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

Vishay Siliconix SI4778DY-T1-GE3

Name: SI4778DY-T1-GE3
Brand: Vishay Siliconix
SKU: SI4778DY-T1-GE3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI4778DY-T1-GE3

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

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

Datasheet:: SI4778DY-T1-GE3.pdf

Description:: MOSFET N-CH 25V 8A 8SO

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Product details

Overview

SI4778DY-T1-GE3 from Vishay Siliconix is an N-channel 25-V TrenchFET® Power MOSFET in SO-8 package, with R_DS(on) = 0.023 Ω at V_GS = 10 V, 8 A continuous drain current (package-limited), and 5.5 nC total gate charge - optimized for high-efficiency DC/DC converter switching in notebook system power rails.

For engineers reviewing the SI4778DY-T1-GE3 datasheet, SI4778DY-T1-GE3 pinout, SI4778DY-T1-GE3 application, or SI4778DY-T1-GE3 equivalent, key selection criteria include its halogen-free and lead-free compliance, low R_DS(on) at 4.5 V drive, robust UIS rating, and thermal resistance (R_thJA = 53 °C/W max) under surface-mount conditions.

Technical Context

This MOSFET employs trench-gate silicon technology to achieve low on-resistance and fast switching with controlled Q_g/Q_gd ratio (5.5 nC / 1.5 nC at 4.5 V), supporting efficient synchronous rectification in buck converters. Its V_GS(th) of 1.0–2.2 V enables reliable turn-on with standard logic-level gate drivers.

The device features 100% R_g and UIS tested units, a body diode with t_rr = 15–30 ns and Q_rr = 8–16 nC, and absolute maximum ratings including V_DS = 25 V, V_GS = ±16 V, and T_J = –55 to +150 °C - suitable for thermally constrained portable power stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	25 V - defines maximum blocking voltage in high-side or low-side switch configurations
R_DS(on)	0.023 Ω @ V_GS = 10 V - enables <190 mW conduction loss at 8 A, critical for thermal management
I_D (continuous)	8 A @ T_C = 25 °C - package-limited current rating for SO-8 footprint without external heatsink
Q_g	5.5 nC @ V_GS = 4.5 V - determines gate drive power and switching speed in 3.3 V–5 V control systems
R_thJA	53 °C/W (max) - sets worst-case junction-to-ambient rise under 1"×1" FR4 mounting, guiding PCB copper area design
V_GS(th)	1.0–2.2 V - ensures full enhancement with common microcontroller GPIO or PWM controller outputs
t_rr	15–30 ns - minimizes body diode reverse recovery loss during hard-switched freewheeling

Pinout & Package

SO-8 (MS-012) surface-mount package with exposed drain pad (pin 1–4 and 6–8 connected to drain); 5.0 mm × 4.0 mm footprint, 1.75 mm max height, JEDEC-compliant lead pitch (1.27 mm).

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 6, 7, 8	Drain (D)	High-current output node; electrically tied to exposed thermal pad - must be soldered to large copper pour for thermal performance
5	Gate (G)	Control input; requires low-impedance drive due to 2.5–3.8 Ω intrinsic gate resistance
Source (S)	Source (S)	Reference node for gate drive and current sensing; pins not assigned - internal connection only

Key Features

Feature	Design Value
TrenchFET® construction	Delivers industry-leading R_DS(on) × Q_g figure-of-merit for 25 V class, reducing combined conduction and switching losses
100% R_g and UIS tested	Ensures gate robustness against transient overvoltage and single-pulse avalanche energy (E_AS = 1.25 mJ) in real-world fault conditions
Halogen-free & Pb-free	Complies with IEC 61249-2-21 and RoHS Directive 2011/65/EU - required for consumer notebook and gaming platform certifications
Low V_GS(th) variation	1.0–2.2 V range supports stable turn-on across temperature (–55 to +150 °C) without gate driver overdesign

