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

onsemi 2N5551RLRAG

Name: 2N5551RLRAG
Brand: onsemi
SKU: 2N5551RLRAG
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N5551RLRAG

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: 2N5551RLRAG.pdf

Description:: TRANS NPN 160V 0.6A TO92

Quantity:: RFQ Add To RFQ list

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Inventory:9,376

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Product details

Overview

2N5551RLRAG from onsemi is an NPN silicon general-purpose amplifier transistor in TO-92 package, rated for V_CEO = 160 V, I_C = 600 mA, and f_T = 100–300 MHz, commonly used in high-voltage linear amplification and switching stages of industrial power supplies and signal conditioning circuits.

For engineers reviewing the 2N5551RLRAG datasheet, pinout, applications, or equivalent options, key selection criteria include breakdown voltage margin (V_CBO = 180 V), low noise figure (NF = 8.0 dB at 1 kHz), DC current gain range (h_FE = 80–250), and thermal resistance (R_JC = 83.3 °C/W) for reliable operation in ambient-temperature-variable designs.

Technical Context

The 2N5551RLRAG operates as a medium-power, high-voltage NPN bipolar junction transistor optimized for linear amplification and fast-switching applications. Its design supports stable h_FE across collector currents from 1 mA to 50 mA and maintains low V_CE(sat) (≤ 0.25 V at I_C/I_B = 10) under moderate drive conditions.

Thermal performance is defined by R_JC = 83.3 °C/W and R_JA = 200 °C/W, enabling operation up to +150 °C junction temperature. The device features low input capacitance (C_ibo = 20 pF) and output capacitance (C_obo = 6.0 pF), supporting bandwidth-critical analog front-ends and RF driver stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	160 Vdc - Enables use in 120 VAC-derived supply rails with safety margin
I_C	600 mAdc - Supports medium-current gain stages without parallel devices
f_T	100–300 MHz - Sufficient for VHF amplification and fast digital switching
h_FE	80–250 - Provides predictable bias stability across production lots
NF	8.0 dB @ 1 kHz - Low-noise performance suitable for preamplifier inputs
R_JC	83.3 °C/W - Allows direct mounting to heatsink for sustained 1 W dissipation

Pinout & Package

2N5551RLRAG uses the standard TO-92 (Case 29-11) through-hole package with bent leads, Pb-free finish, and marking "2N5551" followed by date code. Pin 1 is Emitter, Pin 2 is Base, Pin 3 is Collector - verified per onsemi's official marking diagram and package outline.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Reference node for bias network; connects to ground or emitter resistor in common-emitter configuration
2 (Base)	Control input	Receives forward-biased drive current (I_B) to modulate collector current; requires current-limiting resistor
3 (Collector)	Output current source	Delivers amplified I_C to load; rated for 160 V standoff in active region and 180 V in cutoff

Key Features

Feature	Design Value
High V_CBO rating	180 Vdc - Reduces risk of avalanche breakdown in inductive load switching
Pb-free TO-92 package	RoHS-compliant construction with bent-lead tape-and-ammo shipping format (2N5551RLRAG)
Low C_ibo	20 pF - Minimizes Miller effect in high-gain amplifier stages
Wide h_FE range	80–250 at I_C = 1–50 mA - Enables consistent DC bias design across manufacturing variance

Applications

Industrial Power Supply Feedback Amplifier	Audio Preamp Stage
Use Scenario: Amplifying error signal from optocoupler in isolated 48 V/5 A SMPS feedback loop. IC Role / Device Role / Timing Role: NPN transconductance amplifier converting photocurrent to voltage-controlled duty cycle adjustment. Use Value: V_CEO = 160 V ensures safe operation across full input range (85–265 VAC); h_FE ≥ 80 guarantees stable loop gain over temperature.	Use Scenario: First-stage low-noise voltage amplification in microphone preamplifier before op-amp buffering. IC Role / Device Role / Timing Role: Discrete NPN common-emitter amplifier providing 20–30 dB gain with minimal added noise. Use Value: NF = 8.0 dB at 1 kHz and C_ibo = 20 pF preserve signal integrity and prevent high-frequency roll-off.
High-Voltage Logic Level Shifter	Relay Driver Interface
Use Scenario: Translating 3.3 V microcontroller GPIO to 24 V control signal for PLC input module. IC Role / Device Role / Timing Role: Switching transistor operating in saturation/cutoff to invert and level-shift logic states. Use Value: V_CBO = 180 V and V_CE(sat) ≤ 0.25 V ensure robust off-state isolation and low conduction loss during on-state.	Use Scenario: Driving 12 V, 400 mA coil of industrial relay from MCU GPIO via base resistor. IC Role / Device Role / Timing Role: Medium-current saturated switch interfacing low-power logic to inductive load. Use Value: I_C = 600 mA rating provides 1.5× margin over relay coil current; R_JC = 83.3 °C/W enables continuous operation without heatsink.

Industrial Power Supply Feedback Amplifier

Audio Preamp Stage

Use Scenario: Amplifying error signal from optocoupler in isolated 48 V/5 A SMPS feedback loop.

IC Role / Device Role / Timing Role: NPN transconductance amplifier converting photocurrent to voltage-controlled duty cycle adjustment.

Use Value: V_CEO = 160 V ensures safe operation across full input range (85–265 VAC); h_FE ≥ 80 guarantees stable loop gain over temperature.

Use Scenario: First-stage low-noise voltage amplification in microphone preamplifier before op-amp buffering.

IC Role / Device Role / Timing Role: Discrete NPN common-emitter amplifier providing 20–30 dB gain with minimal added noise.

