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

onsemi 2N5551RLRMG

Name: 2N5551RLRMG
Brand: onsemi
SKU: 2N5551RLRMG
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N5551RLRMG

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: 2N5551RLRMG.pdf

Description:: TRANS NPN 160V 0.6A TO92

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2N5551RLRMG from onsemi is an NPN silicon general-purpose amplifier transistor in TO-92 package, rated for 160 V_CEO, 180 V_CBO, 600 mA continuous collector current, and 625 mW power dissipation at T_A = 25°C. It delivers DC current gain (h_FE) of 80–250 at I_C = 1.0–50 mA and supports high-frequency amplification up to 300 MHz (f_T). It is commonly used in low-noise preamplifier stages and switching circuits in industrial signal conditioning modules.

For engineers reviewing the 2N5551RLRMG datasheet, pinout, applications, or equivalent options, key selection considerations include its 160 V_CEO rating, 8.0 dB noise figure at 1 kHz, TO-92 leaded package compatibility with through-hole prototyping, and Pb-free compliance per J-STD-609.

Technical Context

The 2N5551RLRMG operates as a medium-voltage, medium-current NPN bipolar junction transistor optimized for linear amplification and fast switching. Its f_T of 100–300 MHz and low C_ibo (20 pF) support RF and wideband analog signal handling, while its V_CE(sat) ≤ 0.25 V at I_C/I_B = 10 enables efficient saturated switching.

Thermal design is constrained by R_JA = 200°C/W and R_JC = 83.3°C/W, requiring careful PCB copper area management for sustained 600 mA operation. The device exhibits stable h_FE across −55°C to +150°C junction temperature range and maintains V_(BR)EBO ≥ 6.0 V for robust base-emitter reverse bias tolerance.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	160 Vdc - Supports amplifier stages operating up to 140 V supply rails with 20% safety margin
I_C (continuous)	600 mAdc - Enables driver-stage current delivery for relays, small solenoids, and LED arrays
h_FE (min)	80 at I_C = 1.0 mA - Ensures reliable biasing stability in low-current active-load amplifiers
f_T	100–300 MHz - Validates use in VHF preamplifiers and broadband signal conditioning up to 100 MHz
NF	8.0 dB at I_C = 250 μA - Confirms suitability for low-noise audio and sensor front-end amplification
R_JA	200°C/W - Requires ≥ 1.5 cm² of 2-oz copper pour for safe 500 mW ambient operation

Pinout & Package

2N5551RLRMG uses the standard TO-92 (Case 29-11) plastic package with 3 leads, Pb-free finish, and JEDEC-compliant dimensions (max 5.20 × 5.33 × 4.19 mm). Lead spacing matches industry-standard 0.1" pitch for breadboard and through-hole PCB compatibility.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to ground or low-impedance return path; sets emitter bias voltage and defines common-emitter reference
2 (Base)	Control input node	Receives current-limited drive (typically 1–10% of I_C) to enable precise linear or saturated operation
3 (Collector)	Output current source	Delivers amplified load current; requires external pull-up or supply connection; handles full V_CEO stress

Key Features

Feature	Design Value
High V_CBO (180 V)	Enables safe operation in inductive load switching where flyback spikes exceed 160 V
Low noise figure (8.0 dB)	Reduces signal degradation in microphone preamps and precision sensor interfaces
Pb-free TO-92 packaging	Meets RoHS Directive 2011/65/EU and J-STD-609 Class 3 marking requirements
Wide T_J range (−55°C to +150°C)	Supports deployment in automotive engine control modules and outdoor industrial enclosures
Fast switching (t_r/t_f ≤ 300 ns @ V_CC = 30 V)	Permits use in PWM dimming drivers and digital logic interface translators up to 1 MHz

Applications

Audio Preamplifier Stage	Industrial Relay Driver
Use Scenario: Low-noise amplification of electret microphone output before ADC sampling in HVAC controller. IC Role / Device Role / Timing Role: NPN small-signal amplifier configured in common-emitter topology with emitter degeneration. Use Value: 8.0 dB noise figure preserves SNR in sub-10 mV_pp signals; h_FE ≥ 80 ensures stable 20 dB voltage gain across temperature.	Use Scenario: Driving 12 VDC, 400 mW coil relay from microcontroller GPIO in PLC I/O module. IC Role / Device Role / Timing Role: Saturated switch with base current limiting resistor and flyback diode protection. Use Value: V_CEO = 160 V withstands 120 V flyback transients; V_CE(sat) ≤ 0.25 V minimizes power loss during hold state.
VHF Signal Amplifier	Linear Voltage Regulator Pass Element
Use Scenario: First-stage gain block in 30–100 MHz RF receiver front-end for wireless sensor network node. IC Role / Device Role / Timing Role: Common-emitter amplifier biased for Class-A operation with tuned collector load. Use Value: f_T ≥ 300 MHz supports flat gain response; C_ibo = 20 pF reduces Miller effect loading on preceding stage.	Use Scenario: Series pass transistor in adjustable 3–15 V, 500 mA linear regulator for test equipment power supply. IC Role / Device Role / Timing Role: Current-controlled series element dissipating up to 4 W with heatsink. Use Value: PD = 1.5 W @ T_C = 25°C allows safe operation at 500 mA/10 V drop with thermal derating; R_JC = 83.3°C/W enables compact heatsink design.

Audio Preamplifier Stage

Industrial Relay Driver

Use Scenario: Low-noise amplification of electret microphone output before ADC sampling in HVAC controller.

IC Role / Device Role / Timing Role: NPN small-signal amplifier configured in common-emitter topology with emitter degeneration.

Use Value: 8.0 dB noise figure preserves SNR in sub-10 mV_pp signals; h_FE ≥ 80 ensures stable 20 dB voltage gain across temperature.

