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

STMicroelectronics BU900TP

Name: BU900TP
Brand: STMicroelectronics
SKU: BU900TP
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BU900TP

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: SOT-82

Datasheet:: BU900TP.pdf

Description:: TRANS NPN 370V 5A SOT-82-3

Quantity:: RFQ Add To RFQ list

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Inventory:5,077

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Product details

Overview

BU900TP from STMicroelectronics is an NPN high-voltage power transistor in SOT-82 package, featuring integrated active Zener clamping, 370 V V_CE_S, 5 A continuous collector current, and 80 mJ secondary breakdown energy-designed for unclamped inductive switching in automotive ignition systems.

For engineers reviewing the BU900TP datasheet, BU900TP pinout, BU900TP application, or BU900TP equivalent, key selection criteria include clamping robustness under inductive flyback, thermal resistance (2.27 °C/W), DC current gain (h_FE ≥ 7000 at I_C = 1 A), and verified 100% clamping energy testing.

Technical Context

The BU900TP implements a planar monolithic TRILINTON™ structure with on-die Zener-based active clamping to suppress voltage spikes during turn-off in inductive loads. Its 370 V V_CE_S rating and 8 A peak collector current support high-energy switching transients without external snubbers.

Designed for rugged unclamped operation, it delivers 55 W total dissipation at T_c = 25°C and maintains stable h_FE ≥ 7000 across I_C = 1 A, V_CE = 5 V-enabling precise base drive sizing in high-gain switching topologies.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CE_S	370 V - Withstands full inductive flyback voltage without external clamping circuitry
I_C	5 A continuous - Supports sustained high-current switching in ignition coils and motor drivers
h_FE	≥ 7000 at I_C = 1 A - Enables low-base-drive-current control, reducing driver stage losses
E_s/b	80 mJ - 100% tested secondary breakdown energy ensures reliability under repetitive inductive stress
R_thj-case	2.27 °C/W - Allows direct heatsink mounting with predictable thermal margin up to 55 W dissipation
V_CE(sat)	4 V at I_C = 3 A, I_B = 3 mA - Low saturation voltage minimizes conduction loss in pulsed high-power operation

Pinout & Package

Package: SOT-82 (3-lead TO-225AA variant), metal-can package with case-connected collector for direct thermal path and EMI shielding.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input	Low-impedance gate for driving with minimal base current (I_B ≤ 1 A max)
2 (Collector)	High-side switch node	Internally connected to metal case-must be electrically isolated from heatsink unless referenced to system ground
3 (Emitter)	Current return path	Provides low-inductance emitter connection for fast switching and stable clamping response

Key Features

Feature	Design Value
Integrated active Zener clamping	Eliminates need for external TVS or RCD snubber networks in ignition and regulator designs
100% clamping energy tested	Guarantees per-device robustness against repetitive inductive kickback stress
High h_FE (≥ 7000)	Reduces required base drive power and simplifies driver IC selection
370 V V_CE_S rating	Enables direct use in 24 V and 42 V automotive systems with margin for load dump and inductive overshoot

Applications

Engine Ignition Control

Switching Regulator Primary Switch

Use Scenario: Driving primary winding of automotive ignition coil in distributorless ignition systems (DIS).

IC Role / Device Role / Timing Role: High-voltage, high-current NPN switch turning on/off coil current to generate spark timing pulses.

Use Value: Integrated Zener clamping absorbs 370 V flyback without snubber, enabling compact, reliable coil driver PCBs.

Use Scenario: Primary-side switch in offline flyback or forward converters for industrial power supplies.

IC Role / Device Role / Timing Role: Main power switch handling high dV/dt and inductive energy recovery during MOSFET replacement in legacy bipolar designs.

Use Value: 80 mJ secondary breakdown energy and 55 W dissipation allow safe operation at 100 kHz+ switching with minimal derating.

DC Motor Commutation

Electronic Lamp Ballast

Use Scenario: Brushed DC motor H-bridge upper-leg switch in power tools and HVAC blowers.

IC Role / Device Role / Timing Role: High-current, high-voltage switching element controlling motor phase current direction and magnitude.

Use Value: 5 A continuous current and 8 A peak rating support stall-tolerant motor control without external current limiting.

