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

Vishay Siliconix SI4378DY-T1-E3

Name: SI4378DY-T1-E3
Brand: Vishay Siliconix
SKU: SI4378DY-T1-E3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI4378DY-T1-E3

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

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

Datasheet:: SI4378DY-T1-E3.pdf

Description:: MOSFET N-CH 20V 19A 8SO

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Product details

Overview

SI4378DY-T1-E3 from Vishay Siliconix is an N-channel 20-V (D-S) TrenchFET® Gen II power MOSFET in SO-8 package, delivering 25 A continuous drain current at T_J = 150 °C, R_DS(on) = 0.0027 Ω at V_GS = 4.5 V, and optimized for synchronous rectification in DC/DC converters.

For engineers reviewing the SI4378DY-T1-E3 datasheet, SI4378DY-T1-E3 pinout, SI4378DY-T1-E3 application, or SI4378DY-T1-E3 equivalent, key selection criteria include low R_DS(on) at 2.5 V gate drive, 100% R_g tested gate resistance, and thermal performance validated on 1" × 1" FR4 board per Vishay Document 72918 Rev. C.

Technical Context

This MOSFET uses high-density TrenchFET® Gen II technology to achieve ultra-low on-resistance with gate charge optimization (Q_g = 55 nC, Q_gd = 10 nC) and fast switching (t_r = 65–100 ns, t_f = 50–80 ns). It supports operation down to V_GS(th) = 0.6 V min and handles pulsed drain currents up to 70 A.

The device features a robust safe operating area (SOA) with DC, 10 ms, and single-pulse limits defined at T_C = 25 °C, and includes integrated body diode with V_SD = 0.72–1.1 V at I_S = 2.9 A and trr = 50–80 ns - critical for high-efficiency synchronous rectification topologies.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	20 V - maximum blocking voltage compatible with 12 V and 5 V input rails in POL converters
R_DS(on)	0.0027 Ω @ V_GS = 4.5 V, I_D = 25 A - enables <1 W conduction loss at 25 A
I_D (continuous)	25 A @ T_J = 150 °C - supports high-current output stages without forced air cooling
Q_g	55 nC @ V_DS = 10 V - balances switching speed and gate driver power requirements
V_GS(th)	0.6–1.8 V - ensures reliable turn-on with low-voltage controllers (e.g., 3.3 V logic)
R_thJA	67 °C/W (steady state) - defines thermal derating on standard FR4 PCBs
V_SD	0.72–1.1 V @ I_S = 2.9 A - low forward drop improves reverse recovery efficiency in synchronous mode

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, 7, 8	Drain (D)	Internally connected to common drain terminal and exposed pad - primary current path and thermal conduction path to PCB
6	Gate (G)	Control terminal requiring ≤ ±12 V drive; 100% R_g tested (0.8–2.0 Ω) for consistent switching behavior
Source (S)	Source (S)	Terminal 6 is gate only; source is pins 1–5, 7, 8 - no dedicated source pin; source connects via internal bonding to drain-side leads and substrate

Key Features

Feature	Design Value
Ultra-low R_DS(on)	0.0027 Ω at 4.5 V gate drive enables >95% efficiency in 12 V → 1.2 V POL converters at 25 A
Q_g-optimized structure	55 nC total gate charge reduces switching losses while maintaining manageable gate drive strength requirements
100% R_g tested	Guaranteed gate resistance of 0.8–2.0 Ω eliminates variability in rise/fall time across production lots
TrenchFET® Gen II process	Enables stable R_DS(on) over temperature (normalized to 1.0 at 25 °C, ~1.4 at 125 °C)
Halogen-free option available	Si4378DY-T1-GE3 variant meets IEC 61249-2-21; this part (T1-E3) is Pb-free but not halogen-free

