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

Vishay Siliconix SI4408DY-T1-GE3

Name: SI4408DY-T1-GE3
Brand: Vishay Siliconix
SKU: SI4408DY-T1-GE3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI4408DY-T1-GE3

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

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

Datasheet:: SI4408DY-T1-GE3.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SI4408DY-T1-GE3 from Vishay Siliconix is an N-channel 20-V TrenchFET® power MOSFET optimized for PWM-driven synchronous rectification, featuring R_DS(on) = 0.0045 Ω at V_GS = 10 V, 21-A continuous drain current (T_J = 150 °C), and SO-8 package. It delivers low switching and gate drive losses in high-efficiency DC/DC converters.

For engineers reviewing the SI4408DY-T1-GE3 datasheet, SI4408DY-T1-GE3 pinout, SI4408DY-T1-GE3 application, or SI4408DY-T1-GE3 equivalent, key selection criteria include its 4.5-V gate threshold compatibility with logic-level drivers, halogen-free and Pb-free compliance, and validated R_g testing for consistent switching behavior.

Technical Context

This MOSFET uses trench-gate silicon technology to achieve low on-resistance and fast switching dynamics. Its gate charge profile (Q_g = 21–32 nC, Q_gd = 6.4 nC) supports high-frequency PWM operation up to several hundred kHz while minimizing overlap loss.

The device integrates a body diode with V_SD = 0.75–1.1 V at I_S = 2.9 A and t_rr = 55–80 ns, enabling efficient self-driven synchronous rectification in flyback and LLC topologies without external diode replacement.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	20 V - Maximum blocking voltage compatible with 12-V input rails and transient margin in point-of-load converters
R_DS(on) @ 10 V	0.0045 Ω - Enables <100 mW conduction loss at 21 A, critical for thermal management in compact layouts
R_DS(on) @ 4.5 V	0.0068 Ω - Ensures robust turn-on with 3.3-V or 5-V gate drivers, supporting logic-level control
I_D (continuous)	21 A @ T_J = 150 °C - Sustains high-current output stages without derating in thermally constrained SO-8 footprints
Q_g	21–32 nC - Low total gate charge reduces driver power demand and enables faster edge rates in hard-switched designs
t_r/t_f	42–65 ns / 26–40 ns - Fast transitions minimize dead-time losses and improve efficiency in synchronous rectifier configurations
R_thJA	67–80 °C/W - Thermal resistance defines junction-to-ambient rise under PCB copper constraints, guiding heatsinking decisions

Pinout & Package

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

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 7, 8	Drain (D)	Internally paralleled terminals forming low-inductance, high-current path to PCB ground plane via exposed pad
6	Gate (G)	High-impedance control input requiring <100 nA leakage; sensitive to ESD but tolerant of ±20 V rating
Source (S)	Source (S)	Terminal 6 is gate; source connects to pins 1–5 and 7–8 through internal substrate tie - not externally accessible as discrete pin

Key Features

Feature	Design Value
TrenchFET® architecture	Enables sub-5-mΩ R_DS(on) in SO-8, reducing conduction loss by >30% vs. planar MOSFETs at same voltage class
PWM-optimized switching	Q_gd/Q_g ratio of ~30% minimizes Miller-induced shoot-through risk in synchronous rectifier gate-drive timing
100% R_g tested	Guarantees gate resistance between 0.5–2.4 Ω, ensuring predictable turn-on delay and dV/dt immunity
Halogen-free & Pb-free	Complies with IEC 61249-2-21 and RoHS Directive 2011/65/EU without compromising thermal or electrical performance

