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onsemi BUL146G
- Part No.:
- BUL146G
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-220-3
- Datasheet:
-
BUL146G.pdf
- Description:
- TRANS NPN 400V 6A TO-220
- Quantity:
- Payment:
- Shipping:
Inventory:6,522
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Product details
Overview
BUL146G from onsemi is an NPN bipolar power transistor engineered for high-voltage switching in fluorescent lamp ballasts up to 130 W and switchmode power supplies. It delivers 6.0 A continuous collector current, sustains 400 V collector-emitter voltage, and operates reliably at junction temperatures up to 150°C - enabling robust performance in compact, thermally constrained AC/DC converters and electronic ballast circuits.
For engineers reviewing the BUL146G datasheet, pinout, applications, or equivalent options, this device is selected for its low base drive requirements (high flat hFE), fast switching (ton ≤ 100 ns, toff ≤ 2.5 µs at 125°C), absence of current tail during turn-off, and full characterization at elevated temperature - critical for designing energy-efficient, high-reliability power conversion stages.
Technical Context
The BUL146G employs a state-of-the-art die optimized for hard-switching applications with inductive loads, featuring tightly controlled parametric distributions and validated safe operating area (SOA) up to second breakdown limits. Its design eliminates the need for external base-coil snubbers due to intrinsic fast turn-off behavior and low dynamic saturation voltage.
Thermal management is enabled by a TO-220AB package with 1.25°C/W junction-to-case thermal resistance and full characterization at TC = 125°C - supporting stable operation under sustained high-power pulses in ballast and SMPS primary-side switching roles.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 400 V - Sustains 400 V across collector-emitter during off-state in flyback and forward converter topologies without breakdown. |
| IC (continuous) | 6.0 A - Supports primary-side switching in 100–130 W SMPS and electronic ballast designs without derating at 25°C case temperature. |
| hFE @ 125°C | 12–34 - High and flat DC current gain ensures stable base drive across temperature, reducing gate driver complexity in discrete control circuits. |
| toff @ 125°C | 1.35–2.5 µs - Fast turn-off minimizes switching losses and enables higher-frequency operation in compact magnetic designs. |
| RθJC | 1.25°C/W - Enables efficient heat transfer to heatsink, allowing 100 W dissipation at TC = 25°C with minimal thermal margin overhead. |
| VCE(sat) @ 3 A | 0.20–0.30 V - Low saturation voltage reduces conduction loss and improves efficiency in high-current switching nodes. |
| fT | 14 MHz - Sufficient bandwidth for stable high-speed switching control loop response in self-oscillating and fixed-frequency SMPS. |
Pinout & Package
Package: TO-220AB (Case 221A-09), Pb-free, standard through-hole mounting with isolated heatsink interface capability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Base) | Control input terminal | Receives base current to saturate or cut off the transistor; designed for low-drive operation with hFE ≥ 12 at 125°C. |
| 2 (Collector) | High-voltage power input | Connects to primary winding or high-side rail; rated for 700 V VCES and handles peak currents up to 15 A. |
| 3 (Emitter) | Power return path | Serves as common reference for base drive and load current return; electrically tied to emitter of internal die structure. |
| 4 (Collector) | Secondary collector connection | Dual-collector configuration improves current sharing and thermal distribution; internally connected to Pin 2. |
Key Features
| Feature | Design Value |
|---|---|
| No base coil required for turn-off | Eliminates external snubber components and associated PCB space, cost, and reliability risk in ballast and SMPS designs. |
| Full characterization at 125°C | Ensures guaranteed electrical parameters (hFE, VCE(sat), toff) under real-world thermal stress - no derating assumptions needed. |
| Tight lot-to-lot parametric distribution | Reduces production test variability and simplifies design margining for high-volume lighting and power supply manufacturing. |
| TO-220AB mechanical isolation support | Enables safe mounting to grounded heatsinks with verified creepage/strike distances - critical for Class I safety-compliant ballasts. |
| Pb-free and RoHS compliant | Meets global environmental compliance requirements without sacrificing thermal or electrical performance. |
Applications
| Fluorescent Lamp Ballast | AC/DC Switchmode Power Supply |
|---|---|
|
Use Scenario: Driving resonant LC tank in rapid-start electronic ballasts for T8/T5 lamps up to 130 W. IC Role / Device Role / Timing Role: Primary-side NPN switch controlling high-frequency (20–60 kHz) inverter stage; operates in hard-switched mode with clamped inductive turn-off. Use Value: Eliminates base coil snubber, reduces component count by 2–3 parts per channel, and maintains stable gain over lamp aging and ambient temperature swings. |
Use Scenario: Primary-side switching transistor in offline flyback or forward converters for industrial control power supplies. IC Role / Device Role / Timing Role: High-voltage, medium-current switch handling 300 V DC bus with 1.3–3.0 A peak load current and sub-2.5 µs turn-off. Use Value: Delivers <0.3 V VCE(sat) at 3 A and 125°C, cutting conduction loss by ~35% versus legacy 100 W transistors - directly improving efficiency in 85–265 VAC inputs. |
| Compact LED Driver | UPS Inverter Stage |
|
Use Scenario: High-efficiency buck-derived constant-current driver for commercial LED arrays (50–100 W). IC Role / Device Role / Timing Role: Synchronous rectifier replacement in quasi-resonant topology; used as main switching element with ZVS-assisted turn-on. Use Value: 14 MHz fT and fast ton (<100 ns) enable precise timing control for adaptive frequency modulation - reducing audible noise and EMI. |
