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

Vishay Siliconix SI2318DS-T1-BE3

Name: SI2318DS-T1-BE3
Brand: Vishay Siliconix
SKU: SI2318DS-T1-BE3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI2318DS-T1-BE3

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: SI2318DS-T1-BE3.pdf

Description:: N-CHANNEL 40-V (D-S) MOSFET

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Product details

Overview

SI2318DS-T1-BE3 from Vishay Siliconix is an N-channel TrenchFET® power MOSFET rated for 40 V drain-source voltage, with R_DS(on) = 0.045 Ω at V_GS = 10 V and 3.9 A continuous drain current at T_A = 25 °C. It serves as a low-side load switch in compact DC-DC power stages and motor drive circuits.

For engineers reviewing the SI2318DS-T1-BE3 datasheet, SI2318DS-T1-BE3 pinout, SI2318DS-T1-BE3 application, or SI2318DS-T1-BE3 equivalent, key selection criteria include its SOT-23 package thermal resistance (R_thJA = 166 °C/W), gate threshold voltage range (1–3 V), and verified performance in stepper motor H-bridge half-bridge configurations.

Technical Context

This device uses trench-gate silicon technology to achieve low on-resistance and fast switching with Q_g = 15 nC and t_f = 25 ns. Its gate threshold voltage (V_GS(th)) is specified at 250 µA, enabling reliable turn-on from 3.3 V and 5 V logic-level drivers.

The integrated body diode supports synchronous rectification and reverse-current protection, with V_SD = 1.2 V at I_S = 1.25 A and zero gate bias. Thermal design must account for R_thJF = 50 °C/W (junction-to-foot) and derated power dissipation above 70 °C ambient.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	40 V - Maximum blocking voltage before avalanche conduction
R_DS(on) @ 10 V	0.045 Ω - Enables ≤170 mW conduction loss at 3.9 A
I_D (continuous)	3.9 A @ T_A = 25 °C - Validated steady-state current under FR4 board conditions
Q_g	15 nC - Determines gate driver strength requirement for <20 ns switching
V_GS(th)	1–3 V - Ensures full enhancement with standard 3.3 V microcontroller GPIO
P_D	1.25 W @ T_A = 25 °C - Power limit defined by thermal resistance and board layout
C_iss	540 pF - Impacts high-frequency gate drive impedance and EMI filtering needs

Pinout & Package

SI2318DS-T1-BE3 is housed in a surface-mount SOT-23 (TO-236) package with 3 terminals: Gate (G), Source (S), Drain (D). Dimensions conform to JEDEC MO-218, with footprint requiring minimum pad size per Vishay Application Note 826.

Pin/Terminal	Circuit Role	Design Meaning
G (Pin 1)	Gate control input	Accepts logic-level voltage; requires 15 nC charge for full enhancement
S (Pin 2)	Source reference node	Common return path for load current and gate drive reference
D (Pin 3)	Drain power output	Carries switched load current; thermally connected to exposed drain pad

Key Features

Feature	Design Value
TrenchFET® architecture	Delivers 0.045 Ω R_DS(on) in SOT-23, reducing conduction loss vs. planar MOSFETs
Halogen-free construction	Complies with IEC 61249-2-21, supporting RoHS-compliant industrial assembly
Low gate charge (Q_g)	15 nC enables efficient 1 MHz switching with minimal driver power consumption
Enhanced body diode	V_SD = 1.2 V at 1.25 A supports bidirectional current in H-bridge freewheeling

