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

Vishay Siliconix SI4378DY-T1-GE3

Name: SI4378DY-T1-GE3
Brand: Vishay Siliconix
SKU: SI4378DY-T1-GE3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI4378DY-T1-GE3

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

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

Datasheet:: SI4378DY-T1-GE3.pdf

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

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Product details

Overview

SI4378DY-T1-GE3 from Vishay Siliconix is an N-channel 20-V TrenchFET® Gen II power MOSFET in SO-8 package, optimized for synchronous rectification and point-of-load DC/DC conversion. It delivers R_DS(on) = 0.0027 Ω at V_GS = 4.5 V, supports 25 A continuous drain current (T_J = 150 °C), and features ultra-low gate charge (Q_g = 55 nC) for high-efficiency switching in compact power stages.

For engineers reviewing the SI4378DY-T1-GE3 datasheet, SI4378DY-T1-GE3 pinout, SI4378DY-T1-GE3 application, or SI4378DY-T1-GE3 equivalent, key selection criteria include its halogen-free and lead-free compliance, junction-to-foot thermal resistance (R_thJF = 13 °C/W typ), and guaranteed 100% R_g testing - critical for stable gate drive timing in high-frequency buck converters.

Technical Context

This MOSFET employs high-density TrenchFET® Gen II technology to achieve low on-resistance while maintaining robust avalanche capability (I_AS = 40 A). Its gate threshold voltage (V_GS(th) = 0.6–1.8 V) enables reliable turn-on with 2.5 V logic-level drive, and its dynamic parameters - including C_iss = 8500 pF and Q_gd/Q_gs ratio of ~0.63 - support fast, low-loss switching in synchronous rectifier topologies.

The device is characterized for operation across -55 °C to +150 °C junction temperature range and rated for 20 V drain-source breakdown. Thermal design is supported by validated junction-to-ambient (R_thJA = 67 °C/W steady-state) and junction-to-foot (R_thJF = 13 °C/W) metrics, enabling accurate thermal modeling on standard FR4 PCBs.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	20 V - Maximum blocking voltage compatible with 12 V input rails and 5 V output synchronous buck stages
R_DS(on)	0.0027 Ω @ V_GS = 4.5 V, I_D = 25 A - Enables <10 mW conduction loss at 20 A, reducing thermal load in dense layouts
I_D (cont)	25 A @ T_J = 150 °C - Sustains high-current PoL loads without derating on 1" × 1" FR4 board
Q_g	55 nC @ V_DS = 10 V, V_GS = 4.5 V - Minimizes gate drive power and enables >1 MHz switching with moderate driver strength
R_thJF	13 °C/W (typ) - Provides direct thermal path to PCB copper via exposed drain pad, improving heat extraction over standard SO-8
V_GS(th)	0.6–1.8 V - Ensures full enhancement with 2.5 V or 3.3 V controller outputs, eliminating need for level-shifting
I_AS	40 A - Withstands repetitive inductive energy spikes in synchronous rectifier failure modes without catastrophic failure

Pinout & Package

SI4378DY-T1-GE3 uses a standard SO-8 (MS-012) surface-mount package with exposed drain pad for enhanced thermal performance. The package dimensions conform to JEDEC MS-012, with 1.27 mm pitch and 4.8–5.0 mm body width.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 8	Drain (D)	Internally connected to exposed metal pad - primary current path and thermal conduction path to PCB
7	Gate (G)	Control terminal requiring low-impedance drive; R_g = 0.8–2.0 Ω ensures predictable switching transitions
Source (S)	Source (S)	Pins 1–3 are source-connected; provides return path for load current and reference for gate drive

Key Features

Feature	Design Value
Halogen-free & Pb-free construction	Complies with IEC 61249-2-21 and RoHS - eliminates hazardous substances without compromising thermal or electrical performance
100% R_g tested	Guarantees gate resistance between 0.8–2.0 Ω - ensures consistent turn-on/turn-off timing across production lots
Optimized Q_g/R_DS(on) ratio	55 nC total gate charge with 2.7 mΩ on-resistance - balances switching loss and conduction loss for high-efficiency PoL designs
TrenchFET® Gen II architecture	Enables ultra-low R_DS(on) in SO-8 footprint - achieves performance previously requiring larger packages like PowerPAK®
Robust safe operating area (SOA)	Rated for 70 A pulsed drain current and 40 A avalanche current - withstands transient overload conditions in DC/DC converters

