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

onsemi 2N6428ATA

Name: 2N6428ATA
Brand: onsemi
SKU: 2N6428ATA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N6428ATA

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: 2N6428ATA.pdf

Description:: TRANS NPN 50V 0.2A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2N6428ATA from Fairchild Semiconductor is an NPN epitaxial silicon small-signal amplifier transistor in TO-92 package, rated for V_CEO = 50 V, I_C = 200 mA, P_C = 625 mW, and f_T = 100–700 MHz. It delivers high DC current gain (h_FE ≥ 250 at I_C = 10 µA–1 mA) and low noise performance, used in RF preamplifiers and low-level audio stages.

For engineers reviewing the 2N6428ATA datasheet, pinout, applications, or equivalent options, key selection criteria include its V_CEO/V_CBO ratings, h_FE consistency across bias points, noise figure (3–6 dB at 100 Hz–10 kHz), Cob = 3 pF, and TO-92 mechanical compatibility with legacy through-hole amplifier designs.

Technical Context

This device operates as a linear NPN bipolar junction transistor optimized for low-noise, medium-frequency amplification. Its epitaxial base construction enables stable h_FE over I_C = 10 µA to 1 mA and supports low V_CE(sat) (0.2 V @ I_C = 10 mA, I_B = 0.5 mA).

The 2N6428ATA exhibits frequency-dependent noise behavior: NF = 3 dB / 18.1 nV/√Hz at 100 Hz (R_S = 10 kΩ), and 3.5 dB / 4.3 nV/√Hz at 10 Hz (R_S = 500 Ω), confirming suitability for high-fidelity analog front-ends where source impedance varies.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	50 V - Maximum safe collector-emitter voltage before breakdown under open-base condition
I_C (max)	200 mA - Continuous collector current limit defining small-signal operating envelope
P_C (max)	625 mW - Thermal power dissipation limit at T_A = 25°C, derates linearly above 25°C
h_FE	250–650 - DC current gain range at V_CE = 5 V, supporting stable bias design across I_C = 10 µA–1 mA
f_T	100–700 MHz - Unity-gain bandwidth enabling amplification up to VHF band with proper matching
C_ob	3 pF - Output capacitance at V_CB = 10 V, critical for RF stage stability and tuning range
NF / NV	3–6 dB / 4.1–18.1 nV/√Hz - Low-noise performance validated at 10 Hz–10 kHz, ideal for sensor interface amps

Pinout & Package

2N6428ATA is housed in a standard TO-92 plastic package with 3 leads: Emitter (Lead 1), Base (Lead 2), Collector (Lead 3). Dimensions conform to JEDEC TO-92 outline: body height ≤ 4.58 mm, lead pitch 1.27 mm, overall length 14.47 mm.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Reference node for bias network; connects to ground or emitter degeneration resistor
2 (Base)	Control input	Receives forward-biased drive; requires current-limiting resistor for fixed-bias operation
3 (Collector)	Active output terminal	Delivers amplified current; connects to load resistor or RF tank circuit

Key Features

Feature	Design Value
Low noise figure	NF = 3 dB @ 100 Hz (R_S = 10 kΩ), enabling high-SNR microphone preamps
High f_T bandwidth	Up to 700 MHz ensures usable gain beyond 100 MHz for VHF receiver IF stages
Stable h_FE vs. I_C	h_FE ≥ 250 across I_C = 10 µA–1 mA, simplifying bias point selection
Low V_CE(sat)	0.2 V @ I_C = 10 mA / I_B = 0.5 mA, minimizing voltage headroom loss in low-V_CC designs
TO-92 mechanical standardization	Compatible with legacy PCB footprints and manual assembly tooling

Applications

RF Preamplifier	Low-Noise Audio Amplifier
Use Scenario: Boosting weak signals from antenna elements prior to mixer stage in AM/FM receivers. IC Role / Device Role / Timing Role: Small-signal NPN amplifier configured in common-emitter topology with tuned collector load. Use Value: f_T ≥ 100 MHz and C_ob = 3 pF enable stable gain up to 50 MHz without neutralization.	Use Scenario: First-stage amplification of piezoelectric sensor or electret microphone outputs. IC Role / Device Role / Timing Role: High-h_FE, low-noise transconductance device in common-emitter or common-collector configuration. Use Value: NF = 3 dB @ 100 Hz and h_FE ≥ 250 ensure minimal added noise and consistent gain across production units.
Instrumentation Signal Conditioning	Legacy Analog Test Equipment
Use Scenario: Amplifying low-level thermocouple or strain gauge bridge outputs in portable DMMs. IC Role / Device Role / Timing Role: Precision DC-coupled amplifier with emitter degeneration for linearity and temperature stability. Use Value: V_CEO = 50 V and I_C = 200 mA support rail-to-rail signal swing in ±15 V supplies.	Use Scenario: Replacement transistor in discontinued oscilloscope vertical amplifier modules. IC Role / Device Role / Timing Role: Direct-fit TO-92 discrete amplifier maintaining original gain and bandwidth specs. Use Value: Identical pinout, h_FE distribution, and thermal rating (625 mW) ensure drop-in reliability without board rework.

RF Preamplifier

Low-Noise Audio Amplifier

Use Scenario: Boosting weak signals from antenna elements prior to mixer stage in AM/FM receivers.

IC Role / Device Role / Timing Role: Small-signal NPN amplifier configured in common-emitter topology with tuned collector load.

Use Value: f_T ≥ 100 MHz and C_ob = 3 pF enable stable gain up to 50 MHz without neutralization.

Use Scenario: First-stage amplification of piezoelectric sensor or electret microphone outputs.

IC Role / Device Role / Timing Role: High-h_FE, low-noise transconductance device in common-emitter or common-collector configuration.

