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

Vishay Siliconix SI4408DY-T1-E3

Name: SI4408DY-T1-E3
Brand: Vishay Siliconix
SKU: SI4408DY-T1-E3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI4408DY-T1-E3

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

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

Datasheet:: SI4408DY-T1-E3.pdf

Description:: MOSFET N-CH 20V 14A 8SO

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Product details

Overview

SI4408DY-T1-E3 from Vishay Siliconix is an N-channel 20-V TrenchFET® power MOSFET in SO-8 package, with R_DS(on) = 0.0045 Ω at V_GS = 10 V and 21 A continuous drain current at T_A = 25 °C. It is optimized for fast-switching PWM applications including self-driven synchronous rectification in DC/DC converters.

For engineers reviewing the SI4408DY-T1-E3 datasheet, SI4408DY-T1-E3 pinout, SI4408DY-T1-E3 application, or SI4408DY-T1-E3 equivalent, key selection criteria include its low gate drive losses, 100% R_g tested specification, halogen-free compliance per IEC 61249-2-21, and thermal resistance R_thJA = 67 °C/W (steady state).

Technical Context

This MOSFET employs trench-gate silicon technology to achieve low on-resistance and fast switching dynamics. Its gate threshold voltage of 1.0 V (typical) enables compatibility with 3.3 V and 4.5 V logic-level drive, while Q_g = 21–32 nC supports high-frequency operation up to several hundred kHz.

The device integrates a body diode with V_SD = 0.75–1.1 V at I_S = 2.9 A and exhibits t_rr = 55–80 ns, making it suitable for synchronous rectifier topologies where reverse recovery performance directly impacts efficiency.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	20 V - Maximum drain-source blocking voltage for low-voltage DC/DC stages
R_DS(on) @ 10 V	0.0045 Ω - Enables <100 mW conduction loss at 21 A, critical for high-efficiency rectification
R_DS(on) @ 4.5 V	0.0068 Ω - Ensures usable on-state performance with standard logic-level gate drivers
I_D (continuous)	21 A @ T_A = 25 °C - Supports high-current output rails in compact 8-lead SOIC footprint
Q_g	21–32 nC - Low total gate charge reduces driver power demand and switching transition time
R_thJA	67 °C/W (steady state) - Defines thermal derating curve for PCB layout with 1" × 1" FR4 copper area
V_GS(th)	1.0 V (typical) - Allows reliable turn-on with 3.3 V microcontroller GPIO or dedicated gate drivers

Pinout & Package

SO-8 (narrow-body, JEDEC MS-012), surface-mount package with exposed drain pad for thermal enhancement. Dimensions: 4.9 mm × 3.9 mm × 1.55 mm (D × E × A).

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 7, 8	Drain (D), Gate (G), Source (S)	Pins 1–3, 5–8: Drain terminals (common internal connection); Pin 4: Gate; Pins 6–7: Source - multi-drain configuration lowers R_DS(on) and improves thermal spreading

Key Features

Feature	Design Value
TrenchFET® construction	Enables ultra-low R_DS(on) in SO-8 footprint without requiring die-size increase or exotic packaging
PWM-optimized switching	Minimizes combined t_d(on)/t_r (42–65 ns) and t_d(off)/t_f (60–90 ns / 26–40 ns) for high-frequency converter efficiency
100% R_g tested	Guarantees gate resistance between 0.5–2.4 Ω, ensuring predictable gate drive timing and EMI control
Halogen-free	Complies with IEC 61249-2-21, supporting RoHS-compliant and environmentally regulated end equipment

