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

onsemi 2N4400TA

Name: 2N4400TA
Brand: onsemi
SKU: 2N4400TA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N4400TA

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: 2N4400TA.pdf

Description:: TRANS NPN 40V 0.6A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2N4400TA from Fairchild Semiconductor is an NPN general-purpose bipolar junction transistor (BJT) designed for amplification and switching applications up to 500 mA collector current. It features V_CEO = 40 V, V_CBO = 60 V, V_EBO = 6.0 V, h_FE = 20–150 (at I_C = 1–500 mA), and T_J = –55°C to +150°C, commonly used in low-voltage DC-DC converter control stages and discrete logic-level interface circuits.

For engineers reviewing the 2N4400TA datasheet, pinout, applications, or equivalent options, key selection criteria include verified saturation voltage (V_CE(sat) ≤ 0.75 V at I_C = 500 mA), thermal resistance (R_θJA = 200°C/W in TO-92), breakdown margins, and proven performance in pulse-switching circuits with t_d = 15 ns and t_s = 225 ns.

Technical Context

The 2N4400TA operates as a silicon NPN BJT with fixed-emitter configuration and common-emitter topology. Its DC current gain (h_FE) varies from 20 at I_C = 500 mA to 150 at I_C = 1 mA, supporting both linear amplification and hard-switching modes. The device exhibits V_BE(sat) = 0.75–0.95 V and V_CE(sat) = 0.40–0.75 V across its rated current range.

Small-signal parameters include h_fe = 20–250 (f = 100 MHz, I_C = 1.0 mA), C_ob = 6.5 pF, and C_ib = 30 pF, confirming suitability for audio-frequency amplification and low-speed digital switching. Thermal design must account for R_θJA = 200°C/W and P_D = 625 mW at T_A = 25°C, derating by 5.0 mW/°C above ambient.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum safe collector-emitter voltage before breakdown; defines upper rail limit in switch designs.
I_C (continuous)	600 mA - Absolute max continuous collector current; usable up to 500 mA per functional spec.
h_FE	20–150 - DC current gain range across 1–500 mA; enables predictable base drive sizing.
V_CE(sat)	0.40–0.75 V - Low saturation voltage reduces conduction loss in switching applications.
t_s (storage)	225 ns - Storage time limits maximum switching frequency in saturated-mode operation.
R_θJA	200 °C/W - Junction-to-ambient thermal resistance in TO-92 package; dictates heatsinking needs.
T_J range	–55°C to +150°C - Full industrial temperature operation without derating.

Pinout & Package

2N4400TA is packaged in TO-92, a through-hole plastic case with standard lead orientation (flat side facing viewer: Emitter–Base–Collector from left to right). Pin assignment is confirmed per Fairchild Rev A datasheet and industry-standard TO-92 mechanical drawing.

Pin/Terminal	Circuit Role	Design Meaning
Emitter (E)	Current sink terminal	Reference node for bias network; connects to ground or low-side return path.
Base (B)	Control input	Receives forward-biased current to enable conduction; requires series resistor for current limiting.
Collector (C)	Current source terminal	Connects to load and supply rail; carries full switched/amplified output current.

Key Features

Feature	Design Value
High V_CBO rating	60 V - Enables robust operation in inductive load switching with flyback margin.
Low V_BE(sat)	0.75 V at I_C = 150 mA - Reduces base drive power and simplifies TTL/CMOS interface design.
Verified switching speed	t_d = 15 ns, t_f = 30 ns - Supports reliable operation up to ~1 MHz in non-saturated switching.
Wide temperature range	–55°C to +150°C - Qualified for automotive under-hood and industrial control environments.
TO-92 mechanical compatibility	Standard 0.1" lead pitch, 4.6 mm body height - Direct drop-in replacement for legacy 2N3904/2N2222 footprint designs.

