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

STMicroelectronics MD2009DFX

Name: MD2009DFX
Brand: STMicroelectronics
SKU: MD2009DFX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MD2009DFX

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-3P-3 Full Pack

Datasheet:: MD2009DFX.pdf

Description:: TRANS NPN 700V 10A TO-3PF

Quantity:: RFQ Add To RFQ list

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Inventory:4,369

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Product details

Overview

MD2009DFX from STMicroelectronics is a high-voltage NPN power transistor with integrated freewheeling diode, designed specifically for horizontal deflection output stages in CRT television systems. It features 1500 V V_CES, 10 A continuous collector current, 58 W total dissipation at T_c = 25°C, and TO-3PF fully isolated package compliant with UL standards.

For engineers reviewing the MD2009DFX datasheet, MD2009DFX pinout, MD2009DFX application, or MD2009DFX equivalent, key selection criteria include V_CES rating, h_FE tightness at 5.5 A, integrated diode forward voltage (1.6 V @ 5.5 A), thermal resistance (2.15 °C/W), and isolation withstand voltage (2500 V RMS).

Technical Context

This device employs diffused-collector planar technology with an enhanced high-voltage structure optimized for inductive switching in CRT horizontal deflection circuits. Its design delivers stable h_FE across temperature, low base drive requirement (IB = 1.4 A for IC = 5.5 A), and tight DC current gain distribution (h_FE = 4.7–7 at IC = 5.5 A, V_CE = 5 V).

The integrated freewheeling diode enables self-contained flyback energy recovery during line scan retrace, while the fully isolated TO-3PF package eliminates need for insulating washers between transistor and heatsink-critical for high-reliability CRT TV service life under thermal cycling.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CES	1500 V - Withstands peak flyback voltage during CRT horizontal retrace without breakdown
I_C	10 A continuous - Supports full-line current in standard 50/60 Hz CRT deflection systems
R_thj-case	2.15 °C/W max - Enables 58 W power dissipation with ≤124°C junction rise above 25°C case temp
V_F (diode)	1.6 V @ 5.5 A - Minimizes conduction loss during flyback recovery, reducing thermal stress
h_FE	4.7–7 @ IC = 5.5 A, V_CE = 5 V - Tight gain range simplifies base drive design and improves linearity
V_ISO	2500 V RMS - Fully isolates collector, base, emitter from heatsink per UL safety requirements
t_s/t_f	4.5 / 0.3 µs - Fast switching supports 16 kHz horizontal frequency with minimal switching loss

Pinout & Package

The MD2009DFX is housed in a TO-3PF package: a fully isolated, metal-can power package with three leads (collector, base, emitter), UL-recognized for high-voltage safety compliance. The case serves as the collector terminal, with base and emitter brought out on insulated leads.

Pin/Terminal	Circuit Role	Design Meaning
Case (metal can)	Collector	Primary high-current, high-voltage node; electrically isolated from heatsink by package molding
Lead 1 (center)	Base	Low-impedance control input requiring 1.4 A to saturate at 5.5 A collector current
Lead 2 (right)	Emitter	Reference node for deflection yoke return path; connected internally to freewheeling diode cathode

Key Features

Feature	Design Value
Integrated freewheeling diode	Eliminates external diode component count and layout complexity in CRT deflection stage
Diffused collector "enhanced generation" structure	Improves silicon efficiency and ruggedness against secondary breakdown during inductive turn-off
Tight h_FE range at operating current	Reduces variation in base drive requirements across production lots, easing factory calibration
UL-compliant fully isolated package	Enables direct mounting to grounded heatsink without insulator, improving thermal reliability
Low V_CE(sat) (2.8 V @ 5.5 A)	Lowers conduction loss during active scan period, reducing junction temperature rise

Applications

Horizontal Deflection Output

High-Voltage Flyback Generator

Use Scenario: Driving CRT horizontal deflection yoke in analog broadcast TV receivers (PAL/NTSC) with 15.625–15.734 kHz line frequency.

IC Role / Device Role / Timing Role: Main switching transistor in quasi-resonant flyback topology; conducts during trace, blocks during retrace.

Use Value: 1500 V V_CES and 2500 V isolation ensure safe operation under worst-case flyback overshoot; integrated diode recovers yoke energy without external components.

Use Scenario: Generating EHT (Extra High Tension) for CRT anode via flyback transformer in legacy monitor designs.

IC Role / Device Role / Timing Role: Primary-side switch controlling energy transfer to secondary winding; operates in hard-switched or quasi-resonant mode.

Use Value: Low storage time (4.5 µs) and fast fall time (0.3 µs) minimize switching loss at 16 kHz, preserving efficiency and thermal margin.

Service-Replaceable CRT Power Stage

Legacy Broadcast Equipment Repair

Use Scenario: Field-replaceable horizontal output transistor in professional CRT video monitors used in broadcast studios.