Applications

Stepper Motor Driver	USB Load Switch
Use Scenario: Half-bridge phase leg in bipolar stepper motor controller with 24 V supply and 1.5 A phase current. IC Role / Device Role / Timing Role: Low-side N-channel switch controlling current flow through motor winding. Use Value: 0.045 Ω R_DS(on) limits I²R loss to 100 mW per phase at 1.5 A, reducing thermal stress on PCB.	Use Scenario: Inrush-limited 5 V USB port power switch with automatic overcurrent shutdown. IC Role / Device Role / Timing Role: Single-FET load switch controlled by system PMIC enable signal. Use Value: 3.9 A rating and 1.25 W power dissipation support sustained 1.5 A USB loads without external heatsinking.
DC-DC Synchronous Rectifier	Industrial Sensor Interface
Use Scenario: Secondary-side synchronous rectifier in isolated 12 V → 3.3 V flyback converter. IC Role / Device Role / Timing Role: Actively clamped low-side switch replacing Schottky diode in rectification path. Use Value: Body diode forward voltage of 1.2 V and low R_DS(on) reduce conduction loss by >40% vs. 40 V Schottky.	Use Scenario: 24 V field sensor power switch in programmable logic controller (PLC) input module. IC Role / Device Role / Timing Role: Isolated load switch enabling/disabling sensor excitation under microcontroller command. Use Value: ±20 V gate rating and -55 °C to 150 °C operating range ensure reliability in harsh industrial environments.

Stepper Motor Driver

USB Load Switch

Use Scenario: Half-bridge phase leg in bipolar stepper motor controller with 24 V supply and 1.5 A phase current.

IC Role / Device Role / Timing Role: Low-side N-channel switch controlling current flow through motor winding.

Use Value: 0.045 Ω R_DS(on) limits I²R loss to 100 mW per phase at 1.5 A, reducing thermal stress on PCB.

Use Scenario: Inrush-limited 5 V USB port power switch with automatic overcurrent shutdown.

IC Role / Device Role / Timing Role: Single-FET load switch controlled by system PMIC enable signal.

Use Value: 3.9 A rating and 1.25 W power dissipation support sustained 1.5 A USB loads without external heatsinking.

DC-DC Synchronous Rectifier

Industrial Sensor Interface

Use Scenario: Secondary-side synchronous rectifier in isolated 12 V → 3.3 V flyback converter.

IC Role / Device Role / Timing Role: Actively clamped low-side switch replacing Schottky diode in rectification path.

Use Value: Body diode forward voltage of 1.2 V and low R_DS(on) reduce conduction loss by >40% vs. 40 V Schottky.

Use Scenario: 24 V field sensor power switch in programmable logic controller (PLC) input module.

IC Role / Device Role / Timing Role: Isolated load switch enabling/disabling sensor excitation under microcontroller command.

Use Value: ±20 V gate rating and -55 °C to 150 °C operating range ensure reliability in harsh industrial environments.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
DMN3020LSD-13	R_DS(on) = 0.028 Ω @ 10 V; higher 4.5 A I_D; same SOT-23 package	Better conduction efficiency at high current; slightly higher Q_g (18 nC)	Preferred when minimizing I²R loss at >3 A is critical and gate drive capability allows
AO3400	R_DS(on) = 0.026 Ω @ 10 V; 5.7 A I_D; 1.4 W P_D; same pinout	Higher current capacity but wider V_GS(th) range (0.7–1.4 V) demands tighter gate control	Selected where higher peak load current is required and gate drive voltage stability is assured

Compared with SI2318DS-T1-BE3, DMN3020LSD-13 offers lower on-resistance for improved efficiency at high current, while AO3400 provides greater current headroom but requires more precise gate biasing-both retain SOT-23 compatibility without PCB changes.

Availability

SI2318DS-T1-BE3 is available at Aetrix Electronics and suitable for stepper motor drivers, USB load switches, and industrial sensor interfaces requiring stable component supply and lead-free compliance.

Supply support for SI2318DS-T1-BE3 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 semiconductor manufacturer specializing in discrete power devices, sensors, and passive components, with emphasis on high-reliability and high-efficiency solutions.

The Si2318DS belongs to Vishay's TrenchFET® N-channel MOSFET product line, engineered for space-constrained DC-DC conversion, motor control, and load switching applications demanding low R_DS(on) and robust thermal performance in SOT-23.

FAQ

What is the maximum continuous drain current for SI2318DS-T1-BE3 at 70 °C ambient temperature?