Applications

Power Supply Control	Discrete Logic Interface
Use Scenario: Driving gate of low-side MOSFET in isolated flyback auxiliary supply. IC Role / Device Role / Timing Role: Discrete NPN switch providing level-shifted, current-amplified gate drive signal. Use Value: V_CE(sat) ≤ 0.75 V ensures minimal voltage drop across transistor during on-state, preserving gate drive headroom.	Use Scenario: Converting 3.3 V CMOS logic output to 5 V TTL-compatible signal level. IC Role / Device Role / Timing Role: Active pull-up stage with defined h_FE and fast turn-off (t_f = 30 ns). Use Value: Verified t_s = 225 ns allows clean signal edge transitions without excessive propagation delay in multi-stage logic.
Audio Pre-amplifier Stage	Relay Driver Circuit
Use Scenario: First-stage small-signal amplification in battery-powered microphone preamp. IC Role / Device Role / Timing Role: Common-emitter amplifier with h_fe ≥ 20 at 20 mA and f = 100 MHz. Use Value: C_ib = 30 pF and h_ie = 0.5–7.5 kΩ support stable gain-bandwidth product up to 100 kHz.	Use Scenario: Driving 12 V, 40 mA coil of electromechanical relay in PLC I/O module. IC Role / Device Role / Timing Role: Saturated switch with guaranteed I_C = 500 mA capability and V_CEO = 40 V margin. Use Value: V_CEO = 40 V exceeds typical relay flyback spikes (≤30 V), eliminating need for external clamp diode in many cases.

Power Supply Control

Discrete Logic Interface

Use Scenario: Driving gate of low-side MOSFET in isolated flyback auxiliary supply.

IC Role / Device Role / Timing Role: Discrete NPN switch providing level-shifted, current-amplified gate drive signal.

Use Value: V_CE(sat) ≤ 0.75 V ensures minimal voltage drop across transistor during on-state, preserving gate drive headroom.

Use Scenario: Converting 3.3 V CMOS logic output to 5 V TTL-compatible signal level.

IC Role / Device Role / Timing Role: Active pull-up stage with defined h_FE and fast turn-off (t_f = 30 ns).

Use Value: Verified t_s = 225 ns allows clean signal edge transitions without excessive propagation delay in multi-stage logic.

Audio Pre-amplifier Stage

Relay Driver Circuit

Use Scenario: First-stage small-signal amplification in battery-powered microphone preamp.

IC Role / Device Role / Timing Role: Common-emitter amplifier with h_fe ≥ 20 at 20 mA and f = 100 MHz.

Use Value: C_ib = 30 pF and h_ie = 0.5–7.5 kΩ support stable gain-bandwidth product up to 100 kHz.

Use Scenario: Driving 12 V, 40 mA coil of electromechanical relay in PLC I/O module.

IC Role / Device Role / Timing Role: Saturated switch with guaranteed I_C = 500 mA capability and V_CEO = 40 V margin.

Use Value: V_CEO = 40 V exceeds typical relay flyback spikes (≤30 V), eliminating need for external clamp diode in many cases.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN general-purpose amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
2N2222A	V_CEO = 40 V, I_C = 800 mA, h_FE = 35–300, R_θJA = 200°C/W - higher I_C rating and wider h_FE spread.	Higher current handling supports heavier relay loads; slightly faster t_f (25 ns) but longer t_s (250 ns).	Preferred when >500 mA drive or tighter h_FE consistency is required; same TO-92 footprint.
MPS2222A	V_CEO = 40 V, I_C = 600 mA, h_FE = 35–300, R_θJA = 200°C/W - identical absolute ratings but tighter h_FE binning and lower C_ob (5 pF).	Better high-frequency response due to lower output capacitance; optimized for RF-coupled preamp use.	Select when operating near 100 MHz or requiring reduced Miller effect in cascaded gain stages.

Compared with 2N4400TA, 2N2222A offers higher current headroom and broader h_FE range, while MPS2222A delivers improved RF linearity and tighter parameter distribution-both retain TO-92 compatibility but differ in gain consistency and switching trade-offs.

