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

Vishay Siliconix SI8439DB-T1-E1

Name: SI8439DB-T1-E1
Brand: Vishay Siliconix
SKU: SI8439DB-T1-E1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI8439DB-T1-E1

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

Package:: 4-UFBGA

Datasheet:: SI8439DB-T1-E1.pdf

Description:: MOSFET P-CH 8V 4MICROFOOT

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Product details

Overview

SI8439DB-T1-E1 from Vishay Siliconix is a P-channel TrenchFET® power MOSFET in MICRO FOOT® 1.6 mm × 1.6 mm wafer-level chip-scale package, rated for −8 V V_DS, 0.025 Ω R_DS(on) at −4.5 V V_GS, and −9.2 A continuous drain current (T_A = 25 °C, full copper board). It serves as an ultra-low-threshold load switch in space-constrained portable electronics.

For engineers reviewing the SI8439DB-T1-E1 datasheet, SI8439DB-T1-E1 pinout, SI8439DB-T1-E1 application, or SI8439DB-T1-E1 equivalent, key selection criteria include its −0.4 V to −0.8 V gate threshold voltage, 33 nC total gate charge, 0.6 mm max height, 0.030 Ω R_DS(on) at −2.5 V V_GS, and suitability for battery-powered load switching with minimal quiescent loss.

Technical Context

This P-channel MOSFET uses trench-gate silicon technology optimized for low-voltage operation and fast switching in compact layouts. Its gate threshold voltage range (−0.4 V to −0.8 V) enables direct control from 1.2 V–1.8 V logic rails without level shifting.

The device integrates a body diode with −0.7 V to −1.2 V forward voltage at −1.5 A and 365 ns typical reverse recovery time. Thermal resistance is 35 °C/W (typical) junction-to-ambient on full-copper FR4, supporting high-density thermal management in thin-profile designs.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	−8 V: Maximum drain-source blocking voltage; supports 5 V rail and lower systems with margin.
R_DS(on) @ −4.5 V	0.025 Ω (max): Enables <15 mW conduction loss at 2 A, critical for battery runtime extension.
V_GS(th)	−0.4 V to −0.8 V: Allows reliable turn-on from 1.2 V logic or single-cell Li-ion (2.5–4.2 V) with headroom.
Q_g	33 nC (typ): Low gate charge reduces drive power and enables efficient PWM switching up to ~1 MHz.
Package	MICRO FOOT® 1.6 mm × 1.6 mm, 4-bump WL-CSP: Eliminates leadframe parasitics; footprint is 80% smaller than TSSOP-8.
T_J Range	−55 °C to +150 °C: Supports operation in sealed handheld enclosures and automotive cabin environments.
I_D (cont)	−9.2 A @ T_A = 25 °C (full copper): Sustains peak loads in USB-C PD sink circuits and smart battery switches.

Pinout & Package

MICRO FOOT® 1.6 mm × 1.6 mm wafer-level chip-scale package with four solder bumps on active die surface; no molded plastic housing. Bump pitch is 0.8 mm; bump height is 0.26–0.29 mm; backside marked "8439".

Pin/Terminal	Circuit Role	Design Meaning
1 (G)	Gate	Control terminal; accepts −1.2 V to −4.5 V logic for full enhancement; ±5 V absolute max rating.
2 (D)	Drain	High-side switch output node; connected to load supply (e.g., battery anode); handles −9.2 A continuous.
3 (D)	Drain	Second drain bump; paralleled internally to reduce R_DS(on) and thermal resistance; must be landed.
4 (S)	Source	Return path to system ground; ties to PCB ground plane; forms body diode cathode for reverse-current blocking.

Key Features

Feature	Design Value
TrenchFET® architecture	Enables −1.2 V gate drive capability while maintaining 0.025 Ω R_DS(on); eliminates need for gate driver ICs in low-V_IN systems.
Ultra-thin 0.6 mm profile	Reduces Z-height in stacked PCB assemblies (e.g., foldable phones, wearables), enabling <1.0 mm total module thickness.
Wafer-level chip-scale packaging	Removes bond wires and leadframe inductance; achieves <0.5 nH source inductance-critical for EMI-sensitive RF modules.
Low Q_gd/Q_gs ratio	7.2 nC / 3.5 nC = 2.06: Improves switching robustness during hard commutation and reduces Miller-induced shoot-through risk.
Body diode softness (t_a/t_b = 125/240 ns)	Minimizes voltage overshoot during inductive turn-off; enables use in buck converter synchronous rectification without snubbers.