Use Value: NF = 3 dB @ 100 Hz and h_FE ≥ 250 ensure minimal added noise and consistent gain across production units.

Instrumentation Signal Conditioning

Legacy Analog Test Equipment

Use Scenario: Amplifying low-level thermocouple or strain gauge bridge outputs in portable DMMs.

IC Role / Device Role / Timing Role: Precision DC-coupled amplifier with emitter degeneration for linearity and temperature stability.

Use Value: V_CEO = 50 V and I_C = 200 mA support rail-to-rail signal swing in ±15 V supplies.

Use Scenario: Replacement transistor in discontinued oscilloscope vertical amplifier modules.

IC Role / Device Role / Timing Role: Direct-fit TO-92 discrete amplifier maintaining original gain and bandwidth specs.

Use Value: Identical pinout, h_FE distribution, and thermal rating (625 mW) ensure drop-in reliability without board rework.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2N5088	V_CEO = 30 V (lower), h_FE min = 400, f_T = 50 MHz (lower), same TO-92	Not suitable for 50 V collector supply rails; better for ultra-low-noise <30 V designs	Select 2N5088 only when V_CE < 30 V and higher h_FE is prioritized over bandwidth
BC547C	V_CEO = 45 V, h_FE = 420–800, f_T = 300 MHz, Cob = 4.5 pF, TO-92	Higher Cob reduces HF stability margin; lower V_CEO limits headroom in 50 V systems	Choose BC547C for cost-sensitive consumer audio where 45 V rating suffices and 300 MHz f_T is adequate

Compared with 2N6428ATA, the 2N5088 offers higher minimum h_FE but sacrifices 20 V of collector voltage margin and 200+ MHz bandwidth; the BC547C trades 5 V V_CEO headroom and +1.5 pF Cob for broader h_FE distribution and higher volume availability.

Availability

2N6428ATA is available at Aetrix Electronics and suitable for RF preamplifiers, low-noise audio stages, instrumentation signal conditioning, and legacy test equipment repair requiring stable component supply and TO-92 mechanical compatibility.

Supply support for 2N6428ATA 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 analog, power, and discrete components before its acquisition by ON Semiconductor in 2016.

The 2N6428ATA belongs to Fairchild's legacy 2N-series general-purpose amplifier transistor family, designed for high-fidelity, low-noise linear amplification in consumer, industrial, and communications equipment.

FAQ

What is the maximum collector-emitter voltage rating for the 2N6428ATA?

The 2N6428ATA has a maximum collector-emitter voltage (V_CEO) rating of 50 V at T_A = 25°C. This rating applies under open-base conditions and defines the upper limit for safe DC or peak AC voltage across the collector and emitter terminals without risk of avalanche breakdown. Exceeding this value may cause irreversible device failure.

Does the 2N6428ATA have a specified noise figure, and at what conditions?

Yes, the 2N6428ATA specifies noise figure (NF) and noise voltage (NV) across multiple test configurations. For example, NF = 3 dB / NV = 18.1 nV/√Hz at 100 Hz with R_S = 10 kΩ, and NF = 3.5 dB / NV = 4.3 nV/√Hz at 10 Hz with R_S = 500 Ω. These values are measured per the official Fairchild datasheet Rev. A (February 2000).

What is the pin configuration of the 2N6428ATA in its TO-92 package?

The 2N6428ATA uses standard TO-92 pinout: Lead 1 is Emitter, Lead 2 is Base, and Lead 3 is Collector-viewed with flat side facing outward and leads pointing down. This matches JEDEC TO-92 mechanical specification and ensures compatibility with existing amplifier PCB footprints designed for 2N-series transistors.

How does the 2N6428ATA's f_T vary with operating conditions?

The 2N6428ATA's current gain bandwidth product (f_T) ranges from 100 MHz to 700 MHz depending on test conditions: 100 MHz is typical at V_CE = 5 V, I_C = 1 mA, f = 100 MHz; 700 MHz is the maximum observed under identical bias. This wide span reflects process variation and confirms suitability for VHF amplification when binned or characterized per unit.

Is the 2N6428ATA suitable for switching applications?

The 2N6428ATA is optimized for linear amplification-not fast switching. Its relatively high storage time and lack of specified switching parameters (t_on/t_off, t_fall) indicate it is not characterized for digital or PWM use. For switching, consider purpose-built devices like 2N2222A or MMBT2222ALT1G; the 2N6428ATA should be used only in analog amplifier roles per its datasheet intent.

2N6428ATA 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):: 200 mA

Voltage - Collector Emitter Breakdown (Max):: 50 V

Vce Saturation (Max) @ Ib, Ic:: 600mV @ 5mA, 100mA

Current - Collector Cutoff (Max):: 25nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 250 @ 100µA, 5V

Power - Max:: 625 mW

Frequency - Transition:: 700MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

2N6428ATA FAQ

1.How can I place an order for 2N6428ATA through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N6428ATA 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 2N6428ATA reliable?

The price and inventory of 2N6428ATA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N6428ATA is usually 5 days.

3.What payment methods are accepted for 2N6428ATA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N6428ATA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N6428ATA?

2N6428ATA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N6428ATA 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 2N6428ATA?

For technical support, including 2N6428ATA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N6428ATA requirements.

6.How does Aetrix verify that 2N6428ATA is sourced from the original manufacturer or authorized distributors?

All 2N6428ATA 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 2N6428ATA meets industry standards.

7.What is the process for return or replacement of 2N6428ATA?

All 2N6428ATA units undergo pre-shipment inspection (PSI). If there is an issue with 2N6428ATA, 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 2N6428ATA part is unused and in its original packaging.

Return procedure for 2N6428ATA:

1.Submit a request within 90 days.

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

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