Use Value: NF = 8.0 dB at 1 kHz and C_ibo = 20 pF preserve signal integrity and prevent high-frequency roll-off.

High-Voltage Logic Level Shifter

Relay Driver Interface

Use Scenario: Translating 3.3 V microcontroller GPIO to 24 V control signal for PLC input module.

IC Role / Device Role / Timing Role: Switching transistor operating in saturation/cutoff to invert and level-shift logic states.

Use Value: V_CBO = 180 V and V_CE(sat) ≤ 0.25 V ensure robust off-state isolation and low conduction loss during on-state.

Use Scenario: Driving 12 V, 400 mA coil of industrial relay from MCU GPIO via base resistor.

IC Role / Device Role / Timing Role: Medium-current saturated switch interfacing low-power logic to inductive load.

Use Value: I_C = 600 mA rating provides 1.5× margin over relay coil current; R_JC = 83.3 °C/W enables continuous operation without heatsink.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MPSA42	V_CEO = 300 V, h_FE = 40–150, f_T = 50 MHz	Higher voltage rating but lower gain-bandwidth product	Preferred where >200 V standoff is required; less suitable for high-frequency amplification
BC547C	V_CEO = 45 V, h_FE = 420–800, f_T = 300 MHz	Lower voltage rating but higher h_FE and same f_T	Preferred for low-voltage, high-gain audio stages; unsuitable for >60 V rail applications

Compared with MPSA42 and BC547C, the 2N5551RLRAG uniquely balances 160 V breakdown, 300 MHz f_T, and 80–250 h_FE-making it optimal for industrial feedback amplifiers and medium-voltage switching where both voltage headroom and bandwidth matter.

Availability

2N5551RLRAG is available at Aetrix Electronics and suitable for industrial power supplies, audio preamplifiers, logic level shifters, and relay driver interfaces requiring stable component supply and RoHS-compliant TO-92 packaging.

Supply support for 2N5551RLRAG 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, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The 2N5551RLRAG belongs to onsemi's legacy discrete transistor portfolio, designed specifically for general-purpose amplification and switching in cost-sensitive, reliability-critical industrial and power electronics systems.

FAQ

What is the maximum collector-emitter voltage rating for the 2N5551RLRAG?

The 2N5551RLRAG has a maximum collector-emitter voltage (V_CEO) rating of 160 Vdc, verified per onsemi's official datasheet revision 5. This rating applies under continuous DC operation at T_A = 25°C and defines the upper limit for safe active-region operation before breakdown occurs. Exceeding this voltage risks irreversible avalanche failure.

Does the 2N5551RLRAG have a Pb-free package?

Yes, the 2N5551RLRAG uses a Pb-free TO-92 package, explicitly confirmed in the ordering information table and marked with the Pb-free symbol in the datasheet. It complies with RoHS Directive 2011/65/EU and is supplied in tape-and-ammo packaging per the 2N5551RLRAG part number designation.

What is the typical DC current gain (h_FE) range for the 2N5551RLRAG at I_C = 10 mA?

At I_C = 10 mA and V_CE = 5.0 Vdc, the 2N5551RLRAG exhibits h_FE between 80 and 250, as specified in the Electrical Characteristics table. This wide range reflects production lot variation and must be accounted for in bias network design-typically using emitter degeneration or feedback to ensure stability across all units.

Can the 2N5551RLRAG be used in high-frequency amplifier applications?

Yes, the 2N5551RLRAG supports high-frequency amplifier applications with a current-gain bandwidth product (f_T) of 100–300 MHz at I_C = 10 mA and V_CE = 10 Vdc. Its low C_ibo (20 pF) and C_obo (6.0 pF) minimize parasitic capacitance effects, making it suitable for VHF preamplifiers and RF driver stages up to ~100 MHz with proper layout and matching.

What is the thermal resistance from junction to case (R_JC) for the 2N5551RLRAG?

The thermal resistance from junction to case (R_JC) for the 2N5551RLRAG is 83.3 °C/W, measured under specified test conditions (T_C = 25°C). This value enables calculation of junction temperature rise above case temperature and informs heatsinking decisions-e.g., at 1 W dissipation, ΔT_J−C ≈ 83°C, requiring case-to-ambient thermal path management for reliable long-term operation.

2N5551RLRAG Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

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

Voltage - Collector Emitter Breakdown (Max):: 160 V

Vce Saturation (Max) @ Ib, Ic:: 200mV @ 5mA, 50mA

Current - Collector Cutoff (Max):: 50nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 80 @ 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)

2N5551RLRAG FAQ

1.How can I place an order for 2N5551RLRAG through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N5551RLRAG 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 2N5551RLRAG reliable?

The price and inventory of 2N5551RLRAG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N5551RLRAG is usually 5 days.

3.What payment methods are accepted for 2N5551RLRAG?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N5551RLRAG transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N5551RLRAG?

2N5551RLRAG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N5551RLRAG 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 2N5551RLRAG?

For technical support, including 2N5551RLRAG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N5551RLRAG requirements.

6.How does Aetrix verify that 2N5551RLRAG is sourced from the original manufacturer or authorized distributors?

All 2N5551RLRAG 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 2N5551RLRAG meets industry standards.

7.What is the process for return or replacement of 2N5551RLRAG?

All 2N5551RLRAG units undergo pre-shipment inspection (PSI). If there is an issue with 2N5551RLRAG, 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 2N5551RLRAG part is unused and in its original packaging.

Return procedure for 2N5551RLRAG:

1.Submit a request within 90 days.

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

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