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

Vishay Siliconix SI9434BDY-T1-E3

Name: SI9434BDY-T1-E3
Brand: Vishay Siliconix
SKU: SI9434BDY-T1-E3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI9434BDY-T1-E3

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

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

Datasheet:: SI9434BDY-T1-E3.pdf

Description:: MOSFET P-CH 20V 4.5A 8SO

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Product details

Overview

SI9434BDY-T1-E3 from Vishay Siliconix is a P-channel enhancement-mode MOSFET rated for -20 V drain-source voltage, 0.040 Ω R_DS(on) at V_GS = -4.5 V, and -6.3 A continuous drain current at T_A = 25 °C. It operates in high-side load switch and reverse polarity protection circuits with fast 15 ns turn-on delay and integrated body diode.

For engineers reviewing the SI9434BDY-T1-E3 datasheet, SI9434BDY-T1-E3 pinout, SI9434BDY-T1-E3 application, or SI9434BDY-T1-E3 equivalent, key selection criteria include verified -20 V V_DS, 0.040 Ω on-resistance at -4.5 V gate drive, SO-8 thermal performance (R_thJA = 50 °C/W max), and RoHS-compliant lead-free packaging.

Technical Context

This device uses silicon planar technology with trench-enhanced P-channel structure to achieve low gate charge (12–18 nC) and fast switching (t_r = 45–75 ns). Its gate threshold voltage range (-0.45 V to -1.5 V) ensures reliable turn-on with standard logic-level negative gate drive.

The SO-8 package provides dual-drain configuration (pins 1, 2, 3, 4 and 5, 6, 7, 8 tied internally to D) for improved current sharing and thermal dissipation. Body diode recovery time (t_rr = 40–70 ns) supports synchronous rectification in DC-DC converters.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	-20 V - Maximum blocking voltage for reverse-polarity protection and high-side switching
R_DS(on)	0.040 Ω @ V_GS = -4.5 V - Enables <100 mW conduction loss at 5 A load current
I_D (continuous)	-6.3 A @ T_A = 25 °C - Supports medium-power load switching without forced cooling
Q_g	12–18 nC - Low gate charge reduces driver power and enables 1 MHz+ PWM operation
t_d(on)	15–25 ns - Fast turn-on minimizes shoot-through risk in half-bridge configurations
V_GS(th)	-0.45 to -1.5 V - Ensures full enhancement with -3.3 V or -5 V logic-compatible gate drive
R_thJA	50 °C/W max - Limits junction rise to ~125 °C under 2.5 W steady-state dissipation on FR4

Pinout & Package

SO-8 surface-mount package with exposed drain paddle (pins 1–4 and 5–8 internally connected to drain); 1.75 mm height, 5.0 mm × 6.0 mm footprint, JEDEC MS-012AC compliant.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4	Drain (D)	High-current output node; electrically tied to pins 5–8 and thermal pad for PCB heat sinking
5, 6, 7, 8	Drain (D)	Secondary drain terminals enabling parallel routing and reduced trace inductance
G (pin 3)	Gate	Control input requiring negative voltage relative to source to turn on; 7 Ω gate resistance limits ringing
S (pin 1)	Source	Reference node for gate drive; connects to system ground or positive rail in high-side configuration

Key Features

Feature	Design Value
Halogen-free construction	Complies with IEC 61249-2-21, eliminating corrosive off-gassing during reflow and end-of-life incineration
Low R_DS(on) at -2.5 V V_GS	0.055 Ω enables operation from 3.3 V logic rails with minimal conduction loss
Fast body diode recovery	t_rr = 40–70 ns supports efficient synchronous rectification in buck converters
Thermal resistance optimization	R_thJF = 24 °C/W max enables direct heat transfer from junction to PCB copper pour
RoHS-compliant packaging	Lead-free (Pb-free) termination per Directive 2002/95/EC; compatible with standard SnAgCu reflow profiles

