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

Vishay Siliconix SI4398DY-T1-GE3

Name: SI4398DY-T1-GE3
Brand: Vishay Siliconix
SKU: SI4398DY-T1-GE3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI4398DY-T1-GE3

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

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

Datasheet:: SI4398DY-T1-GE3.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SI4398DY-T1-GE3 from Vishay Siliconix is an N-channel enhancement-mode MOSFET optimized for synchronous rectification in low-power DC/DC converters, featuring 20 V V_DS, 0.0028 Ω R_DS(on) at V_GS = 10 V, and 25 A continuous drain current at T_J = 150 °C. Its ultra-low gate charge (Q_gd = 7.5 nC) and halogen-free, RoHS-compliant SO-8 package support high-efficiency POL and OR-ing applications.

For engineers reviewing the SI4398DY-T1-GE3 datasheet, SI4398DY-T1-GE3 pinout, SI4398DY-T1-GE3 application, or SI4398DY-T1-GE3 equivalent, key selection criteria include verified R_DS(on) at 4.5 V (0.0040 Ω), 100 % UIS testing, thermal resistance R_thJA = 67 °C/W (steady state), and SO-8 footprint compatibility with industry-standard layout practices.

Technical Context

This MOSFET employs a trench-gate silicon process to achieve extremely low Q_gd/Q_g ratio (7.5/50 nC), minimizing switching losses in high-frequency synchronous rectifier topologies. Its gate threshold voltage (1.0–3.0 V) ensures robust turn-on control with 4.5 V logic-level drive while maintaining low leakage (I_DSS ≤ 1 µA at 20 V).

The device integrates a fast-recovery body diode (t_rr = 50–80 ns, dI/dt = 100 A/µs) and is 100 % R_g-tested for gate resistance consistency (0.7–2.1 Ω). Thermal design is supported by validated R_thJF = 13–16 °C/W (junction-to-foot), enabling efficient heat transfer through the exposed drain pad in SO-8 packages.

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 POL converters
R_DS(on) @ V_GS = 10 V	0.0028 Ω - Enables <10 mW conduction loss at 25 A, critical for >95 % efficiency in 5–12 V output converters
R_DS(on) @ V_GS = 4.5 V	0.0040 Ω - Ensures reliable on-state performance with standard 5 V or 4.5 V gate drivers without level-shifting
Q_gd	7.5 nC - Reduces Miller-induced switching delay and dv/dt-induced false turn-on in hard-switched topologies
t_r/t_f	15–23 ns / 23–35 ns - Supports >1 MHz switching frequencies with minimal overlap loss in synchronous buck stages
R_thJA	67 °C/W (steady state) - Defines thermal derating curve for 1"×1" FR4 PCB layouts without heatsink
I_D (T_J = 150 °C)	25 A - Specifies maximum continuous current under worst-case junction temperature for reliability-limited operation

Pinout & Package

SI4398DY-T1-GE3 is housed in a surface-mount SO-8 package with exposed drain pad for thermal and electrical performance. Pin 1–8 follow standard SO-8 numbering; pins 1, 2, 3, 4, 5, 6, 7 are source terminals (S), pin 8 is gate (G), and the exposed pad (underside) is drain (D).

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 7	Source (S)	Seven paralleled source connections reduce package inductance and improve current sharing in high-di/dt synchronous rectification
8	Gate (G)	Single gate input with R_g = 0.7–2.1 Ω - enables direct drive from PWM controllers without external gate resistor
Exposed Pad	Drain (D)	Thermally and electrically connected to drain - must be soldered to large copper pour for R_thJF = 13 °C/W performance

Key Features

Feature	Design Value
Ultra-low Q_gd	7.5 nC - Directly reduces switching energy loss and improves EMI profile in high-frequency DC/DC converters
Halogen-free & RoHS	Compliant per IEC 61249-2-21 and Directive 2002/95/EC - meets environmental requirements for industrial and telecom end equipment
100 % UIS tested	Rated for 40 A avalanche current and 80 mJ single-pulse energy - ensures ruggedness against inductive switching transients
Low R_DS(on) at 4.5 V	0.0040 Ω - guarantees stable on-resistance with standard logic-level gate drivers, eliminating need for bootstrap or charge-pump circuits
Fast body diode	t_rr = 50–80 ns - minimizes reverse recovery loss during dead-time conduction in synchronous rectifiers

