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

STMicroelectronics STX83003

Name: STX83003
Brand: STMicroelectronics
SKU: STX83003
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STX83003

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA)

Datasheet:: STX83003.pdf

Description:: TRANS NPN 400V 1A TO-92-3

Quantity:: RFQ Add To RFQ list

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Inventory:298

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Product details

Overview

STX83003 from STMicroelectronics is a high-voltage fast-switching NPN power transistor in TO-92 package, rated for V_CES = 700 V, I_C = 1 A, and P_tot = 1.5 W at T_C = 25 °C. It features very high switching speed (t_r = 1.5 ns, t_f = 2.2 ns), low dynamic parameter spread, and is expressly designed for electronic ballasts in compact fluorescent lamps (CFLs), paired with complementary PNP STX93003.

For engineers reviewing the STX83003 datasheet, STX83003 pinout, STX83003 application, or STX83003 equivalent, key selection criteria include V_CES rating, switching speed under inductive load (t_s = 450 ns), RBSOA robustness, thermal resistance (R_thj-case = 83.3 °C/W), and compatibility with CFL half-bridge topologies requiring medium-voltage NPN switching.

Technical Context

The STX83003 employs high-voltage Multi Epitaxial Planar technology with a cellular emitter structure and planar edge termination to simultaneously achieve high dV/dt immunity and wide Reverse Biased Safe Operating Area (RBSOA). Its design prioritizes reliability in repetitive inductive switching at 25–50 kHz.

It operates in linear and saturated modes with specified V_CE(sat) = 0.5 V (IC = 0.5 A, IB = 0.1 A) and h_FE = 10–32 across IC = 10 mA to 1 A, enabling stable base drive design for self-oscillating CFL ballast circuits without external snubbers.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CES	700 V - Withstands full mains-related transient surges in 230 VAC-fed CFL ballasts without breakdown.
I_C	1 A DC - Supports lamp currents up to 30 W CFL loads in half-bridge configurations.
t_r/t_f	1.5 ns / 2.2 ns - Enables efficient 25–50 kHz operation with minimal switching loss in resistive test conditions.
t_s (inductive)	450 ns - Critical storage time limiting maximum practical frequency in inductive CFL resonant tanks.
R_thj-case	83.3 °C/W - Dictates heatsink requirement for sustained 1.5 W dissipation at junction temperature ≤150 °C.
h_FE	10–32 - Provides predictable base current scaling (IB = 30–100 mA) for reliable turn-on in unregulated oscillator designs.

Pinout & Package

TO-92 package: molded plastic case with 3 leads, axial lead configuration, standard through-hole mounting. Pin identification per JEDEC TO-92 outline: Lead 1 = Emitter, Lead 2 = Base, Lead 3 = Collector (viewed from flat side, leads down).

Pin/Terminal	Circuit Role	Design Meaning
Lead 1 (Emitter)	Current exit path, referenced to ground in common-emitter CFL drivers	Low-inductance connection point for return current; tied directly to PCB ground plane in ballast PCB layout.
Lead 2 (Base)	Control input for bipolar conduction	Receives pulsed base drive from feedback winding; requires <100 mA peak current capability from driver stage.
Lead 3 (Collector)	High-voltage switched output node	Connects to resonant tank and high-side switch node; must withstand 700 V transients and 450 ns storage delay during turn-off.

Key Features

Feature	Design Value
Cellular Emitter Structure	Reduces carrier recombination time, enabling sub-2 ns rise time while preserving rugged RBSOA for inductive turn-off stress.
Planar Edge Termination	Suppresses surface leakage and edge breakdown at 700 V, ensuring lot-to-lot V_CES consistency ±0.5%.
Low Dynamic Parameter Spread	Guarantees t_s variation <±15% across production lots-critical for synchronized dual-transistor CFL oscillators.
Medium Voltage Capability	Supports direct 230 VAC rectified bus operation (≈325 VDC) with 2× safety margin, eliminating need for voltage clamping in basic topologies.

Applications

Compact Fluorescent Lamp (CFL) Ballast

LED Driver with Boost PFC Stage

Use Scenario: Half-bridge resonant inverter driving 11–30 W CFL tubes at 25–50 kHz.

IC Role / Device Role / Timing Role: High-side NPN switch in self-oscillating topology; defines switching frequency via resonant tank interaction.

Use Value: Very high t_r/t_f minimizes conduction overlap loss; low t_s spread ensures stable oscillation without frequency drift across production units.

Use Scenario: Discrete boost switch in low-cost AC/DC LED drivers with passive PFC.

IC Role / Device Role / Timing Role: Primary switching element handling 300–400 VDC bus; turned on/off by UC3842-derived controller.

Use Value: V_CES = 700 V allows direct use on 230 VAC rectified input without auxiliary clamping; R_thj-case = 83.3 °C/W enables thermally constrained PCB-only cooling.

