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

onsemi 2N5550

Name: 2N5550
Brand: onsemi
SKU: 2N5550
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N5550

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 Long Body

Datasheet:: 2N5550.pdf

Description:: TRANS NPN 140V 0.6A TO92

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2N5550 from onsemi is an NPN silicon general-purpose amplifier transistor in TO-92 package, rated for 140 V_CEO, 600 mA continuous collector current, and 625 mW power dissipation at 25°C ambient. It delivers DC current gain (h_FE) of 60–250 at I_C = 1.0–50 mA, with f_T up to 300 MHz, and is used in low-noise preamplifier stages, signal switching, and voltage amplifier circuits.

For engineers reviewing the 2N5550 datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO/V_CBO voltage margin, h_FE consistency across operating current, thermal resistance (R_JA = 200°C/W), noise figure (NF = 10 dB), and TO-92 lead-form compatibility for through-hole prototyping and industrial control boards.

Technical Context

The 2N5550 operates as a medium-voltage, medium-current linear amplifier with junction temperature range from −55°C to +150°C. Its breakdown ratings (V_CEO = 140 V, V_CBO = 160 V) support use in high-impedance collector loads, while its 100–300 MHz f_T enables RF-capable small-signal amplification up to VHF band.

It exhibits low saturation voltages (V_CE(sat) ≤ 0.25 V at I_C/I_B = 10) and base-emitter saturation voltage (V_BE(sat) ≤ 1.2 V), enabling efficient switching in active-mode gain control and analog multiplexing. Input capacitance (C_ibo = 30 pF) and output capacitance (C_obo = 6.0 pF) are specified at 1 MHz, supporting stable frequency response in tuned amplifier designs.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	140 V - Maximum safe collector-emitter voltage before avalanche breakdown; defines upper rail limit in amplifier supply design.
I_C (continuous)	600 mA - Continuous collector current rating; sets maximum load drive capability without derating at 25°C.
P_D @ T_A = 25°C	625 mW - Power dissipation limit at room ambient; requires heatsinking or derating above 25°C (5.0 mW/°C).
h_FE	60–250 - DC current gain range across I_C = 1–50 mA; determines base drive requirements and bias stability.
f_T	100–300 MHz - Transition frequency; confirms usable bandwidth for small-signal amplification up to ~100 MHz.
NF	10 dB @ I_C = 250 µA - Noise figure at low collector current; indicates suitability for low-level audio or sensor preamplifier stages.

Pinout & Package

2N5550 uses TO-92 (Case 29, Style 1) plastic package with 3 leads, standardized for through-hole mounting and manual prototyping. Pin 1 is Emitter, Pin 2 is Base, Pin 3 is Collector - verified per marking diagram and package outline on page 6 of ON Semiconductor datasheet 2N5550/D Rev. 4.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Reference node for bias network; connects to ground or emitter degeneration resistor in common-emitter configuration.
2 (Base)	Control input	Receives forward-biased current to modulate collector current; requires current-limiting resistor in series with driving source.
3 (Collector)	Output current source	Delivers amplified current to load; placed at high-side of load in common-emitter stage with pull-up resistor or transformer coupling.

Key Features

Feature	Design Value
High V_CBO (160 V)	Enables robust operation in high-impedance collector circuits where transient voltage spikes may exceed supply rails.
Low noise figure (10 dB)	Supports high-fidelity amplification of microvolt-level signals in instrumentation front-ends and RF receiver IF stages.
Wide h_FE range (60–250)	Allows flexible bias design across production lots; accommodates variation without circuit redesign when using emitter degeneration.
TO-92 mechanical standardization	Ensures compatibility with legacy PCB footprints, breadboards, and hand-soldering workflows in development and repair environments.

Applications

Audio Preamplifier Stage	Industrial Sensor Signal Conditioning
Use Scenario: Amplifying low-amplitude microphone or piezoelectric sensor outputs prior to ADC sampling in embedded data loggers. IC Role / Device Role / Timing Role: Linear NPN amplifier in common-emitter configuration with emitter degeneration for stable DC bias and AC gain. Use Value: 10 dB noise figure and 60–250 h_FE enable >40 dB voltage gain with minimal added noise, preserving signal integrity at sub-mV levels.	Use Scenario: Isolating and scaling 4–20 mA loop signals or thermocouple outputs in PLC analog input modules. IC Role / Device Role / Timing Role: Transconductance amplifier with fixed-gain feedback network to convert current-to-voltage with linearity <0.5% error. Use Value: 140 V_CEO withstands field-induced transients on industrial wiring; TO-92 allows compact layout in multi-channel I/O cards.
RF Intermediate Frequency Amplifier	Relay Driver Interface
Use Scenario: Boosting 10.7 MHz IF signals in AM/FM radio receivers before demodulation. IC Role / Device Role / Timing Role: Tuned small-signal amplifier with parallel LC collector load and baseband-coupled input. Use Value: f_T up to 300 MHz ensures flat gain response across 10–30 MHz band; C_obo = 6.0 pF minimizes loading on tank circuit Q.	Use Scenario: Driving 12 V/50 mA electromagnetic relays from microcontroller GPIO pins in HVAC control panels. IC Role / Device Role / Timing Role: Switching transistor in common-emitter saturated mode with forced β = 10. Use Value: V_CE(sat) ≤ 0.25 V at I_C = 50 mA reduces relay coil power loss; 600 mA I_C rating provides 10× safety margin.

Audio Preamplifier Stage

Industrial Sensor Signal Conditioning

Use Scenario: Amplifying low-amplitude microphone or piezoelectric sensor outputs prior to ADC sampling in embedded data loggers.

IC Role / Device Role / Timing Role: Linear NPN amplifier in common-emitter configuration with emitter degeneration for stable DC bias and AC gain.

