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

onsemi NJT4031NT3G

Name: NJT4031NT3G
Brand: onsemi
SKU: NJT4031NT3G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: NJT4031NT3G

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-261-4, TO-261AA

Datasheet:: NJT4031NT3G.pdf

Description:: TRANS NPN 40V 3A SOT223

Quantity:: RFQ Add To RFQ list

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Inventory:1,157

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Product details

Overview

NJT4031NT3G from onsemi is an NPN silicon bipolar power transistor in SOT-223 package, rated for 40 V_CEO, 3.0 A_C, and 2.0 W at T_A = 25°C, with V_CE(sat) ≤ 0.300 V at I_C = 3.0 A / I_B = 0.3 A, used in DC-DC converter switching stages and linear regulator pass elements.

For engineers reviewing the NJT4031NT3G datasheet, pinout, applications, or equivalent options, key selection criteria include its AEC-Q101 qualification, 215 MHz f_T, low saturation voltage under high current, thermal resistance of 64°C/W (junction-to-case), and Pb-free RoHS-compliant SOT-223 packaging.

Technical Context

This device operates as a medium-power NPN switch with DC current gain (h_FE) ranging from 100 to 500 depending on collector current-220 min at I_C = 0.5 A, 100 min at I_C = 3.0 A-and supports fast switching via 215 MHz current-gain bandwidth product under 500 mA bias.

Its safe operating area (SOA) accommodates pulsed loads up to 5.0 A peak, while thermal design relies on the SOT-223's exposed collector pad: R_θJA is 64°C/W when mounted on 1"² FR-4 copper and degrades to 155°C/W on minimal 7.6 mm² pad, requiring careful PCB layout for sustained 3 A operation.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum blocking voltage between collector and emitter with base open; defines upper rail limit in switching applications.
I_C Continuous	3.0 A - Sustained collector current capability; requires ≥1"² copper pad for full 2.0 W dissipation at 25°C ambient.
V_CE(sat)	0.300 V @ I_C=3.0 A/I_B=0.3 A - Low saturation voltage minimizes conduction loss in high-current linear or switching regulators.
f_T	215 MHz - Current-gain bandwidth product enables use in medium-frequency switching (e.g., <100 kHz PWM with margin).
h_FE	100–500 - Wide DC gain range supports both high-current saturation (low drive) and precision analog amplification at lower currents.
R_θJC	64°C/W - Junction-to-case thermal resistance confirms direct heat transfer path through exposed collector tab to heatsink or PCB.

Pinout & Package

SOT-223 (Case 318E, Style 1) package with exposed collector pad (pins 2 and 4 tied internally to collector), standard 4-pin configuration optimized for thermal performance and surface-mount assembly.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control terminal; requires ~0.3 A drive current to saturate at 3.0 A collector load per h_FE and V_BE(sat) specs.
2 & 4	Collector	Power output node; electrically connected to exposed metal tab for thermal conduction and mechanical mounting.
3	Emitter	Reference/return path; common connection point for load return and base-emitter bias network.

Key Features

Feature	Design Value
AEC-Q101 Qualified	Validated for automotive underhood applications including engine control modules and body electronics with temperature cycling and HBM ESD robustness.
Pb-Free, Halogen-Free	Meets RoHS Directive 2011/65/EU and JEDEC JS709C; eliminates lead-based solder compatibility concerns and hazardous substance reporting obligations.
UL 94 V-0 Rated Epoxy	Flame-retardant molding compound withstands 0.125" thickness test; satisfies safety requirements for industrial power supplies and motor drives.
Low V_CE(sat) at High I_C	0.300 V max at 3.0 A ensures <0.9 W conduction loss, reducing thermal stress versus alternatives with >0.5 V saturation.

