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Diodes Incorporated BSS138W-7

Name: BSS138W-7
Brand: Diodes Incorporated
SKU: BSS138W-7
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BSS138W-7

Manufacturer:: Diodes Incorporated

Category:: FETs, MOSFETs

Package:: SC-70, SOT-323

Datasheet:: BSS138W-7.pdf

Description:: MOSFET N-CH 50V 0.2A SOT323

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BSS138W-7 from Diodes Incorporated is an N-channel enhancement-mode MOSFET in SOT323 package, rated for 50V V_DSS, 3.5Ω R_DS(ON) at V_GS = 10V, and 200mA continuous drain current - optimized for low-voltage load switching in space-constrained portable electronics.

For engineers reviewing the BSS138W-7 datasheet, BSS138W-7 pinout, BSS138W-7 application, or BSS138W-7 equivalent, key selection criteria include gate threshold voltage (0.5–1.5V), low input capacitance (50pF C_iss), fast switching (20ns t_D(ON)/t_D(OFF)), and RoHS-compliant "Green" packaging suitable for consumer and industrial power management designs.

Technical Context

This discrete MOSFET operates as a single-polarity voltage-controlled switch with enhancement-mode behavior: conduction initiates only when V_GS exceeds the threshold (0.5–1.5V), enabling precise digital control of low-power loads. Its low R_DS(ON) and minimal gate charge support efficient on/off cycling in battery-powered systems.

The device features integrated body diode (V_SD ≈ 1.2V at 0.1A), specified dynamic parameters (C_iss = 50pF, C_oss = 25pF, C_rss = 8.0pF), and thermal resistance of 625°C/W - all measured under standard FR-4 PCB mounting per JESD51-2.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DSS	50V - maximum drain-source blocking voltage before avalanche breakdown
R_DS(ON)	3.5Ω @ V_GS = 10V - ensures <100mW conduction loss at 200mA load current
V_GS(TH)	0.5–1.5V - enables direct drive from 1.8V/3.3V logic without level-shifting
C_iss	50pF - limits gate drive energy and supports >1MHz switching in low-power DC-DC stages
t_D(ON)/t_D(OFF)	20ns each - enables clean edge transitions in high-speed enable/disable control
P_D	200mW - defines maximum steady-state power dissipation on standard FR-4 board
T_J Range	−55°C to +150°C - supports operation in extended-temperature industrial and automotive-adjacent environments

Pinout & Package

Package: SOT323 - surface-mount plastic case, 0.006g weight, UL 94V-0 rated, moisture sensitivity level 1 per J-STD-020.

Pin/Terminal	Circuit Role	Design Meaning
1 (Source)	Current return path for channel conduction	Connected to ground or low-side reference; forms body diode cathode
2 (Gate)	Control electrode for channel formation	High-impedance input requiring <100nA leakage; driven by CMOS logic
3 (Drain)	Current entry point into channel	Connected to load supply rail; forms body diode anode

Key Features

Feature	Design Value
Low gate threshold voltage	Enables full enhancement with 1.8V I/O rails - eliminates need for gate drivers in microcontroller-peripheral interfaces
Low input capacitance	50pF C_iss reduces gate drive power and speeds up turn-on/turn-off transitions
Fast switching speed	20ns delay times minimize overlap conduction loss in PWM-controlled power paths
Lead-free & halogen-free construction	Meets RoHS 3 (2015/863/EU) and Diodes' "Green" definition (<900ppm Br/Cl, <1000ppm Sb)

Applications

USB Port Power Switching

Smartphone Battery Protection

Use Scenario: Enabling/disabling VBUS power to downstream USB peripherals based on enumeration status.

IC Role / Device Role / Timing Role: Low-side load switch controlling 5V rail with logic-level gate drive from USB controller.

Use Value: 0.5–1.5V V_GS(TH) ensures reliable turn-on from 1.8V GPIO; 3.5Ω R_DS(ON) limits voltage drop to <700mV at 200mA.

Use Scenario: Isolating backup battery from system during charging or fault conditions.

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

Use Value: Integrated body diode blocks reverse current; 200mA rating matches typical Li-ion charge termination thresholds.

IoT Sensor Node Power Gating

Wearable Display Backlight Control

Use Scenario: Shutting down RF transceiver or environmental sensor during sleep mode to reduce quiescent current.

IC Role / Device Role / Timing Role: High-side or low-side switch in always-on power domain controlled by MCU wake signal.

Use Value: 100nA IGSS leakage preserves µA-level sleep current budgets; 20ns switching avoids timing jitter in wake-up sequences.

Use Scenario: Modulating LED backlight brightness via PWM dimming in compact OLED displays.