The SI2318DS-T1-BE3 supports 2.4 A continuous drain current at T_A = 70 °C, as specified in the Absolute Maximum Ratings table. This derating reflects thermal limitations of the SOT-23 package on standard FR4 board; actual current capability depends on PCB copper area and airflow. The SI2318DS-T1-BE3 datasheet confirms this value under steady-state conditions with no pulse duty cycle applied.

Does SI2318DS-T1-BE3 support logic-level gate drive from a 3.3 V microcontroller?

Yes, SI2318DS-T1-BE3 has a gate threshold voltage range of 1–3 V, ensuring full enhancement with 3.3 V logic-level signals. At V_GS = 4.5 V, it delivers R_DS(on) = 0.058 Ω and I_D = 3.5 A, making it compatible with common 3.3 V MCU GPIOs without level-shifting. The SI2318DS-T1-BE3 specification sheet validates this behavior across temperature and process variations.

What is the thermal resistance junction-to-ambient for SI2318DS-T1-BE3 under steady-state conditions?

The SI2318DS-T1-BE3 has a maximum junction-to-ambient thermal resistance (R_thJA) of 166 °C/W under steady-state conditions on a 1" × 1" FR4 board, as stated in the Thermal Resistance Ratings table. This value assumes standard JEDEC test conditions and defines the worst-case temperature rise per watt of power dissipated. The SI2318DS-T1-BE3 thermal performance is validated per JESD51-2.

Is SI2318DS-T1-BE3 halogen-free and RoHS compliant?

Yes, SI2318DS-T1-BE3 is both halogen-free per IEC 61249-2-21 and RoHS-compliant, as confirmed in the Features section and Ordering Information. The "-BE3" suffix denotes lead-free and halogen-free packaging, verified by Vishay's material declarations and certified by third-party testing. The SI2318DS-T1-BE3 meets all applicable environmental regulations for industrial and consumer electronics.

Can SI2318DS-T1-BE3 be used in reverse-conducting applications such as freewheeling paths?

Yes, SI2318DS-T1-BE3 integrates a body diode with V_SD = 1.2 V at I_S = 1.25 A and zero gate bias, enabling use in freewheeling and reverse-current paths. Its diode exhibits soft recovery characteristics suitable for stepper motor and DC-DC converter applications. The SI2318DS-T1-BE3 datasheet specifies this parameter under TJ = 25 °C and confirms functionality across the full operating temperature range.

SI2318DS-T1-BE3 Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Siliconix

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 40 V

Current - Continuous Drain (Id) @ 25°C:: 3A (Ta)

Drive Voltage (Max Rds On, Min Rds On):: 4.5V, 10V

Rds On (Max) @ Id, Vgs:: 45mOhm @ 3.9A, 10V

Vgs(th) (Max) @ Id:: 3V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 15 nC @ 10 V

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 540 pF @ 20 V

FET Feature:: -

Power Dissipation (Max):: 750mW (Ta)

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3 (TO-236)

SI2318DS-T1-BE3 FAQ

1.How can I place an order for SI2318DS-T1-BE3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI2318DS-T1-BE3 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 SI2318DS-T1-BE3 reliable?

The price and inventory of SI2318DS-T1-BE3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI2318DS-T1-BE3 is usually 5 days.

3.What payment methods are accepted for SI2318DS-T1-BE3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI2318DS-T1-BE3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI2318DS-T1-BE3?

SI2318DS-T1-BE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI2318DS-T1-BE3 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 SI2318DS-T1-BE3?

For technical support, including SI2318DS-T1-BE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI2318DS-T1-BE3 requirements.

6.How does Aetrix verify that SI2318DS-T1-BE3 is sourced from the original manufacturer or authorized distributors?

All SI2318DS-T1-BE3 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 SI2318DS-T1-BE3 meets industry standards.

7.What is the process for return or replacement of SI2318DS-T1-BE3?

All SI2318DS-T1-BE3 units undergo pre-shipment inspection (PSI). If there is an issue with SI2318DS-T1-BE3, 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 SI2318DS-T1-BE3 part is unused and in its original packaging.

Return procedure for SI2318DS-T1-BE3:

1.Submit a request within 90 days.

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

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