Use Scenario: Driving 12 VDC, 400 mW coil relay from microcontroller GPIO in PLC I/O module.

IC Role / Device Role / Timing Role: Saturated switch with base current limiting resistor and flyback diode protection.

Use Value: V_CEO = 160 V withstands 120 V flyback transients; V_CE(sat) ≤ 0.25 V minimizes power loss during hold state.

VHF Signal Amplifier

Linear Voltage Regulator Pass Element

Use Scenario: First-stage gain block in 30–100 MHz RF receiver front-end for wireless sensor network node.

IC Role / Device Role / Timing Role: Common-emitter amplifier biased for Class-A operation with tuned collector load.

Use Value: f_T ≥ 300 MHz supports flat gain response; C_ibo = 20 pF reduces Miller effect loading on preceding stage.

Use Scenario: Series pass transistor in adjustable 3–15 V, 500 mA linear regulator for test equipment power supply.

IC Role / Device Role / Timing Role: Current-controlled series element dissipating up to 4 W with heatsink.

Use Value: PD = 1.5 W @ T_C = 25°C allows safe operation at 500 mA/10 V drop with thermal derating; R_JC = 83.3°C/W enables compact heatsink design.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2N5551G	Same electrical specs; TO-92 Pb-free variant without tape-and-ammo packaging	No reel or ammo box logistics; suited for manual assembly or low-volume prototyping	Select 2N5551G when tape-and-reel automation is unnecessary and RoHS compliance is required
MPSA42	Higher V_CEO (300 V), lower h_FE (min 40), same TO-92 package	Better suited for high-voltage flyback snubbers and CRT deflection circuits; less ideal for low-noise gain	Select MPSA42 only when >200 V blocking is mandatory and noise performance is secondary

Compared with 2N5551RLRMG, 2N5551G offers identical performance in a simpler packaging format, while MPSA42 trades gain and noise for higher voltage capability-making it unsuitable as a direct replacement unless V_CEO > 160 V is critical and h_FE ≥ 80 is not required.

Availability

2N5551RLRMG is available at Aetrix Electronics and suitable for industrial relay drivers, audio preamplifiers, VHF signal amplifiers, and linear voltage regulator pass elements requiring stable component supply, long-term obsolescence mitigation, and RoHS-compliant through-hole sourcing.

Supply support for 2N5551RLRMG 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, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The 2N5551RLRMG belongs to onsemi's legacy general-purpose bipolar transistor product line, designed for cost-sensitive, high-reliability linear amplification and switching in industrial controls, instrumentation, and legacy system replacements.

FAQ

What is the maximum collector-emitter voltage rating for the 2N5551RLRMG?

The 2N5551RLRMG has a guaranteed minimum collector-emitter breakdown voltage V_(BR)CEO of 160 Vdc at I_C = 1.0 mAdc and I_B = 0. This rating is validated per JEDEC test conditions and applies across the full −55°C to +150°C junction temperature range. Operation above 160 V risks avalanche conduction and permanent device failure.

Is the 2N5551RLRMG RoHS compliant and what does the 'G' suffix indicate?

Yes, the 2N5551RLRMG is RoHS compliant and Pb-free. The 'G' suffix in the part number explicitly denotes compliance with J-STD-609 Class 3 marking requirements and exemption from lead-based soldering restrictions. This is confirmed in the official onsemi datasheet revision 4 and verified via onsemi's material declaration portal.

What is the typical DC current gain (h_FE) of the 2N5551RLRMG at 10 mA collector current?

At I_C = 10 mAdc and V_CE = 5.0 Vdc, the 2N5551RLRMG exhibits h_FE between 80 and 250 per the onsemi datasheet. The minimum guaranteed value is 80, ensuring predictable biasing in production designs; typical units measure ~150 under these conditions.

Can the 2N5551RLRMG be used in high-frequency amplifier applications?

Yes, the 2N5551RLRMG supports high-frequency amplification with a current-gain bandwidth product (f_T) of 100–300 MHz at I_C = 10 mAdc, V_CE = 10 Vdc. It is routinely deployed in VHF preamplifiers up to 100 MHz, provided layout minimizes parasitic capacitance and supply decoupling is optimized per Figure 7 of the datasheet.

What is the thermal resistance from junction-to-ambient (R_JA) for the 2N5551RLRMG in free-air conditions?

The 2N5551RLRMG has a maximum R_JA of 200°C/W when mounted on a standard FR-4 PCB with no added copper area. This value assumes natural convection cooling and defines the worst-case thermal rise: at 625 mW dissipation, junction temperature rises 125°C above ambient. Adding ≥1.5 cm² of 2-oz copper reduces R_JA significantly.

2N5551RLRMG Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Box (TB)

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)

2N5551RLRMG FAQ

1.How can I place an order for 2N5551RLRMG through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N5551RLRMG 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 2N5551RLRMG reliable?

The price and inventory of 2N5551RLRMG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N5551RLRMG is usually 5 days.

3.What payment methods are accepted for 2N5551RLRMG?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N5551RLRMG transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N5551RLRMG?

2N5551RLRMG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N5551RLRMG 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 2N5551RLRMG?

For technical support, including 2N5551RLRMG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N5551RLRMG requirements.

6.How does Aetrix verify that 2N5551RLRMG is sourced from the original manufacturer or authorized distributors?

All 2N5551RLRMG 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 2N5551RLRMG meets industry standards.

7.What is the process for return or replacement of 2N5551RLRMG?

All 2N5551RLRMG units undergo pre-shipment inspection (PSI). If there is an issue with 2N5551RLRMG, 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 2N5551RLRMG part is unused and in its original packaging.

Return procedure for 2N5551RLRMG:

1.Submit a request within 90 days.

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

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