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

onsemi BU406TU

Name: BU406TU
Brand: onsemi
SKU: BU406TU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BU406TU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BU406TU.pdf

Description:: TRANS NPN 200V 7A TO-220-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BU406TU from ON Semiconductor is an NPN silicon power transistor designed for horizontal deflection output stages in CRT televisions and monitors, featuring 200 V_CEO, 7 A continuous collector current, 60 W power dissipation at T_C = 25°C, and fast switching with 0.75 µs inductive crossover time.

For engineers reviewing the BU406TU datasheet, pinout, applications, or equivalent options, key selection criteria include high-voltage sustain capability (V_CEO(sus) = 200 V), low saturation voltage (V_CE(sat) ≤ 1 V at 5 A/0.5 A), thermal resistance (R_JC = 2.08 °C/W), and TO-220AB package compatibility with legacy CRT deflection designs.

Technical Context

The BU406TU operates as a high-voltage, medium-power NPN switching transistor optimized for inductive flyback operation in horizontal output stages. It supports V_CEV = 400 V and V_CBO = 400 V, enabling robust voltage margin during linearity-critical retrace intervals.

Its dynamic performance includes f_T = 10 MHz, C_ob = 80 pF, and safe operating area bounded by thermal limit (25°C–100°C curves) and second breakdown-critical for sustained 15.734 kHz switching under reactive load conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	200 Vdc - Sustains full horizontal scan voltage without breakdown
I_C (cont.)	7 Adc - Supports peak horizontal deflection current in standard CRT yoke loads
P_D @ T_C=25°C	60 W - Enables high-power pulse operation with heatsink mounting
V_CE(sat)	≤1 V at I_C=5 A, I_B=0.5 A - Minimizes conduction loss and thermal stress
f_T	10 MHz - Ensures adequate gain-bandwidth for stable 15–20 kHz switching
R_JC	2.08 °C/W - Allows direct thermal path to heatsink for reliable 60 W operation
t_c	0.75 µs - Limits overlap loss during inductive turn-off in flyback circuits

Pinout & Package

BU406TU is housed in a TO-220AB (Case 221A-Style 1) Pb-free plastic package with integral metal tab for heatsinking. Pin 1 is Base, Pins 2 & 4 are Collector (internally tied), and Pin 3 is Emitter - configured for high-current, high-voltage switching with dual-collector thermal and current-handling redundancy.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control input requiring ~0.5 A drive for full saturation at 5 A collector current
2, 4	Collector	Dual-terminal connection to high-voltage flyback node; shares current and thermal load
3	Emitter	Low-side return path; referenced to ground or damper diode cathode in standard H.O.T. configuration

Key Features

Feature	Design Value
High-voltage blocking	V_CEV = 400 V enables 2× safety margin over 200 V_CEO in CRT flyback transients
Fast switching speed	0.75 µs inductive crossover time reduces switching loss in 15.734 kHz horizontal output
Low saturation voltage	V_CE(sat) ≤ 1 V at rated current minimizes power dissipation during conduction phase
Pb-free RoHS compliance	G-suffix package meets environmental requirements without compromising thermal or electrical performance
Thermal robustness	R_JC = 2.08 °C/W supports stable 60 W operation with standard TO-220 heatsinks

Applications

TV Horizontal Deflection Output	CRT Monitor Output Stage
Use Scenario: Driving flyback transformer primary in 15.734 kHz horizontal scanning circuit of analog TV receivers. IC Role / Device Role / Timing Role: High-voltage NPN switch controlling yoke current and generating EHT via transformer action. Use Value: 200 V_CEO and 400 V_CEV withstand retrace overshoot; 0.75 µs t_c ensures minimal overlap loss.	Use Scenario: Switching horizontal deflection yoke in professional CRT monitors with tight geometry correction. IC Role / Device Role / Timing Role: Main output transistor in self-oscillating or externally synchronized horizontal output stage. Use Value: 7 A I_C and 60 W P_D support higher yoke inductance and longer scan lines without thermal derating.
Legacy Display Repair	Industrial CRT-Based Instrumentation
Use Scenario: Drop-in replacement for failed BU406/BUT11A in discontinued TV chassis (e.g., RCA, Zenith). IC Role / Device Role / Timing Role: Direct functional replacement maintaining identical pinout, SOA, and drive requirements. Use Value: TO-220AB footprint and matching V_CEO/I_C/t_c specs ensure no board modification or bias adjustment needed.	Use Scenario: Horizontal sweep generator in oscilloscope CRTs and radar display systems requiring long-term reliability. IC Role / Device Role / Timing Role: Primary switching element in high-stability, low-drift deflection circuits operating continuously for hours. Use Value: −65°C to +150°C junction range and 2.08 °C/W R_JC enable stable operation in sealed, convection-limited enclosures.

TV Horizontal Deflection Output

CRT Monitor Output Stage

Use Scenario: Driving flyback transformer primary in 15.734 kHz horizontal scanning circuit of analog TV receivers.

IC Role / Device Role / Timing Role: High-voltage NPN switch controlling yoke current and generating EHT via transformer action.

Use Value: 200 V_CEO and 400 V_CEV withstand retrace overshoot; 0.75 µs t_c ensures minimal overlap loss.

Use Scenario: Switching horizontal deflection yoke in professional CRT monitors with tight geometry correction.

IC Role / Device Role / Timing Role: Main output transistor in self-oscillating or externally synchronized horizontal output stage.

Use Value: 7 A I_C and 60 W P_D support higher yoke inductance and longer scan lines without thermal derating.