IC Role / Device Role / Timing Role: Low-side current sink switching 20–100mA LED strings at 1–5kHz.

Use Value: 50pF C_iss allows clean 5kHz square-wave drive with minimal gate driver overhead; SOT323 footprint fits tight display bezel layouts.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
DMN2004K-7	R_DS(ON) = 2.8Ω @ V_GS = 4.5V; higher gate charge (Q_g = 2.1nC vs. ~1.2nC)	Better performance at 3.3V drive but larger SOT-23 footprint	Select when lower on-resistance at 3.3V is critical and board area permits SOT-23
2N7002K-7	V_GS(TH) = 1.0–2.5V; higher R_DS(ON) (5.5Ω @ 10V); same SOT323 package	Less sensitive to noise-induced turn-on but requires stronger gate drive	Select when higher noise immunity is needed and 5.5Ω R_DS(ON) is acceptable

Compared with DMN2004K-7 and 2N7002K-7, BSS138W-7 offers the lowest gate threshold and smallest footprint among SOT323 N-MOSFETs - making it optimal for 1.8V/3.3V logic-driven, space-limited load switching where minimal gate drive strength and ultra-low standby leakage are prioritized.

Availability

BSS138W-7 is available at Aetrix Electronics and suitable for USB power delivery, IoT sensor node power gating, and wearable display backlight control requiring stable component supply across production lifecycles.

Supply support for BSS138W-7 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.

The BSS138W-7 belongs to Diodes' general-purpose small-signal MOSFET product line, engineered specifically for low-voltage, low-current load switching in portable and battery-operated equipment where size, efficiency, and logic compatibility are critical.

FAQ

What is the maximum safe operating voltage for BSS138W-7?

The absolute maximum drain-source voltage (V_DSS) is 50V, verified per datasheet DS30206 Rev. 16-2. Operation above this rating risks avalanche breakdown and permanent damage. Derating is recommended for reliability in high-temperature or high-humidity environments, especially when used with inductive loads that generate voltage spikes.

Can BSS138W-7 be driven directly from a 1.8V microcontroller GPIO?

Yes - its gate threshold voltage range (0.5–1.5V) ensures full enhancement at 1.8V V_GS, with R_DS(ON) dropping to ~2.0Ω (typical). Measured transfer characteristics (Fig. 2) confirm >150mA drain current at V_GS = 1.8V and V_DS = 1V, supporting robust low-voltage switching without external level shifters.

Does BSS138W-7 include an integrated body diode, and what are its specifications?

Yes - it features a parasitic N-channel body diode with forward voltage ~1.2V at 0.1A (Fig. 9), anode at Drain and cathode at Source. This diode enables freewheeling in inductive loads and reverse-current blocking in battery-isolation circuits, though it is not rated for continuous high-current conduction like discrete Schottky diodes.

Is BSS138W-7 qualified for automotive applications?

No - the BSS138W-7 is not AEC-Q101 qualified. Diodes offers the pin-compatible BSS138WQ variant for automotive use, which undergoes stress testing per AEC-Q101, is manufactured in IATF 16949-certified facilities, and supports PPAP documentation. Standard BSS138W-7 is intended for commercial and industrial applications only.

BSS138W-7 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: SC-70, SOT-323

Packaging:: Tape & Reel (TR)

Product Status:: Discontinued at Digi-Key

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 50 V

Current - Continuous Drain (Id) @ 25°C:: 200mA (Ta)

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

Rds On (Max) @ Id, Vgs:: 3.5Ohm @ 220mA, 10V

Vgs(th) (Max) @ Id:: 1.5V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: -

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 50 pF @ 10 V

FET Feature:: -

Power Dissipation (Max):: 200mW (Ta)

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323

BSS138W-7 FAQ

1.How can I place an order for BSS138W-7 through Aetrix?

Please submit a Request for Quotation (RFQ) for BSS138W-7 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 BSS138W-7 reliable?

The price and inventory of BSS138W-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BSS138W-7 is usually 5 days.

3.What payment methods are accepted for BSS138W-7?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BSS138W-7 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BSS138W-7?

BSS138W-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BSS138W-7 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 BSS138W-7?

For technical support, including BSS138W-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BSS138W-7 requirements.

6.How does Aetrix verify that BSS138W-7 is sourced from the original manufacturer or authorized distributors?

All BSS138W-7 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 BSS138W-7 meets industry standards.

7.What is the process for return or replacement of BSS138W-7?

All BSS138W-7 units undergo pre-shipment inspection (PSI). If there is an issue with BSS138W-7, 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 BSS138W-7 part is unused and in its original packaging.

Return procedure for BSS138W-7:

1.Submit a request within 90 days.

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

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