Availability

2N4400TA is available at Aetrix Electronics and suitable for power supply control, discrete logic interface, audio pre-amplifier stage, and relay driver circuit applications requiring stable component supply and long-term industrial availability.

Supply support for 2N4400TA 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The 2N4400TA belongs to Fairchild's legacy general-purpose BJT family, engineered for cost-sensitive, high-reliability linear amplification and switching in industrial controls, consumer power supplies, and interface circuits.

FAQ

What is the maximum continuous collector current for the 2N4400TA?

The 2N4400TA has an absolute maximum continuous collector current (I_C) rating of 600 mA per its Fairchild datasheet. However, functional specifications confirm reliable operation up to 500 mA with specified V_CE(sat), h_FE, and thermal derating. At 500 mA, V_CE(sat) ≤ 0.75 V and h_FE ≥ 20 are guaranteed, making 500 mA the practical design limit for sustained switching or amplification in TO-92 packaging.

Is the 2N4400TA pin-compatible with the 2N2222A?

Yes, the 2N4400TA is pin-compatible with the 2N2222A in TO-92 packaging: both follow the E-B-C pinout (left-to-right, flat side facing viewer). Mechanical dimensions, lead pitch, and terminal assignments match exactly. However, electrical differences-including h_FE range, t_s, and V_BE(sat)-require verification in the target circuit before direct substitution.

What is the typical storage time (t_s) of the 2N4400TA and why does it matter?

The 2N4400TA has a typical storage time (t_s) of 225 ns under V_CC = 30 V, I_C = 150 mA conditions. This parameter reflects minority carrier removal delay during turn-off and directly limits maximum usable switching frequency in saturated-mode applications. Circuits requiring >100 kHz switching should evaluate unsaturated (active-region) operation or consider faster alternatives like MPS2222A.

Does the 2N4400TA meet industrial temperature requirements?

Yes, the 2N4400TA is rated for full industrial temperature operation from –55°C to +150°C junction temperature. Its thermal characteristics-including R_θJA = 200°C/W and P_D = 625 mW at 25°C ambient-are validated across this range. Derating curves confirm usable power dissipation down to –55°C and up to +125°C ambient, supporting deployment in motor drives, power supplies, and outdoor control systems.

Can the 2N4400TA be used in audio amplifier designs?

Yes, the 2N4400TA is suitable for low-noise audio pre-amplifier stages. Its small-signal h_fe = 20–250 at 100 MHz, C_ib = 30 pF, and h_ie = 0.5–7.5 kΩ support stable gain up to 100 kHz. Measured V_BE(ON) and h_FE consistency across temperature ensure predictable bias point stability, and its low V_CE(sat) minimizes distortion in Class-A emitter-follower configurations.

2N4400TA Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Tape & Box (TB)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 600 mA

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

Vce Saturation (Max) @ Ib, Ic:: 750mV @ 50mA, 500mA

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: 50 @ 150mA, 1V

Power - Max:: 625 mW

Frequency - Transition:: -

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

2N4400TA FAQ

1.How can I place an order for 2N4400TA through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N4400TA 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 2N4400TA reliable?

The price and inventory of 2N4400TA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N4400TA is usually 5 days.

3.What payment methods are accepted for 2N4400TA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N4400TA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N4400TA?

2N4400TA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N4400TA 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 2N4400TA?

For technical support, including 2N4400TA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N4400TA requirements.

6.How does Aetrix verify that 2N4400TA is sourced from the original manufacturer or authorized distributors?

All 2N4400TA 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 2N4400TA meets industry standards.

7.What is the process for return or replacement of 2N4400TA?

All 2N4400TA units undergo pre-shipment inspection (PSI). If there is an issue with 2N4400TA, 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 2N4400TA part is unused and in its original packaging.

Return procedure for 2N4400TA:

1.Submit a request within 90 days.

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

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