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

STMicroelectronics BUV20

Name: BUV20
Brand: STMicroelectronics
SKU: BUV20
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BUV20

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-204AA, TO-3

Datasheet:: BUV20.pdf

Description:: TRANS NPN 125V 50A TO-3

Quantity:: RFQ Add To RFQ list

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Inventory:6,630

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Product details

Overview

BUV20 from STMicroelectronics is a high-current NPN silicon power transistor in a TO-3 metal package, designed for linear and switching applications in industrial equipment. It delivers 50 A continuous collector current, 250 W total power dissipation at T_case ≤ 25 °C, and 125 V V_CEO, with fast switching (t_on = 1.5 µs, t_f = 0.3 µs) and rugged 200 °C junction temperature rating. It is used in switching regulators and high-reliability industrial power stages.

For engineers reviewing the BUV20 datasheet, BUV20 pinout, BUV20 application, or BUV20 equivalent, key selection considerations include its 125 V V_CEO rating under zero-base-drive conditions, 0.7 °C/W junction-to-case thermal resistance, 20–60 h_FE gain range at 25–50 A, and pulsed sustaining voltage capability up to 125 V with inductive load.

Technical Context

The BUV20 employs a multiepitaxial planar structure optimized for high-current switching and linear operation. Its design supports robust operation under inductive loads (L = 25 mH) with specified V_CE(sus) = 125 V at I_C = 200 mA and pulsed conditions (300 µs, ≤2% duty cycle).

It features low saturation voltages-V_CE(sat) = 0.3 V at I_C = 25 A / I_B = 2.5 A-and high base-emitter breakdown (V_(BR)EB0 = 7 V at I_E = 50 mA), enabling stable drive in high-power amplifier and regulator topologies where base control integrity is critical.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	125 V - Maximum collector-emitter voltage with open base, defining safe blocking capability in switch-off state
I_C	50 A - Continuous collector current rating, supporting high-power output stages without forced cooling
P_tot	250 W - Total power dissipation at case temperature ≤25 °C, requiring heatsinking for sustained operation
R_thj-case	0.7 °C/W - Junction-to-case thermal resistance, enabling efficient heat transfer to external heatsink
t_on/t_f	1.5 µs / 0.3 µs - Fast turn-on and fall times under resistive load, reducing switching losses in SMPS
h_FE	20–60 - DC current gain range across 25–50 A, indicating predictable base drive requirements for power stage design
V_CE(sat)	0.3–1.2 V - Collector-emitter saturation voltage spanning 25–50 A, directly impacting conduction loss and thermal load

Pinout & Package

Package: TO-3 (version "S") metal case with three terminals-Collector (case), Base (center lead), Emitter (outer lead). The metal case serves as the collector terminal and provides mechanical rigidity and thermal path.

Pin/Terminal	Circuit Role	Design Meaning
Case (Metal Body)	Collector	Primary current-carrying terminal and thermal interface; electrically connected to collector, requires isolation mounting
Center Lead	Base	Control input for bipolar conduction; requires current-limited drive due to 10 A max I_B rating
Outer Lead	Emitter	Current return path; referenced to ground or negative rail in common-emitter configurations

Key Features

Feature	Design Value
High ruggedness	Rated for 200 °C junction temperature and 125 V sustaining voltage under inductive switching stress
Fast switching speed	1.5 µs turn-on and 0.3 µs fall time enable efficient operation in 20–100 kHz switching regulators
High current capability	50 A continuous collector current supports >1 kW linear or switching power stages with appropriate heatsinking
Low thermal resistance	0.7 °C/W junction-to-case enables compact thermal design when mounted on aluminum heatsinks
TO-3 mechanical robustness	Metal case withstands vibration, thermal cycling, and high-voltage isolation requirements in industrial environments

Applications

Switching Regulators

Industrial Motor Drives

Use Scenario: High-efficiency DC-DC conversion in industrial power supplies operating at 20–50 kHz.

IC Role / Device Role / Timing Role: Main switching transistor in single-ended forward or push-pull topology.

Use Value: Low V_CE(sat) and fast t_f reduce conduction and switching losses, improving efficiency above 92% at full load.

Use Scenario: Gate drive amplification and current amplification in servo amplifier output stages.

IC Role / Device Role / Timing Role: Linear power output device delivering precise analog current to motor windings.

Use Value: Stable h_FE over 25–50 A and 200 °C T_j rating ensure consistent gain and reliability during extended thermal transients.

High-Voltage Amplifiers

Welding Equipment Power Stages

Use Scenario: Audio and RF power amplification in broadcast transmitters and test equipment.

