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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

Diodes Incorporated DSS4240T-7

Name: DSS4240T-7
Brand: Diodes Incorporated
SKU: DSS4240T-7
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: DSS4240T-7

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

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

Datasheet:: DSS4240T-7.pdf

Description:: TRANS NPN 40V 2A SOT-23-3

Quantity:: RFQ Add To RFQ list

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Inventory:430,183

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Product details

Overview

DSS4240T-7 from Diodes Incorporated is a 40V NPN low-saturation transistor in SOT23 package, designed for high-efficiency switching in power management and load control circuits. It delivers 2A continuous collector current, 180mV max V_CE(sat) at 1A, and 60mΩ equivalent on-resistance at 0.5A - enabling compact, thermally efficient designs in DC-DC converters and motor drivers.

For engineers reviewing the DSS4240T-7 datasheet, DSS4240T-7 pinout, DSS4240T-7 application, or DSS4240T-7 equivalent, key selection criteria include its 40V BV_CEO, JEDEC-qualified reliability, 730mW power dissipation, and automotive-grade qualification path via Q-suffix variants.

Technical Context

This NPN bipolar junction transistor operates with fixed-base drive and supports linear and saturated switching modes. Its 100MHz f_T, 350 minimum h_FE at 0.1A, and low R_CE(sat) enable fast turn-on and minimal conduction loss in medium-current switching nodes.

The device features robust thermal performance: 75°C/W R_θJL to solder point and 51°C/W R_θJC, validated under JEDEC AEC-Q stress conditions. ESD ratings include 4kV HBM and 1kV CDM, supporting industrial environments without additional protection circuitry.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40V - supports 36V nominal bus systems with 10% margin for transients
I_C (continuous)	2A - drives solenoids, LED strings, or logic-level MOSFET gates directly
V_CE(sat) max	180mV @ I_C=1A, I_B=50mA - reduces conduction loss to ≤180mW at 1A
R_CE(sat)	60mΩ @ I_C=0.5A - enables precise current sensing via voltage drop across collector-emitter
P_D	730mW - achievable with 15mm×15mm 1oz copper pad; derates linearly above +25°C
f_T	100MHz - sufficient for PWM frequencies up to ~10MHz with stable gain
ESD HBM	4000V - meets IEC 61000-4-2 Level 3 for system-level ESD immunity

Pinout & Package

Package: SOT23 - surface-mount plastic package with matte tin-plated leads, UL 94V-0 rated, 0.008g weight, moisture sensitivity level 1.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current return path to ground or low-side reference	Low-impedance connection for emitter-follower or low-side switch configurations
2 (Base)	Control input for bipolar current amplification	Requires ~50mA drive for full saturation at 2A; compatible with 3.3V/5V logic via series resistor
3 (Collector)	High-current output node connected to load supply	Thermally coupled to PCB copper via lead; supports 3A peak pulse current for inrush limiting

Key Features

Feature	Design Value
Low V_CE(sat)	180mV max at 1A enables <180mW conduction loss, reducing thermal footprint in space-constrained layouts
High h_FE	350 min at 0.1A allows low base-drive current, easing MCU GPIO or driver IC loading
JEDEC-qualified reliability	Qualified per AEC-Q101 standards with PPAP capability - suitable for automotive subsystems requiring change control
Green construction	Halogen- and antimony-free, RoHS 3 compliant (<900ppm Br/Cl, <1000ppm Sb) - meets global environmental compliance mandates

Applications

Power Supply Sequencing

LED Constant-Current Driver

Use Scenario: Controlled ramp-up of 12V/24V rail in multi-rail systems using discrete enable logic.

IC Role / Device Role / Timing Role: Low-side switch enabling main DC-DC converter input, driven by microcontroller GPIO.

Use Value: 180mV V_CE(sat) limits voltage drop during sequencing, preserving input regulation margin for downstream regulators.

Use Scenario: Driving 1–3 high-brightness LEDs in automotive interior lighting with analog dimming.

IC Role / Device Role / Timing Role: Current-regulating pass element in constant-current sink configuration.

Use Value: 60mΩ R_CE(sat) enables accurate current sense across emitter resistor without significant headroom loss.

Brushed DC Motor Control

Industrial Solenoid Interface

Use Scenario: H-bridge half-bridge leg for 24V, 1.5A brushed motors in HVAC actuators.

IC Role / Device Role / Timing Role: High-current NPN switch in totem-pole or complementary pair with PNP DSS5240T.

Use Value: 3A I_CM handles motor stall current; 100MHz f_T supports PWM commutation up to 20kHz without phase lag.

Use Scenario: Driving 24V/1.2A industrial solenoids in PLC I/O modules with opto-isolated control.