Applications

Synchronous Rectifier in Low-Power DC/DC Converters	POL (Point-of-Load) Converter
Use Scenario: Replacing Schottky diodes in 5–12 V output buck converters delivering up to 30 A at 300 kHz–1 MHz. IC Role / Device Role / Timing Role: N-channel power switch operating in synchronous rectification mode, driven by controller's low-side gate signal. Use Value: Reduces conduction loss by >60 % vs. 40 V Schottky, enabling >96 % peak efficiency at 20 A load with 12 V input.	Use Scenario: High-density voltage regulation for FPGA, ASIC, or microprocessor cores requiring tight regulation and fast transient response. IC Role / Device Role / Timing Role: Low-side synchronous rectifier in integrated POL modules with integrated inductor and controller. Use Value: Enables compact 12 mm × 12 mm module size via SO-8 footprint and low thermal resistance (R_thJF = 13 °C/W).
OR-ing Circuit in Redundant Power Supplies	Hot-Swap Controller Back-End Switch
Use Scenario: Parallel connection of two 12 V power supplies where only the higher-voltage rail powers the load, preventing backfeed. IC Role / Device Role / Timing Role: Forward-biased N-channel MOSFET acting as ideal diode, controlled by dedicated OR-ing controller. Use Value: Achieves <10 mV forward drop at 20 A (vs. 300–400 mV for Schottky), reducing power loss and thermal stress in 1U server chassis.	Use Scenario: In-rush current limiting and fault isolation in 12 V intermediate bus systems with hot-plug capability. IC Role / Device Role / Timing Role: Load switch placed between hot-swap controller output and downstream capacitive load. Use Value: Withstands 70 A pulsed drain current (I_DM) and 40 A avalanche current, surviving repeated hot-insertion surges without failure.

Synchronous Rectifier in Low-Power DC/DC Converters

POL (Point-of-Load) Converter

Use Scenario: Replacing Schottky diodes in 5–12 V output buck converters delivering up to 30 A at 300 kHz–1 MHz.

IC Role / Device Role / Timing Role: N-channel power switch operating in synchronous rectification mode, driven by controller's low-side gate signal.

Use Value: Reduces conduction loss by >60 % vs. 40 V Schottky, enabling >96 % peak efficiency at 20 A load with 12 V input.

Use Scenario: High-density voltage regulation for FPGA, ASIC, or microprocessor cores requiring tight regulation and fast transient response.

IC Role / Device Role / Timing Role: Low-side synchronous rectifier in integrated POL modules with integrated inductor and controller.

Use Value: Enables compact 12 mm × 12 mm module size via SO-8 footprint and low thermal resistance (R_thJF = 13 °C/W).

OR-ing Circuit in Redundant Power Supplies

Hot-Swap Controller Back-End Switch

Use Scenario: Parallel connection of two 12 V power supplies where only the higher-voltage rail powers the load, preventing backfeed.

IC Role / Device Role / Timing Role: Forward-biased N-channel MOSFET acting as ideal diode, controlled by dedicated OR-ing controller.

Use Value: Achieves <10 mV forward drop at 20 A (vs. 300–400 mV for Schottky), reducing power loss and thermal stress in 1U server chassis.

Use Scenario: In-rush current limiting and fault isolation in 12 V intermediate bus systems with hot-plug capability.

IC Role / Device Role / Timing Role: Load switch placed between hot-swap controller output and downstream capacitive load.

Use Value: Withstands 70 A pulsed drain current (I_DM) and 40 A avalanche current, surviving repeated hot-insertion surges without failure.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
Si7157DP-T1-GE3	V_DS = 30 V, R_DS(on) = 0.0035 Ω @ 10 V, SO-8, but higher Q_gd = 10.5 nC	Higher voltage rating suits 24 V input systems; less optimal for 12 V POL due to increased gate charge	Select when 30 V blocking is required and switching frequency < 500 kHz
IRF7478PBF	V_DS = 20 V, R_DS(on) = 0.0032 Ω @ 10 V, SO-8, but no 100 % UIS test and R_thJA = 75 °C/W	Lacks avalanche ruggedness validation and has higher thermal resistance - limits reliability in high-derate conditions	Acceptable for cost-sensitive non-critical applications where UIS margin and thermal headroom are not primary concerns

Compared with Si7157DP-T1-GE3 and IRF7478PBF, SI4398DY-T1-GE3 delivers superior switching efficiency at high frequency due to lower Q_gd, guaranteed UIS robustness for transient immunity, and best-in-class thermal resistance for compact thermal design in space-constrained POL modules.

