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

Vishay Siliconix SI4434DY-T1-GE3

Name: SI4434DY-T1-GE3
Brand: Vishay Siliconix
SKU: SI4434DY-T1-GE3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI4434DY-T1-GE3

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

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

Datasheet:: SI4434DY-T1-GE3.pdf

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

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Product details

Overview

SI4434DY-T1-GE3 from Vishay Siliconix is a lead-free and halogen-free N-channel 250-V MOSFET in SO-8 package, optimized for PWM switching in telecom power supplies. 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.

For engineers reviewing the SI4434DY-T1-GE3 datasheet, SI4434DY-T1-GE3 pinout, SI4434DY-T1-GE3 application, or SI4434DY-T1-GE3 equivalent, key selection criteria include its 250-V V_DS, SO-8 thermal performance (R_thJA = 65 °C/W steady-state), 34 nC total gate charge, and suitability for primary-side switching in compact distributed power architectures.

Technical Context

This trench-based power MOSFET uses Vishay's PWM-optimized TrenchFET® architecture to minimize conduction and switching losses in hard-switched DC-DC converters. Its gate threshold voltage (2.0–4.0 V) and low Q_gd/Q_gs ratio support stable, fast turn-on with reduced risk of shoot-through in half-bridge configurations.

The device integrates an intrinsic body diode with V_SD = 0.75–1.2 V at I_S = 2.8 A and t_rr = 100–150 ns, enabling synchronous rectification support in flyback and forward topologies. Thermal design is anchored by R_thJF = 17 °C/W (typ.) to the drain foot, facilitating direct heatsinking via PCB copper.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	250 V - Supports primary-side switching in 48 V telecom and 36–75 V intermediate bus applications without derating.
R_DS(on)	0.155 Ω @ V_GS = 10 V, I_D = 3.0 A - Enables ≤0.9 W conduction loss at full rated current.
I_D (continuous)	3.0 A @ T_A = 25 °C - Validated for sustained operation on 1" × 1" FR4 board with no forced airflow.
Q_g	34 nC (typ.) @ V_DS = 100 V - Reduces gate drive power and enables efficient 500 kHz–1 MHz PWM control.
t_r/t_f	23/19 ns (typ.) - Supports fast edge rates while maintaining EMI control in high-density power modules.
E_AS	8.4 mJ - Withstands single-pulse inductive energy during overcurrent or startup fault conditions.

Pinout & Package

SO-8 (JEDEC MS-012) surface-mount package with exposed drain pad for thermal enhancement; dimensions per Vishay drawing 71192 (D = 4.80–5.00 mm, E = 3.80–4.00 mm, H = 5.80–6.20 mm).

Pin/Terminal	Circuit Role	Design Meaning
1 (G)	Gate	Control terminal; requires ≥10 V drive for full enhancement; R_g = 0.6–1.8 Ω limits ringing and EMI.
2 (S)	Source	Power return path; referenced to driver ground; connects to source of synchronous rectifier in secondary-side designs.
3 (D)	Drain	Main power output node; tied to exposed pad for thermal conduction to PCB copper pour or heatsink.
4 (D)	Drain	Parallel drain connection; shares current and thermal load with Pin 3 to reduce resistance and junction temperature.
5 (D)	Drain	Third drain terminal; enhances current handling and thermal dissipation in high-reliability telecom modules.
6 (D)	Drain	Fourth drain terminal; completes quad-drain configuration for low-inductance, low-resistance high-current paths.
7 (S)	Source	Secondary source connection; improves current sharing and reduces source inductance in high-frequency switching.
8 (G)	Gate	Redundant gate input; used for gate loop balancing or paralleling; must be connected to same driver as Pin 1.

Key Features

Feature	Design Value
PWM-optimized TrenchFET® structure	Minimizes Q_gd/Q_g ratio to improve switching efficiency and reduce Miller-induced oscillation in hard-switched converters.
100% R_g tested	Ensures consistent gate resistance (0.6–1.8 Ω) across production lots, critical for predictable gate drive timing and EMI behavior.
Avalanche-rated (E_AS = 8.4 mJ)	Guarantees ruggedness against inductive kickback in unregulated or transient-loaded telecom power stages.
Halogen-free & Pb-free (IEC 61249-2-21)	Meets RoHS and JEDEC J-STD-020 reflow compliance for industrial and telecom manufacturing environments.

