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

Vishay Siliconix SI4409DY-T1-E3

Name: SI4409DY-T1-E3
Brand: Vishay Siliconix
SKU: SI4409DY-T1-E3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI4409DY-T1-E3

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

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

Datasheet:: SI4409DY-T1-E3.pdf

Description:: MOSFET P-CH 150V 1.3A 8SO

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Product details

Overview

SI4409DY-T1-E3 from Vishay Siliconix is a P-channel 150-V TrenchFET® Power MOSFET in SO-8 package, with R_DS(on) = 1.2 Ω at V_GS = −10 V, continuous drain current of −1.3 A (T_C = 25 °C), total gate charge of 4.8 nC (V_GS = −6 V), and 100 % UIS tested - used as active clamp switch in isolated DC/DC converters.

For engineers reviewing the SI4409DY-T1-E3 datasheet, SI4409DY-T1-E3 pinout, SI4409DY-T1-E3 application, or SI4409DY-T1-E3 equivalent, key selection criteria include negative V_DS rating, low Q_g for fast switching, SO-8 thermal performance, and body diode recovery characteristics in high-frequency flyback topologies.

Technical Context

This MOSFET employs trench-gate silicon technology optimized for high-voltage P-channel operation, featuring a −150 V V_DS rating and guaranteed avalanche energy of 0.8 mJ. Its gate threshold voltage range (−2 V to −4 V) enables reliable enhancement-mode turn-on with standard logic-level gate drivers.

The device integrates a source-drain body diode with t_rr = 43–70 ns and Q_rr = 95–150 nC, supporting synchronous rectification and active clamp reset functions. Thermal resistance from junction-to-foot is 22 °C/W (typical), enabling direct PCB copper pour heatsinking without external heatsinks in space-constrained converters.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	−150 V - supports primary-side clamping in 48 V–100 V input isolated DC/DC converters
R_DS(on)	1.2 Ω @ V_GS = −10 V - delivers <1.6 W conduction loss at −1.3 A continuous current
I_D (cont.)	−1.3 A @ T_C = 25 °C - rated for sustained operation in thermally managed SO-8 footprints
Q_g	4.8 nC @ V_GS = −6 V - enables efficient gate drive with low-power controllers in <500 kHz designs
E_AS	0.8 mJ - withstands repetitive unclamped inductive switching events in active clamp circuits
R_thJF	22 °C/W (typ.) - allows direct thermal coupling to PCB copper, reducing need for thermal vias or heatsinks
V_GS(th)	−2 V to −4 V - ensures robust turn-on margin with −5 V or −8 V gate drive rails

Pinout & Package

SI4409DY-T1-E3 is housed in a standard SO-8 surface-mount package (5.0 mm × 6.0 mm × 1.75 mm), with exposed drain pad on underside for enhanced thermal conduction to PCB copper pour.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 7, 8	Drain (D)	Internally connected to common drain node and exposed thermal pad - must be soldered to large copper area for thermal management
6	Gate (G)	Control terminal requiring −6 V to −10 V for full enhancement; low C_iss (332 pF) reduces driver loading
Sources tied internally to pins 1–5 and 7–8	Source (S)	Common source node; body diode anode - referenced to system ground in high-side clamp configuration

Key Features

Feature	Design Value
TrenchFET® construction	Enables higher cell density and lower R_DS(on) per mm² vs. planar P-channel MOSFETs at −150 V
100 % UIS tested	Guarantees ruggedness against unclamped inductive switching stress during active clamp transitions
Halogen-free (IEC 61249-2-21)	Meets RoHS-compliant manufacturing requirements without compromising gate oxide reliability
Low Q_gd/Q_g ratio (2.5/4.8 nC)	Improves hard-switching EMI profile and reduces Miller-induced shoot-through risk in half-bridge configurations
Body diode t_rr = 43 ns (typ.)	Minimizes reverse recovery losses when used as synchronous rectifier or clamp diode replacement