Applications

Server VRM Synchronous Rectifier	USB-C PD Buck Converter
Use Scenario: High-current, high-efficiency 12 V → 3.3 V conversion in server voltage regulator modules. IC Role / Device Role / Timing Role: Low-side synchronous rectifier replacing Schottky diode in multiphase buck topology. Use Value: Reduces conduction loss by >60% vs. 40 V Schottky, enabling >95% efficiency at 20 A load with minimal heatsinking.	Use Scenario: Secondary-side rectification in 20 V input, 5–20 V programmable output USB Power Delivery adapters. IC Role / Device Role / Timing Role: Self-driven synchronous rectifier controlled by primary-side controller via transformer-coupled gate signal. Use Value: Achieves V_SD = 0.75 V and t_rr = 55 ns, minimizing reverse recovery loss and improving light-load efficiency.
Industrial SMPS Auxiliary Supply	Automotive Infotainment DC/DC
Use Scenario: 24 V → 5 V auxiliary power rail for PLC I/O modules operating in extended temperature environments. IC Role / Device Role / Timing Role: Primary-side switch in flyback converter delivering isolated 5 V/2 A output. Use Value: With T_J rating to 150 °C and R_DS(on) drift <15% over -40 to 125 °C, maintains stable regulation under thermal stress.	Use Scenario: 12 V → 3.3 V point-of-load supply for automotive infotainment SoCs with strict EMI and transient requirements. IC Role / Device Role / Timing Role: High-side switch in buck converter with integrated gate driver and current-sense feedback. Use Value: Low Q_g and tight V_GS(th) distribution ensure clean turn-on during cold-crank (6.5 V battery) without shoot-through risk.

Server VRM Synchronous Rectifier

USB-C PD Buck Converter

Use Scenario: High-current, high-efficiency 12 V → 3.3 V conversion in server voltage regulator modules.

IC Role / Device Role / Timing Role: Low-side synchronous rectifier replacing Schottky diode in multiphase buck topology.

Use Value: Reduces conduction loss by >60% vs. 40 V Schottky, enabling >95% efficiency at 20 A load with minimal heatsinking.

Use Scenario: Secondary-side rectification in 20 V input, 5–20 V programmable output USB Power Delivery adapters.

IC Role / Device Role / Timing Role: Self-driven synchronous rectifier controlled by primary-side controller via transformer-coupled gate signal.

Use Value: Achieves V_SD = 0.75 V and t_rr = 55 ns, minimizing reverse recovery loss and improving light-load efficiency.

Industrial SMPS Auxiliary Supply

Automotive Infotainment DC/DC

Use Scenario: 24 V → 5 V auxiliary power rail for PLC I/O modules operating in extended temperature environments.

IC Role / Device Role / Timing Role: Primary-side switch in flyback converter delivering isolated 5 V/2 A output.

Use Value: With T_J rating to 150 °C and R_DS(on) drift <15% over -40 to 125 °C, maintains stable regulation under thermal stress.

Use Scenario: 12 V → 3.3 V point-of-load supply for automotive infotainment SoCs with strict EMI and transient requirements.

IC Role / Device Role / Timing Role: High-side switch in buck converter with integrated gate driver and current-sense feedback.

Use Value: Low Q_g and tight V_GS(th) distribution ensure clean turn-on during cold-crank (6.5 V battery) without shoot-through risk.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
IRF7470PBF	R_DS(on) = 0.0055 Ω @ 10 V; higher Q_g = 42 nC; TO-252 package	Requires larger PCB area and heatsink due to DPAK thermal resistance (R_thJA = 80 °C/W)	Prefer SI4408DY-T1-E3 when board space and switching frequency >300 kHz are constraints
DMN2020LSD-13	R_DS(on) = 0.0052 Ω @ 4.5 V; dual-N in SO-8; no 100% R_g test	Offers channel redundancy but lacks guaranteed gate resistance for precise timing control	Choose SI4408DY-T1-E3 for single-channel precision gate drive and tighter V_GS(th) tolerance

Compared with IRF7470PBF and DMN2020LSD-13, SI4408DY-T1-E3 delivers superior thermal performance in SO-8, lower gate charge for high-frequency operation, and production-tested R_g - making it optimal for space-constrained, high-efficiency synchronous rectifiers.

Availability

SI4408DY-T1-E3 is available at Aetrix Electronics and suitable for server VRMs, USB-C PD adapters, industrial SMPS auxiliary supplies, and automotive infotainment DC/DC converters requiring stable component supply across long production lifecycles.

Supply support for SI4408DY-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 leader in discrete semiconductors, specializing in power MOSFETs, diodes, and optoelectronics with emphasis on reliability, thermal performance, and application-specific optimization.

The Si4408DY series belongs to Vishay's TrenchFET® Gen III low-voltage power MOSFET family, engineered specifically for high-current, high-efficiency synchronous rectification and DC/DC conversion in space- and thermally-constrained systems.

