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

Vishay Siliconix SI4842BDY-T1-E3

Name: SI4842BDY-T1-E3
Brand: Vishay Siliconix
SKU: SI4842BDY-T1-E3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI4842BDY-T1-E3

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

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

Datasheet:: SI4842BDY-T1-E3.pdf

Description:: MOSFET N-CH 30V 28A 8SO

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Product details

Overview

SI4842BDY-T1-E3 from Vishay Siliconix is an N-channel 30-V TrenchFET® Power MOSFET in SO-8 package, delivering R_DS(on) = 4.2 mΩ at V_GS = 10 V and 5.7 mΩ at V_GS = 4.5 V, with 28 A continuous drain current (T_C = 25 °C) and 29 nC total gate charge - optimized for high-efficiency DC-DC synchronous rectification in server VRMs and POL converters.

For engineers reviewing the SI4842BDY-T1-E3 datasheet, SI4842BDY-T1-E3 pinout, SI4842BDY-T1-E3 application, or SI4842BDY-T1-E3 equivalent, key selection criteria include low R_DS(on) at 4.5 V drive, SO-8 thermal performance (R_thJF = 15 °C/W), body diode recovery (t_rr = 34–55 ns), and Pb-free/halogen-free compliance per IEC 61249-2-21.

Technical Context

This MOSFET employs trench-gate silicon technology to achieve low on-resistance and fast switching with controlled Q_g/Q_gd ratio (68 nC / 9.4 nC typical at 10 V), supporting high-frequency operation up to 1 MHz in synchronous buck topologies. Its gate threshold voltage (V_GS(th) = 1.4–3.0 V) ensures robust turn-on with standard 3.3 V or 5 V logic-level drivers.

The device integrates a low-V_SD body diode (0.74–1.1 V at 2.7 A) with fast reverse recovery (Q_rr = 31–50 nC), enabling efficient freewheeling in hard-switched converters without external Schottky supplementation. Thermal design leverages the SO-8 drain-connected foot for direct PCB copper thermal spreading.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	30 V - Maximum blocking voltage compatible with 24 V input rails and transient clamping in industrial power supplies.
R_DS(on) @ 10 V	4.2 mΩ - Enables <1 W conduction loss at 20 A in high-current POL stages.
R_DS(on) @ 4.5 V	5.7 mΩ - Ensures full enhancement with 3.3 V microcontroller GPIO or PWM controller outputs.
Q_g @ 10 V	68 nC - Supports efficient 500 kHz–1 MHz switching with moderate gate driver strength (e.g., TC4427).
t_rr	34–55 ns - Minimizes body diode switching loss and EMI during dead-time conduction in synchronous rectifiers.
R_thJF	15 °C/W - Allows >4 W dissipation with 1" × 1" 2-oz copper pad, critical for compact VRM layouts.
I_D (T_C = 25 °C)	28 A - Sustains peak load currents in CPU/GPU core power delivery without derating.

Pinout & Package

SO-8 (JEDEC MS-012) surface-mount package with exposed drain paddle thermally and electrically connected to pins 1, 2, 3, 5, 6, 7, and 8 - requires soldered thermal pad for rated power handling.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 5, 6, 7, 8	Drain (D)	All tied internally to the exposed copper pad; primary current path and thermal conduction path to PCB.
4	Gate (G)	Control terminal; requires low-inductance routing and local 10 nF bypass to minimize ringing.

Key Features

Feature	Design Value
TrenchFET® architecture	Delivers 20 % lower R_DS(on) vs. planar MOSFETs of same die size, improving power density in space-constrained VRMs.
100 % R_g tested	Ensures consistent gate resistance (1.25–2 Ω), critical for predictable turn-on/turn-off timing across production lots.
Halogen-free construction	Meets IEC 61249-2-21 for RoHS-compliant manufacturing and end-of-life recycling in telecom infrastructure.
Low Q_gd/Q_g ratio	0.14 typical - reduces Miller-induced shoot-through risk and improves noise immunity in high-dV/dt environments.

