Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

Vishay Siliconix SI4409DY-T1-GE3

Name: SI4409DY-T1-GE3
Brand: Vishay Siliconix
SKU: SI4409DY-T1-GE3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: SI4409DY-T1-GE3

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

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

Datasheet:: SI4409DY-T1-GE3.pdf

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

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:4,623

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

SI4409DY-T1-GE3 from Vishay Siliconix is a P-channel enhancement-mode TrenchFET® power MOSFET rated for -150 V drain-source voltage, 1.2 Ω R_DS(on) at V_GS = -10 V, and -1.3 A continuous drain current at T_C = 25 °C. It serves as an active clamp switch in isolated DC/DC converters, delivering robust avalanche capability (E_AS = 0.8 mJ) and halogen-free, lead-free compliance.

For engineers reviewing the SI4409DY-T1-GE3 datasheet, SI4409DY-T1-GE3 pinout, SI4409DY-T1-GE3 application, or SI4409DY-T1-GE3 equivalent, key selection criteria include its -150 V V_DS, low gate charge (4.8 nC at V_GS = -6 V), SO-8 package thermal performance (R_thJA = 47 °C/W typ.), and body diode recovery characteristics (t_rr = 43 ns).

Technical Context

This MOSFET employs trench-gate silicon technology to achieve high-voltage blocking with low on-resistance and fast switching. Its negative threshold voltage (-2 to -4 V) ensures reliable turn-on with standard negative gate drive in high-side or clamp configurations.

The device is fully characterized for unclamped inductive switching (UIS), with specified single-pulse avalanche energy of 0.8 mJ and I_AS = 4 A. Thermal design relies on junction-to-foot resistance (R_thJF = 22 °C/W typ.) and SO-8 footprint compatibility with standard PCB layout practices.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	-150 V - Supports high-voltage isolation stages without derating in 100–120 V_AC input-derived topologies.
R_DS(on)	1.2 Ω at V_GS = -10 V - Enables <1.5 W conduction loss at -1.3 A, suitable for low-duty-cycle clamp operation.
Q_g	4.8 nC at V_GS = -6 V - Reduces gate drive power and enables efficient operation with low-current drivers in flyback/snubber circuits.
E_AS	0.8 mJ - Withstands repetitive energy transients during active clamp reset without degradation.
t_rr	43 ns - Limits reverse recovery losses and EMI generation when used with synchronous rectifiers or resonant stages.
R_thJF	22 °C/W - Allows direct thermal coupling to copper pour or heatsink via exposed drain pad in SO-8 package.

Pinout & Package

SI4409DY-T1-GE3 is housed in a standard SO-8 surface-mount package with exposed drain pad for thermal management. Pin numbering follows JEDEC MS-012, with pins 1–4 on left side and 5–8 on right side (top view).

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 6, 7, 8	Drain (D)	Internally connected to exposed pad - primary current path and thermal conduction path to PCB copper.
5	Gate (G)	Control terminal requiring negative voltage relative to source to turn on; low C_iss (332 pF) eases drive design.
Source (S)	Source (S)	Common reference node for gate drive and load return; pins 1–4 and 6–8 are internally tied to drain, not source.

Key Features

Feature	Design Value
TrenchFET® architecture	Delivers optimized R_DS(on) × Q_g figure-of-merit for high-voltage switching efficiency in clamp and snubber roles.
100 % UIS tested	Each unit validated for unclamped inductive switching stress, ensuring reliability in active clamp topologies with variable leakage inductance.
Halogen-free & Pb-free	Complies with IEC 61249-2-21 and RoHS Directive 2011/65/EU - suitable for industrial and telecom equipment with strict material declarations.
Low Q_gd/Q_gs ratio	Q_gd = 2.5 nC / Q_gs = 1.5 nC enables stable Miller plateau control and reduces risk of spurious turn-on in high-dV/dt environments.

