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

STMicroelectronics BUF420AW

Name: BUF420AW
Brand: STMicroelectronics
SKU: BUF420AW
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BUF420AW

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-247-3

Datasheet:: BUF420AW.pdf

Description:: TRANS NPN 450V 30A TO-247-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BUF420AW from STMicroelectronics is a high-voltage, fast-switching NPN power transistor fabricated in High Voltage Multi Epitaxial Planar technology with cellular emitter and planar edge termination. It delivers 450 V V_CEO, 30 A I_C, 200 W P_tot, <1 µs storage time (t_s), and 70–150 A/µs dI_C/dt - enabling robust operation in hard-switched SMPS and motor control inverters.

For engineers reviewing the BUF420AW datasheet, BUF420AW pinout, BUF420AW application, or BUF420AW equivalent, key selection criteria include its snubberless 500 V V_CEW at 125°C, low 0.8 V V_CE(sat) at 10 A/1 A, wide RBSOA, and minimal lot-to-lot parametric spread for production reliability.

Technical Context

The BUF420AW employs a cellular emitter structure and planar edge termination to simultaneously maximize switching speed and ruggedness under inductive turn-off stress. Its RBSOA is widened by optimized base doping and epitaxial layer design, supporting reliable operation without snubbers up to 500 V at T_C = 125°C.

It features low base-drive requirements (1 A for 10 A I_C, 4 A for 20 A I_C) and fast dynamic performance: t_s/t_f/t_c = 1.0/0.05/0.08 µs at 25°C and 2.0/0.10/0.18 µs at 100°C under standardized inductive load conditions (V_CC = 50 V, L = 0.25 mH).

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	450 V - maximum collector-emitter voltage with open base; defines safe blocking capability in flyback and forward converters.
I_C	30 A continuous - rated DC collector current at T_C = 25°C; supports high-power motor drive stages and industrial SMPS output switches.
V_CE(sat)	0.8 V @ 10 A/1 A - low saturation voltage reduces conduction loss and thermal stress in high-duty-cycle applications.
t_s	1.0 µs @ 25°C - short storage time enables high-frequency switching (>100 kHz) with minimal switching loss penalty.
dI_C/dt	70 A/µs @ 25°C - high rate-of-rise capability ensures stable turn-on under high di/dt loads like PFC and resonant converters.
R_thj-case	0.63 °C/W - low thermal resistance allows 200 W dissipation with modest heatsinking; critical for compact power stage designs.
V_CEW	500 V @ T_C = 125°C - maximum snubberless switching voltage; eliminates need for RC snubbers in well-designed 400 V bus systems.

Pinout & Package

BUF420AW is housed in a TO-247 package with isolated mounting flange, designed for high-power thermal management and high-voltage isolation. Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter - confirmed per STMicroelectronics mechanical drawing P025P and application schematics.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (Tab)	Collector	Electrically connected to metal tab; must be insulated from heatsink unless system ground reference permits direct mounting.
Pin 2	Base	Low-impedance control input requiring ≤1 A DC drive for 10 A I_C; sensitive to ESD and overvoltage.
Pin 3	Emitter	Power return path; referenced to driver ground; carries full load current and must be routed with low-inductance layout.

Key Features

Feature	Design Value
Cellular Emitter Structure	Enables uniform current distribution and reduced local hot-spot risk during high-current switching transients.
Planar Edge Termination	Improves voltage blocking uniformity and increases ruggedness against edge breakdown in high-dV/dt environments.
Wide RBSOA	Supports reliable operation under inductive switching stress without derating, even at elevated case temperatures.
Low Base-Drive Requirement	1 A base current suffices for 10 A collector conduction - reduces gate-driver IC cost and PCB space in discrete BJT drivers.
Minimal Lot-to-Lot Spread	Guarantees consistent V_CE(sat), h_FE, and t_s across production lots - essential for volume manufacturing repeatability.

Applications

Switch-Mode Power Supplies

Motor Control Inverters

Use Scenario: Primary-side switch in 300–400 V input offline flyback and forward converters operating at 50–150 kHz.

IC Role / Device Role / Timing Role: High-voltage NPN power switch handling full primary current and voltage stress during PWM on/off transitions.

Use Value: Snubberless 500 V V_CEW at 125°C and <1 µs t_s reduce component count and improve efficiency vs. legacy bipolar transistors.

Use Scenario: Upper-leg switch in three-phase IGBT/Bipolar inverter stages driving industrial AC induction motors (1–5 kW).

IC Role / Device Role / Timing Role: Hard-switched power stage element managing inductive back-EMF and commutation energy during PWM vector control.

Use Value: Wide RBSOA and 150 A/µs dI_C/dt ensure reliable turn-off under high di/dt motor phase currents without secondary breakdown.