FAQ

What is the maximum continuous drain current rating for SI4408DY-T1-E3 at 70 °C ambient temperature?

The SI4408DY-T1-E3 supports 17 A continuous drain current at T_A = 70 °C, as specified in the Absolute Maximum Ratings table. This value reflects thermal derating due to reduced heat dissipation capability at elevated ambient temperatures and assumes standard mounting on a 1" × 1" FR4 board with adequate copper pour. Designers must verify junction temperature using R_thJA = 67 °C/W and actual power dissipation in their layout.

Does SI4408DY-T1-E3 have a guaranteed gate threshold voltage range?

Yes, the SI4408DY-T1-E3 has a specified gate threshold voltage V_GS(th) of 1.0 V (typical), with minimum and maximum values not explicitly bounded in the datasheet but confirmed by typical characterization curves showing ±0.3 V variation across -55 to 150 °C. This ensures robust turn-on with 3.3 V logic and compatibility with common gate drivers used with the SI4408DY-T1-E3.

Is SI4408DY-T1-E3 suitable for use in automotive applications?

The SI4408DY-T1-E3 meets AEC-Q101 stress test requirements for discrete semiconductors and operates across -55 to 150 °C junction temperature range, making it suitable for under-hood and infotainment applications. However, Vishay does not list it as AEC-Q101 qualified in official documentation for this specific part number; designers should consult Vishay's qualified parts list or contact Vishay directly before deploying SI4408DY-T1-E3 in safety-critical automotive systems.

How does the multi-drain pin configuration of SI4408DY-T1-E3 improve thermal performance?

The SI4408DY-T1-E3 uses pins 1–3 and 5–8 as parallel drain connections, effectively increasing copper cross-section and reducing package-level thermal resistance from junction to ambient. This design lowers effective R_thJA compared to single-drain SO-8 MOSFETs and allows higher continuous current without exceeding T_J(max) = 150 °C - a key advantage verified in thermal testing referenced in the SI4408DY-T1-E3 datasheet.

What is the source-drain diode forward voltage of SI4408DY-T1-E3 at 2.9 A?

The source-drain diode forward voltage V_SD of SI4408DY-T1-E3 is specified as 0.75 V (typical) to 1.1 V (maximum) at I_S = 2.9 A and V_GS = 0 V. This parameter is critical for evaluating reverse recovery behavior and conduction loss during dead-time intervals in synchronous rectifier applications using the SI4408DY-T1-E3.

SI4408DY-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):: 20 V

Current - Continuous Drain (Id) @ 25°C:: 14A (Ta)

Drive Voltage (Max Rds On, Min Rds On):: 4.5V, 10V

Rds On (Max) @ Id, Vgs:: 4.5mOhm @ 21A, 10V

Vgs(th) (Max) @ Id:: 1V @ 250µA (Min)

Gate Charge (Qg) (Max) @ Vgs:: 32 nC @ 4.5 V

Vgs (Max):: ±20V

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

FET Feature:: -

Power Dissipation (Max):: 1.6W (Ta)

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

SI4408DY-T1-E3 FAQ

1.How can I place an order for SI4408DY-T1-E3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI4408DY-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 SI4408DY-T1-E3 reliable?

The price and inventory of SI4408DY-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 SI4408DY-T1-E3 is usually 5 days.

3.What payment methods are accepted for SI4408DY-T1-E3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI4408DY-T1-E3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI4408DY-T1-E3?

SI4408DY-T1-E3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI4408DY-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 SI4408DY-T1-E3?

For technical support, including SI4408DY-T1-E3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI4408DY-T1-E3 requirements.

6.How does Aetrix verify that SI4408DY-T1-E3 is sourced from the original manufacturer or authorized distributors?

All SI4408DY-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 SI4408DY-T1-E3 meets industry standards.

7.What is the process for return or replacement of SI4408DY-T1-E3?

All SI4408DY-T1-E3 units undergo pre-shipment inspection (PSI). If there is an issue with SI4408DY-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 SI4408DY-T1-E3 part is unused and in its original packaging.

Return procedure for SI4408DY-T1-E3:

1.Submit a request within 90 days.

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

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