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

STMicroelectronics STL73D-AP

Name: STL73D-AP
Brand: STMicroelectronics
SKU: STL73D-AP
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STL73D-AP

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

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

Datasheet:: STL73D-AP.pdf

Description:: TRANS NPN 400V 1.5A TO-92-3

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Product details

Overview

STL73D-AP from STMicroelectronics is a high-voltage fast-switching NPN power transistor with 700 V V_CES, 1.5 A I_C, and integrated antiparallel collector-emitter diode, designed for electronic ballasts in compact fluorescent lamps (CFLs). It features 0.15 V V_CE(sat) at 0.3 A/60 mA, 1 µs rise time, and TO-92 package for space-constrained lighting drivers.

For engineers reviewing the STL73D-AP datasheet, STL73D-AP pinout, STL73D-AP application, or STL73D-AP equivalent, key selection criteria include V_CEO = 400 V, t_r/t_f ≤ 1/0.7 µs, h_FE group L/H classification, integrated diode VF = 1.5 V @ 0.5 A, and R_thJC = 83 °C/W thermal resistance - all critical for CFL half-bridge switching reliability.

Technical Context

This device uses high-voltage multi-epitaxial planar technology with cellular emitter structure and planar edge termination to simultaneously achieve high voltage blocking (V_CES = 700 V) and fast switching (t_r = 1 µs, t_f = 0.7 µs). Its integrated antiparallel diode enables self-commutated operation in resonant CFL ballast topologies without external freewheeling components.

The transistor is optimized for resistive and inductive load switching at V_CC = 125 V and V_Clamp = 300 V, with specified storage time t_s = 4 µs (resistive) and 0.3 µs (inductive), supporting stable operation in high-frequency (>20 kHz) lamp ignition and regulation circuits.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CES	700 V - Enables direct connection to rectified mains in universal-input CFL ballasts without additional snubbing.
I_C	1.5 A continuous - Supports lamp currents up to 36 W with margin for surge and aging.
V_CE(sat)	0.15 V @ 0.3 A/60 mA - Minimizes conduction loss and junction heating in high-duty-cycle operation.
t_r/t_f	1 µs / 0.7 µs - Ensures clean zero-voltage switching transitions in series-resonant lamp drivers.
V_F (integrated diode)	1.5 V @ 0.5 A - Provides low-loss reverse recovery path during commutation, reducing EMI and stress on gate drive.
R_thJC	83 °C/W - Allows 1.5 W dissipation at T_C = 25 °C, compatible with PCB-mounted TO-92 heatsinking in enclosed fixtures.
h_FE group	L (10–16) or H (15–21) - Enables consistent gain binning for predictable base drive design across production lots.

Pinout & Package

STL73D-AP is housed in a standard TO-92 plastic package (JEDEC TO-92 variant), with lead finish compliant with ECOPACK® environmental specifications. The package dimensions conform to ST's mechanical drawing for ammopack shipment (suffix "-AP"), including pitch P0 = 12.6 mm and body height H = 19.5 mm max.

Pin/Terminal	Circuit Role	Design Meaning
E (Emitter)	Current return path and reference node	Connected to ground or low-side switch node; carries full load current and must be routed with low-inductance layout.
B (Base)	Control input for bipolar conduction	Requires 60–250 mA peak drive; sensitive to ESD; needs series resistor to limit IB during fast transitions.
C (Collector)	High-voltage output terminal	Connects to lamp resonant tank; withstands 700 V transient spikes; internal diode anode tied to this pin.

Key Features

Feature	Design Value
Integrated antiparallel diode	Eliminates need for external flyback diode in half-bridge CFL drivers, reducing BOM count and board area by ~15 mm².
Cellular emitter + planar edge termination	Enables simultaneous 700 V breakdown and 1 µs rise time while maintaining wide RBSOA for safe operation under lamp short-circuit conditions.
Low V_CE(sat) at rated current	0.15 V at 0.3 A reduces conduction loss to <15 mW, enabling >92% efficiency in 20–30 W ballast designs.
h_FE group classification (L/H)	Allows precise base drive sizing: group L supports 60 mA IB for 0.3 A IC; group H allows same current with 40 mA IB, easing driver IC selection.

Applications

Compact Fluorescent Lamp (CFL) Ballast

LED Driver with Resonant Topology

Use Scenario: Driving 18–36 W compact fluorescent tubes in universal AC input (100–240 VAC) fixtures with electronic ballast circuitry.

IC Role / Device Role / Timing Role: Main switching transistor in half-bridge resonant inverter stage; switches at 20–60 kHz to ignite and regulate lamp current.

Use Value: Integrated diode and 700 V rating eliminate external clamp diodes and reduce component count; fast switching minimizes switching losses during lamp warm-up phase.

Use Scenario: High-efficiency constant-current LED driver using LLC resonant converter for commercial downlights.

IC Role / Device Role / Timing Role: Low-side switch in asymmetrical half-bridge configuration; handles 350 mA–1 A LED string current with soft-switching capability.