High-Voltage DC-DC Converters

Capacitor Discharge Circuits

Use Scenario: Step-up converter switch in battery-powered HV systems (e.g., medical imaging, laser drivers) with 200–400 V output.

IC Role / Device Role / Timing Role: Main energy transfer switch subjected to repetitive high-voltage, high-current pulses with strict timing control.

Use Value: Low 0.8 V V_CE(sat) and 0.63 °C/W R_thj-case minimize conduction loss and thermal rise in sealed, fanless enclosures.

Use Scenario: Triggered discharge switch in pulsed-power systems (e.g., flash lamps, defibrillators) requiring precise microsecond-scale pulse shaping.

IC Role / Device Role / Timing Role: Fast, high-current switch initiating controlled capacitor dump into load with sub-microsecond timing fidelity.

Use Value: 70–150 A/µs dI_C/dt and <0.1 µs t_f enable sharp current rise and repeatable pulse edge definition under heavy capacitive loads.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BUL49D	Lower V_CEO (400 V), higher V_CE(sat) (1.2 V @ 10 A), slower t_s (2.5 µs)	Suitable only for ≤350 V bus systems; requires snubber above 300 V; less efficient in high-frequency SMPS.	Choose when cost sensitivity outweighs voltage margin and switching speed requirements.
BU508A	Higher V_CEO (1000 V), but slower t_s (3.5 µs), no specified V_CEW, larger R_thj-case (0.8 °C/W)	Better for ultra-high-voltage applications (≥700 V), but unsuitable for >50 kHz switching due to storage delay.	Prefer for line-frequency or low-frequency HV rectifier/switching where speed is secondary to blocking voltage.

Compared with BUL49D and BU508A, BUF420AW uniquely balances 450 V blocking, sub-µs switching, and snubberless 500 V operation - making it optimal for high-efficiency, high-frequency, medium-power industrial power conversion where thermal and timing margins are tight.

Availability

BUF420AW is available at Aetrix Electronics and suitable for switch-mode power supplies, motor control inverters, and high-voltage DC-DC converters requiring stable component supply, long-term manufacturability, and consistent parametric performance across production lots.

Supply support for BUF420AW 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, designing and manufacturing analog, power, MCU, and sensor solutions for industrial, automotive, and consumer markets.

The BUF series targets high-frequency, high-reliability power switching applications - specifically engineered for snubberless operation, minimal parametric drift, and rugged inductive load handling in industrial power electronics.

FAQ

What is the maximum recommended case temperature for continuous operation?

The BUF420AW has a maximum operating junction temperature of 150°C and a thermal resistance of 0.63°C/W. For continuous 200 W dissipation, the case temperature must not exceed 25°C - meaning active heatsinking with forced air or liquid cooling is required. Derating curves in the datasheet show 100 W max at T_C = 100°C.

Does BUF420AW require a negative base turn-off voltage?

Yes - the datasheet specifies V_BB = –5 V in inductive switching test conditions to ensure rapid carrier extraction and minimize storage time. Applying –3 V to –5 V during turn-off reduces t_s by up to 2× versus zero-bias turn-off, especially critical above 50 kHz.

Can BUF420AW replace IGBTs in motor drive applications?

It can replace low-speed IGBTs in <50 kHz motor drives where lower conduction loss and tighter V_CE(sat) tolerance are prioritized - but not in high-frequency or high-voltage (>600 V) applications. Unlike IGBTs, it lacks built-in body diode and requires external freewheeling diodes with matched recovery characteristics.

Is the TO-247 package electrically insulated?

No - the metal tab (Pin 1, Collector) is electrically connected to the collector terminal. Electrical isolation from the heatsink requires a mica or ceramic insulator plus conductive thermal paste. STMicroelectronics' P025P mechanical drawing confirms the tab is non-isolated and must be treated as live at collector potential.

BUF420AW Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-247-3

Packaging:: Tube

Product Status:: Active

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 30 A

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

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 4A, 20A

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: -

Power - Max:: 200 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-247-3

BUF420AW FAQ

1.How can I place an order for BUF420AW through Aetrix?

Please submit a Request for Quotation (RFQ) for BUF420AW 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 BUF420AW reliable?

The price and inventory of BUF420AW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BUF420AW is usually 5 days.

3.What payment methods are accepted for BUF420AW?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BUF420AW transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BUF420AW?

BUF420AW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BUF420AW 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 BUF420AW?

For technical support, including BUF420AW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BUF420AW requirements.

6.How does Aetrix verify that BUF420AW is sourced from the original manufacturer or authorized distributors?

All BUF420AW 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 BUF420AW meets industry standards.

7.What is the process for return or replacement of BUF420AW?

All BUF420AW units undergo pre-shipment inspection (PSI). If there is an issue with BUF420AW, 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 BUF420AW part is unused and in its original packaging.

Return procedure for BUF420AW:

1.Submit a request within 90 days.

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

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