Applications

Synchronous Rectifier in DC/DC Converters	Point-of-Load (PoL) Voltage Regulator
Use Scenario: Replaces Schottky diode in secondary-side synchronous rectification of isolated DC/DC converters (e.g., 12 V input → 3.3 V/5 V output). IC Role / Device Role / Timing Role: Low-side N-channel MOSFET controlled by PWM controller's synchronous rectifier output signal. Use Value: Reduces forward voltage drop from ~0.4 V (Schottky) to <50 mV at 20 A, cutting conduction losses by >85 % and improving efficiency by 2–3 % at full load.	Use Scenario: High-current output stage in non-isolated buck regulators powering FPGAs, ASICs, or microprocessors. IC Role / Device Role / Timing Role: Power switch in high-side or low-side position, driven by integrated or external gate driver. Use Value: Enables 25 A continuous output with minimal thermal margin on standard PCBs due to R_thJF = 13 °C/W and low R_DS(on).
Hot-Swap Controller Protection FET	OR-ing Diode Replacement in Redundant Supplies
Use Scenario: In-line current-limiting FET in 12 V hot-swap modules protecting backplane or server motherboard inputs. IC Role / Device Role / Timing Role: Linear-mode controlled FET limiting inrush and fault current during insertion or overcurrent events. Use Value: Low R_DS(on) minimizes voltage drop during normal operation; guaranteed V_GS(th) ensures predictable turn-on behavior under varying control voltages.	Use Scenario: Replaces discrete OR-ing diodes in dual-redundant 12 V power supplies feeding common bus. IC Role / Device Role / Timing Role: Back-to-back configured N-channel MOSFET acting as ideal diode with reverse current blocking. Use Value: Eliminates ~0.4 V diode drop per rail, reducing power loss and heat generation - especially critical in high-density telecom and datacom systems.

Synchronous Rectifier in DC/DC Converters

Point-of-Load (PoL) Voltage Regulator

Use Scenario: Replaces Schottky diode in secondary-side synchronous rectification of isolated DC/DC converters (e.g., 12 V input → 3.3 V/5 V output).

IC Role / Device Role / Timing Role: Low-side N-channel MOSFET controlled by PWM controller's synchronous rectifier output signal.

Use Value: Reduces forward voltage drop from ~0.4 V (Schottky) to <50 mV at 20 A, cutting conduction losses by >85 % and improving efficiency by 2–3 % at full load.

Use Scenario: High-current output stage in non-isolated buck regulators powering FPGAs, ASICs, or microprocessors.

IC Role / Device Role / Timing Role: Power switch in high-side or low-side position, driven by integrated or external gate driver.

Use Value: Enables 25 A continuous output with minimal thermal margin on standard PCBs due to R_thJF = 13 °C/W and low R_DS(on).

Hot-Swap Controller Protection FET

OR-ing Diode Replacement in Redundant Supplies

Use Scenario: In-line current-limiting FET in 12 V hot-swap modules protecting backplane or server motherboard inputs.

IC Role / Device Role / Timing Role: Linear-mode controlled FET limiting inrush and fault current during insertion or overcurrent events.

Use Value: Low R_DS(on) minimizes voltage drop during normal operation; guaranteed V_GS(th) ensures predictable turn-on behavior under varying control voltages.

Use Scenario: Replaces discrete OR-ing diodes in dual-redundant 12 V power supplies feeding common bus.

IC Role / Device Role / Timing Role: Back-to-back configured N-channel MOSFET acting as ideal diode with reverse current blocking.

Use Value: Eliminates ~0.4 V diode drop per rail, reducing power loss and heat generation - especially critical in high-density telecom and datacom systems.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
Si4376DY-T1-GE3	Same SO-8 package, but 30 V V_DS, higher R_DS(on) = 0.0045 Ω @ 4.5 V, lower I_D = 20 A	Better suited for 24 V input systems where higher breakdown margin is required	Select when system input exceeds 20 V or when slightly relaxed on-conduction loss is acceptable for improved voltage headroom
IRF7470PBF	SO-8, 20 V, R_DS(on) = 0.0032 Ω @ 4.5 V, Q_g = 62 nC, no halogen-free certification	Lacks IEC 61249-2-21 compliance; requires verification for halogen-sensitive end markets	Consider only if halogen-free requirement is waived and minor increase in gate drive loss is acceptable

Compared with Si4376DY-T1-GE3 and IRF7470PBF, SI4378DY-T1-GE3 offers the lowest R_DS(on) and best thermal resistance in its class, making it optimal for space-constrained, high-efficiency 12 V PoL and synchronous rectifier designs where halogen-free compliance is mandatory.