IC Role / Device Role / Timing Role: Class AB or Class C output stage transistor handling high-voltage swing and peak current.

Use Value: 160 V V_CBO and 125 V V_CEO(sus) support operation with ≥100 V supply rails and reactive loads.

Use Scenario: Primary switching element in inverter-based arc welding machines with repetitive 50–200 A pulses.

IC Role / Device Role / Timing Role: High-current pulse switch controlling primary winding current in step-down transformer circuits.

Use Value: 60 A I_CM peak rating and 0.3 µs t_f minimize energy loss during rapid current commutation cycles.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BUV21	V_CEO = 140 V (higher), I_C = 40 A (lower), P_tot = 175 W (lower)	Better voltage margin but reduced current and power handling	Select when higher blocking voltage is prioritized over peak current delivery
2N3055	V_CEO = 60 V (lower), I_C = 15 A (lower), R_thj-case = 3.0 °C/W (higher)	Legacy part with significantly lower voltage, current, and thermal performance	Only suitable for low-power legacy replacements where 125 V/50 A capability is not required

Compared with BUV21 and 2N3055, the BUV20 uniquely balances 125 V blocking, 50 A current, and 0.7 °C/W thermal resistance-making it optimal for modern industrial switching regulators where both voltage headroom and thermal efficiency are critical.

Availability

BUV20 is available at Aetrix Electronics and suitable for switching regulators, industrial motor drives, high-voltage amplifiers, and welding equipment power stages requiring stable component supply and long-term industrial availability.

Supply support for BUV20 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 ICs.

The BUV20 belongs to ST's high-power bipolar transistor product line, engineered for rugged industrial and military-grade linear and switching power applications demanding high current, high voltage, and thermal resilience.

FAQ

Is the BUV20 pin-compatible with standard TO-3 NPN transistors like the 2N3055?

No-the BUV20 uses TO-3 "version S" mechanical dimensions with specific lead spacing (e.g., center-to-outer lead pitch of 16.5–17.2 mm), differing from legacy TO-3 variants. Mounting hole alignment and lead bending must follow ST's mechanical drawing (page 3 of datasheet), not generic TO-3 templates.

What is the maximum safe operating area (SOA) limit for the BUV20 at 100 °C case temperature?

At T_case = 100 °C, the BUV20's SOA is limited by secondary breakdown and thermal constraints: maximum V_CE drops to ~60 V at I_C = 50 A, and pulse width must remain ≤300 µs with ≤2% duty cycle to avoid junction runaway per datasheet Figure 5.

Can the BUV20 be used in avalanche mode for inductive load protection?

No-ST does not specify or guarantee avalanche energy rating (E_AS) for the BUV20. Its V_CE(sus) = 125 V is measured under controlled pulsed conditions with external base clamping (R_BE = 100 Ω); unclamped inductive switching may exceed safe operating limits.

Does the BUV20 require a minimum base drive current to achieve specified V_CE(sat)?

Yes-V_CE(sat) = 0.3 V is guaranteed only at I_C = 25 A with I_B = 2.5 A (h_FE ≈ 10). For I_C = 50 A, I_B = 5 A is required to maintain V_CE(sat) ≤ 0.6 V; insufficient base drive increases conduction loss and thermal stress.

BUV20 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-204AA, TO-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 50 A

Voltage - Collector Emitter Breakdown (Max):: 125 V

Vce Saturation (Max) @ Ib, Ic:: 1.2V @ 5A, 50A

Current - Collector Cutoff (Max):: 3mA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 20 @ 25A, 2V

Power - Max:: 250 W

Frequency - Transition:: 8MHz

Operating Temperature:: 200°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Chassis Mount

Supplier Device Package:: TO-3

BUV20 FAQ

1.How can I place an order for BUV20 through Aetrix?

Please submit a Request for Quotation (RFQ) for BUV20 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 BUV20 reliable?

The price and inventory of BUV20 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BUV20 is usually 5 days.

3.What payment methods are accepted for BUV20?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BUV20 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BUV20?

BUV20 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BUV20 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 BUV20?

For technical support, including BUV20 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BUV20 requirements.

6.How does Aetrix verify that BUV20 is sourced from the original manufacturer or authorized distributors?

All BUV20 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 BUV20 meets industry standards.

7.What is the process for return or replacement of BUV20?

All BUV20 units undergo pre-shipment inspection (PSI). If there is an issue with BUV20, 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 BUV20 part is unused and in its original packaging.

Return procedure for BUV20:

1.Submit a request within 90 days.

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

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