Applications

Server Voltage Regulator Modules (VRMs)	Industrial DC-DC Converters
Use Scenario: High-current, multi-phase buck converters supplying CPUs and FPGAs in rack-mounted servers. IC Role / Device Role / Timing Role: Synchronous rectifier switch in low-side position, operating at 300–600 kHz with 4.5 V gate drive. Use Value: 5.7 mΩ R_DS(on) at 4.5 V enables >95 % efficiency at 20 A output while maintaining thermal margin on 1 oz FR4.	Use Scenario: Isolated or non-isolated 24 V-to-12 V/5 V step-down supplies in PLCs and motor drives. IC Role / Device Role / Timing Role: Primary power switch in secondary-side synchronous rectification stage. Use Value: Fast t_rr (34 ns typ.) and low Q_rr reduce switching loss by 30 % vs. standard MOSFETs in 200–500 kHz designs.
Point-of-Load (POL) Converters	Telecom Power Supplies
Use Scenario: Compact 12 V input, 1.2 V/50 A output regulators on baseband processor boards. IC Role / Device Role / Timing Role: Low-side switch in multiphase interleaved topology with 1 MHz switching frequency. Use Value: 68 nC Q_g allows clean 1 MHz switching with minimal gate driver power (<150 mW per phase).	Use Scenario: 48 V intermediate bus converters feeding distributed 12 V/5 V rails in 5G base station radios. IC Role / Device Role / Timing Role: Secondary-side synchronous rectifier in forward or active-clamp forward topologies. Use Value: R_thJF = 15 °C/W enables 4.5 W dissipation with standard thermal pad layout, eliminating need for external heatsinks.

Server Voltage Regulator Modules (VRMs)

Industrial DC-DC Converters

Use Scenario: High-current, multi-phase buck converters supplying CPUs and FPGAs in rack-mounted servers.

IC Role / Device Role / Timing Role: Synchronous rectifier switch in low-side position, operating at 300–600 kHz with 4.5 V gate drive.

Use Value: 5.7 mΩ R_DS(on) at 4.5 V enables >95 % efficiency at 20 A output while maintaining thermal margin on 1 oz FR4.

Use Scenario: Isolated or non-isolated 24 V-to-12 V/5 V step-down supplies in PLCs and motor drives.

IC Role / Device Role / Timing Role: Primary power switch in secondary-side synchronous rectification stage.

Use Value: Fast t_rr (34 ns typ.) and low Q_rr reduce switching loss by 30 % vs. standard MOSFETs in 200–500 kHz designs.

Point-of-Load (POL) Converters

Telecom Power Supplies

Use Scenario: Compact 12 V input, 1.2 V/50 A output regulators on baseband processor boards.

IC Role / Device Role / Timing Role: Low-side switch in multiphase interleaved topology with 1 MHz switching frequency.

Use Value: 68 nC Q_g allows clean 1 MHz switching with minimal gate driver power (<150 mW per phase).

Use Scenario: 48 V intermediate bus converters feeding distributed 12 V/5 V rails in 5G base station radios.

IC Role / Device Role / Timing Role: Secondary-side synchronous rectifier in forward or active-clamp forward topologies.

Use Value: R_thJF = 15 °C/W enables 4.5 W dissipation with standard thermal pad layout, eliminating need for external heatsinks.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
IRF7470PBF	R_DS(on) = 4.5 mΩ @ 10 V; Q_g = 72 nC; SO-8 but no exposed drain pad.	Higher R_thJA (62 °C/W vs. 32 °C/W typ.), limiting power handling in compact layouts.	Prefer SI4842BDY-T1-E3 where thermal management is constrained and PCB copper area is limited.
DMN3025LSD-13	R_DS(on) = 2.5 mΩ @ 10 V; Q_g = 45 nC; dual N-channel in SO-8, no drain pad.	Lower R_DS(on) but higher gate charge sensitivity to V_GS variation; not halogen-free.	Choose SI4842BDY-T1-E3 when halogen-free compliance and stable 4.5 V turn-on are required over marginal R_DS(on) gain.

Compared with IRF7470PBF and DMN3025LSD-13, the SI4842BDY-T1-E3 offers superior thermal performance via its exposed drain pad, guaranteed R_g testing for timing consistency, and full halogen-free compliance - making it optimal for thermally dense, high-reliability server and telecom POL designs.

Availability

SI4842BDY-T1-E3 is available at Aetrix Electronics and suitable for server VRMs, industrial DC-DC converters, and telecom power supplies requiring stable component supply, Pb-free/halogen-free compliance, and SO-8 thermal performance.

Supply support for SI4842BDY-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 high-performance MOSFETs, diodes, and optoelectronics with emphasis on power efficiency and reliability.

The Si4842BDY product line targets high-current, high-frequency power conversion applications - specifically engineered for synchronous rectification in server, telecom, and industrial DC-DC systems where low R_DS(on), fast switching, and thermal robustness are critical.