Applications

Server VRM Synchronous Rectifier	Industrial DC/DC Converter
Use Scenario: High-current, high-efficiency 12 V to 1.2 V conversion in server CPU voltage regulator modules. IC Role / Device Role / Timing Role: Primary synchronous rectifier switch replacing Schottky diode in buck converter low-side position. Use Value: R_DS(on) = 0.0027 Ω at 4.5 V reduces conduction loss by >60% vs. typical 40 V Schottky, directly improving VRM thermal margin.	Use Scenario: Isolated 48 V to 12 V DC/DC supply in programmable logic controller (PLC) power stage. IC Role / Device Role / Timing Role: Secondary-side synchronous rectifier in forward or active-clamp forward topology. Use Value: Low V_GS(th) (0.6 V min) ensures reliable turn-on with gate drive derived from transformer reset winding, eliminating external bias supply.
Point-of-Load Regulator	Telecom Base Station PSU
Use Scenario: Compact 5 V to 0.85 V POL module for FPGA core power in telecom line cards. IC Role / Device Role / Timing Role: Low-side switch in multiphase buck converter with 2.5 V gate drive capability. Use Value: R_DS(on) = 0.0042 Ω at V_GS = 2.5 V enables efficient operation with low-voltage gate drivers, reducing driver IC count and BOM cost.	Use Scenario: 54 V input to 12 V intermediate bus converter in macro base station power system. IC Role / Device Role / Timing Role: Synchronous rectifier in LLC resonant converter secondary side. Use Value: Fast reverse recovery (trr = 50–80 ns) and low Q_rr minimize switching losses during zero-voltage switching transitions, sustaining >94% peak efficiency.

Server VRM Synchronous Rectifier

Industrial DC/DC Converter

Use Scenario: High-current, high-efficiency 12 V to 1.2 V conversion in server CPU voltage regulator modules.

IC Role / Device Role / Timing Role: Primary synchronous rectifier switch replacing Schottky diode in buck converter low-side position.

Use Value: R_DS(on) = 0.0027 Ω at 4.5 V reduces conduction loss by >60% vs. typical 40 V Schottky, directly improving VRM thermal margin.

Use Scenario: Isolated 48 V to 12 V DC/DC supply in programmable logic controller (PLC) power stage.

IC Role / Device Role / Timing Role: Secondary-side synchronous rectifier in forward or active-clamp forward topology.

Use Value: Low V_GS(th) (0.6 V min) ensures reliable turn-on with gate drive derived from transformer reset winding, eliminating external bias supply.

Point-of-Load Regulator

Telecom Base Station PSU

Use Scenario: Compact 5 V to 0.85 V POL module for FPGA core power in telecom line cards.

IC Role / Device Role / Timing Role: Low-side switch in multiphase buck converter with 2.5 V gate drive capability.

Use Value: R_DS(on) = 0.0042 Ω at V_GS = 2.5 V enables efficient operation with low-voltage gate drivers, reducing driver IC count and BOM cost.

Use Scenario: 54 V input to 12 V intermediate bus converter in macro base station power system.

IC Role / Device Role / Timing Role: Synchronous rectifier in LLC resonant converter secondary side.

Use Value: Fast reverse recovery (trr = 50–80 ns) and low Q_rr minimize switching losses during zero-voltage switching transitions, sustaining >94% peak efficiency.

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) = 0.0032 Ω @ 4.5 V, Q_g = 42 nC, SO-8 package	Lower gate charge improves switching efficiency but higher R_DS(on) increases conduction loss at >20 A	Prefer IRF7470PBF where gate drive strength is limited and load current stays below 20 A
DMN2020LFG-7	R_DS(on) = 0.0025 Ω @ 4.5 V, Q_g = 60 nC, lead-free and halogen-free, same SO-8 footprint	Marginally lower R_DS(on) but higher Q_g increases driver loss; fully compliant with IEC 61249-2-21	Choose DMN2020LFG-7 when halogen-free compliance is mandatory and thermal design accommodates extra gate drive power

Compared with IRF7470PBF and DMN2020LFG-7, SI4378DY-T1-E3 offers the best balance of ultra-low R_DS(on), moderate Q_g, and proven thermal performance on standard FR4 - making it optimal for high-current, thermally constrained POL designs where both conduction and switching losses must be minimized simultaneously.

Availability

SI4378DY-T1-E3 is available at Aetrix Electronics and suitable for server VRMs, industrial DC/DC converters, and point-of-load regulators requiring stable component supply and verified thermal performance on 1" × 1" FR4 boards.