Applications

Automotive Engine Control Unit (ECU)	Industrial DC-DC Converter
Use Scenario: Switching high-side load drivers for fuel injectors and ignition coils in 12 V vehicle systems. IC Role / Device Role / Timing Role: NPN power switch controlling inductive loads with flyback protection and precise pulse-width modulation. Use Value: AEC-Q101 qualification ensures reliability across −40°C to +150°C junction range; 40 V rating covers battery transients up to ISO 7637-2 Pulse 5a.	Use Scenario: Pass transistor in adjustable linear post-regulator stage following buck converter for low-noise 3.3 V or 5 V rails. IC Role / Device Role / Timing Role: Linear regulator pass element delivering stable output with minimal dropout and ripple sensitivity. Use Value: Low V_CE(sat) reduces thermal overhead; 215 MHz f_T supports fast transient response to load steps without oscillation.
Consumer Appliance Motor Driver	Telecom Power Management
Use Scenario: Half-bridge high-side switch in BLDC fan or pump controllers within HVAC and white goods. IC Role / Device Role / Timing Role: Medium-current switching transistor driving gate of MOSFET half-bridge or directly powering small PMDC motors. Use Value: 3.0 A continuous rating handles startup surges; SOT-223 thermal pad enables compact heatsinking on cost-sensitive PCBs.	Use Scenario: Overcurrent protection switch in redundant 48 V telecom power distribution units (PDUs). IC Role / Device Role / Timing Role: Current-limiting series pass device activated during fault conditions to isolate downstream circuits. Use Value: Fast SOA response and 5.0 A peak rating allow brief surge handling; UL 94 V-0 epoxy meets telecom fire safety standards.

Automotive Engine Control Unit (ECU)

Industrial DC-DC Converter

Use Scenario: Switching high-side load drivers for fuel injectors and ignition coils in 12 V vehicle systems.

IC Role / Device Role / Timing Role: NPN power switch controlling inductive loads with flyback protection and precise pulse-width modulation.

Use Value: AEC-Q101 qualification ensures reliability across −40°C to +150°C junction range; 40 V rating covers battery transients up to ISO 7637-2 Pulse 5a.

Use Scenario: Pass transistor in adjustable linear post-regulator stage following buck converter for low-noise 3.3 V or 5 V rails.

IC Role / Device Role / Timing Role: Linear regulator pass element delivering stable output with minimal dropout and ripple sensitivity.

Use Value: Low V_CE(sat) reduces thermal overhead; 215 MHz f_T supports fast transient response to load steps without oscillation.

Consumer Appliance Motor Driver

Telecom Power Management

Use Scenario: Half-bridge high-side switch in BLDC fan or pump controllers within HVAC and white goods.

IC Role / Device Role / Timing Role: Medium-current switching transistor driving gate of MOSFET half-bridge or directly powering small PMDC motors.

Use Value: 3.0 A continuous rating handles startup surges; SOT-223 thermal pad enables compact heatsinking on cost-sensitive PCBs.

Use Scenario: Overcurrent protection switch in redundant 48 V telecom power distribution units (PDUs).

IC Role / Device Role / Timing Role: Current-limiting series pass device activated during fault conditions to isolate downstream circuits.

Use Value: Fast SOA response and 5.0 A peak rating allow brief surge handling; UL 94 V-0 epoxy meets telecom fire safety standards.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD44H11T4G	Higher V_CEO (80 V), lower f_T (30 MHz), same SOT-223 package and 3 A rating.	Better suited for higher-voltage industrial motor controls but slower switching than NJT4031NT3G.	Select when system transients exceed 40 V or when lower-speed, higher-voltage blocking is required.
ZTX653STZ	Lower V_CEO (30 V), higher h_FE (250–600), same 3 A rating and SOT-223 footprint.	Optimized for low-drive, high-gain linear amplification rather than high-current saturation.	Select when base drive current is constrained or precision analog gain stability is prioritized over 40 V blocking.

Compared with MJD44H11T4G and ZTX653STZ, the NJT4031NT3G delivers optimal balance of 40 V blocking, 215 MHz f_T, and low 0.300 V saturation at 3 A-making it preferred for automotive-grade DC-DC and ECU load switching where speed, voltage margin, and thermal efficiency intersect.

Availability

NJT4031NT3G is available at Aetrix Electronics and suitable for automotive engine control units, industrial DC-DC converters, and consumer appliance motor drivers requiring stable component supply and long-term lifecycle support.

Supply support for NJT4031NT3G 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, cloud, and IoT markets.

The NJT4031NT3G belongs to onsemi's Bipolar Power Transistor family, designed specifically for robust, high-reliability switching and linear regulation in harsh-environment applications demanding AEC-Q101 compliance and thermal resilience.

FAQ

What is the maximum continuous collector current rating for the NJT4031NT3G?

The NJT4031NT3G has a maximum continuous collector current (I_C) rating of 3.0 A at T_C = 25°C. This rating assumes proper thermal management using a 1"² copper pad on FR-4 PCB. At elevated case temperatures or reduced copper area, derating is required per the power derating curve in the datasheet.

Is the NJT4031NT3G qualified for automotive applications?

Yes, the NJT4031NT3G is AEC-Q101 qualified and PPAP capable. It meets stringent automotive reliability requirements including temperature cycling, humidity testing, and HBM ESD up to Class 3B (8 kV), making it suitable for engine control, body electronics, and ADAS subsystems.

What is the typical current-gain bandwidth product (f_T) of the NJT4031NT3G?

The NJT4031NT3G has a typical current-gain bandwidth product (f_T) of 215 MHz, measured at I_C = 500 mA, V_CE = 10 V, and f_test = 1.0 MHz. This enables reliable operation in medium-frequency switching applications such as PWM-controlled power stages below 100 kHz.

Does the NJT4031NT3G have a RoHS-compliant and halogen-free package?

Yes, the NJT4031NT3G features a Pb-free, halogen-free/BFR-free epoxy package compliant with RoHS Directive 2011/65/EU. The molding compound also meets UL 94 V-0 flammability rating at 0.125" thickness.

What is the thermal resistance from junction to case (R_θJC) for the NJT4031NT3G?

The NJT4031NT3G has a thermal resistance from junction to case (R_θJC) of 64°C/W when mounted on a 1"² (645 mm²) copper collector pad on FR-4 board. This value is critical for calculating junction temperature rise under load and must be used with actual power dissipation to ensure T_J remains within −55°C to +150°C limits.

NJT4031NT3G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-261-4, TO-261AA

Packaging:: Tape & Reel (TR)

Product Status:: Active

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 3 A

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

Vce Saturation (Max) @ Ib, Ic:: 300mV @ 300mA, 3A

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 200 @ 1A, 1V

Power - Max:: 2 W

Frequency - Transition:: 215MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-223 (TO-261)

NJT4031NT3G FAQ

1.How can I place an order for NJT4031NT3G through Aetrix?

Please submit a Request for Quotation (RFQ) for NJT4031NT3G 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 NJT4031NT3G reliable?

The price and inventory of NJT4031NT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NJT4031NT3G is usually 5 days.

3.What payment methods are accepted for NJT4031NT3G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NJT4031NT3G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for NJT4031NT3G?

NJT4031NT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your NJT4031NT3G 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 NJT4031NT3G?

For technical support, including NJT4031NT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NJT4031NT3G requirements.

6.How does Aetrix verify that NJT4031NT3G is sourced from the original manufacturer or authorized distributors?

All NJT4031NT3G 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 NJT4031NT3G meets industry standards.

7.What is the process for return or replacement of NJT4031NT3G?

All NJT4031NT3G units undergo pre-shipment inspection (PSI). If there is an issue with NJT4031NT3G, 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 NJT4031NT3G part is unused and in its original packaging.

Return procedure for NJT4031NT3G:

1.Submit a request within 90 days.

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

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