Applications

Telecom Power Supply	Distributed Power Architecture
Use Scenario: Primary-side switch in isolated 48 V input, 12 V output flyback converter for central office line cards. IC Role / Device Role / Timing Role: High-voltage power switch controlling energy transfer into transformer primary winding during PWM on-time. Use Value: 250 V rating avoids derating margin issues; 0.155 Ω R_DS(on) maintains >92% efficiency at 3 A load under 60 °C ambient.	Use Scenario: Input-stage switch in modular 24–48 V DC-DC brick powering server baseboard management controllers. IC Role / Device Role / Timing Role: Regulated high-side switch enabling hot-swap and inrush control before downstream buck regulation. Use Value: Avalanche energy rating ensures survival during input capacitor charging transients; SO-8 footprint simplifies layout in space-constrained modules.
Miniature Power Module	Industrial AC-DC Adapter
Use Scenario: Main switch in 10 W, 5 V/2 A isolated flyback module for IoT gateway power rails. IC Role / Device Role / Timing Role: Primary-side switching element operating at 500 kHz with fixed-frequency PWM control. Use Value: Low Q_g (34 nC) reduces gate driver losses; quad-drain SO-8 package lowers thermal resistance to enable <100 °C T_J at full load.	Use Scenario: Primary switch in universal-input (85–264 VAC) offline flyback adapter for industrial HMIs. IC Role / Device Role / Timing Role: High-voltage switching transistor handling peak rectified voltages up to 375 V. Use Value: 250 V V_DS provides sufficient margin above 375 V peak; 150 °C max T_J rating supports sealed enclosure operation.

Telecom Power Supply

Distributed Power Architecture

Use Scenario: Primary-side switch in isolated 48 V input, 12 V output flyback converter for central office line cards.

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

Use Value: 250 V rating avoids derating margin issues; 0.155 Ω R_DS(on) maintains >92% efficiency at 3 A load under 60 °C ambient.

Use Scenario: Input-stage switch in modular 24–48 V DC-DC brick powering server baseboard management controllers.

IC Role / Device Role / Timing Role: Regulated high-side switch enabling hot-swap and inrush control before downstream buck regulation.

Use Value: Avalanche energy rating ensures survival during input capacitor charging transients; SO-8 footprint simplifies layout in space-constrained modules.

Miniature Power Module

Industrial AC-DC Adapter

Use Scenario: Main switch in 10 W, 5 V/2 A isolated flyback module for IoT gateway power rails.

IC Role / Device Role / Timing Role: Primary-side switching element operating at 500 kHz with fixed-frequency PWM control.

Use Value: Low Q_g (34 nC) reduces gate driver losses; quad-drain SO-8 package lowers thermal resistance to enable <100 °C T_J at full load.

Use Scenario: Primary switch in universal-input (85–264 VAC) offline flyback adapter for industrial HMIs.

IC Role / Device Role / Timing Role: High-voltage switching transistor handling peak rectified voltages up to 375 V.

Use Value: 250 V V_DS provides sufficient margin above 375 V peak; 150 °C max T_J rating supports sealed enclosure operation.

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel high-voltage MOSFET applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
STP2N250	250 V, 2.5 A, R_DS(on) = 0.22 Ω @ 10 V, TO-220 package	Higher R_DS(on) and through-hole mounting limit use in compact, high-efficiency modules	Prefer SI4434DY-T1-GE3 for SO-8 space constraints and lower conduction loss.
IRF640NPBF	200 V, 18 A, R_DS(on) = 0.18 Ω @ 10 V, TO-220 package	Lower V_DS rating and higher Q_g (67 nC) increase stress in 48 V telecom primary-side designs	SI4434DY-T1-GE3 offers superior voltage margin and switching efficiency for telecom-grade reliability.