Applications

Active Clamp Flyback Converter	Isolated Telecom DC/DC Module
Use Scenario: High-efficiency 48 V input flyback converter with active clamp reset to recover leakage energy and reduce voltage stress on main switch. IC Role / Device Role / Timing Role: SI4409DY-T1-E3 serves as the active clamp switch, turning on during main switch off-time to recycle transformer leakage energy into the clamp capacitor. Use Value: −150 V rating accommodates reflected output voltage plus leakage spike; low Q_g enables precise timing control with minimal gate drive power.	Use Scenario: Compact 28 V–56 V telecom power module delivering ±12 V outputs with tight regulation and high reliability. IC Role / Device Role / Timing Role: SI4409DY-T1-E3 operates as the high-side clamp FET in a dual-active-clamp forward topology, managing core reset and voltage balancing. Use Value: 100 % UIS testing ensures long-term reliability under transient overloads; SO-8 footprint supports automated assembly and thermal via integration.
Industrial PoE++ Midspan Injector	Medical Isolated Auxiliary Supply
Use Scenario: IEEE 802.3bt-compliant midspan injector supplying up to 90 W over Category 6A cabling with reinforced isolation. IC Role / Device Role / Timing Role: SI4409DY-T1-E3 functions as the auxiliary clamp switch in the isolated DC/DC stage powering the PD interface controller and sensing circuitry. Use Value: Halogen-free construction meets IEC 60601-1 flammability requirements; −1.3 A rating supports burst-mode auxiliary loads without derating.	Use Scenario: 5 V/3.3 V isolated auxiliary supply for patient-connected monitoring equipment requiring 4 kV reinforced isolation and low EMI. IC Role / Device Role / Timing Role: SI4409DY-T1-E3 implements the clamp switch in a low-noise, low-EMI active clamp forward converter meeting CISPR 32 Class B limits. Use Value: Low Crss (13 pF) minimizes capacitive coupling across isolation barrier; R_thJF = 22 °C/W enables stable operation within sealed enclosures.

Active Clamp Flyback Converter

Isolated Telecom DC/DC Module

Use Scenario: High-efficiency 48 V input flyback converter with active clamp reset to recover leakage energy and reduce voltage stress on main switch.

IC Role / Device Role / Timing Role: SI4409DY-T1-E3 serves as the active clamp switch, turning on during main switch off-time to recycle transformer leakage energy into the clamp capacitor.

Use Value: −150 V rating accommodates reflected output voltage plus leakage spike; low Q_g enables precise timing control with minimal gate drive power.

Use Scenario: Compact 28 V–56 V telecom power module delivering ±12 V outputs with tight regulation and high reliability.

IC Role / Device Role / Timing Role: SI4409DY-T1-E3 operates as the high-side clamp FET in a dual-active-clamp forward topology, managing core reset and voltage balancing.

Use Value: 100 % UIS testing ensures long-term reliability under transient overloads; SO-8 footprint supports automated assembly and thermal via integration.

Industrial PoE++ Midspan Injector

Medical Isolated Auxiliary Supply

Use Scenario: IEEE 802.3bt-compliant midspan injector supplying up to 90 W over Category 6A cabling with reinforced isolation.

IC Role / Device Role / Timing Role: SI4409DY-T1-E3 functions as the auxiliary clamp switch in the isolated DC/DC stage powering the PD interface controller and sensing circuitry.

Use Value: Halogen-free construction meets IEC 60601-1 flammability requirements; −1.3 A rating supports burst-mode auxiliary loads without derating.

Use Scenario: 5 V/3.3 V isolated auxiliary supply for patient-connected monitoring equipment requiring 4 kV reinforced isolation and low EMI.

IC Role / Device Role / Timing Role: SI4409DY-T1-E3 implements the clamp switch in a low-noise, low-EMI active clamp forward converter meeting CISPR 32 Class B limits.

Use Value: Low Crss (13 pF) minimizes capacitive coupling across isolation barrier; R_thJF = 22 °C/W enables stable operation within sealed enclosures.

Equivalent & Alternatives

The following parts are listed as comparable options for similar P-channel high-voltage clamp switch applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
IXTP1R2P15T	TO-220 package, R_DS(on) = 1.2 Ω @ −10 V, but higher Q_g (16 nC) and no SO-8 thermal pad	Requires heatsink and manual assembly; unsuitable for high-density SMT layouts	Select when board-level thermal mass is insufficient and discrete heatsinking is available
Si7157DP-T1-GE3	SO-8, −100 V V_DS, R_DS(on) = 0.85 Ω @ −10 V, Q_g = 5.2 nC - lower voltage rating, lower R_DS(on)	Limited to ≤48 V input systems; not suitable for 100 V bus clamp applications	Select for cost-sensitive 24–48 V industrial supplies where −150 V margin is unnecessary

Compared with IXTP1R2P15T and Si7157DP-T1-GE3, SI4409DY-T1-E3 uniquely balances −150 V capability, SO-8 manufacturability, and 4.8 nC gate charge - making it optimal for compact, high-reliability active clamp converters where voltage margin and thermal integration are critical.

Availability

SI4409DY-T1-E3 is available at Aetrix Electronics and suitable for active clamp flyback converters, isolated telecom DC/DC modules, and medical auxiliary power supplies requiring stable component supply, lead-free compliance, and long-lifecycle support.