Availability

SI4398DY-T1-GE3 is available at Aetrix Electronics and suitable for synchronous rectification, point-of-load regulation, and OR-ing applications requiring stable component supply, consistent halogen-free compliance, and validated avalanche ruggedness.

Supply support for SI4398DY-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, specializing in high-performance MOSFETs, diodes, and optoelectronics with emphasis on power efficiency and reliability.

The Si4398DY series belongs to Vishay's low-voltage, high-current logic-level MOSFET product line, engineered specifically for high-efficiency synchronous rectification and OR-ing in space-constrained DC/DC converters.

FAQ

What is the maximum continuous drain current for SI4398DY-T1-GE3 at 70 °C ambient?

The SI4398DY-T1-GE3 supports 20 A continuous drain current at T_A = 70 °C, as specified in its Absolute Maximum Ratings table. This value accounts for thermal derating on a standard 1" × 1" FR4 board and assumes proper PCB copper area for heat dissipation. The SI4398DY-T1-GE3 maintains this rating while delivering 0.0040 Ω R_DS(on) at 4.5 V gate drive, ensuring stable performance in thermally constrained POL designs.

Does SI4398DY-T1-GE3 have a fully rated avalanche capability?

Yes, the SI4398DY-T1-GE3 is 100 % tested for Unclamped Inductive Switching (UIS) per JEDEC standards, with a rated single-pulse avalanche energy (E_AS) of 80 mJ and avalanche current (I_AS) of 40 A. This validated ruggedness allows the SI4398DY-T1-GE3 to safely absorb inductive energy during hard-switching events in synchronous buck converters without requiring external snubbers or protection circuits.

What is the gate threshold voltage range for SI4398DY-T1-GE3?

The SI4398DY-T1-GE3 has a gate threshold voltage (V_GS(th)) range of 1.0 V to 3.0 V, measured at V_DS = V_GS and I_D = 250 µA. This wide threshold ensures robust turn-on behavior across process and temperature variations while remaining compatible with 3.3 V and 5 V logic-level gate drivers - a key feature distinguishing the SI4398DY-T1-GE3 from higher-threshold alternatives.

Is SI4398DY-T1-GE3 compatible with lead-free reflow processes?

Yes, the SI4398DY-T1-GE3 is explicitly qualified for lead-free reflow soldering per J-STD-020, as indicated by the "-T1-GE3" suffix denoting lead-free and halogen-free construction. Its SO-8 package withstands peak reflow temperatures up to 260 °C, and the SI4398DY-T1-GE3 complies with IPC/JEDEC J-STD-020D moisture sensitivity level (MSL) 1, eliminating bake requirements prior to assembly.

How does the SO-8 package of SI4398DY-T1-GE3 manage thermal performance?

The SI4398DY-T1-GE3 uses an SO-8 package with an exposed drain pad that provides a low-impedance thermal path from junction to PCB. Its steady-state junction-to-foot thermal resistance (R_thJF) is 13–16 °C/W, enabling efficient heat transfer into internal or external copper planes. This thermal architecture allows the SI4398DY-T1-GE3 to sustain 25 A continuous current at T_J = 150 °C when mounted on a 1" × 1" FR4 board with adequate copper area.

SI4398DY-T1-GE3 Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Siliconix

Series:: -

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):: 4.5V, 10V

Rds On (Max) @ Id, Vgs:: 2.8mOhm @ 25A, 10V

Vgs(th) (Max) @ Id:: 3V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 50 nC @ 4.5 V

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 5620 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

SI4398DY-T1-GE3 FAQ

1.How can I place an order for SI4398DY-T1-GE3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI4398DY-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 SI4398DY-T1-GE3 reliable?

The price and inventory of SI4398DY-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 SI4398DY-T1-GE3 is usually 5 days.

3.What payment methods are accepted for SI4398DY-T1-GE3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI4398DY-T1-GE3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI4398DY-T1-GE3?

SI4398DY-T1-GE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI4398DY-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 SI4398DY-T1-GE3?

For technical support, including SI4398DY-T1-GE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI4398DY-T1-GE3 requirements.

6.How does Aetrix verify that SI4398DY-T1-GE3 is sourced from the original manufacturer or authorized distributors?

All SI4398DY-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 SI4398DY-T1-GE3 meets industry standards.

7.What is the process for return or replacement of SI4398DY-T1-GE3?

All SI4398DY-T1-GE3 units undergo pre-shipment inspection (PSI). If there is an issue with SI4398DY-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 SI4398DY-T1-GE3 part is unused and in its original packaging.

Return procedure for SI4398DY-T1-GE3:

1.Submit a request within 90 days.

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

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