Applications

DC/DC Converter	Gaming Power Delivery
Use Scenario: Synchronous buck converter in CPU/GPU VRM for mid-tier gaming laptops. IC Role / Device Role / Timing Role: Low-side switch handling high-frequency (300–600 kHz), high-current (up to 8 A) freewheeling path. Use Value: 0.023 Ω R_DS(on) at 10 V reduces conduction loss by >35% vs. legacy 30 mΩ alternatives, directly improving VRM efficiency and thermal margin.	Use Scenario: Point-of-load regulator supplying GPU memory subsystem in compact gaming notebooks. IC Role / Device Role / Timing Role: High-side switch in compact 25 V input buck stage with tight layout constraints. Use Value: SO-8 package with integrated drain pad enables direct thermal coupling to PCB ground plane, sustaining 8 A continuous current without discrete heatsink.
Notebook System Power	Portable SSD Power Management
Use Scenario: Main 5 V/3.3 V system rail generation from battery or adapter input in ultrabooks. IC Role / Device Role / Timing Role: Secondary-side switch in dual-phase interleaved converter for low ripple and fast transient response. Use Value: 5.5 nC Q_g at 4.5 V allows clean switching with low-power gate drivers (e.g., Si823x isolators), minimizing driver supply load.	Use Scenario: Load switch controlling 3.3 V power to NVMe SSD module during sleep/wake transitions. IC Role / Device Role / Timing Role: Hot-swap enable FET with controlled turn-on slew rate via gate resistor. Use Value: Body diode t_rr ≤ 30 ns prevents shoot-through during bidirectional current transients in PCIe link power sequencing.

DC/DC Converter

Gaming Power Delivery

Use Scenario: Synchronous buck converter in CPU/GPU VRM for mid-tier gaming laptops.

IC Role / Device Role / Timing Role: Low-side switch handling high-frequency (300–600 kHz), high-current (up to 8 A) freewheeling path.

Use Value: 0.023 Ω R_DS(on) at 10 V reduces conduction loss by >35% vs. legacy 30 mΩ alternatives, directly improving VRM efficiency and thermal margin.

Use Scenario: Point-of-load regulator supplying GPU memory subsystem in compact gaming notebooks.

IC Role / Device Role / Timing Role: High-side switch in compact 25 V input buck stage with tight layout constraints.

Use Value: SO-8 package with integrated drain pad enables direct thermal coupling to PCB ground plane, sustaining 8 A continuous current without discrete heatsink.

Notebook System Power

Portable SSD Power Management

Use Scenario: Main 5 V/3.3 V system rail generation from battery or adapter input in ultrabooks.

IC Role / Device Role / Timing Role: Secondary-side switch in dual-phase interleaved converter for low ripple and fast transient response.

Use Value: 5.5 nC Q_g at 4.5 V allows clean switching with low-power gate drivers (e.g., Si823x isolators), minimizing driver supply load.

Use Scenario: Load switch controlling 3.3 V power to NVMe SSD module during sleep/wake transitions.

IC Role / Device Role / Timing Role: Hot-swap enable FET with controlled turn-on slew rate via gate resistor.

Use Value: Body diode t_rr ≤ 30 ns prevents shoot-through during bidirectional current transients in PCIe link power sequencing.

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel 25 V power MOSFET applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
Si7157DP-T1-GE3	R_DS(on) = 0.025 Ω @ 10 V; Q_g = 6.3 nC; same SO-8 package but higher R_thJA (58 °C/W max)	Slightly lower current capability (7.5 A) and reduced thermal margin in dense layouts	Acceptable where board space permits minor efficiency trade-off and thermal headroom exists
IRLML6344TRPBF	R_DS(on) = 0.035 Ω @ 4.5 V; Q_g = 5.2 nC; Micro3 package (smaller, no exposed drain)	Limited to 4.3 A continuous; lacks UIS rating and halogen-free certification	Only suitable for low-power, non-critical loads where footprint reduction outweighs reliability and compliance requirements

Compared with Si7157DP-T1-GE3 and IRLML6344TRPBF, SI4778DY-T1-GE3 delivers superior thermal performance (lower R_thJA), certified halogen-free compliance, and higher avalanche ruggedness - making it the preferred choice for volume notebook and gaming OEM designs requiring long-term supply stability and regulatory alignment.

Availability

SI4778DY-T1-GE3 is available at Aetrix Electronics and suitable for DC/DC converter design, notebook system power architecture, and gaming platform power delivery requiring stable component supply, full RoHS/halogen-free compliance, and verified thermal performance on standard FR4 PCBs.