Applications

Active Clamp Flyback Converter	Isolated Forward Converter
Use Scenario: High-efficiency 65–100 W AC/DC adapter using active clamp flyback to recover leakage energy and reduce voltage stress on main switch. IC Role / Device Role / Timing Role: SI4409DY-T1-GE3 operates as the clamp switch, turning on synchronously with main FET turn-off to absorb and recycle leakage inductance energy. Use Value: -150 V rating accommodates reflected output voltage plus leakage spike; 0.8 mJ E_AS handles worst-case transient energy without failure.	Use Scenario: Telecom power supply with 48 V input and 12 V/5 A output, requiring tight regulation and low standby loss. IC Role / Device Role / Timing Role: SI4409DY-T1-GE3 functions as the forward transformer reset switch, clamping core flux and enabling zero-voltage switching transitions. Use Value: Fast t_rr (43 ns) minimizes dead-time losses; SO-8 thermal performance supports >75 °C ambient operation without forced air.
Industrial DC/DC Isolator	Programmable Logic Controller (PLC) Power Module
Use Scenario: 24 V input to ±15 V dual-output isolated converter for analog sensor signal conditioning in factory automation. IC Role / Device Role / Timing Role: SI4409DY-T1-GE3 acts as the auxiliary clamp FET in a double-ended topology, managing transformer reset and improving cross-regulation. Use Value: -1.3 A I_D rating supports peak clamp currents up to 2 A (IDM); R_DS(on) stability over temperature ensures consistent loss across -40 to +125 °C.	Use Scenario: DIN-rail mounted PLC with redundant 24 V backup supply requiring high reliability and long service life. IC Role / Device Role / Timing Role: SI4409DY-T1-GE3 serves as the secondary-side active clamp element in an isolated buck-boost stage, enhancing efficiency and reducing heat buildup. Use Value: Halogen-free construction meets IEC 60754-2 and UL 94 V-0 requirements; 150 °C T_J(max) supports extended lifetime under continuous thermal stress.

Active Clamp Flyback Converter

Isolated Forward Converter

Use Scenario: High-efficiency 65–100 W AC/DC adapter using active clamp flyback to recover leakage energy and reduce voltage stress on main switch.

IC Role / Device Role / Timing Role: SI4409DY-T1-GE3 operates as the clamp switch, turning on synchronously with main FET turn-off to absorb and recycle leakage inductance energy.

Use Value: -150 V rating accommodates reflected output voltage plus leakage spike; 0.8 mJ E_AS handles worst-case transient energy without failure.

Use Scenario: Telecom power supply with 48 V input and 12 V/5 A output, requiring tight regulation and low standby loss.

IC Role / Device Role / Timing Role: SI4409DY-T1-GE3 functions as the forward transformer reset switch, clamping core flux and enabling zero-voltage switching transitions.

Use Value: Fast t_rr (43 ns) minimizes dead-time losses; SO-8 thermal performance supports >75 °C ambient operation without forced air.

Industrial DC/DC Isolator

Programmable Logic Controller (PLC) Power Module

Use Scenario: 24 V input to ±15 V dual-output isolated converter for analog sensor signal conditioning in factory automation.

IC Role / Device Role / Timing Role: SI4409DY-T1-GE3 acts as the auxiliary clamp FET in a double-ended topology, managing transformer reset and improving cross-regulation.

Use Value: -1.3 A I_D rating supports peak clamp currents up to 2 A (IDM); R_DS(on) stability over temperature ensures consistent loss across -40 to +125 °C.

Use Scenario: DIN-rail mounted PLC with redundant 24 V backup supply requiring high reliability and long service life.

IC Role / Device Role / Timing Role: SI4409DY-T1-GE3 serves as the secondary-side active clamp element in an isolated buck-boost stage, enhancing efficiency and reducing heat buildup.

Use Value: Halogen-free construction meets IEC 60754-2 and UL 94 V-0 requirements; 150 °C T_J(max) supports extended lifetime under continuous thermal stress.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
IRF9540NPBF	R_DS(on) = 200 mΩ higher at -10 V; Q_g = 72 nC vs. 4.8 nC; TO-220 package	Larger footprint, higher gate drive loss, lower switching frequency suitability	Choose only if SO-8 mounting is unavailable and thermal mass from TO-220 is beneficial in low-frequency (<100 kHz) designs.
Si7157DP-T1-GE3	V_DS = -60 V; R_DS(on) = 0.125 Ω; SO-8; halogen-free	Not suitable for >100 V systems; better for low-voltage synchronous rectification	Select only for sub-60 V isolated topologies where lower conduction loss outweighs voltage limitation.

Compared with IRF9540NPBF and Si7157DP-T1-GE3, the SI4409DY-T1-GE3 uniquely balances -150 V capability, SO-8 form factor, and ultra-low gate charge-making it optimal for compact, high-frequency active clamp circuits where board space and driver simplicity are critical.

