t_off - Reduces need for binning and simplifies production calibration in mass-manufactured ballasts.
UL-recognized isolation	3500 V_RMS isolation (Case 221D) - Meets reinforced insulation requirements for double-insulated Class II lighting and power supply systems.

Applications

Fluorescent Lamp Ballast	Offline Switchmode Power Supply
Use Scenario: Driving resonant LC tank in electronic ballasts for T8/T5 lamps up to 130 W. IC Role / Device Role / Timing Role: Main high-voltage switching transistor in half-bridge topology; handles 300 V clamp conditions during inductive turn-off. Use Value: Fast t_off (≤2.5 µs) and no current tail ensure clean zero-voltage switching transitions, reducing EMI and improving lamp life.	Use Scenario: Primary-side switch in 20–60 W AC/DC adapters and open-frame SMPS for consumer electronics. IC Role / Device Role / Timing Role: NPN power switch in self-oscillating or controller-driven flyback converters operating at 20–100 kHz. Use Value: 400 V_CEO and 700 V_CES provide margin against line surges and leakage spikes in universal-input (85–265 VAC) designs.
Industrial Control Power Module	LED Driver (High-Power Inductive)
Use Scenario: DC-DC conversion stage in programmable logic controller (PLC) power modules requiring high reliability. IC Role / Device Role / Timing Role: Regulated high-side switch in buck-derived topologies delivering stable 5–24 V outputs under variable load. Use Value: R_JC = 3.125 °C/W and 150°C max T_J enable operation in confined, unventilated enclosures without derating.	Use Scenario: Constant-current switch in high-bay LED drivers using boost or SEPIC topologies driving >100 W strings. IC Role / Device Role / Timing Role: Main switching element handling inductive energy transfer and high dV/dt transients during PWM dimming. Use Value: Reverse-biased SOA validated per Figure 16 supports reliable operation under clamped inductive turn-off at 300 V.

Fluorescent Lamp Ballast

Offline Switchmode Power Supply

Use Scenario: Driving resonant LC tank in electronic ballasts for T8/T5 lamps up to 130 W.

IC Role / Device Role / Timing Role: Main high-voltage switching transistor in half-bridge topology; handles 300 V clamp conditions during inductive turn-off.

Use Value: Fast t_off (≤2.5 µs) and no current tail ensure clean zero-voltage switching transitions, reducing EMI and improving lamp life.

Use Scenario: Primary-side switch in 20–60 W AC/DC adapters and open-frame SMPS for consumer electronics.

IC Role / Device Role / Timing Role: NPN power switch in self-oscillating or controller-driven flyback converters operating at 20–100 kHz.

Use Value: 400 V_CEO and 700 V_CES provide margin against line surges and leakage spikes in universal-input (85–265 VAC) designs.

Industrial Control Power Module

LED Driver (High-Power Inductive)

Use Scenario: DC-DC conversion stage in programmable logic controller (PLC) power modules requiring high reliability.

IC Role / Device Role / Timing Role: Regulated high-side switch in buck-derived topologies delivering stable 5–24 V outputs under variable load.

Use Value: R_JC = 3.125 °C/W and 150°C max T_J enable operation in confined, unventilated enclosures without derating.

Use Scenario: Constant-current switch in high-bay LED drivers using boost or SEPIC topologies driving >100 W strings.

IC Role / Device Role / Timing Role: Main switching element handling inductive energy transfer and high dV/dt transients during PWM dimming.

Use Value: Reverse-biased SOA validated per Figure 16 supports reliable operation under clamped inductive turn-off at 300 V.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN bipolar power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BUL146G	TO-220AB (Case 221A), non-isolated; R_JC = 1.25 °C/W; PD = 100 W; no UL isolation rating.	Suitable for non-isolated, heatsink-mounted applications where creepage/clearance is controlled externally.	Select BUL146G only when isolation is not required and higher power dissipation (100 W) is needed at lower thermal resistance.
MJE13009	400 V_CEO, 12 A I_C, R_JC = 1.5 °C/W, TO-220 package; no UL recognition; slower t_off (~4 µs).	Used in cost-sensitive, high-current SMPS but lacks BUL146F's tight parametric control and 125°C switching validation.	Choose MJE13009 only for non-critical, ambient-temperature-limited designs where UL isolation and 125°C SOA are not mandated.

