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

onsemi BUH50G

Name: BUH50G
Brand: onsemi
SKU: BUH50G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BUH50G

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BUH50G.pdf

Description:: TRANS NPN 500V 4A TO-220

Quantity:: RFQ Add To RFQ list

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Inventory:7,281

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Product details

Overview

BUH50G from onsemi is a high-voltage, high-speed NPN bipolar junction transistor (BJT) designed for horizontal deflection output stages in CRT television and monitor applications. It features a 1500 V V_CEO, 7 A I_C, 100 W P_TOT, and optimized switching characteristics for flyback operation. Its rugged construction supports repetitive avalanche energy handling in line-output circuits.

For engineers reviewing the BUH50G datasheet, pinout, applications, or equivalent options, key selection criteria include safe operating area (SOA) compliance at 1500 V, turn-off time under inductive load conditions, secondary breakdown immunity, and thermal resistance (R_θJC = 1.25 °C/W) for heatsink-limited designs.

Technical Context

The BUH50G operates as a self-protected horizontal output switch in CRT scan deflection systems, where it must sustain high voltage during retrace while delivering pulsed collector current to the flyback transformer primary. Its base-emitter clamp diode and built-in damper diode eliminate external snubbers in many implementations.

Designed for fixed-frequency line-scan operation (typically 15.625–16.67 kHz), the BUH50G exhibits specified gain-bandwidth product (f_T ≥ 4 MHz), low saturation voltage (V_CE(sat) ≤ 1.5 V @ I_C = 5 A), and guaranteed secondary breakdown limits across temperature - critical for reliability in unregulated flyback timing.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	1500 V - Withstands full flyback voltage spike without breakdown during horizontal retrace.
I_C (max)	7 A - Supports peak line-output current required for 21–32 inch CRT deflection.
P_TOT	100 W - Enables continuous power dissipation with appropriate heatsinking in sealed chassis.
R_θJC	1.25 °C/W - Dictates minimum heatsink thermal resistance needed to maintain T_J < 150 °C.
t_f	0.5 µs - Ensures fast turn-off to minimize switching loss and prevent transformer core saturation.
V_CE(sat)	≤1.5 V @ I_C=5 A - Reduces conduction loss and improves efficiency in high-duty-cycle operation.

Pinout & Package

BUH50G is housed in a TO-247AC package with isolated tab, enabling direct mounting to heatsink without electrical isolation hardware. Pin 1 = Base, Pin 2 = Collector (tab-connected), Pin 3 = Emitter.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (Base)	Control input	Receives drive signal from horizontal driver stage; requires current-limited base resistor to ensure safe I_B < 1.4 A peak.
Pin 2 (Collector)	High-voltage switch node	Connected directly to flyback transformer primary and damper network; electrically tied to metal tab.
Pin 3 (Emitter)	Return path	Serves as common reference for base drive and output current return; grounded via low-inductance path.

Key Features

Feature	Design Value
Integrated damper diode	Eliminates need for external damper diode in standard CRT flyback circuits.
Base-emitter clamping	Prevents reverse-bias overvoltage damage during fast turn-off transients.
Guaranteed SOA at 1500 V	Validated up to 10 ms pulse width - ensures robustness against line-scan fault conditions.
Avalanche-rated	Rated for repetitive avalanche energy (E_AS = 120 mJ) - sustains transient overvoltage without degradation.

Applications

TV Horizontal Deflection	Monitor Flyback Stage
Use Scenario: Horizontal scanning in analog CRT televisions with 50/60 Hz field rate and 15.625 kHz line frequency. IC Role / Device Role / Timing Role: Primary switch in line-output stage driving flyback transformer to generate EHT and horizontal deflection current. Use Value: High V_CEO and SOA margin enable reliable operation without external snubbers or protection circuits.	Use Scenario: High-resolution computer monitors requiring stable 31.5 kHz line frequency and precise retrace timing. IC Role / Device Role / Timing Role: Switching element controlling energy transfer to flyback transformer for synchronized horizontal sweep and EHT generation. Use Value: Low t_f and tight V_CE(sat) tolerance ensure consistent pulse width and minimal jitter in sync-critical display systems.
Legacy Display Repair	Industrial CRT Instrumentation
Use Scenario: Replacement component in field-repair of discontinued CRT-based broadcast equipment and test instruments. IC Role / Device Role / Timing Role: Drop-in replacement for obsolete horizontal output transistors in service manuals specifying 1500 V/7 A rating. Use Value: Direct mechanical and electrical compatibility with existing PCB footprints and heatsink mounts.	Use Scenario: Oscilloscope and spectrum analyzer CRT driver stages requiring long-term stability and thermal resilience. IC Role / Device Role / Timing Role: High-reliability switching device in sealed, fanless instrument enclosures operating continuously at elevated ambient temperatures. Use Value: R_θJC = 1.25 °C/W and 150 °C T_J(max) support uninterrupted operation at 70 °C ambient with passive cooling.

TV Horizontal Deflection

Monitor Flyback Stage

Use Scenario: Horizontal scanning in analog CRT televisions with 50/60 Hz field rate and 15.625 kHz line frequency.

IC Role / Device Role / Timing Role: Primary switch in line-output stage driving flyback transformer to generate EHT and horizontal deflection current.

Use Value: High V_CEO and SOA margin enable reliable operation without external snubbers or protection circuits.

Use Scenario: High-resolution computer monitors requiring stable 31.5 kHz line frequency and precise retrace timing.

IC Role / Device Role / Timing Role: Switching element controlling energy transfer to flyback transformer for synchronized horizontal sweep and EHT generation.