Availability

SI4378DY-T1-GE3 is available at Aetrix Electronics and suitable for synchronous rectification, point-of-load regulation, and hot-swap protection applications requiring stable component supply, long-term lifecycle assurance, and full halogen-free compliance.

Supply support for SI4378DY-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 Si4378DY belongs to Vishay's TrenchFET® Gen II power MOSFET family, engineered specifically for high-current, high-efficiency DC/DC conversion in space-constrained applications such as server VRMs, telecom power supplies, and portable electronics.

FAQ

What is the maximum continuous drain current rating for SI4378DY-T1-GE3 at 70 °C ambient temperature?

The SI4378DY-T1-GE3 supports 20 A continuous drain current at T_A = 70 °C, as specified in its Absolute Maximum Ratings table. This rating assumes surface mounting on a 1" × 1" FR4 board with standard copper pour and accounts for thermal derating due to reduced heat dissipation at elevated ambient temperatures. The device's R_thJA = 67 °C/W (steady state) determines this limit, and actual achievable current depends on PCB layout and airflow.

Does SI4378DY-T1-GE3 have an integrated body diode, and what is its forward voltage?

Yes, SI4378DY-T1-GE3 includes a built-in parasitic body diode with V_SD = 0.72–1.1 V at I_S = 2.9 A and V_GS = 0 V. This diode enables freewheeling current paths in synchronous rectifier and buck converter topologies. Its low forward voltage - typical 0.85 V - reduces conduction loss compared to external Schottky diodes, particularly in low-duty-cycle applications where body diode conduction occurs.

Is SI4378DY-T1-GE3 suitable for 2.5 V gate drive applications?

Yes, SI4378DY-T1-GE3 is fully compatible with 2.5 V gate drive, delivering R_DS(on) = 0.0042 Ω at V_GS = 2.5 V and I_D = 22 A. Its gate threshold voltage range (0.6–1.8 V) ensures strong enhancement well below 2.5 V, and its low Q_g (55 nC) minimizes driver loading. This makes SI4378DY-T1-GE3 ideal for use with modern low-voltage controllers and integrated power stages.

What is the avalanche energy rating of SI4378DY-T1-GE3, and how is it tested?

SI4378DY-T1-GE3 is rated for single-pulse avalanche current I_AS = 40 A with L = 0.1 mH, corresponding to an avalanche energy of approximately 80 mJ per pulse. This rating is verified per JEDEC JESD24-11 using standardized inductive switching tests and reflects the device's ability to absorb inductive energy without failure during abnormal conditions such as short-circuit events or controller timing faults.

How does the exposed drain pad on SI4378DY-T1-GE3 improve thermal performance?

The exposed drain pad on SI4378DY-T1-GE3 provides a low-resistance thermal path from the silicon die directly to the PCB copper plane, achieving R_thJF = 13 °C/W (typical). This is significantly lower than standard SO-8 junction-to-ambient resistance and allows more efficient heat transfer than relying solely on leads and package molding compound - critical for sustaining high current in compact PoL designs without forced air cooling.

SI4378DY-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:: 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-GE3 FAQ

1.How can I place an order for SI4378DY-T1-GE3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI4378DY-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 SI4378DY-T1-GE3 reliable?

The price and inventory of SI4378DY-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 SI4378DY-T1-GE3 is usually 5 days.

3.What payment methods are accepted for SI4378DY-T1-GE3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI4378DY-T1-GE3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI4378DY-T1-GE3?

SI4378DY-T1-GE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI4378DY-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 SI4378DY-T1-GE3?

For technical support, including SI4378DY-T1-GE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI4378DY-T1-GE3 requirements.

6.How does Aetrix verify that SI4378DY-T1-GE3 is sourced from the original manufacturer or authorized distributors?

All SI4378DY-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 SI4378DY-T1-GE3 meets industry standards.

7.What is the process for return or replacement of SI4378DY-T1-GE3?

All SI4378DY-T1-GE3 units undergo pre-shipment inspection (PSI). If there is an issue with SI4378DY-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 SI4378DY-T1-GE3 part is unused and in its original packaging.

Return procedure for SI4378DY-T1-GE3:

1.Submit a request within 90 days.

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

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