Supply support for SI4378DY-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 and passive components, specializing in high-reliability power MOSFETs, diodes, and optoelectronics for industrial, automotive, and computing markets.

The Si4378DY product line targets high-efficiency, high-current DC/DC conversion with emphasis on low-voltage gate drive compatibility, thermal robustness, and production consistency - specifically engineered for synchronous rectification in next-generation power supplies.

FAQ

What is the maximum continuous drain current rating for SI4378DY-T1-E3 at 70 °C ambient?

The SI4378DY-T1-E3 supports 20 A continuous drain current at T_A = 70 °C, as specified in the Absolute Maximum Ratings table under "Continuous Drain Current (T_J = 150 °C)" with derating applied per thermal resistance R_thJA = 67 °C/W. This value assumes standard mounting on 1" × 1" FR4 board per Vishay test conditions in Document 72918 Rev. C.

Does SI4378DY-T1-E3 have a guaranteed gate resistance specification?

Yes, SI4378DY-T1-E3 undergoes 100% R_g testing with a guaranteed range of 0.8 Ω to 2.0 Ω, as stated in the Features section and confirmed in the Specifications table under "Gate Resistance". This ensures consistent gate drive timing and predictable switching behavior across all units.

Is SI4378DY-T1-E3 suitable for 2.5 V gate drive applications?

Yes, SI4378DY-T1-E3 is explicitly characterized for 2.5 V gate drive: R_DS(on) = 0.0042 Ω at V_GS = 2.5 V and I_D = 22 A, and V_GS(th) minimum is 0.6 V. Its low threshold enables full enhancement with 2.5 V logic-level controllers commonly used in POL regulators.

What is the thermal resistance from junction to ambient for SI4378DY-T1-E3 in steady-state conditions?

The steady-state maximum junction-to-ambient thermal resistance (R_thJA) for SI4378DY-T1-E3 is 80 °C/W, with a typical value of 67 °C/W, measured on a 1" × 1" FR4 board per Vishay's test method. This value is critical for calculating junction temperature rise under real-world PCB layout conditions.

How does the body diode performance of SI4378DY-T1-E3 compare to standard Schottky rectifiers?

The SI4378DY-T1-E3 body diode has V_SD = 0.72–1.1 V at I_S = 2.9 A and reverse recovery time t_rr = 50–80 ns - significantly faster and lower forward drop than most 20 V Schottky diodes used in synchronous rectification. This enables higher efficiency and reduced EMI in hard-switched and resonant topologies.

SI4378DY-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:: 19A (Ta)

Drive Voltage (Max Rds On, Min Rds On):: 2.5V, 4.5V

Rds On (Max) @ Id, Vgs:: 2.7mOhm @ 25A, 4.5V

Vgs(th) (Max) @ Id:: 1.8V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 55 nC @ 4.5 V

Vgs (Max):: ±12V

Input Capacitance (Ciss) (Max) @ Vds:: 8500 pF @ 10 V

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

SI4378DY-T1-E3 FAQ

1.How can I place an order for SI4378DY-T1-E3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI4378DY-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 SI4378DY-T1-E3 reliable?

The price and inventory of SI4378DY-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 SI4378DY-T1-E3 is usually 5 days.

3.What payment methods are accepted for SI4378DY-T1-E3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI4378DY-T1-E3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI4378DY-T1-E3?

SI4378DY-T1-E3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI4378DY-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 SI4378DY-T1-E3?

For technical support, including SI4378DY-T1-E3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI4378DY-T1-E3 requirements.

6.How does Aetrix verify that SI4378DY-T1-E3 is sourced from the original manufacturer or authorized distributors?

All SI4378DY-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 SI4378DY-T1-E3 meets industry standards.

7.What is the process for return or replacement of SI4378DY-T1-E3?

All SI4378DY-T1-E3 units undergo pre-shipment inspection (PSI). If there is an issue with SI4378DY-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 SI4378DY-T1-E3 part is unused and in its original packaging.

Return procedure for SI4378DY-T1-E3:

1.Submit a request within 90 days.

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

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