IC Role / Device Role / Timing Role: Ruggedized power switch handling repetitive 5–10 A peak currents with high dv/dt stress during retrace.

Use Value: Stable h_FE vs. temperature and 150°C max junction rating support long-term reliability under continuous studio operation.

Use Scenario: Refurbishment of vintage NTSC/PAL test equipment (e.g., waveform monitors, vectorscopes) requiring authentic replacement parts.

IC Role / Device Role / Timing Role: Direct-fit replacement for obsolete horizontal output transistors in service manuals (e.g., replacing BU2520DX equivalents).

Use Value: TO-3PF mechanical compatibility and identical pinout allow drop-in replacement without board modification or thermal redesign.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BU2520DX	V_CES = 1500 V, but no integrated diode; R_thj-case = 2.5 °C/W	Requires external freewheeling diode and insulating washer due to non-isolated TO-218 package	Select when legacy board layout already includes discrete diode and isolation hardware
ST13009D	V_CES = 400 V only; h_FE looser (5–15); no integrated diode	Not suitable for CRT flyback - limited to low-voltage SMPS or motor drive	Avoid for CRT deflection; only consider for non-CRT 400 V switching where cost is primary constraint

Compared with BU2520DX, MD2009DFX reduces BOM count and thermal interface complexity via integrated diode and UL-isolated package; versus ST13009D, it provides 3.75× higher V_CES and guaranteed flyback capability essential for CRT horizontal output.

Availability

MD2009DFX is available at Aetrix Electronics and suitable for CRT television repair, broadcast equipment refurbishment, and legacy analog video system maintenance requiring stable component supply and long-lifecycle support.

Supply support for MD2009DFX 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, digital, and mixed-signal ICs and discrete power devices for industrial, automotive, and consumer markets.

The MD series targets high-reliability horizontal deflection applications in CRT-based video systems, emphasizing ruggedness, thermal stability, and integrated safety features for legacy display infrastructure.

FAQ

Is MD2009DFX pin-compatible with BU2520DX?

Yes-both use TO-3PF packages with identical lead assignments (case = collector, center lead = base, right lead = emitter). However, MD2009DFX's integrated diode and fully isolated construction eliminate the need for external diode and insulating hardware required by BU2520DX's non-isolated TO-218 variant.

What is the maximum safe operating frequency for MD2009DFX in CRT deflection?

MD2009DFX is characterized for 16 kHz operation (typical CRT horizontal frequency) with validated safe operating area up to that frequency. Its 4.5 µs storage time and 0.3 µs fall time support reliable switching at 15.625–15.734 kHz without secondary breakdown risk under specified inductive load conditions.

Does MD2009DFX require a heatsink? If so, what thermal interface is recommended?

Yes-a heatsink is mandatory. Due to its 2.15 °C/W R_thj-case, even at 30 W dissipation, junction temperature rises ~65°C above case temperature. ST recommends direct mounting to an aluminum heatsink using thermally conductive grease (e.g., Dow Corning TC-5052); no insulator is needed thanks to the UL-isolated TO-3PF package.

Can MD2009DFX be used in modern LCD or LED TV power supplies?

No-it is not designed for modern switch-mode power supplies. Its 1500 V V_CES, 16 A I_CM, and optimized SOA target CRT horizontal deflection waveforms (high dv/dt, inductive flyback), not the lower-voltage, higher-frequency PWM topologies used in LCD/LED backlight or main power conversion.

MD2009DFX Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-3P-3 Full Pack

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 10 A

Voltage - Collector Emitter Breakdown (Max):: 700 V

Vce Saturation (Max) @ Ib, Ic:: 2.8V @ 1.4A, 5.5A

Current - Collector Cutoff (Max):: 200µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 5 @ 5.5A, 5V

Power - Max:: 58 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-3PF

MD2009DFX FAQ

1.How can I place an order for MD2009DFX through Aetrix?

Please submit a Request for Quotation (RFQ) for MD2009DFX 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 MD2009DFX reliable?

The price and inventory of MD2009DFX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MD2009DFX is usually 5 days.

3.What payment methods are accepted for MD2009DFX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MD2009DFX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MD2009DFX?

MD2009DFX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MD2009DFX 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 MD2009DFX?

For technical support, including MD2009DFX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MD2009DFX requirements.

6.How does Aetrix verify that MD2009DFX is sourced from the original manufacturer or authorized distributors?

All MD2009DFX 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 MD2009DFX meets industry standards.

7.What is the process for return or replacement of MD2009DFX?

All MD2009DFX units undergo pre-shipment inspection (PSI). If there is an issue with MD2009DFX, 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 MD2009DFX part is unused and in its original packaging.

Return procedure for MD2009DFX:

1.Submit a request within 90 days.

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

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