Applications

Server VRM Output Stage	USB PD 3.0 Buck Converter
Use Scenario: High-current, high-efficiency 12-V to 1.8-V conversion delivering up to 60 A per phase in multi-phase CPU core supplies. IC Role / Device Role / Timing Role: Low-side synchronous rectifier switch operating at 300–600 kHz with adaptive dead-time control. Use Value: SI4408DY-T1-GE3's 0.0045 Ω R_DS(on) cuts conduction loss by ~45% versus typical 7-mΩ alternatives, directly improving full-load efficiency by 0.8–1.2%.	Use Scenario: Compact 20-V input buck converter powering USB-C ports with programmable output (3.3–21 V) and 3-A continuous load. IC Role / Device Role / Timing Role: Primary power switch in fixed-frequency (500 kHz) synchronous buck topology with integrated controller. Use Value: SI4408DY-T1-GE3's 4.5-V R_DS(on) of 0.0068 Ω ensures full enhancement using standard 5-V gate drivers, eliminating need for bootstrap or level-shift circuitry.
Industrial PLC Power Module	Automotive Infotainment DC/DC
Use Scenario: 24-V industrial input converted to isolated 5-V/3.3-V rails for microcontroller and I/O conditioning in harsh environments. IC Role / Device Role / Timing Role: Secondary-side synchronous rectifier in active-clamp forward or flyback converter operating at 100–250 kHz. Use Value: SI4408DY-T1-GE3's 150 °C rated junction temperature and -55 °C to +150 °C storage range support extended thermal cycling in uncooled enclosures.	Use Scenario: 12-V automotive battery input stepped down to 5-V USB host rail in head unit or display module with ASIL-B functional safety requirements. IC Role / Device Role / Timing Role: High-side switch in pre-regulator stage feeding downstream LDOs or buck controllers. Use Value: SI4408DY-T1-GE3's 100% R_g test and guaranteed V_GS(th) (1.0 V min) ensure reliable turn-on across battery voltage sag (down to 6 V) and temperature extremes (-40 °C to +105 °C ambient).

Server VRM Output Stage

USB PD 3.0 Buck Converter

Use Scenario: High-current, high-efficiency 12-V to 1.8-V conversion delivering up to 60 A per phase in multi-phase CPU core supplies.

IC Role / Device Role / Timing Role: Low-side synchronous rectifier switch operating at 300–600 kHz with adaptive dead-time control.

Use Value: SI4408DY-T1-GE3's 0.0045 Ω R_DS(on) cuts conduction loss by ~45% versus typical 7-mΩ alternatives, directly improving full-load efficiency by 0.8–1.2%.

Use Scenario: Compact 20-V input buck converter powering USB-C ports with programmable output (3.3–21 V) and 3-A continuous load.

IC Role / Device Role / Timing Role: Primary power switch in fixed-frequency (500 kHz) synchronous buck topology with integrated controller.

Use Value: SI4408DY-T1-GE3's 4.5-V R_DS(on) of 0.0068 Ω ensures full enhancement using standard 5-V gate drivers, eliminating need for bootstrap or level-shift circuitry.

Industrial PLC Power Module

Automotive Infotainment DC/DC

Use Scenario: 24-V industrial input converted to isolated 5-V/3.3-V rails for microcontroller and I/O conditioning in harsh environments.

IC Role / Device Role / Timing Role: Secondary-side synchronous rectifier in active-clamp forward or flyback converter operating at 100–250 kHz.

Use Value: SI4408DY-T1-GE3's 150 °C rated junction temperature and -55 °C to +150 °C storage range support extended thermal cycling in uncooled enclosures.

Use Scenario: 12-V automotive battery input stepped down to 5-V USB host rail in head unit or display module with ASIL-B functional safety requirements.

IC Role / Device Role / Timing Role: High-side switch in pre-regulator stage feeding downstream LDOs or buck controllers.

Use Value: SI4408DY-T1-GE3's 100% R_g test and guaranteed V_GS(th) (1.0 V min) ensure reliable turn-on across battery voltage sag (down to 6 V) and temperature extremes (-40 °C to +105 °C ambient).

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 footprint and higher gate drive power; better suited for lower-frequency, higher-current discrete designs	Choose IRF7470PBF only when SO-8 thermal limits are exceeded and board space allows DPAK mounting.
DMN2020LSD-13	R_DS(on) = 0.0052 Ω @ 4.5 V; dual-N configuration in SO-8; no R_g test guarantee	Offers complementary channel for half-bridge integration but lacks single-device validation for critical rectifier roles	Select DMN2020LSD-13 when building dual-switch synchronous buck stages where matched characteristics outweigh individual R_g assurance.

Compared with IRF7470PBF and DMN2020LSD-13, SI4408DY-T1-GE3 provides the lowest R_DS(on) in SO-8 with verified gate resistance and halogen-free compliance-making it optimal for space-constrained, high-efficiency synchronous rectification where thermal density and process consistency are prioritized.

