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

STMicroelectronics BUL805

Name: BUL805
Brand: STMicroelectronics
SKU: BUL805
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BUL805

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BUL805.pdf

Description:: TRANS NPN 450V 5A TO-220

Quantity:: RFQ Add To RFQ list

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Inventory:1,836

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Product details

Overview

BUL805 from STMicroelectronics is a high-voltage fast-switching NPN power transistor in TO-220 package, rated for V_CEO = 450 V, I_C = 5 A, P_tot = 80 W at T_C = 25°C, and designed specifically for power factor correction (PFC) in high-frequency electronic fluorescent lamp ballasts using half-bridge voltage-fed topology.

For engineers reviewing the BUL805 datasheet, BUL805 pinout, BUL805 application, or BUL805 equivalent, this device's high switching speed, low dynamic parameter spread, and cellular emitter structure are critical for stable PFC operation in compact lighting inverters requiring reliable high-voltage switching under thermal stress.

Technical Context

The BUL805 employs high-voltage multi-epitaxial planar technology with planar edge termination to achieve fast turn-on/turn-off times and robust voltage blocking. Its cellular emitter layout minimizes base charge storage, reducing switching losses in high-frequency (≥20 kHz) PFC stages.

It operates with V_CE(sat) ≤ 0.8 V at I_C = 3 A / I_B = 0.6 A and maintains h_FE ≥ 10 at I_C = 2 A, enabling efficient base drive in self-oscillating or IC-controlled half-bridge configurations without external snubbers.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	450 V - Sustains full bridge mid-point voltage swing in 230 VAC-fed half-bridge PFC without breakdown
I_C	5 A continuous - Supports >75 W PFC output in compact ballast designs with forced-air or heatsink cooling
P_tot	80 W at T_C = 25°C - Requires thermal design with R_thj-case ≤ 1.56°C/W to maintain T_J ≤ 150°C
V_CE(sat)	0.4–0.8 V - Minimizes conduction loss across 1–3 A load range, critical for efficiency in discontinuous conduction mode (DCM) PFC
h_FE	10–20 - Enables direct TTL-compatible base drive in simple oscillator-based ballast controllers
R_thj-case	1.56°C/W max - Dictates minimum heatsink size; compatible with standard TO-220 mounting hardware

Pinout & Package

TO-220 package: 3-pin through-hole, vertical mounting, metal tab (collector) electrically connected to pin 2. Standard lead-free ECOPACK® construction compliant with JEDEC JESD97.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to ground or low-side switch node; carries full load current with minimal parasitic inductance
2 (Collector / Tab)	High-voltage output terminal	Electrically tied to metal tab; must be isolated from chassis unless system common is collector-referenced
3 (Base)	Control input	Receives low-current drive signal; requires series resistor (typically 10–47 Ω) to limit peak I_B ≤ 4 A

Key Features

Feature	Design Value
High voltage capability	V_CES = 800 V enables margin against voltage spikes in inductive half-bridge switching
Very high switching speed	Low stored charge and planar edge termination reduce t_f/t_r, supporting >50 kHz operation without excessive EMI
Low lot-to-lot parameter spread	Tight control of h_FE, V_CE(sat), and leakage ensures consistent PFC loop stability across production batches
Cellular emitter structure	Improves current sharing and thermal uniformity during high-current pulses, extending reliability in thermally constrained ballasts

Applications

Electronic Ballast Control

PFC Half-Bridge Stage

Use Scenario: High-frequency (25–65 kHz) fluorescent lamp driver with integrated PFC stage.

IC Role / Device Role / Timing Role: Main switching transistor in voltage-fed half-bridge, directly driven by oscillator IC or discrete timing network.

Use Value: Delivers stable zero-voltage switching transitions and low conduction loss, enabling >90% system efficiency in <100 mm³ form factor.

Use Scenario: Active PFC front-end for 230 VAC input, feeding downstream DC-DC converter.

IC Role / Device Role / Timing Role: High-voltage switch in boost-derived half-bridge configuration, operating in DCM or CCM based on controller.

Use Value: Maintains V_CE < 450 V under transient overvoltage while sustaining 5 A peak current, meeting EN61000-3-2 harmonic limits.

Compact Lighting Inverter

Industrial Lamp Driver

Use Scenario: Space-constrained LED retrofit tube with integrated magnetic ballast replacement.