Compared with STP2N250 and IRF640NPBF, the SI4434DY-T1-GE3 provides lower R_DS(on), smaller SO-8 footprint, and tighter gate charge control-making it optimal for thermally constrained, high-frequency telecom and distributed power applications where voltage margin and layout density are critical.

Availability

SI4434DY-T1-GE3 is available at Aetrix Electronics and suitable for telecom power supplies, distributed power architectures, and miniature power modules requiring stable component supply, halogen-free compliance, and proven avalanche ruggedness.

Supply support for SI4434DY-T1-GE3 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 leader in discrete semiconductors and passive components, specializing in high-reliability power MOSFETs, diodes, and optoelectronics for industrial and telecom infrastructure.

The Si4434DY belongs to Vishay's TrenchFET® Gen II family, engineered specifically for high-efficiency, high-voltage primary-side switching in compact, regulated DC-DC converters and offline power supplies.

FAQ

What is the maximum continuous drain current rating for SI4434DY-T1-GE3 at 70 °C ambient?

The SI4434DY-T1-GE3 supports 1.7 A continuous drain current at T_A = 70 °C when mounted on a 1" × 1" FR4 board, per its Absolute Maximum Ratings table. This derating reflects thermal limitations of the SO-8 package without additional heatsinking or airflow. The SI4434DY-T1-GE3 datasheet specifies this value under steady-state conditions with no forced cooling.

Does SI4434DY-T1-GE3 have a specified avalanche energy rating?

Yes, the SI4434DY-T1-GE3 is fully avalanche-rated with a single-pulse avalanche energy (E_AS) of 8.4 mJ, measured at I_AS = 13 A and L = 0.1 mH. This rating is production-tested and guaranteed per Vishay's qualification standards, confirming robustness against inductive switching faults in telecom power applications.

What is the gate threshold voltage range for SI4434DY-T1-GE3?

The SI4434DY-T1-GE3 has a gate threshold voltage (V_GS(th)) range of 2.0 V to 4.0 V, measured at V_DS = V_GS and I_D = 250 µA. This range ensures reliable turn-on with standard 5 V or 10 V gate drivers while avoiding false triggering from noise in noisy telecom environments.

Is SI4434DY-T1-GE3 compatible with lead-free reflow soldering processes?

Yes, the SI4434DY-T1-GE3 is qualified for lead-free reflow per JEDEC J-STD-020, with a peak reflow temperature of 260 °C. Its halogen-free construction (per IEC 61249-2-21) and Pb-free terminations make it compliant with RoHS and IPC Class 3 assembly requirements for telecom and industrial equipment.

How many drain terminals does the SI4434DY-T1-GE3 SO-8 package feature?

The SI4434DY-T1-GE3 SO-8 package features four dedicated drain terminals (Pins 3, 4, 5, and 6), plus an exposed drain pad underneath the body. This multi-terminal configuration reduces package resistance and inductance, improving thermal transfer and current handling-key for high-reliability telecom power stages.

SI4434DY-T1-GE3 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-GE3 FAQ

1.How can I place an order for SI4434DY-T1-GE3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI4434DY-T1-GE3 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-GE3 reliable?

The price and inventory of SI4434DY-T1-GE3 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-GE3 is usually 5 days.

3.What payment methods are accepted for SI4434DY-T1-GE3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI4434DY-T1-GE3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI4434DY-T1-GE3?

SI4434DY-T1-GE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI4434DY-T1-GE3 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-GE3?

For technical support, including SI4434DY-T1-GE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI4434DY-T1-GE3 requirements.

6.How does Aetrix verify that SI4434DY-T1-GE3 is sourced from the original manufacturer or authorized distributors?

All SI4434DY-T1-GE3 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-GE3 meets industry standards.

7.What is the process for return or replacement of SI4434DY-T1-GE3?

All SI4434DY-T1-GE3 units undergo pre-shipment inspection (PSI). If there is an issue with SI4434DY-T1-GE3, 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-GE3 part is unused and in its original packaging.

Return procedure for SI4434DY-T1-GE3:

1.Submit a request within 90 days.

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

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