Use Value: 10 dB noise figure and 60–250 h_FE enable >40 dB voltage gain with minimal added noise, preserving signal integrity at sub-mV levels.

Use Scenario: Isolating and scaling 4–20 mA loop signals or thermocouple outputs in PLC analog input modules.

IC Role / Device Role / Timing Role: Transconductance amplifier with fixed-gain feedback network to convert current-to-voltage with linearity <0.5% error.

Use Value: 140 V_CEO withstands field-induced transients on industrial wiring; TO-92 allows compact layout in multi-channel I/O cards.

RF Intermediate Frequency Amplifier

Relay Driver Interface

Use Scenario: Boosting 10.7 MHz IF signals in AM/FM radio receivers before demodulation.

IC Role / Device Role / Timing Role: Tuned small-signal amplifier with parallel LC collector load and baseband-coupled input.

Use Value: f_T up to 300 MHz ensures flat gain response across 10–30 MHz band; C_obo = 6.0 pF minimizes loading on tank circuit Q.

Use Scenario: Driving 12 V/50 mA electromagnetic relays from microcontroller GPIO pins in HVAC control panels.

IC Role / Device Role / Timing Role: Switching transistor in common-emitter saturated mode with forced β = 10.

Use Value: V_CE(sat) ≤ 0.25 V at I_C = 50 mA reduces relay coil power loss; 600 mA I_C rating provides 10× safety margin.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2N5551	V_CEO = 160 V (vs. 140 V), V_CBO = 180 V, h_FE min = 80 at I_C = 10 mA	Higher voltage headroom; preferred in 15–24 V supply systems with transient risk	Select 2N5551 when V_CEO margin >20 V is required; otherwise 2N5550 offers cost-effective performance for ≤15 V rails.
BC547B	V_CEO = 45 V, I_C = 100 mA, h_FE = 200–450, TO-92 package	Lower voltage/current rating; optimized for low-power logic interfacing, not high-voltage amplification	Choose BC547B only for ≤5 V, <50 mA applications; not suitable as drop-in replacement for 2N5550 in high-voltage designs.

Compared with 2N5551 and BC547B, the 2N5550 occupies a mid-tier niche: higher voltage capability than BC547B but lower cost and wider h_FE tolerance than 2N5551, making it optimal for 12 V industrial amplifiers where reliability and manufacturability outweigh marginal voltage gains.

Availability

2N5550 is available at Aetrix Electronics and suitable for industrial sensor interfaces, audio preamplifier stages, and relay driver circuits requiring stable component supply across long-lifecycle embedded programs.

Supply support for 2N5550 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 manufacturer specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The 2N5550 belongs to onsemi's legacy discrete transistor portfolio designed for general-purpose linear amplification and switching in cost-sensitive, high-reliability industrial and consumer electronics.

FAQ

What is the maximum collector-emitter voltage rating for the 2N5550?

The 2N5550 has a maximum collector-emitter voltage (V_CEO) rating of 140 Vdc, tested at I_C = 1.0 mAdc with base open. This rating defines the absolute upper limit for voltage applied between collector and emitter before breakdown occurs, and must be respected with appropriate safety margin in circuit design.

Does the 2N5550RLRPG variant include lead-free packaging?

Yes, the 2N5550RLRPG variant is explicitly marked as Pb−Free in the ON Semiconductor ordering table and carries the "G" suffix per their packaging nomenclature. It uses the same TO-92 package and electrical specifications as the standard 2N5550, with RoHS-compliant terminations and soldering profiles.

What is the typical DC current gain (h_FE) of the 2N5550 at 10 mA collector current?

At I_C = 10 mAdc and V_CE = 5.0 Vdc, the 2N5550 exhibits a minimum h_FE of 60 and a maximum of 250 per the datasheet's Electrical Characteristics table. The typical value falls within this range and varies by unit; design should accommodate the full 60–250 span using emitter degeneration for stability.

Can the 2N5550 be used in RF amplifier applications?

Yes, the 2N5550 supports RF amplifier use with a transition frequency (f_T) of 100–300 MHz and low output capacitance (C_obo = 6.0 pF). It is commonly deployed in VHF-band intermediate frequency amplifiers (e.g., 10.7 MHz IF stages), where its gain-bandwidth product and noise performance meet system requirements without requiring microwave-grade devices.

What is the thermal resistance from junction to ambient (R_JA) for the 2N5550 in TO-92 package?

The thermal resistance from junction to ambient (R_JA) for the 2N5550 in TO-92 package is 200°C/W, measured under standard JEDEC test conditions. This value assumes no heatsink and natural convection cooling; actual board layout, copper area, and airflow significantly affect real-world thermal performance.

2N5550 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 Long Body

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN

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

Voltage - Collector Emitter Breakdown (Max):: 140 V

Vce Saturation (Max) @ Ib, Ic:: 250mV @ 5mA, 50mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 60 @ 10mA, 5V

Power - Max:: 625 mW

Frequency - Transition:: 300MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92 (TO-226)

2N5550 FAQ

1.How can I place an order for 2N5550 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N5550 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 2N5550 reliable?

The price and inventory of 2N5550 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N5550 is usually 5 days.

3.What payment methods are accepted for 2N5550?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N5550 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N5550?

2N5550 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N5550 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 2N5550?

For technical support, including 2N5550 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N5550 requirements.

6.How does Aetrix verify that 2N5550 is sourced from the original manufacturer or authorized distributors?

All 2N5550 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 2N5550 meets industry standards.

7.What is the process for return or replacement of 2N5550?

All 2N5550 units undergo pre-shipment inspection (PSI). If there is an issue with 2N5550, 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 2N5550 part is unused and in its original packaging.

Return procedure for 2N5550:

1.Submit a request within 90 days.

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

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