Use Scenario: DC-AC inverter switching element in line-interactive UPS systems delivering 800–1200 VA output. IC Role / Device Role / Timing Role: Half-bridge leg switch handling 400 V DC link and 6 A continuous output current with forced-air cooling. Use Value: SOA-rated for inductive switching at 125°C ensures reliable operation during battery-mode overload transients without secondary breakdown failure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN power transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STBUL146 | Same die, identical VCEO/IC/hFE specs, but packaged in ST's TO-220FP (fullpack) variant with different leadframe geometry. | Requires verification of creepage distance compliance for ballast safety certification; not UL recognized like BUL146FG. | Select when sourcing flexibility is prioritized and UL recognition is not required in end-equipment certification. |
| MJD122G | Lower VCEO (200 V), lower IC (3 A), higher RθJC (2.5°C/W); shares same TO-220AB footprint but reduced SOA margins. | Suitable only for low-line (<120 VAC) SMPS or auxiliary supplies - cannot replace BUL146G in 230 VAC ballast or universal-input designs. | Use only in cost-sensitive, low-power applications where 400 V rating and 6 A current are not required. |
Compared with STBUL146 and MJD122G, the BUL146G uniquely combines 400 V VCEO, 6 A IC, and full 125°C characterization in a UL-recognized package option - making it the only drop-in solution for certified 130 W fluorescent ballasts and universal-input SMPS requiring long-term thermal stability.
Availability
BUL146G is available at Aetrix Electronics and suitable for fluorescent lamp ballasts, AC/DC switchmode power supplies, compact LED drivers, and UPS inverter stages requiring stable component supply, consistent parametric performance, and RoHS-compliant manufacturing.
Supply support for BUL146G 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 BUL146G belongs to onsemi's SWITCHMODE™ bipolar power transistor family, designed specifically for high-reliability, high-efficiency switching in fluorescent lamp ballasts and offline power conversion systems.
FAQ
What is the maximum operating temperature for the BUL146G?
The BUL146G has a specified operating junction temperature range of −65°C to +150°C. All key electrical parameters - including hFE, VCE(sat), and switching times - are fully characterized at 125°C, ensuring predictable performance in thermally demanding applications such as enclosed electronic ballasts and sealed power supplies. The BUL146G must be mounted with appropriate heatsinking to maintain TJ ≤ 150°C under continuous load.
Does the BUL146G require a base drive coil for turn-off?
No, the BUL146G does not require a base drive coil for turn-off. Its die design eliminates current tail during switching transitions, enabling clean, fast turn-off without external snubbers. This feature is explicitly confirmed in the datasheet under "Features" and validated in dynamic saturation voltage measurements (Figure 18), making the BUL146G ideal for simplified, high-reliability ballast and SMPS designs.
What is the thermal resistance from junction to case for the BUL146G?
The BUL146G has a maximum thermal resistance of 1.25°C/W from junction to case (RθJC). This value is measured on the standard TO-220AB package (Case 221A-09) and enables 100 W total device dissipation at TC = 25°C. Derating is required above 25°C at 0.8 W/°C, as specified in the Maximum Ratings table on page 1 of the BUL146G datasheet.
Is the BUL146G pin-compatible with other TO-220 NPN transistors?
The BUL146G uses the standard TO-220AB pinout (Pin 1 = Base, Pin 2 = Collector, Pin 3 = Emitter, Pin 4 = Collector), matching industry-standard layouts. However, direct pin compatibility does not guarantee functional equivalence - alternatives must match VCEO ≥ 400 V, IC ≥ 6 A, and SOA ratings for inductive switching. Always verify safe operating area curves and thermal derating before substitution.
What safety certifications apply to the BUL146G?
The BUL146G itself is not UL-recognized; however, its variant BUL146FG (TO-220 Fullpak) is UL Recognized to 3500 VRMS (File # E69369). For safety-critical applications like Class I fluorescent ballasts, designers should select BUL146FG or confirm isolation compliance via creepage/strike distance validation per IEC 61347-2-3 when using BUL146G with proper mounting techniques.
BUL146G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- SWITCHMODE™
- Package/Case:
- TO-220-3
- 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:
- 100 W
- Frequency - Transition:
- 14MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220
BUL146G FAQ
1.How can I place an order for BUL146G through Aetrix?
Please submit a Request for Quotation (RFQ) for BUL146G 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 BUL146G reliable?
The price and inventory of BUL146G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BUL146G is usually 5 days.
3.What payment methods are accepted for BUL146G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BUL146G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BUL146G?
BUL146G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BUL146G 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 BUL146G?
For technical support, including BUL146G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BUL146G requirements.
6.How does Aetrix verify that BUL146G is sourced from the original manufacturer or authorized distributors?
All BUL146G 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 BUL146G meets industry standards.
7.What is the process for return or replacement of BUL146G?
All BUL146G units undergo pre-shipment inspection (PSI). If there is an issue with BUL146G, 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 BUL146G part is unused and in its original packaging.
Return procedure for BUL146G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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