Use Scenario: High-frequency AC ballast for fluorescent lamps in commercial lighting fixtures.

IC Role / Device Role / Timing Role: Resonant switch in series-resonant inverter topology, managing lamp ignition and regulation.

Use Value: Stable h_FE and low V_CE(sat) ensure consistent lamp starting and dimming linearity across temperature.

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
BU901T	V_CE_S = 400 V, I_C = 5 A, no integrated Zener clamping	Requires external clamping network; higher voltage margin but added BOM and layout complexity	Select when absolute maximum V_CE margin > 400 V is required and external snubber design is acceptable
BU508A	V_CE_S = 1500 V, I_C = 12 A, h_FE ≈ 10–20, no integrated clamping	Lower gain demands high-current base drive; suited for very high-voltage, low-frequency applications only	Select only for ultra-high-voltage (>1 kV) linear or quasi-resonant ballasts where gain and speed are secondary

Compared with BU901T and BU508A, the BU900TP uniquely combines integrated Zener clamping, high h_FE, and verified 80 mJ secondary breakdown-making it optimal for compact, high-reliability ignition and mid-voltage switching where snubber-free operation and low drive loss are critical.

Availability

BU900TP is available at Aetrix Electronics and suitable for engine ignition control, switching regulators, and motor control applications requiring stable component supply and long-term industrial availability.

Supply support for BU900TP 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, delivering innovative silicon solutions for automotive, industrial, and power applications.

The BU900TP belongs to ST's high-voltage bipolar power transistor family, engineered specifically for rugged unclamped inductive switching in automotive and industrial systems where reliability under transient stress is non-negotiable.

FAQ

Is BU900TP still in active production?

No-BU900TP is marked as Obsolete by STMicroelectronics per its official datasheet revision history. However, Aetrix Electronics maintains legacy inventory with full traceability and supports design-in continuity through controlled allocation and cross-reference guidance for qualified replacements.

Can BU900TP replace a MOSFET in switching regulator designs?

Yes, but with design adjustments: its 4 V V_CE(sat) yields higher conduction loss than typical MOSFET R_DS(on), requiring careful thermal management. Base drive must supply ≥3 mA for 3 A switching, unlike MOSFET gate-drive simplicity. It excels where ruggedness and integrated clamping outweigh efficiency trade-offs.

What is the role of the metal case in SOT-82 packaging?

The metal case in BU900TP's SOT-82 package is internally connected to the collector terminal, serving as both thermal conduction path and electromagnetic shield. It must be electrically isolated from heatsinks unless the collector node is grounded in the application-failure to isolate risks short-circuiting the output stage.

Does the "100% clamping energy tested" specification apply to production units?

Yes-per ST's datasheet, every BU900TP unit undergoes 100% functional testing of clamping energy capability at 80 mJ under standardized inductive load conditions (I_C = 4 A, L = 10 mH). This is not a sampling test but a per-device qualification metric.

BU900TP Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: SOT-82

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN - Trilinton, Zener Clamp

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

Voltage - Collector Emitter Breakdown (Max):: 370 V

Vce Saturation (Max) @ Ib, Ic:: 4V @ 3mA, 3A

Current - Collector Cutoff (Max):: 100µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 7000 @ 1A, 5V

Power - Max:: 55 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: SOT-82-3

BU900TP FAQ

1.How can I place an order for BU900TP through Aetrix?

Please submit a Request for Quotation (RFQ) for BU900TP 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 BU900TP reliable?

The price and inventory of BU900TP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BU900TP is usually 5 days.

3.What payment methods are accepted for BU900TP?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BU900TP transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BU900TP?

BU900TP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BU900TP 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 BU900TP?

For technical support, including BU900TP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BU900TP requirements.

6.How does Aetrix verify that BU900TP is sourced from the original manufacturer or authorized distributors?

All BU900TP 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 BU900TP meets industry standards.

7.What is the process for return or replacement of BU900TP?

All BU900TP units undergo pre-shipment inspection (PSI). If there is an issue with BU900TP, 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 BU900TP part is unused and in its original packaging.

Return procedure for BU900TP:

1.Submit a request within 90 days.

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

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