Supply support for SI4778DY-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 demanding industrial and computing applications.

The SI4778DY product line targets high-efficiency, space-constrained power conversion in portable computing - engineered for low R_DS(on), fast switching, and robust operation in thermally aggressive environments.

FAQ

What is the maximum continuous drain current rating for SI4778DY-T1-GE3 under typical PCB mounting conditions?

The SI4778DY-T1-GE3 is rated for 8 A continuous drain current when mounted on a 1" × 1" FR4 board at T_C = 25 °C, limited by package thermal capacity rather than silicon capability. At T_A = 70 °C, derating reduces this to 6.4 A per datasheet note b and c. This rating assumes proper soldering of the exposed drain pad to a thermal copper area.

Does SI4778DY-T1-GE3 support 3.3 V logic-level gate drive?

Yes, SI4778DY-T1-GE3 is fully specified for 4.5 V gate drive, with R_DS(on) = 0.028 Ω at V_GS = 4.5 V and I_D = 6.3 A. Its V_GS(th) range (1.0–2.2 V) ensures reliable turn-on with 3.3 V microcontroller outputs, though full 8 A current capability requires ≥4.5 V to minimize conduction loss.

What is the significance of the "-GE3" suffix in SI4778DY-T1-GE3?

The "-GE3" suffix denotes that SI4778DY-T1-GE3 is both lead (Pb)-free and halogen-free per IEC 61249-2-21, distinguishing it from the "-E3" variant (Pb-free only). This dual compliance is mandatory for CE-marked consumer electronics, including notebooks and gaming devices sold in EU and other regulated markets.

How does the body diode performance of SI4778DY-T1-GE3 impact synchronous rectifier design?

The SI4778DY-T1-GE3 body diode has t_rr = 15–30 ns and Q_rr = 8–16 nC, enabling low-loss freewheeling in synchronous buck topologies. When used as a synchronous rectifier, its fast recovery minimizes voltage spikes and cross-conduction risk during dead-time transitions - critical for maintaining efficiency above 90% in 300–600 kHz VRMs.

Is SI4778DY-T1-GE3 suitable for automotive infotainment power supplies?

No - SI4778DY-T1-GE3 is not AEC-Q101 qualified and lacks automotive-grade screening, temperature cycling validation, or extended lifetime testing. While its -55 to +150 °C operating range overlaps with some automotive ambient conditions, Vishay positions this part exclusively for commercial computing applications such as notebooks and gaming platforms.

SI4778DY-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):: 25 V

Current - Continuous Drain (Id) @ 25°C:: 8A (Tc)

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

Rds On (Max) @ Id, Vgs:: 23mOhm @ 7A, 10V

Vgs(th) (Max) @ Id:: 2.2V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 18 nC @ 10 V

Vgs (Max):: ±16V

Input Capacitance (Ciss) (Max) @ Vds:: 680 pF @ 13 V

FET Feature:: -

Power Dissipation (Max):: 2.4W (Ta), 5W (Tc)

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

SI4778DY-T1-GE3 FAQ

1.How can I place an order for SI4778DY-T1-GE3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI4778DY-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 SI4778DY-T1-GE3 reliable?

The price and inventory of SI4778DY-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 SI4778DY-T1-GE3 is usually 5 days.

3.What payment methods are accepted for SI4778DY-T1-GE3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI4778DY-T1-GE3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI4778DY-T1-GE3?

SI4778DY-T1-GE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI4778DY-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 SI4778DY-T1-GE3?

For technical support, including SI4778DY-T1-GE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI4778DY-T1-GE3 requirements.

6.How does Aetrix verify that SI4778DY-T1-GE3 is sourced from the original manufacturer or authorized distributors?

All SI4778DY-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 SI4778DY-T1-GE3 meets industry standards.

7.What is the process for return or replacement of SI4778DY-T1-GE3?

All SI4778DY-T1-GE3 units undergo pre-shipment inspection (PSI). If there is an issue with SI4778DY-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 SI4778DY-T1-GE3 part is unused and in its original packaging.

Return procedure for SI4778DY-T1-GE3:

1.Submit a request within 90 days.

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

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