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

STMicroelectronics BUL810

Name: BUL810
Brand: STMicroelectronics
SKU: BUL810
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BUL810

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-247-3

Datasheet:: BUL810.pdf

Description:: TRANS NPN 450V 15A TO-247-3

Quantity:: RFQ Add To RFQ list

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Inventory:2,643

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Product details

Overview

BUL810 from STMicroelectronics is a high-voltage fast-switching NPN power transistor designed for primary-side switching in lighting and SMPS circuits. It features 1000 V V_CES, 15 A I_C, 125 W P_tot at T_c = 25 °C, 1.5 µs typical storage time (t_s), and TO-247 package - used in electronic ballasts for fluorescent lamps and halogen lamp transformers.

For engineers reviewing the BUL810 datasheet, BUL810 pinout, BUL810 application, or BUL810 equivalent, key selection criteria include V_CES = 1000 V, t_s/t_f ≤ 2.3 µs/110 ns under inductive load, low base-drive requirement (I_B = 1.6 A for I_C = 8 A), and guaranteed characterization at 125 °C junction temperature.

Technical Context

The BUL810 employs high-voltage multiepitaxial mesa technology with a hollow emitter structure to minimize minority carrier storage and achieve fast switching. Its rugged safe operating area (SOA) supports repetitive inductive turn-off at V_CL = 350 V and L = 200 µH.

It is fully characterized across temperature (25 °C and 125 °C case), with specified V_CEO(sus) = 450 V at I_C = 100 mA and guaranteed h_FE ≥ 10 at I_C = 5 A, enabling stable current control in high-voltage flyback and resonant topologies.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CES	1000 V - Withstands full mains-related transients in 230 VAC-fed lighting and SMPS primary switches.
I_C	15 A continuous - Supports >100 W output in compact flyback or half-bridge converters without forced cooling.
t_s / t_f	1.5 µs / 55 ns (T_c = 25 °C) - Enables >100 kHz switching with low switching loss in electronic ballasts.
V_CE(sat)	1.5 V @ I_C = 8 A, I_B = 1.6 A - Limits conduction loss to <1.2 W, easing thermal design in TO-247 package.
R_thj-case	1 °C/W max - Allows 125 W dissipation with ≤125 °C junction rise above 25 °C heatsink temperature.
h_FE	10–40 - Provides predictable base drive scaling for gate driver or discrete base resistor design.
T_J(max)	150 °C - Rated for sustained operation in enclosed luminaires and sealed power supplies.

Pinout & Package

Supplied in TO-247 package: isolated metal tab (collector), 3-pin through-hole outline with 5.45 mm lead pitch (e), 20.0 mm body width (D), and 14.5 mm height (L). Mounting hole øP = 3.6 mm.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input	Low-impedance drive node requiring ~1.6 A peak for full 8 A collector conduction; sensitive to layout inductance.
2 (Collector)	High-voltage switch node	Connected to heatsink via isolated mounting; carries full primary current and voltage stress in flyback topology.
3 (Emitter)	Power return reference	Low-inductance emitter connection critical for minimizing voltage overshoot during turn-off; tied to ground plane or snubber return.

Key Features

Feature	Design Value
Hollow emitter structure	Reduces minority carrier lifetime to cut storage time by >30% vs. conventional planar NPN transistors.
Full 125 °C characterization	Guarantees t_s, V_CE(sat), and h_FE performance in thermally constrained lamp housings and sealed PSUs.
Low base-drive requirement	Enables direct drive from small-signal BJTs or low-current logic outputs without Darlington buffering.
Rugged SOA with inductive load rating	Validated for repetitive switching into L = 200 µH with V_CL = 350 V, supporting reliable operation in magnetic ballasts.

Applications

Electronic Ballast for Fluorescent Lamps

Electronic Transformer for Halogen Lamps

Use Scenario: High-frequency AC generation (20–60 kHz) to drive preheat and sustain fluorescent tubes without magnetic core losses.

IC Role / Device Role / Timing Role: Primary-side hard-switched NPN transistor in push-pull or half-bridge inverter stage.

Use Value: 1000 V V_CES withstands open-circuit tube ignition spikes; 1.5 µs t_s enables efficient 50 kHz operation with minimal dead-time loss.

Use Scenario: Step-down AC-AC conversion for 12 V halogen lamps using high-frequency square-wave inversion and ferrite transformer.

IC Role / Device Role / Timing Role: Switching element in self-oscillating or fixed-frequency flyback-derived topology.

Use Value: Low V_CE(sat) (1.5 V) minimizes conduction loss in compact, unventilated transformers; TO-247 package allows direct heatsinking to metal housing.

Switch-Mode Power Supply (SMPS)

Inductive Load Driver (e.g., Solenoid Control)

Use Scenario: Primary-side switch in offline 30–100 W flyback converters for industrial control power supplies.

IC Role / Device Role / Timing Role: Main energy transfer switch turning on/off at 60–100 kHz with clamp or RCD snubber.

Use Value: Guaranteed 450 V V_CEO(sus) ensures robustness against reflected voltage spikes; 125 W P_tot supports high-duty-cycle operation.

Use Scenario: Fast turn-off of high-inductance solenoids or relay coils in automated lighting control panels.

IC Role / Device Role / Timing Role: Active clamp switch managing stored coil energy during de-energization.

Use Value: 110 ns fall time (t_f) limits voltage overshoot across coil; 150 °C T_J(max) accommodates ambient temperatures up to 85 °C in panel-mounted enclosures.

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage NPN switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
STBUL810	Same die, identical specs, but in TO-218 package (lower R_thj-case = 0.9 °C/W, no mounting hole).	Preferred where higher power density and lower thermal resistance are needed; not interchangeable mechanically with TO-247 footprint.	Select STBUL810 only if board layout allows TO-218 and thermal margin is critical.
BU508A	Lower V_CES = 1000 V same, but slower: t_s = 4 µs typ, V_CE(sat) = 2.0 V @ 8 A, no 125 °C characterization.	Suitable for <50 kHz designs with relaxed efficiency targets; not recommended for compact ballasts requiring tight thermal control.	Choose BU508A only for cost-sensitive, non-enclosed, low-frequency SMPS where switching loss is secondary.

Compared with STBUL810 and BU508A, the BUL810 uniquely balances 1000 V capability, sub-2 µs storage time, and full 125 °C validation - making it optimal for thermally constrained, high-frequency lighting inverters where reliability and size matter.

Availability

BUL810 is available at Aetrix Electronics and suitable for electronic ballasts, halogen lamp transformers, and low-cost switch-mode power supplies requiring stable component supply and long-lifecycle support.

Supply support for BUL810 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, delivering intelligent power, analog, and microcontroller solutions for industrial, automotive, and consumer markets.

The BUL series belongs to ST's high-voltage bipolar power transistor product line, engineered specifically for cost-effective, high-reliability switching in lighting and auxiliary power applications - emphasizing ruggedness, thermal stability, and manufacturability.

FAQ

Is BUL810 still in active production?

No - STMicroelectronics has marked BUL810 as Obsolete (as confirmed in Rev 4, March 2008 datasheet). However, Aetrix Electronics maintains legacy inventory with full traceability and offers extended supply support, including cross-reference guidance and engineering consultation for migration paths.

Can BUL810 be used in avalanche mode?

No - BUL810 is not rated for repetitive avalanche operation. Its safe operating area (SOA) is defined for forward-biased switching only. The datasheet specifies no E_AS rating, and V_CEO(sus) = 450 V reflects sustaining voltage under controlled inductive turn-off, not avalanche breakdown.

What is the maximum recommended gate/base resistor value?

For reliable 8 A switching at 100 kHz, base resistor should limit I_B to ≥1.6 A peak. With V_BE(sat) ≈ 1.6 V and driver supply ≥12 V, R_B ≤ (12 V − 1.6 V)/1.6 A = 6.5 Ω. A 4.7 Ω ±5% resistor is commonly used, verified in ST's reference test circuit (Figure 11).

Does BUL810 require a heatsink in 15 A operation?

Yes - at I_C = 15 A and V_CE(sat) ≈ 2.0 V (worst-case), conduction loss exceeds 30 W. Even with R_thj-case = 1 °C/W, junction temperature would exceed 150 °C without a heatsink. A minimum 2°C/W heatsink is required for continuous 15 A use at 25 °C ambient.

BUL810 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-247-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 15 A

Voltage - Collector Emitter Breakdown (Max):: 450 V

Vce Saturation (Max) @ Ib, Ic:: 5V @ 2.4A, 12A

Current - Collector Cutoff (Max):: 250µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 10 @ 5A, 5V

Power - Max:: 125 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-247-3

BUL810 FAQ

1.How can I place an order for BUL810 through Aetrix?

Please submit a Request for Quotation (RFQ) for BUL810 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 BUL810 reliable?

The price and inventory of BUL810 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BUL810 is usually 5 days.

3.What payment methods are accepted for BUL810?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BUL810 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BUL810?

BUL810 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BUL810 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 BUL810?

For technical support, including BUL810 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BUL810 requirements.

6.How does Aetrix verify that BUL810 is sourced from the original manufacturer or authorized distributors?

All BUL810 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 BUL810 meets industry standards.

7.What is the process for return or replacement of BUL810?

All BUL810 units undergo pre-shipment inspection (PSI). If there is an issue with BUL810, 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 BUL810 part is unused and in its original packaging.

Return procedure for BUL810:

1.Submit a request within 90 days.

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

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