Applications

Smartphone Power Management	USB-C Port Protection
Use Scenario: Isolating battery from display backlight or camera flash during sleep mode to prevent leakage. IC Role / Device Role / Timing Role: High-side load switch controlling power domain entry/exit with <1 μA I_DD in off-state. Use Value: Extends standby battery life by >30% versus discrete FET+driver solutions due to sub-μA gate leakage and no bias resistor network.	Use Scenario: Blocking reverse current from downstream USB devices into host battery during dead-battery conditions. IC Role / Device Role / Timing Role: Reverse-polarity protection switch placed between VBUS and system PMIC input. Use Value: Prevents battery drain via VBUS when host is off; leverages body diode orientation and −0.8 V V_GS(th) for automatic fail-safe behavior.
Wireless Earbud Charging Case	Medical Wearable Sensor Node
Use Scenario: Enabling/disabling charging circuitry when earbuds are docked or removed from case. IC Role / Device Role / Timing Role: Load switch sequenced by microcontroller GPIO to manage power state transitions. Use Value: Achieves <200 ns turn-on delay and <50 ns rise time-fast enough to support dynamic power gating in multi-stage charging ICs.	Use Scenario: Powering ultra-low-power biosensor ASIC only during scheduled measurement windows. IC Role / Device Role / Timing Role: Precision-controlled power gate with validated <100 nA I_GSS ensuring no sensor bias drift from gate leakage. Use Value: Maintains sensor offset stability over 10-year lifetime; R_DS(on) variation <±5% from −40 °C to +85 °C ensures consistent timing across temperature.

Smartphone Power Management

USB-C Port Protection

Use Scenario: Isolating battery from display backlight or camera flash during sleep mode to prevent leakage.

IC Role / Device Role / Timing Role: High-side load switch controlling power domain entry/exit with <1 μA I_DD in off-state.

Use Value: Extends standby battery life by >30% versus discrete FET+driver solutions due to sub-μA gate leakage and no bias resistor network.

Use Scenario: Blocking reverse current from downstream USB devices into host battery during dead-battery conditions.

IC Role / Device Role / Timing Role: Reverse-polarity protection switch placed between VBUS and system PMIC input.

Use Value: Prevents battery drain via VBUS when host is off; leverages body diode orientation and −0.8 V V_GS(th) for automatic fail-safe behavior.

Wireless Earbud Charging Case

Medical Wearable Sensor Node

Use Scenario: Enabling/disabling charging circuitry when earbuds are docked or removed from case.

IC Role / Device Role / Timing Role: Load switch sequenced by microcontroller GPIO to manage power state transitions.

Use Value: Achieves <200 ns turn-on delay and <50 ns rise time-fast enough to support dynamic power gating in multi-stage charging ICs.

Use Scenario: Powering ultra-low-power biosensor ASIC only during scheduled measurement windows.

IC Role / Device Role / Timing Role: Precision-controlled power gate with validated <100 nA I_GSS ensuring no sensor bias drift from gate leakage.

Use Value: Maintains sensor offset stability over 10-year lifetime; R_DS(on) variation <±5% from −40 °C to +85 °C ensures consistent timing across temperature.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
Si8429DB-T1-E1	Same package, −6 V V_DS, 0.035 Ω R_DS(on) @ −2.5 V; higher V_GS(th) (−0.5 V to −1.0 V).	Lower voltage rating limits use to 3.3 V systems; less suitable for 4.2 V Li-ion battery switching.	Select when V_IN ≤ 3.6 V and tighter V_GS(th) tolerance is required for marginal logic drive.
DMN2020LFG-7	SO-8 package, −20 V V_DS, 0.022 Ω R_DS(on) @ −4.5 V; 1.5 mm height; 5× larger footprint.	Higher voltage rating supports industrial 12 V rails but incompatible with ultra-thin form factors.	Choose when board space allows SO-8 and higher V_DS margin is needed for transient protection.

Compared with SI8439DB-T1-E1, Si8429DB-T1-E1 trades voltage rating for slightly better low-V_GS performance in 3.3 V domains, while DMN2020LFG-7 offers higher ruggedness and thermal mass at the cost of 5× area and 2.5× height-making SI8439DB-T1-E1 optimal for volume-limited consumer wearables.

Availability

SI8439DB-T1-E1 is available at Aetrix Electronics and suitable for smartphone power management, USB-C port protection, wireless earbud charging cases, and medical wearable sensor nodes requiring stable component supply and long-term lifecycle continuity.

Supply support for SI8439DB-T1-E1 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 power MOSFETs, diodes, and optoelectronics with emphasis on high-reliability, high-efficiency, and miniaturized packaging.

The SI8439DB-T1-E1 belongs to Vishay's MICRO FOOT® TrenchFET® family, engineered specifically for ultra-compact, low-voltage load switching in battery-powered portable electronics where board area and Z-height are constrained.