Use Value: 0.7 µs fall time ensures clean turn-off during zero-voltage switching transitions; 83 °C/W R_thJC supports thermal stability at 75 °C ambient in enclosed housings.

Induction Heating Control

DC-DC Converter for Industrial Sensors

Use Scenario: Low-power induction heater for small-appliance cooking elements (≤500 W) requiring rapid thermal response.

IC Role / Device Role / Timing Role: Switching element in Class-E oscillator driving 100–300 kHz resonant tank; operates in hard-switched mode with controlled dv/dt.

Use Value: 400 V V_CEO(sus) sustains clamped inductive kickback; 0.3 µs inductive-load storage time prevents secondary breakdown during fault transients.

Use Scenario: Isolated 12 V to 5 V DC-DC converter powering analog sensor front-ends in factory automation modules.

IC Role / Device Role / Timing Role: Primary-side switch in flyback topology operating at 100 kHz; handles 1.2 A peak primary current with tight duty cycle control.

Use Value: Tight h_FE spread (±30%) ensures consistent current gain across batches, simplifying feedback loop compensation and improving output regulation accuracy.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BU2520DX	V_CES = 1000 V, I_C = 2 A, no integrated diode, TO-220FP package	Higher voltage margin but requires external diode and larger heatsink; suited for higher-power (>50 W) ballasts	Select when system-level V_SW exceeds 600 V or thermal budget allows TO-220 footprint
STN9360	V_CES = 600 V, I_C = 1.2 A, integrated diode, SOT-223 package	Lower voltage rating and smaller package; limited to 15–25 W CFLs with tighter thermal constraints	Select for cost-sensitive, lower-wattage designs where PCB space is extremely limited

Compared with BU2520DX and STN9360, STL73D-AP uniquely balances 700 V capability, integrated diode, TO-92 form factor, and 1 µs switching speed - making it optimal for standardized 18–36 W CFL ballasts where board area, BOM count, and thermal management are co-constrained.

Availability

STL73D-AP is available at Aetrix Electronics and suitable for compact fluorescent lamp ballasts, resonant LED drivers, and industrial DC-DC converters requiring stable component supply, consistent h_FE binning, and integrated diode functionality.

Supply support for STL73D-AP 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, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The STL series targets lighting control applications, specifically engineered for high-reliability, high-frequency switching in electronic ballasts where voltage robustness, thermal stability, and integration density are critical.

FAQ

What is the maximum allowable case temperature for continuous operation?

The STL73D-AP has a maximum junction temperature of 150 °C and a thermal resistance R_thJC of 83 °C/W. With 1.5 W total dissipation at T_C = 25 °C, the case temperature must not exceed 100 °C to maintain 50 °C safety margin. Derating is required above 25 °C ambient per the datasheet's thermal curves.

Does the integrated diode support bidirectional current flow in the collector-emitter path?

No - the integrated diode is unidirectional and oriented anode-to-collector, cathode-to-emitter. It conducts only during reverse-biased conditions (e.g., inductive flyback), not during normal forward conduction. It does not enable true bidirectional switching or replace a synchronous rectifier.

Can STL73D-AP replace STL73D in existing designs?

Yes - STL73D-AP is identical in electrical and mechanical specifications to STL73D, differing only in packaging (ammopack vs. bag). Pinout, marking (L73DL), TO-92 footprint, and all electrical parameters are fully interchangeable. No redesign or requalification is needed.

What is the recommended base drive configuration for reliable switching?

A 100 Ω series resistor between driver and base limits peak IB to ~200 mA during turn-on, matching the 1.5 A IBM rating. A 10 kΩ pull-down resistor from base to emitter ensures fast turn-off and prevents latch-up. Drive waveform should avoid overshoot exceeding V_EBO = 9 V to prevent emitter-base junction damage.

STL73D-AP Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

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

Packaging:: Tape & Box (TB)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 1.5 A

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

Vce Saturation (Max) @ Ib, Ic:: 1V @ 250mA, 1A

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: 10 @ 600mA, 3V

Power - Max:: 1.5 W

Frequency - Transition:: -

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

STL73D-AP FAQ

1.How can I place an order for STL73D-AP through Aetrix?

Please submit a Request for Quotation (RFQ) for STL73D-AP 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 STL73D-AP reliable?

The price and inventory of STL73D-AP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STL73D-AP is usually 5 days.

3.What payment methods are accepted for STL73D-AP?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STL73D-AP transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STL73D-AP?

STL73D-AP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STL73D-AP 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 STL73D-AP?

For technical support, including STL73D-AP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STL73D-AP requirements.

6.How does Aetrix verify that STL73D-AP is sourced from the original manufacturer or authorized distributors?

All STL73D-AP 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 STL73D-AP meets industry standards.

7.What is the process for return or replacement of STL73D-AP?

All STL73D-AP units undergo pre-shipment inspection (PSI). If there is an issue with STL73D-AP, 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 STL73D-AP part is unused and in its original packaging.

Return procedure for STL73D-AP:

1.Submit a request within 90 days.

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

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