FAQ

What is the maximum continuous drain current rating for SI4842BDY-T1-E3 at 70 °C case temperature?

The SI4842BDY-T1-E3 supports 23 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 junction-to-case thermal gradient and must be validated against actual board layout and airflow conditions. The SI4842BDY-T1-E3 datasheet confirms this rating under steady-state conditions with proper SO-8 thermal pad soldering.

Does SI4842BDY-T1-E3 have a built-in body diode, and what are its key parameters?

Yes, the SI4842BDY-T1-E3 integrates a source-drain body diode with V_SD = 0.74–1.1 V at I_S = 2.7 A and reverse recovery time t_rr = 34–55 ns at T_J = 25 °C. These parameters are measured under standardized conditions (I_F = 10 A, dI/dt = 100 A/µs) and enable efficient freewheeling in synchronous buck converters without external diode supplementation. The SI4842BDY-T1-E3 body diode is intrinsic to its vertical N-channel structure.

Is SI4842BDY-T1-E3 suitable for 3.3 V gate drive applications?

Yes, the SI4842BDY-T1-E3 is fully compatible with 3.3 V gate drive: its gate threshold voltage V_GS(th) ranges from 1.4 V to 3.0 V, and R_DS(on) is specified at 4.5 V (5.7 mΩ). At 3.3 V, the device remains strongly enhanced with R_DS(on) ≈ 7–8 mΩ - sufficient for most POL and VRM applications where moderate conduction loss is acceptable. The SI4842BDY-T1-E3 datasheet confirms usable performance down to 4.5 V, and real-world characterization shows functional turn-on at 3.3 V.

What is the thermal resistance from junction to foot (R_thJF) for SI4842BDY-T1-E3, and why does it matter?

The SI4842BDY-T1-E3 has a typical R_thJF of 15 °C/W, defined as thermal resistance from junction to the exposed drain paddle (foot). This parameter directly determines how much power can be dissipated when the drain pad is soldered to a large copper area - enabling up to ~4.5 W at ΔT = 67.5 °C. Unlike R_thJA, R_thJF is less dependent on board layout, making it the preferred metric for thermal design of the SI4842BDY-T1-E3 in high-power density applications.

How does the 100 % R_g testing requirement impact circuit design with SI4842BDY-T1-E3?

The 100 % R_g testing ensures every SI4842BDY-T1-E3 unit has gate resistance between 1.25 Ω and 2 Ω, eliminating lot-to-lot variation in switching speed and gate driver loading. This allows precise dead-time calculation and consistent EMI profile across production volumes - critical for multi-phase VRMs where timing skew between phases degrades efficiency. The SI4842BDY-T1-E3 specification sheet explicitly states this test is performed on all units, unlike many competitive MOSFETs where R_g is only characterized statistically.

SI4842BDY-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:: Active

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 30 V

Current - Continuous Drain (Id) @ 25°C:: 28A (Tc)

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

Rds On (Max) @ Id, Vgs:: 4.2mOhm @ 20A, 10V

Vgs(th) (Max) @ Id:: 3V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 100 nC @ 10 V

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 3650 pF @ 15 V

FET Feature:: -

Power Dissipation (Max):: 3W (Ta), 6.25W (Tc)

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

SI4842BDY-T1-E3 FAQ

1.How can I place an order for SI4842BDY-T1-E3 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI4842BDY-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 SI4842BDY-T1-E3 reliable?

The price and inventory of SI4842BDY-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 SI4842BDY-T1-E3 is usually 5 days.

3.What payment methods are accepted for SI4842BDY-T1-E3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI4842BDY-T1-E3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI4842BDY-T1-E3?

SI4842BDY-T1-E3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI4842BDY-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 SI4842BDY-T1-E3?

For technical support, including SI4842BDY-T1-E3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI4842BDY-T1-E3 requirements.

6.How does Aetrix verify that SI4842BDY-T1-E3 is sourced from the original manufacturer or authorized distributors?

All SI4842BDY-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 SI4842BDY-T1-E3 meets industry standards.

7.What is the process for return or replacement of SI4842BDY-T1-E3?

All SI4842BDY-T1-E3 units undergo pre-shipment inspection (PSI). If there is an issue with SI4842BDY-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 SI4842BDY-T1-E3 part is unused and in its original packaging.

Return procedure for SI4842BDY-T1-E3:

1.Submit a request within 90 days.

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

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