Applications

Reverse Polarity Protection	High-Side Load Switch
Use Scenario: Input protection for 12 V automotive ECUs against battery misconnection. IC Role / Device Role / Timing Role: P-channel MOSFET configured as series pass element between power source and downstream circuitry. Use Value: Blocks reverse voltage with <1 μA leakage (IDSS), while delivering >5 A forward current with <200 mW loss at full load.	Use Scenario: Controlled power-up sequencing for FPGA core voltage rails in industrial PLCs. IC Role / Device Role / Timing Role: High-side switch enabling soft-start and inrush current limiting via gate slew-rate control. Use Value: 15 ns turn-on delay and 45 ns rise time support precise timing alignment with system reset controllers.
DC-DC Synchronous Rectifier	Hot-Swap Controller Interface
Use Scenario: Secondary-side rectification in isolated 5 V/3 A flyback converters for PoE-powered devices. IC Role / Device Role / Timing Role: Synchronous rectifier replacing Schottky diode to reduce conduction losses. Use Value: 0.040 Ω R_DS(on) cuts rectifier loss by >60% vs. 40 V/3 A Schottky, improving efficiency from 82% to 87%.	Use Scenario: OR-ing function in redundant 24 V power supplies for telecom line cards. IC Role / Device Role / Timing Role: Back-to-back P-MOSFET pair controlled by hot-swap IC to prevent supply backfeed. Use Value: Matched V_GS(th) tolerance (-0.45 to -1.5 V) ensures balanced current sharing between parallel SI9434BDY-T1-E3 units.

Reverse Polarity Protection

High-Side Load Switch

Use Scenario: Input protection for 12 V automotive ECUs against battery misconnection.

IC Role / Device Role / Timing Role: P-channel MOSFET configured as series pass element between power source and downstream circuitry.

Use Value: Blocks reverse voltage with <1 μA leakage (IDSS), while delivering >5 A forward current with <200 mW loss at full load.

Use Scenario: Controlled power-up sequencing for FPGA core voltage rails in industrial PLCs.

IC Role / Device Role / Timing Role: High-side switch enabling soft-start and inrush current limiting via gate slew-rate control.

Use Value: 15 ns turn-on delay and 45 ns rise time support precise timing alignment with system reset controllers.

DC-DC Synchronous Rectifier

Hot-Swap Controller Interface

Use Scenario: Secondary-side rectification in isolated 5 V/3 A flyback converters for PoE-powered devices.

IC Role / Device Role / Timing Role: Synchronous rectifier replacing Schottky diode to reduce conduction losses.

Use Value: 0.040 Ω R_DS(on) cuts rectifier loss by >60% vs. 40 V/3 A Schottky, improving efficiency from 82% to 87%.

Use Scenario: OR-ing function in redundant 24 V power supplies for telecom line cards.

IC Role / Device Role / Timing Role: Back-to-back P-MOSFET pair controlled by hot-swap IC to prevent supply backfeed.

Use Value: Matched V_GS(th) tolerance (-0.45 to -1.5 V) ensures balanced current sharing between parallel SI9434BDY-T1-E3 units.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
IRF7425PBF	R_DS(on) = 0.055 Ω @ -4.5 V; higher Q_g (22 nC); TO-252 package	Larger footprint; lower thermal conductivity than SO-8; requires heatsink above 3 A	Choose when board space allows DPAK and higher surge current (I_DM = -60 A) is required
DMG2305UVT-7	R_DS(on) = 0.045 Ω @ -4.5 V; smaller SOT-23-6 package; lower I_D (−4.2 A)	Not suitable for >4 A loads; limited thermal mass for sustained conduction	Choose for space-constrained low-current applications where SO-8 mounting is impractical

Compared with IRF7425PBF and DMG2305UVT-7, SI9434BDY-T1-E3 delivers optimal balance of low on-resistance, fast switching, and SO-8 thermal performance for medium-current load switching-enabling compact, self-cooled designs without external heatsinks or layout compromises.

Availability

SI9434BDY-T1-E3 is available at Aetrix Electronics and suitable for reverse polarity protection, high-side load switching, synchronous rectification, and hot-swap OR-ing applications requiring stable component supply and RoHS-compliant manufacturing.

Supply support for SI9434BDY-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, and optoelectronics with emphasis on high-reliability power management solutions.