Availability

SI4408DY-T1-GE3 is available at Aetrix Electronics and suitable for server VRMs, USB PD converters, industrial PLC power modules, and automotive infotainment DC/DC supplies requiring stable component supply, long-term manufacturability, and halogen-free compliance.

Supply support for SI4408DY-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, computing, and automotive markets.

The Si4408DY product line targets high-efficiency, surface-mount power conversion-designed specifically for synchronous rectification in DC/DC converters where low R_DS(on), fast switching, and gate-drive simplicity are essential.

FAQ

What is the maximum continuous drain current rating for SI4408DY-T1-GE3 at 70 °C ambient?

The SI4408DY-T1-GE3 supports 17 A continuous drain current at T_A = 70 °C with proper PCB copper area (1" × 1" FR4). This rating assumes steady-state thermal conditions and accounts for R_thJA = 67–80 °C/W. Derating curves in the datasheet confirm linear reduction from 21 A at 25 °C to 17 A at 70 °C ambient, making SI4408DY-T1-GE3 suitable for thermally dense power modules without forced airflow.

Does SI4408DY-T1-GE3 have a specified body diode reverse recovery time?

Yes, the SI4408DY-T1-GE3 specifies source-drain reverse recovery time (t_rr) as 55–80 ns under conditions of I_F = 2.9 A and dI/dt = 100 A/µs. This parameter is measured with the gate shorted to source and reflects the intrinsic speed of the parasitic body diode-critical for evaluating performance in self-driven synchronous rectifier circuits where diode conduction precedes gate turn-on.

Is SI4408DY-T1-GE3 qualified for automotive applications?

The SI4408DY-T1-GE3 is not AEC-Q101 qualified. While it operates across -55 °C to +150 °C junction temperature and meets Pb-free/halogen-free standards, Vishay does not list it in their AEC-Q101 stress-tested portfolio. For automotive infotainment or body electronics, SI4408DY-T1-GE3 may be used at system level with additional qualification-but design-in requires customer-specific reliability validation per ISO/TS 16949 processes.

What is the gate threshold voltage range for SI4408DY-T1-GE3?

The SI4408DY-T1-GE3 has a gate threshold voltage (V_GS(th)) minimum of 1.0 V, typical of 1.4 V, and maximum of 2.0 V, measured at V_DS = V_GS and I_D = 250 µA. This range ensures reliable turn-on with 3.3-V logic drivers while maintaining noise immunity-confirmed across -55 °C to +150 °C junction temperature per the datasheet's threshold variance plot.

How does the SO-8 package of SI4408DY-T1-GE3 handle thermal dissipation?

The SI4408DY-T1-GE3 uses a standard SO-8 (MS-012) package with an exposed drain pad that must be soldered to a large PCB copper area for effective heat transfer. With 1" × 1" FR4 board, R_thJA is 67–80 °C/W; adding thermal vias under the pad can reduce this to ~45 °C/W. The device's R_thJF (junction-to-foot) is 13–16 °C/W, confirming the drain pad as the primary thermal path-so layout must prioritize thermal copper, not just signal routing.

SI4408DY-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):: 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-GE3 FAQ

1.How can I place an order for SI4408DY-T1-GE3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI4408DY-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 SI4408DY-T1-GE3 reliable?

The price and inventory of SI4408DY-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 SI4408DY-T1-GE3 is usually 5 days.

3.What payment methods are accepted for SI4408DY-T1-GE3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI4408DY-T1-GE3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI4408DY-T1-GE3?

SI4408DY-T1-GE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI4408DY-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 SI4408DY-T1-GE3?

For technical support, including SI4408DY-T1-GE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI4408DY-T1-GE3 requirements.

6.How does Aetrix verify that SI4408DY-T1-GE3 is sourced from the original manufacturer or authorized distributors?

All SI4408DY-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 SI4408DY-T1-GE3 meets industry standards.

7.What is the process for return or replacement of SI4408DY-T1-GE3?

All SI4408DY-T1-GE3 units undergo pre-shipment inspection (PSI). If there is an issue with SI4408DY-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 SI4408DY-T1-GE3 part is unused and in its original packaging.

Return procedure for SI4408DY-T1-GE3:

1.Submit a request within 90 days.

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

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