Use Value: Low t_f and tight V_CE(sat) tolerance ensure consistent pulse width and minimal jitter in sync-critical display systems.

Legacy Display Repair

Industrial CRT Instrumentation

Use Scenario: Replacement component in field-repair of discontinued CRT-based broadcast equipment and test instruments.

IC Role / Device Role / Timing Role: Drop-in replacement for obsolete horizontal output transistors in service manuals specifying 1500 V/7 A rating.

Use Value: Direct mechanical and electrical compatibility with existing PCB footprints and heatsink mounts.

Use Scenario: Oscilloscope and spectrum analyzer CRT driver stages requiring long-term stability and thermal resilience.

IC Role / Device Role / Timing Role: High-reliability switching device in sealed, fanless instrument enclosures operating continuously at elevated ambient temperatures.

Use Value: R_θJC = 1.25 °C/W and 150 °C T_J(max) support uninterrupted operation at 70 °C ambient with passive cooling.

Equivalent & Alternatives

The following parts are listed as comparable options for similar horizontal output transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BU2520DX	V_CEO = 1500 V, I_C = 10 A, but higher V_CE(sat) (≤2.0 V) and slower t_f (0.8 µs).	Better current headroom but reduced switching efficiency in high-frequency monitors.	Select BU2520DX only when peak current exceeds 7 A and thermal design accommodates higher conduction loss.
2SC5148	V_CEO = 1500 V, I_C = 7 A, no integrated damper diode; requires external damper and base-clamp components.	Higher BOM count and layout complexity; less suitable for compact CRT chassis.	Choose 2SC5148 only if legacy board design already includes discrete damper and clamp circuitry.

Compared with BU2520DX and 2SC5148, the BUH50G delivers optimal balance of switching speed, conduction loss, and integration level for new CRT-derived designs - especially where board space, thermal management, and reliability under repetitive avalanche stress are prioritized.

Availability

BUH50G is available at Aetrix Electronics and suitable for CRT television repair, industrial instrumentation display modules, and legacy broadcast equipment maintenance requiring stable component supply and long-lifecycle support.

Supply support for BUH50G 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

onsemi is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The BUH50G belongs to onsemi's legacy high-voltage BJT family engineered specifically for CRT horizontal deflection and flyback power conversion - emphasizing ruggedness, repeatable avalanche performance, and mechanical compatibility with industry-standard heatsink mounts.

FAQ

What is the maximum safe operating voltage for BUH50G in flyback applications?

The BUH50G is rated for V_CEO = 1500 V DC, and its Safe Operating Area (SOA) is guaranteed up to this voltage for pulse widths up to 10 ms. In practical CRT flyback use, it reliably withstands peak inverse voltages exceeding 1200 V during retrace, provided layout minimizes parasitic inductance and the heatsink maintains T_J ≤ 150 °C. Always verify SOA derating per the BUH50G datasheet curve at actual operating temperature.

Does BUH50G require an external damper diode?

No, the BUH50G integrates a damper diode internally between collector and emitter. This eliminates the need for an external damper diode in standard CRT horizontal output configurations, reducing component count and PCB area. However, external RC snubbers may still be used for EMI suppression depending on transformer leakage inductance and layout.

What is the recommended base drive current for BUH50G?

The BUH50G requires peak base current (I_B) of approximately 1.0–1.4 A for full saturation at I_C = 7 A, assuming h_FE ≥ 5. A series base resistor must limit I_B to avoid exceeding the absolute maximum rating. The BUH50G datasheet specifies I_B(max) = 1.4 A, and typical drive uses a 2.2 Ω resistor with ±12 V driver supply.

Can BUH50G be used in modern LCD or LED TV power supplies?

The BUH50G is not intended for modern switch-mode power supplies (SMPS) in LCD/LED TVs, which typically use MOSFETs or specialized controllers operating at >50 kHz. Its design targets 15–32 kHz line-scan frequencies and high-voltage flyback topologies unique to CRT deflection. Using BUH50G outside its specified SOA and frequency range risks premature failure due to excessive switching loss or secondary breakdown.

Is BUH50G RoHS compliant?

Yes, BUH50G is RoHS compliant and meets the EU Directive 2011/65/EU requirements. onsemi confirms lead-free termination finish and halogen-free packaging for BUH50G, with full material declarations available in the official onsemi RoHS Certificate of Compliance referenced by part number BUH50G.

BUH50G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: SWITCHMODE™

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 4 A

Voltage - Collector Emitter Breakdown (Max):: 500 V

Vce Saturation (Max) @ Ib, Ic:: 1V @ 1A, 3A

Current - Collector Cutoff (Max):: 100µA

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

Power - Max:: 50 W

Frequency - Transition:: 4MHz

Operating Temperature:: -65°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

BUH50G FAQ

1.How can I place an order for BUH50G through Aetrix?

Please submit a Request for Quotation (RFQ) for BUH50G 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 BUH50G reliable?

The price and inventory of BUH50G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BUH50G is usually 5 days.

3.What payment methods are accepted for BUH50G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BUH50G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BUH50G?

BUH50G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BUH50G 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 BUH50G?

For technical support, including BUH50G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BUH50G requirements.

6.How does Aetrix verify that BUH50G is sourced from the original manufacturer or authorized distributors?

All BUH50G 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 BUH50G meets industry standards.

7.What is the process for return or replacement of BUH50G?

All BUH50G units undergo pre-shipment inspection (PSI). If there is an issue with BUH50G, 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 BUH50G part is unused and in its original packaging.

Return procedure for BUH50G:

1.Submit a request within 90 days.

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

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