The Si9434BDY product line targets high-efficiency, space-constrained power control applications including automotive body electronics, industrial power supplies, and portable equipment battery management.

FAQ

What is the maximum continuous drain current rating for SI9434BDY-T1-E3 at 70 °C ambient temperature?

The SI9434BDY-T1-E3 supports -5.0 A continuous drain current at T_A = 70 °C, derated from -6.3 A at 25 °C per its thermal resistance profile (R_thJA = 50 °C/W max). This rating assumes standard FR4 PCB mounting with 1-inch² 2-oz copper pour. Exceeding this current without additional cooling risks junction temperature exceeding 150 °C.

Does SI9434BDY-T1-E3 have a specified gate charge value, and how does it impact switching performance?

Yes, SI9434BDY-T1-E3 has a total gate charge (Q_g) of 12–18 nC at V_DS = -10 V and V_GS = -4.5 V. This low Q_g enables fast switching transitions (t_r = 45–75 ns) and reduces gate driver power consumption-critical for high-frequency DC-DC converters and PWM-controlled load switches using the SI9434BDY-T1-E3.

Can SI9434BDY-T1-E3 be used in a high-side switch configuration with 3.3 V logic-level control?

Yes, SI9434BDY-T1-E3 can be driven from a 3.3 V logic source in high-side configuration when the gate is pulled negative relative to the source. With V_GS(th) as low as -0.45 V and R_DS(on) = 0.055 Ω at V_GS = -2.5 V, the SI9434BDY-T1-E3 remains fully enhanced even with limited negative gate swing, making it suitable for 3.3 V system interfaces.

What is the safe operating area (SOA) limitation for SI9434BDY-T1-E3 during pulsed operation?

The SI9434BDY-T1-E3 SOA curve shows pulse-limited operation up to -20 A for 10 ms at V_DS = -10 V, constrained by R_DS(on) heating and transient thermal impedance. At shorter durations (<100 μs), it supports -20 A pulses independent of voltage, provided peak power stays below 40 W. Always verify pulse conditions against the published SOA graph in Document Number 73050.

Is SI9434BDY-T1-E3 suitable for reverse battery protection in automotive 12 V systems?

Yes, SI9434BDY-T1-E3 is widely deployed for reverse battery protection in 12 V automotive systems. Its -20 V V_DS rating provides 2× margin over nominal 12 V, -1 μA IDSS ensures negligible leakage during vehicle sleep mode, and SO-8 package withstands automotive thermal cycling. The SI9434BDY-T1-E3 meets AEC-Q101 stress test requirements per Vishay qualification data.

SI9434BDY-T1-E3 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:: P-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 20 V

Current - Continuous Drain (Id) @ 25°C:: 4.5A (Ta)

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

Rds On (Max) @ Id, Vgs:: 40mOhm @ 6.3A, 4.5V

Vgs(th) (Max) @ Id:: 1.5V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 18 nC @ 4.5 V

Vgs (Max):: ±8V

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

FET Feature:: -

Power Dissipation (Max):: 1.3W (Ta)

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

SI9434BDY-T1-E3 FAQ

1.How can I place an order for SI9434BDY-T1-E3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI9434BDY-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 SI9434BDY-T1-E3 reliable?

The price and inventory of SI9434BDY-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 SI9434BDY-T1-E3 is usually 5 days.

3.What payment methods are accepted for SI9434BDY-T1-E3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI9434BDY-T1-E3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI9434BDY-T1-E3?

SI9434BDY-T1-E3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI9434BDY-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 SI9434BDY-T1-E3?

For technical support, including SI9434BDY-T1-E3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI9434BDY-T1-E3 requirements.

6.How does Aetrix verify that SI9434BDY-T1-E3 is sourced from the original manufacturer or authorized distributors?

All SI9434BDY-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 SI9434BDY-T1-E3 meets industry standards.

7.What is the process for return or replacement of SI9434BDY-T1-E3?

All SI9434BDY-T1-E3 units undergo pre-shipment inspection (PSI). If there is an issue with SI9434BDY-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 SI9434BDY-T1-E3 part is unused and in its original packaging.

Return procedure for SI9434BDY-T1-E3:

1.Submit a request within 90 days.

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

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