IC Role / Device Role / Timing Role: Primary switch in resonant inverter stage, co-located with PFC transistor on shared heatsink.

Use Value: Low R_thj-case and high T_J(max) = 150°C allow operation at 75°C ambient without derating in sealed enclosures.

Use Scenario: High-reliability industrial fluorescent fixture operating continuously at 60°C ambient.

IC Role / Device Role / Timing Role: Voltage-switched power transistor in hardened half-bridge, protected by fast-acting base clamping.

Use Value: Tight V_CEO(sus) = 450 V and low I_CEO = 250 µA ensure long-term stability under thermal cycling and humidity exposure.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
STBUL805	Same die, tape-and-reel packaging instead of tube; identical electrical specs and pinout	No functional difference; selected only for automated assembly compatibility	Choose STBUL805 for SMT line integration; BUL805 remains optimal for manual or semi-automated through-hole production
BU508A	Lower V_CEO = 1000 V but higher V_CE(sat) = 1.5 V at I_C = 3 A; slower switching due to larger die area	Used in lower-frequency (<15 kHz), higher-power (>150 W) ballasts where voltage margin outweighs efficiency needs	Select BU508A only when V_CEO > 600 V is mandatory and thermal budget allows higher conduction loss

Compared with STBUL805 (identical function, different packaging) and BU508A (higher voltage but lower speed and efficiency), the BUL805 offers the best balance of switching performance, thermal manageability, and cost for standardized 25–65 kHz fluorescent PFC designs.

Availability

BUL805 is available at Aetrix Electronics and suitable for electronic ballast control, PFC half-bridge stages, and compact lighting inverters requiring stable component supply with documented thermal and switching behavior.

Supply support for BUL805 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, specializing in power management, analog, microcontrollers, and automotive-grade ICs.

The BUL805 belongs to ST's high-voltage bipolar transistor product line, engineered specifically for energy-efficient lighting systems and industrial power conversion where ruggedness, consistency, and high-frequency switching are essential.

FAQ

Is BUL805 RoHS-compliant and lead-free?

Yes. The BUL805 is manufactured in ST's ECOPACK® package with lead-free second-level interconnect, fully compliant with RoHS Directive 2011/65/EU and JEDEC JESD97 marking standards. The inner box label confirms its lead-free status and soldering profile limits.

What is the maximum safe operating frequency for BUL805 in PFC applications?

The BUL805 supports stable operation up to 100 kHz in optimized layouts, but its recommended maximum for sustained reliability in PFC half-bridge topologies is 65 kHz. Above this, switching losses increase significantly due to finite t_f/t_r, requiring tighter gate drive control and enhanced thermal management.

Can BUL805 replace BU2508DF in existing ballast designs?

No. BU2508DF is a Darlington transistor with integrated driver and different pinout (base-emitter-collector vs. emitter-base-collector). BUL805 lacks built-in base resistors and has lower gain, requiring redesign of base drive circuitry and thermal layout before substitution.

Does BUL805 require a heatsink in typical 40 W ballast operation?

Yes. Even at 40 W output, junction temperature exceeds 150°C without heatsinking due to P_tot > 5 W under switching conditions. A minimum 15 cm² aluminum heatsink (R_th ≈ 25°C/W) is required to keep T_J ≤ 125°C at 50°C ambient, per thermal data in Table 3.

BUL805 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 5 A

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

Vce Saturation (Max) @ Ib, Ic:: 800mV @ 600mA, 3A

Current - Collector Cutoff (Max):: 250µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 10 @ 2A, 5V

Power - Max:: 80 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

BUL805 FAQ

1.How can I place an order for BUL805 through Aetrix?

Please submit a Request for Quotation (RFQ) for BUL805 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 BUL805 reliable?

The price and inventory of BUL805 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BUL805 is usually 5 days.

3.What payment methods are accepted for BUL805?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BUL805 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BUL805?

BUL805 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BUL805 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 BUL805?

For technical support, including BUL805 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BUL805 requirements.

6.How does Aetrix verify that BUL805 is sourced from the original manufacturer or authorized distributors?

All BUL805 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 BUL805 meets industry standards.

7.What is the process for return or replacement of BUL805?

All BUL805 units undergo pre-shipment inspection (PSI). If there is an issue with BUL805, 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 BUL805 part is unused and in its original packaging.

Return procedure for BUL805:

1.Submit a request within 90 days.

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

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