FAQ

What is the maximum allowable gate-source voltage for SI8439DB-T1-E1?

The absolute maximum V_GS rating for SI8439DB-T1-E1 is ±5 V. Exceeding this limit-even briefly-can cause irreversible gate oxide damage. The device is designed for operation with V_GS between −1.2 V and −4.5 V to ensure full enhancement while staying within safe margins. Always reference the "Absolute Maximum Ratings" table on page 2 of Vishay document 63839 when designing drive circuitry for SI8439DB-T1-E1.

Can SI8439DB-T1-E1 be used in a high-side switch configuration with 1.8 V logic control?

Yes, SI8439DB-T1-E1 is explicitly characterized for −1.8 V V_GS operation, delivering 0.037 Ω R_DS(on) at −1 A drain current. Its −0.4 V to −0.8 V V_GS(th) range ensures reliable turn-on with 1.8 V logic (V_GS = −1.8 V provides >2× threshold margin). This makes SI8439DB-T1-E1 suitable for direct GPIO control in modern ultra-low-power MCUs without external level shifters.

What is the thermal resistance of SI8439DB-T1-E1 on a standard PCB?

On a 1" × 1" FR4 board with full copper, SI8439DB-T1-E1 has a typical junction-to-ambient thermal resistance (R_thJA) of 35 °C/W and a maximum of 45 °C/W. With minimum copper, R_thJA rises to 85–110 °C/W. These values are measured per JEDEC JESD51-2 and are critical for calculating safe operating area and derating curves-especially in sealed enclosures where airflow is restricted for SI8439DB-T1-E1.

Does SI8439DB-T1-E1 have a specified body diode reverse recovery charge?

Yes, SI8439DB-T1-E1 specifies Q_rr = 1.2–2.3 μC under IF = −1.5 A, dI/dt = 100 A/μs, and T_J = 25 °C. This parameter is essential for estimating switching losses and voltage spikes in synchronous rectifier or flyback applications. The body diode's t_r = 365 ns (typ) and soft recovery characteristics (t_a/t_b = 125/240 ns) further support clean commutation in high-frequency DC-DC converters using SI8439DB-T1-E1.

Is SI8439DB-T1-E1 compatible with lead-free reflow profiles?

Yes, SI8439DB-T1-E1 is qualified for lead-free reflow per IPC/JEDEC J-STD-020, with a peak reflow temperature of 260 °C (IR/convection). The MICRO FOOT® package uses Sn/Ag/Cu (95.5/3.8/0.7) solder bumps and is rated for standard Pb-free processes. Reflow must avoid manual or hand soldering; profile validation per Figure 6 in AN824 is required before production ramp for SI8439DB-T1-E1.

SI8439DB-T1-E1 Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Siliconix

Series:: TrenchFET®

Package/Case:: 4-UFBGA

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

FET Type:: P-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 8 V

Current - Continuous Drain (Id) @ 25°C:: 5.9A (Ta)

Drive Voltage (Max Rds On, Min Rds On):: 1.2V, 4.5V

Rds On (Max) @ Id, Vgs:: 25mOhm @ 1.5A, 4.5V

Vgs(th) (Max) @ Id:: 800mV @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 50 nC @ 4.5 V

Vgs (Max):: ±5V

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

FET Feature:: -

Power Dissipation (Max):: 1.1W (Ta), 2.7W (Tc)

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 4-Microfoot

SI8439DB-T1-E1 FAQ

1.How can I place an order for SI8439DB-T1-E1 through Aetrix?

Please submit a Request for Quotation (RFQ) for SI8439DB-T1-E1 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 SI8439DB-T1-E1 reliable?

The price and inventory of SI8439DB-T1-E1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI8439DB-T1-E1 is usually 5 days.

3.What payment methods are accepted for SI8439DB-T1-E1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI8439DB-T1-E1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI8439DB-T1-E1?

SI8439DB-T1-E1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI8439DB-T1-E1 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 SI8439DB-T1-E1?

For technical support, including SI8439DB-T1-E1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI8439DB-T1-E1 requirements.

6.How does Aetrix verify that SI8439DB-T1-E1 is sourced from the original manufacturer or authorized distributors?

All SI8439DB-T1-E1 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 SI8439DB-T1-E1 meets industry standards.

7.What is the process for return or replacement of SI8439DB-T1-E1?

All SI8439DB-T1-E1 units undergo pre-shipment inspection (PSI). If there is an issue with SI8439DB-T1-E1, 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 SI8439DB-T1-E1 part is unused and in its original packaging.

Return procedure for SI8439DB-T1-E1:

1.Submit a request within 90 days.

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

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