Legacy Display Repair

Industrial CRT-Based Instrumentation

Use Scenario: Drop-in replacement for failed BU406/BUT11A in discontinued TV chassis (e.g., RCA, Zenith).

IC Role / Device Role / Timing Role: Direct functional replacement maintaining identical pinout, SOA, and drive requirements.

Use Value: TO-220AB footprint and matching V_CEO/I_C/t_c specs ensure no board modification or bias adjustment needed.

Use Scenario: Horizontal sweep generator in oscilloscope CRTs and radar display systems requiring long-term reliability.

IC Role / Device Role / Timing Role: Primary switching element in high-stability, low-drift deflection circuits operating continuously for hours.

Use Value: −65°C to +150°C junction range and 2.08 °C/W R_JC enable stable operation in sealed, convection-limited enclosures.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BUT11AF	V_CEO = 150 V, I_C = 10 A, R_JC = 1.7 °C/W - lower voltage rating but higher current and better thermal resistance	Suitable only where V_CE stress remains below 150 V; requires verification of flyback voltage margin	Select when higher current headroom is prioritized over voltage margin, and PCB layout allows same TO-220AB footprint
2SC5200	V_CEO = 230 V, I_C = 15 A, f_T = 30 MHz - higher voltage, current, and bandwidth than BU406TU	Overqualified for standard CRT deflection; may require gate/base drive redesign due to higher C_ob and h_FE variation	Choose for upgraded deflection stages needing extended SOA or future-proofing; not drop-in without drive circuit review

Compared with BUT11AF and 2SC5200, the BU406TU offers optimal balance of 200 V blocking, 7 A capability, and proven 15.734 kHz timing behavior in legacy CRT designs-making it the most directly applicable choice where voltage margin and thermal stability are primary constraints.

Availability

BU406TU is available at Aetrix Electronics and suitable for CRT television repair, legacy monitor refurbishment, and industrial instrumentation requiring stable component supply with long-life availability assurance.

Supply support for BU406TU 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

ON Semiconductor is a global semiconductor manufacturer specializing in power management, analog, sensor, and discrete devices for automotive, industrial, and consumer applications.

The BU406TU belongs to ON Semiconductor's high-voltage NPN power transistor product line, engineered specifically for horizontal deflection output stages in CRT-based video equipment where reliability under repetitive high-voltage switching is critical.

FAQ

What is the maximum collector-emitter voltage rating for BU406TU?

The BU406TU has a maximum collector-emitter voltage rating (V_CEO) of 200 Vdc under DC conditions and a sustaining voltage (V_CEO(sus)) of 200 Vdc at I_C = 100 mA with base open. Its V_CEV rating is 400 Vdc, providing critical margin against flyback transients in CRT horizontal output circuits. This specification is verified per ON Semiconductor's BU406/D datasheet Rev. 11.

Is BU406TU pin-compatible with BU406G?

Yes, BU406TU is pin-compatible with BU406G. Both use the TO-220AB (Case 221A-Style 1) package with identical pinout: Pin 1 = Base, Pins 2 & 4 = Collector, Pin 3 = Emitter. The "TU" suffix denotes tape-and-reel packaging per ON Semiconductor's ordering conventions, while "G" indicates Pb-free construction - both share identical electrical and thermal specifications.

What is the thermal resistance from junction to case for BU406TU?

The thermal resistance from junction to case (R_JC) for BU406TU is 2.08 °C/W, measured under standard test conditions. This value enables efficient heat transfer to an external heatsink and supports the device's 60 W power dissipation rating at T_C = 25°C. Mounting must ensure flat, clean contact between the metal tab and heatsink surface for optimal thermal performance.

Can BU406TU be used in place of BU407 in a CRT design?

BU406TU can replace BU407 only if the circuit's maximum V_CE stress remains ≤200 V. BU407 has a lower V_CEO rating of 150 V but identical package and pinout. Substituting BU406TU provides higher voltage margin (200 V vs. 150 V), improving reliability in designs prone to flyback overshoot - however, verify that base drive and SOA remain within BU406TU's specified limits.

What is the typical switching crossover time for BU406TU under inductive load?

The typical inductive load crossover time (t_c) for BU406TU is 0.75 µs, measured under V_CC = 40 Vdc, I_C = 5 Adc, I_B1 = I_B2 = 0.5 Adc, and L = 150 µH. This parameter directly impacts switching efficiency in horizontal deflection stages and is confirmed in the Electrical Characteristics table of the official BU406/D datasheet.

BU406TU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 7 A

Voltage - Collector Emitter Breakdown (Max):: 200 V

Vce Saturation (Max) @ Ib, Ic:: 1V @ 500mA, 5A

Current - Collector Cutoff (Max):: 5mA

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

Power - Max:: 60 W

Frequency - Transition:: 10MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220-3

BU406TU FAQ

1.How can I place an order for BU406TU through Aetrix?

Please submit a Request for Quotation (RFQ) for BU406TU 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 BU406TU reliable?

The price and inventory of BU406TU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BU406TU is usually 5 days.

3.What payment methods are accepted for BU406TU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BU406TU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BU406TU?

BU406TU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BU406TU 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 BU406TU?

For technical support, including BU406TU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BU406TU requirements.

6.How does Aetrix verify that BU406TU is sourced from the original manufacturer or authorized distributors?

All BU406TU 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 BU406TU meets industry standards.

7.What is the process for return or replacement of BU406TU?

All BU406TU units undergo pre-shipment inspection (PSI). If there is an issue with BU406TU, 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 BU406TU part is unused and in its original packaging.

Return procedure for BU406TU:

1.Submit a request within 90 days.

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

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