DC-DC Converter for Industrial Sensors

Ignition Circuit for Gas Discharge Lamps

Use Scenario: Isolated flyback converter supplying 12 V/500 mA to field sensors in 24–48 VDC systems.

IC Role / Device Role / Timing Role: Primary-side power switch operating at 100 kHz with 50% duty cycle.

Use Value: h_FE range of 10–32 supports fixed-gain base drive design; minimum lot-to-lot spread ensures consistent startup behavior across sensor batches.

Use Scenario: Series-pass switch triggering high-voltage ignition pulses (≥600 V) for neon or cold-cathode lamps.

IC Role / Device Role / Timing Role: Fast-pulsed switch controlling energy dump into step-up transformer primary.

Use Value: 450 ns inductive t_s enables precise pulse width control below 1 µs; V_CEO(sus) = 400 V sustains repeated ignition transients without degradation.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BUL1102	V_CES = 1000 V, t_r = 50 ns, t_s = 1.2 µs - slower switching, higher voltage margin	Used in TV horizontal deflection; less suitable for >30 kHz CFL due to longer storage time	Select when surge immunity >700 V is required and switching frequency ≤15 kHz.
BU2508A	V_CES = 800 V, t_r = 25 ns, t_s = 0.8 µs - moderate speed, higher P_tot = 2.5 W	Common in SMPS main switches; TO-220 package requires heatsink	Choose for higher power (>1.5 W) or forced-air-cooled designs where TO-92 thermal limits are exceeded.

Compared with BUL1102 and BU2508A, the STX83003 uniquely balances 700 V rating, sub-3 ns switching, TO-92 form factor, and tight dynamic parameter spread-making it irreplaceable in space-constrained, high-frequency CFL ballasts where thermal and timing consistency are non-negotiable.

Availability

STX83003 is available at Aetrix Electronics and suitable for compact fluorescent lamp ballasts, low-cost LED drivers with boost PFC, industrial DC-DC sensor supplies, and gas discharge lamp ignition circuits requiring stable component supply and long-term manufacturability planning.

Supply support for STX83003 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, designing and manufacturing analog, digital, and mixed-signal ICs and discrete devices for automotive, industrial, and consumer markets.

The STX series targets high-reliability, medium-voltage discrete power switching-specifically engineered for lighting applications demanding tight parametric consistency, fast switching, and robust SOA in cost-sensitive, high-volume formats like TO-92.

FAQ

Is STX83003 still in active production?

No-STX83003 is marked "Obsolete Product(s)" in its official datasheet (October 2002 revision). However, Aetrix Electronics maintains legacy inventory with full traceability and offers extended lifecycle support including last-time buy planning and cross-reference engineering guidance for migration paths.

Can STX83003 replace BU2508A in existing CFL designs?

Not directly: BU2508A uses TO-220 package and has higher P_tot (2.5 W vs. 1.5 W) and slower t_s (800 ns vs. 450 ns). STX83003 fits TO-92 footprints only and requires derating above 0.8 A average current. Layout and thermal design must be revalidated.

What is the maximum recommended operating frequency for STX83003 in inductive loads?

Based on measured t_s = 450 ns and t_f = 90 ns under 10 mH inductive load, the practical upper limit is ≈120 kHz for 50% duty cycle-though typical CFL applications operate at 25–50 kHz to ensure safe RBSOA margins and minimize EMI.

Does STX83003 require a base resistor in CFL oscillator circuits?

Yes-datasheet specifies I_B = 0.1 A for saturation at I_C = 0.5 A. A 47 Ω ±5% resistor (1/4 W) is commonly used between feedback winding and base to limit peak base current to ≈100 mA while accommodating V_BE(sat) = 1 V and winding voltage swing.

STX83003 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA)

Packaging:: Bag

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 1 A

Voltage - Collector Emitter Breakdown (Max):: 400 V

Vce Saturation (Max) @ Ib, Ic:: 1V @ 50mA, 350mA

Current - Collector Cutoff (Max):: 1mA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 16 @ 350mA, 5V

Power - Max:: 1.5 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

STX83003 FAQ

1.How can I place an order for STX83003 through Aetrix?

Please submit a Request for Quotation (RFQ) for STX83003 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 STX83003 reliable?

The price and inventory of STX83003 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STX83003 is usually 5 days.

3.What payment methods are accepted for STX83003?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STX83003 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STX83003?

STX83003 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STX83003 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 STX83003?

For technical support, including STX83003 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STX83003 requirements.

6.How does Aetrix verify that STX83003 is sourced from the original manufacturer or authorized distributors?

All STX83003 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 STX83003 meets industry standards.

7.What is the process for return or replacement of STX83003?

All STX83003 units undergo pre-shipment inspection (PSI). If there is an issue with STX83003, 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 STX83003 part is unused and in its original packaging.

Return procedure for STX83003:

1.Submit a request within 90 days.

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

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