Availability

SI4409DY-T1-GE3 is available at Aetrix Electronics and suitable for active clamp flyback converters, isolated forward power supplies, and industrial DC/DC isolators requiring stable component supply, long-term lifecycle support, and halogen-free compliance.

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

The Si4409DY product line delivers high-voltage P-channel TrenchFET® MOSFETs engineered for active clamp, snubber, and high-side switching in isolated DC/DC converters operating up to 150 V.

FAQ

What is the maximum continuous drain current for SI4409DY-T1-GE3 at 70 °C case temperature?

The SI4409DY-T1-GE3 supports -1.0 A continuous drain current at T_C = 70 °C, as specified in the Absolute Maximum Ratings table. This value reflects thermal derating due to reduced heat dissipation capability at elevated case temperatures and must be applied in thermal design calculations alongside R_thJF = 22 °C/W to ensure junction temperature remains ≤150 °C.

Does SI4409DY-T1-GE3 have integrated gate protection?

No, the SI4409DY-T1-GE3 does not include integrated gate protection circuitry. Its gate-source voltage rating is ±20 V, and external Zener clamping or series resistance is recommended in high-noise environments. The device relies on proper PCB layout and gate driver design to avoid exceeding V_GS limits, especially during fast switching transients.

Can SI4409DY-T1-GE3 be used in synchronous rectification applications?

The SI4409DY-T1-GE3 is not optimized for synchronous rectification due to its relatively high R_DS(on) (1.2 Ω) and P-channel configuration, which requires negative gate drive timing. It is designed for active clamp and snubber roles-not low-loss bidirectional conduction. For synchronous rectification, N-channel devices with lower R_DS(on) and dedicated gate drivers are preferred.

What is the body diode forward voltage of SI4409DY-T1-GE3 at -1 A?

The SI4409DY-T1-GE3 exhibits a source-drain diode forward voltage (V_SD) of -0.7 V to -1.2 V at I_S = -1 A and V_GS = 0 V, per the Drain-Source Body Diode Characteristics table. This range reflects typical variation across production lots and temperature; design margins should use -1.2 V for worst-case loss estimation.

Is SI4409DY-T1-GE3 suitable for automotive applications?

The SI4409DY-T1-GE3 is not AEC-Q101 qualified and lacks automotive-specific qualification data such as HTOL or temperature cycling reports. While its -55 to +150 °C operating range covers automotive under-hood temperatures, Vishay does not list it for automotive use. For automotive designs, consult Vishay's AEC-Q101-qualified P-channel MOSFET portfolio instead of relying on SI4409DY-T1-GE3.

SI4409DY-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:: 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-GE3 FAQ

1.How can I place an order for SI4409DY-T1-GE3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI4409DY-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 SI4409DY-T1-GE3 reliable?

The price and inventory of SI4409DY-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 SI4409DY-T1-GE3 is usually 5 days.

3.What payment methods are accepted for SI4409DY-T1-GE3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI4409DY-T1-GE3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI4409DY-T1-GE3?

SI4409DY-T1-GE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI4409DY-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 SI4409DY-T1-GE3?

For technical support, including SI4409DY-T1-GE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI4409DY-T1-GE3 requirements.

6.How does Aetrix verify that SI4409DY-T1-GE3 is sourced from the original manufacturer or authorized distributors?

All SI4409DY-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 SI4409DY-T1-GE3 meets industry standards.

7.What is the process for return or replacement of SI4409DY-T1-GE3?

All SI4409DY-T1-GE3 units undergo pre-shipment inspection (PSI). If there is an issue with SI4409DY-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 SI4409DY-T1-GE3 part is unused and in its original packaging.

Return procedure for SI4409DY-T1-GE3:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-11 Comparator Circuit: Voltage Thresholds, Op-Amp Differences, LM393 and Practical Design

Comparator circuit design covering voltage thresholds, input limits, open-collector outputs, LM393 wiring, op-amp differences, hysteresis, timing, window detection and practical fault diagnosis.

2026-09-10 Schmitt Trigger Explained: Hysteresis, Circuits, Inverters and Applications

Schmitt triggers use separate rising and falling thresholds to stabilize slow or noisy signals. This guide covers hysteresis, 74HC14 and 74HCT14 selection, comparator calculations, RC oscillators and p…

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …