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Home > Products > Discrete Semiconductor Products > Transistors > FETs, MOSFETs > FETs, MOSFETs

Vishay Siliconix SI4434DY-T1-E3

Name: SI4434DY-T1-E3
Brand: Vishay Siliconix
SKU: SI4434DY-T1-E3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI4434DY-T1-E3

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: SI4434DY-T1-E3.pdf

Description:: MOSFET N-CH 250V 2.1A 8SO

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Product details

Overview

SI4434DY-T1-E3 from Vishay Siliconix is an N-channel 250-V (D-S) TrenchFET® power MOSFET optimized for PWM switching in primary-side power conversion. It delivers R_DS(on) = 0.155 Ω at V_GS = 10 V, supports 3.0 A continuous drain current at T_A = 25 °C, and features 100% R_g tested and avalanche-rated operation. It is used in telecom power supplies and miniature power modules.

For engineers reviewing the SI4434DY-T1-E3 datasheet, SI4434DY-T1-E3 pinout, SI4434DY-T1-E3 application, or SI4434DY-T1-E3 equivalent, key selection criteria include its 250-V V_DS, SO-8 package thermal performance (R_thJA = 65 °C/W steady-state), 34 nC total gate charge, and verified avalanche energy rating of 8.4 mJ.

Technical Context

This MOSFET employs Vishay's trench-based silicon process to achieve low on-resistance with controlled gate charge profile-Q_g = 34–50 nC and Q_gd = 10.5 nC-enabling efficient high-frequency PWM operation. Its gate threshold voltage (V_GS(th) = 2.0–4.0 V) ensures reliable turn-on with standard logic-level drivers.

The device integrates a body diode with V_SD = 0.75–1.2 V at I_S = 2.8 A and t_rr = 100–150 ns, supporting synchronous rectification and flyback recovery. Absolute maximum ratings include 250 V V_DS, ±20 V V_GS, and 13 A I_AS for single-pulse avalanche robustness.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	250 V - Withstands up to 250 V drain-source blocking voltage, suitable for offline and intermediate bus applications.
R_DS(on)	0.155 Ω @ V_GS = 10 V, I_D = 3.0 A - Enables low conduction loss in primary-side switch designs at rated current.
I_D (continuous)	3.0 A @ T_A = 25 °C - Supports stable operation in compact SO-8 layouts with adequate board copper.
Q_g	34 nC typical - Reduces driver power demand and switching loss in 100–500 kHz PWM converters.
E_AS	8.4 mJ - Confirmed single-pulse avalanche energy rating improves reliability under inductive load transients.
R_thJA	65 °C/W (steady-state) - Defines thermal derating curve for ambient-limited power dissipation in FR4 PCBs.
V_GS(th)	2.0–4.0 V - Ensures clean turn-on with 3.3 V or 5 V gate drive without requiring level-shifting circuitry.

Pinout & Package

SI4434DY-T1-E3 is housed in a standard SO-8 (narrow) surface-mount package per JEDEC MS-012, with exposed drain pads for thermal enhancement. Pin 1 is Gate, Pins 2–4 and 6–8 are Source, and Pins 5 and 7 are Drain (dual-drain configuration).

Pin/Terminal	Circuit Role	Design Meaning
1	Gate	Control terminal; accepts 0–10 V logic-level drive; requires <1.2 Ω gate resistance for optimal switching.
2, 3, 4, 6, 8	Source	Power return path; electrically common; connects to ground or low-side reference in half-bridge topologies.
5, 7	Drain	High-voltage power input/output node; dual pins reduce current density and improve thermal spreading to PCB copper.

Key Features

Feature	Design Value
PWM-optimized TrenchFET®	Low Q_gd/Q_g ratio (≈0.31) minimizes Miller-induced switching delay and improves hard-switching efficiency.
100% R_g tested	Guarantees gate resistance between 0.6–1.8 Ω, enabling predictable gate drive loop design and EMI control.
Avalanche rated	Rated for 13 A I_AS and 8.4 mJ E_AS, allowing safe operation during inductive turn-off transients without external snubbers.
Halogen-free construction	Complies with IEC 61249-2-21; eliminates brominated flame retardants while maintaining UL 94 V-0 flammability rating.

Applications

Telecom Power Supplies	Distributed Power Architectures
Use Scenario: Primary-side switch in isolated AC/DC front-end converters delivering 50–200 W for base station RF amplifiers and optical line cards. IC Role / Device Role / Timing Role: High-voltage power switch controlling energy transfer across transformer primary winding during PWM cycles. Use Value: 250 V V_DS and 8.4 mJ E_AS ensure robustness against line surges and transformer leakage spikes in unregulated mains environments.	Use Scenario: DC/DC brick input stage converting 48 V intermediate bus to 12 V or 5 V for server blade subsystems. IC Role / Device Role / Timing Role: Synchronous rectifier or active clamp switch operating at 250–350 kHz with tight duty-cycle control. Use Value: Low 0.155 Ω R_DS(on) and 34 nC Q_g reduce conduction + switching losses, improving full-load efficiency by ≥0.8% vs. legacy MOSFETs.
Miniature Power Modules	Industrial AC/DC Adapters
Use Scenario: Integrated 10–30 W power module for IoT edge controllers, where PCB area and thermal mass are constrained. IC Role / Device Role / Timing Role: Primary-side switch in flyback topology with integrated transformer and feedback circuitry. Use Value: SO-8 footprint and 65 °C/W R_thJA allow thermal management using only 1" × 1" FR4 board, eliminating heatsinks.	Use Scenario: Universal-input (90–264 VAC) adapter for industrial HMIs and programmable logic controllers. IC Role / Device Role / Timing Role: Main switching element in quasi-resonant flyback controller IC reference designs. Use Value: Verified V_GS(th) range (2.0–4.0 V) ensures compatibility with industry-standard QR controller gate drivers without external bias networks.

Telecom Power Supplies

Distributed Power Architectures

Use Scenario: Primary-side switch in isolated AC/DC front-end converters delivering 50–200 W for base station RF amplifiers and optical line cards.

IC Role / Device Role / Timing Role: High-voltage power switch controlling energy transfer across transformer primary winding during PWM cycles.

Use Value: 250 V V_DS and 8.4 mJ E_AS ensure robustness against line surges and transformer leakage spikes in unregulated mains environments.

Use Scenario: DC/DC brick input stage converting 48 V intermediate bus to 12 V or 5 V for server blade subsystems.

IC Role / Device Role / Timing Role: Synchronous rectifier or active clamp switch operating at 250–350 kHz with tight duty-cycle control.

Use Value: Low 0.155 Ω R_DS(on) and 34 nC Q_g reduce conduction + switching losses, improving full-load efficiency by ≥0.8% vs. legacy MOSFETs.

Miniature Power Modules

Industrial AC/DC Adapters

Use Scenario: Integrated 10–30 W power module for IoT edge controllers, where PCB area and thermal mass are constrained.

IC Role / Device Role / Timing Role: Primary-side switch in flyback topology with integrated transformer and feedback circuitry.

Use Value: SO-8 footprint and 65 °C/W R_thJA allow thermal management using only 1" × 1" FR4 board, eliminating heatsinks.

Use Scenario: Universal-input (90–264 VAC) adapter for industrial HMIs and programmable logic controllers.

IC Role / Device Role / Timing Role: Main switching element in quasi-resonant flyback controller IC reference designs.

Use Value: Verified V_GS(th) range (2.0–4.0 V) ensures compatibility with industry-standard QR controller gate drivers without external bias networks.

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel 250-V power MOSFET applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
STP2NK25Z	250 V V_DS, R_DS(on) = 2.5 Ω @ 10 V - significantly higher on-resistance; TO-92 package.	Lower power (<1 W), discrete replacement in legacy linear regulators or low-current auxiliary supplies.	Select STP2NK25Z only when board space permits through-hole mounting and thermal budget allows higher conduction loss.
IXTP2N250	250 V V_DS, R_DS(on) = 6.5 Ω @ 10 V, TO-220 package - higher R_DS(on), larger footprint, better heatsinking.	Higher-power (>10 W), forced-air-cooled industrial SMPS where SO-8 thermal limits are exceeded.	Choose IXTP2N250 when >5 W continuous dissipation is required and PCB layout accommodates TO-220 mounting and heatsink interface.

Compared with STP2NK25Z and IXTP2N250, SI4434DY-T1-E3 provides the lowest R_DS(on) and smallest footprint among 250 V N-channel MOSFETs in production, making it optimal for space-constrained, medium-power primary-side switching where SO-8 thermal performance suffices.

Availability

SI4434DY-T1-E3 is available at Aetrix Electronics and suitable for telecom power supplies, distributed power architectures, and miniature power modules requiring stable component supply and lead-free compliance.

Supply support for SI4434DY-T1-E3 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

Vishay Siliconix is a global semiconductor manufacturer specializing in discrete power devices, optoelectronics, and passive components, with emphasis on high-reliability and high-efficiency solutions.

The Si4434DY product line targets high-frequency, medium-power primary-side switching in isolated DC/DC and AC/DC converters, balancing low R_DS(on), fast switching, and rugged avalanche performance in compact packages.

FAQ

What is the maximum continuous drain current for SI4434DY-T1-E3 at 70 °C ambient temperature?

The SI4434DY-T1-E3 supports 1.7 A continuous drain current at T_A = 70 °C under steady-state conditions, as specified in the Absolute Maximum Ratings table. This derating reflects thermal limitations of the SO-8 package on standard FR4 PCBs. For higher current operation, forced airflow or enhanced copper pour is required to maintain junction temperature ≤150 °C. The SI4434DY-T1-E3 datasheet confirms this value under "Continuous Drain Current (T_J = 150 °C)" with note "a. Surface Mounted on 1" x 1" FR4 board."

Does SI4434DY-T1-E3 have a built-in body diode, and what are its forward voltage characteristics?

Yes, SI4434DY-T1-E3 includes an integrated body diode with V_SD = 0.75–1.2 V at I_S = 2.8 A and V_GS = 0 V. Its reverse recovery time t_rr is 100–150 ns under I_F = 2.8 A and dI/dt = 100 A/µs. These parameters make the SI4434DY-T1-E3 suitable for freewheeling and synchronous rectification in flyback and resonant topologies where diode conduction occurs during dead-time intervals.

Is SI4434DY-T1-E3 RoHS and halogen-free compliant?

Yes, SI4434DY-T1-E3 is both RoHS-compliant and halogen-free per IEC 61249-2-21. The "-E3" suffix explicitly denotes lead-free (Pb-free) termination, and Vishay documentation confirms halogen-free construction for this variant. No brominated or chlorinated flame retardants are used in the molding compound, satisfying strict environmental requirements for industrial and telecom equipment.

What is the gate threshold voltage range for SI4434DY-T1-E3, and how does it affect drive requirements?

The gate threshold voltage V_GS(th) for SI4434DY-T1-E3 is 2.0–4.0 V at I_D = 250 µA, ensuring reliable turn-on with standard 3.3 V or 5 V logic-level drivers. This range avoids unintended conduction near 0 V while guaranteeing full enhancement at 10 V gate drive. The SI4434DY-T1-E3 does not require gate voltage boosting or level-shifting circuitry in most PWM controller interfaces.

Can SI4434DY-T1-E3 be used in avalanche mode, and what is its rated single-pulse energy?

Yes, SI4434DY-T1-E3 is fully avalanche-rated with a guaranteed single-pulse avalanche energy E_AS of 8.4 mJ and peak avalanche current I_AS of 13 A (L = 0.1 mH). This rating is production-tested-not just design-simulated-and enables robust operation during transformer leakage energy discharge or output short-circuit events without external clamping. The SI4434DY-T1-E3 datasheet specifies these values in the Absolute Maximum Ratings table under "Avalanche Current" and "Single Pulse Avalanche Energy."

SI4434DY-T1-E3 Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Siliconix

Series:: TrenchFET®

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 250 V

Current - Continuous Drain (Id) @ 25°C:: 2.1A (Ta)

Drive Voltage (Max Rds On, Min Rds On):: 6V, 10V

Rds On (Max) @ Id, Vgs:: 155mOhm @ 3A, 10V

Vgs(th) (Max) @ Id:: 4V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 50 nC @ 10 V

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: -

FET Feature:: -

Power Dissipation (Max):: 1.56W (Ta)

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

SI4434DY-T1-E3 FAQ

1.How can I place an order for SI4434DY-T1-E3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI4434DY-T1-E3 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 SI4434DY-T1-E3 reliable?

The price and inventory of SI4434DY-T1-E3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI4434DY-T1-E3 is usually 5 days.

3.What payment methods are accepted for SI4434DY-T1-E3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI4434DY-T1-E3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI4434DY-T1-E3?

SI4434DY-T1-E3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI4434DY-T1-E3 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 SI4434DY-T1-E3?

For technical support, including SI4434DY-T1-E3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI4434DY-T1-E3 requirements.

6.How does Aetrix verify that SI4434DY-T1-E3 is sourced from the original manufacturer or authorized distributors?

All SI4434DY-T1-E3 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 SI4434DY-T1-E3 meets industry standards.

7.What is the process for return or replacement of SI4434DY-T1-E3?

All SI4434DY-T1-E3 units undergo pre-shipment inspection (PSI). If there is an issue with SI4434DY-T1-E3, 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 SI4434DY-T1-E3 part is unused and in its original packaging.

Return procedure for SI4434DY-T1-E3:

1.Submit a request within 90 days.

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

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