IC Role / Device Role / Timing Role: Final-stage power switch interfacing between isolation barrier and inductive load.

Use Value: 40V BV_CEO withstands 2.5× nominal voltage during inductive kickback; 730mW PD sustains 100% duty cycle with minimal heatsinking.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN low-saturation transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ZXTN4240F	Direct replacement: same 40V/2A rating, lower 150mV V_CE(sat) at 1A, improved 120MHz f_T	Drop-in compatible in new designs; requires no layout change but offers better efficiency at high frequency	Select ZXTN4240F for new designs - Diodes explicitly recommends it over DSS4240T-7
MMBT4401	Lower 40V BV_CEO but only 600mA I_C, 750mV V_CE(sat) at 150mA - not a functional substitute for 2A loads	Only suitable for signal switching or sub-500mA loads; insufficient for motor/solenoid drive	Use MMBT4401 only where current demand is ≤0.5A and thermal budget allows higher V_CE(sat)

Compared with DSS4240T-7, ZXTN4240F improves switching efficiency and bandwidth while maintaining pinout compatibility, whereas MMBT4401 lacks the current and saturation voltage performance required for equivalent load-driving applications.

Availability

DSS4240T-7 is available at Aetrix Electronics and suitable for power supply sequencing, LED constant-current drivers, brushed DC motor control, and industrial solenoid interfaces requiring stable component supply and JEDEC-qualified reliability.

Supply support for DSS4240T-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, specializing in high-reliability components for automotive, industrial, and computing markets.

The DSS4240T belongs to Diodes' low-saturation NPN transistor product line, engineered for high-current switching in space-constrained, thermally demanding applications such as power management and actuator control.

FAQ

Is DSS4240T-7 qualified for automotive applications?

No - DSS4240T-7 itself is not AEC-Q101 qualified. However, Diodes offers automotive-grade equivalents with Q-suffix (e.g., DSS4240Q), manufactured in IATF 16949 facilities and PPAP-capable. These variants meet AEC-Q101 stress testing requirements and support change-controlled automotive design flows.

What is the recommended base resistor value for driving DSS4240T-7 from a 3.3V MCU GPIO?

For 2A collector current and guaranteed saturation, use I_B ≥ 200mA (per datasheet). With 3.3V GPIO and ~0.85V V_BE(sat), a 12Ω resistor yields ~204mA base drive. A 10Ω 1W resistor is preferred for thermal margin; ensure MCU can source 200mA continuously or use a buffer stage.

Can DSS4240T-7 replace a MOSFET in low-side switching applications?

Yes - but only where gate drive simplicity and cost outweigh efficiency needs. Unlike MOSFETs, DSS4240T-7 requires sustained base current (e.g., 50mA at 1A I_C), increasing driver complexity. Use it when V_CE(sat) loss is acceptable and BJT drive infrastructure already exists.

Why does the datasheet state "NOT RECOMMENDED FOR NEW DESIGNS"?

Diodes explicitly recommends ZXTN4240F as the upgraded replacement: it matches DSS4240T-7's pinout and electrical specs while improving V_CE(sat) (150mV vs. 180mV) and f_T (120MHz vs. 100MHz). This reflects a product lifecycle transition - DSS4240T-7 remains available for legacy support but not for new bill-of-materials.

DSS4240T-7 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Not For New Designs

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 2 A

Voltage - Collector Emitter Breakdown (Max):: 40 V

Vce Saturation (Max) @ Ib, Ic:: 320mV @ 200mA, 2A

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 300 @ 1A, 2V

Power - Max:: 600 mW

Frequency - Transition:: 100MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

DSS4240T-7 FAQ

1.How can I place an order for DSS4240T-7 through Aetrix?

Please submit a Request for Quotation (RFQ) for DSS4240T-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 DSS4240T-7 reliable?

The price and inventory of DSS4240T-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DSS4240T-7 is usually 5 days.

3.What payment methods are accepted for DSS4240T-7?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DSS4240T-7 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for DSS4240T-7?

DSS4240T-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your DSS4240T-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 DSS4240T-7?

For technical support, including DSS4240T-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DSS4240T-7 requirements.

6.How does Aetrix verify that DSS4240T-7 is sourced from the original manufacturer or authorized distributors?

All DSS4240T-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 DSS4240T-7 meets industry standards.

7.What is the process for return or replacement of DSS4240T-7?

All DSS4240T-7 units undergo pre-shipment inspection (PSI). If there is an issue with DSS4240T-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 DSS4240T-7 part is unused and in its original packaging.

Return procedure for DSS4240T-7:

1.Submit a request within 90 days.

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

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