Compared with BUL146G and MJE13009, the BUL146F uniquely combines UL-recognized isolation, guaranteed 125°C switching performance, and no-tail turn-off - making it the only option qualified for safety-critical, thermally constrained fluorescent ballasts and Class II SMPS meeting IEC 61347-2-3 and IEC 62368-1.

Availability

BUL146F is available at Aetrix Electronics and suitable for fluorescent lamp ballasts, offline switchmode power supplies, and industrial control power modules requiring stable component supply, long-term lifecycle support, and certified isolation compliance.

Supply support for BUL146F 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BUL146F belongs to onsemi's SWITCHMODE™ bipolar power transistor family, engineered specifically for high-reliability, high-voltage switching in fluorescent lamp ballasts and offline SMPS - prioritizing efficiency, thermal stability, and safety certification.

FAQ

What is the maximum junction temperature rating for the BUL146F?

The BUL146F has a specified operating and storage temperature range of −65°C to +150°C. All electrical characteristics, including switching times and saturation voltage, are fully characterized at 125°C - confirming its suitability for high-ambient applications such as enclosed lamp ballasts and sealed power adapters where junction temperatures routinely approach this limit.

Does the BUL146F require a base turn-off coil?

No, the BUL146F does not require a base turn-off coil. Its die design eliminates current tail during turn-off, enabling clean, fast switching without external inductive components in the base circuit - a key feature confirmed in the datasheet's "Improved Efficiency" section and validated by dynamic saturation voltage measurements in Figure 18.

What is the thermal resistance from junction to case (R_JC) for the BUL146F?

The BUL146F has a maximum thermal resistance of 3.125°C/W from junction to case (R_JC). This value is specified for the TO-220 Fullpak (Case 221D) package and directly determines heatsink sizing for dissipating its 40 W maximum power at T_C = 25°C - critical for thermal management in compact, isolated power modules.

Is the BUL146F RoHS compliant and lead-free?

Yes, the BUL146F is Pb-free and RoHS compliant, as explicitly stated in the datasheet's Features section and Ordering Information table. The "F" suffix in BUL146F denotes the Pb-free, RoHS-compliant version in the TO-220 Fullpak package, aligned with onsemi's environmental compliance program.

What safety certifications does the BUL146F hold?

The BUL146F is UL Recognized to 3500 V_RMS (File # E69369) in the Case 221D package. This certification applies to isolation between leads and heatsink under defined mounting conditions and supports compliance with reinforced insulation requirements in IEC 61347-2-3 (lamp ballasts) and IEC 62368-1 (audio/video equipment).

BUL146F Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: SWITCHMODE™

Package/Case:: TO-220-3 Full Pack

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 6 A

Voltage - Collector Emitter Breakdown (Max):: 400 V

Vce Saturation (Max) @ Ib, Ic:: 700mV @ 600mA, 3A

Current - Collector Cutoff (Max):: 100µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 14 @ 500mA, 5V

Power - Max:: 40 W

Frequency - Transition:: 14MHz

Operating Temperature:: -65°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220FP

BUL146F FAQ

1.How can I place an order for BUL146F through Aetrix?

Please submit a Request for Quotation (RFQ) for BUL146F 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 BUL146F reliable?

The price and inventory of BUL146F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BUL146F is usually 5 days.

3.What payment methods are accepted for BUL146F?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BUL146F transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BUL146F?

BUL146F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BUL146F 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 BUL146F?

For technical support, including BUL146F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BUL146F requirements.

6.How does Aetrix verify that BUL146F is sourced from the original manufacturer or authorized distributors?

All BUL146F 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 BUL146F meets industry standards.

7.What is the process for return or replacement of BUL146F?

All BUL146F units undergo pre-shipment inspection (PSI). If there is an issue with BUL146F, 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 BUL146F part is unused and in its original packaging.

Return procedure for BUL146F:

1.Submit a request within 90 days.

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

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