Supply support for SI4409DY-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, specializing in MOSFETs, diodes, optoelectronics, and passive components with emphasis on power efficiency and reliability.

The Si4409DY product line targets high-voltage P-channel switching in isolated power conversion, designed specifically for active clamp, synchronous rectification, and high-side load switching applications demanding ruggedness and thermal efficiency.

FAQ

What is the maximum continuous drain current rating for SI4409DY-T1-E3 at 70 °C case temperature?

The SI4409DY-T1-E3 has a continuous drain current rating of −1.0 A at T_C = 70 °C, as specified in the Absolute Maximum Ratings table. This reflects thermal derating due to reduced heat dissipation capability at elevated case temperatures. The SI4409DY-T1-E3 maintains safe operation under these conditions when mounted on a 1" × 1" FR4 board with appropriate copper pour. Always verify layout thermal performance using the provided R_thJF = 22 °C/W (typ.) value.

Does SI4409DY-T1-E3 support gate drive from a standard 5 V microcontroller?

No - SI4409DY-T1-E3 requires a negative gate-source voltage for turn-on, with V_GS(th) ranging from −2 V to −4 V. A 5 V microcontroller output cannot directly drive it. Gate drive requires a level-shifted or inverted signal, such as from a dedicated P-channel gate driver (e.g., LM5113) or isolated gate driver with negative output capability. The SI4409DY-T1-E3 is not compatible with 0–5 V logic-level drive without external inversion.

What is the body diode forward voltage of SI4409DY-T1-E3 at −1 A and 25 °C?

The body diode forward voltage (V_SD) of SI4409DY-T1-E3 is −0.7 V to −1.2 V at I_S = −1 A and V_GS = 0 V, TJ = 25 °C. This parameter is critical when the SI4409DY-T1-E3 operates in synchronous rectifier mode or during dead-time conduction. The wide range reflects process variation and temperature dependence; design margins should accommodate the upper bound (−1.2 V) for worst-case power loss calculation.

Is SI4409DY-T1-E3 qualified for automotive applications?

No - SI4409DY-T1-E3 is not AEC-Q101 qualified and lacks automotive-grade screening, extended temperature validation, or PPAP documentation. It is intended for industrial, telecom, and medical power applications. For automotive use, Vishay offers AEC-Q101-qualified alternatives such as the SQ4409EY-T1_GE3, which shares the same die but undergoes additional qualification testing. The SI4409DY-T1-E3 should not be deployed in automotive ECUs or ADAS systems without full requalification.

How does the 100 % UIS test impact reliability of SI4409DY-T1-E3 in active clamp circuits?

The 100 % UIS (Unclamped Inductive Switching) test verifies that every SI4409DY-T1-E3 unit can safely absorb a defined inductive energy pulse (E_AS = 0.8 mJ) without failure. In active clamp circuits, this ensures robustness against voltage overshoot during leakage energy transfer - a common stress condition. Unlike sample-tested parts, 100 % UIS screening eliminates infant mortality risk for SI4409DY-T1-E3 in high-reliability clamp applications, directly improving field lifetime.

SI4409DY-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:: P-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 150 V

Current - Continuous Drain (Id) @ 25°C:: 1.3A (Tc)

Drive Voltage (Max Rds On, Min Rds On):: 6V, 10V

Rds On (Max) @ Id, Vgs:: 1.2Ohm @ 500mA, 10V

Vgs(th) (Max) @ Id:: 4V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 12 nC @ 10 V

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 332 pF @ 50 V

FET Feature:: -

Power Dissipation (Max):: 2.2W (Ta), 4.6W (Tc)

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

SI4409DY-T1-E3 FAQ

1.How can I place an order for SI4409DY-T1-E3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI4409DY-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 SI4409DY-T1-E3 reliable?

The price and inventory of SI4409DY-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 SI4409DY-T1-E3 is usually 5 days.

3.What payment methods are accepted for SI4409DY-T1-E3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI4409DY-T1-E3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI4409DY-T1-E3?

SI4409DY-T1-E3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI4409DY-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 SI4409DY-T1-E3?

For technical support, including SI4409DY-T1-E3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI4409DY-T1-E3 requirements.

6.How does Aetrix verify that SI4409DY-T1-E3 is sourced from the original manufacturer or authorized distributors?

All SI4409DY-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 SI4409DY-T1-E3 meets industry standards.

7.What is the process for return or replacement of SI4409DY-T1-E3?

All SI4409DY-T1-E3 units undergo pre-shipment inspection (PSI). If there is an issue with SI4409DY-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 SI4409DY-T1-E3 part is unused and in its original packaging.

Return procedure for SI4409DY-T1-E3:

1.Submit a request within 90 days.

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

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