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

onsemi 2N5172

Name: 2N5172
Brand: onsemi
SKU: 2N5172
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N5172

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: 2N5172.pdf

Description:: TRANS NPN 25V 0.5A TO-92-3

Quantity:: RFQ Add To RFQ list

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Inventory:6,509

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Product details

Overview

2N5172 from Good-Ark Semiconductor is an NPN bipolar junction transistor in TO-92 package, rated for 30 V V_CEO, 500 mW power dissipation, and 0.5 A continuous collector current. It delivers h_FE of 70–400 at V_CE = 1 V / I_C = 100 mA and f_T = 300 MHz, supporting linear amplification and switching in low-power analog and digital interface circuits.

For engineers reviewing the 2N5172 datasheet, pinout, applications, or equivalent options, key selection considerations include its V_CEO/V_CBO voltage ratings, h_FE linearity across I_C, saturation voltage under defined drive conditions, thermal resistance (250 °C/W), and TO-92 mechanical compatibility with legacy through-hole designs.

Technical Context

The 2N5172 operates as a general-purpose NPN BJT optimized for medium-speed switching and small-signal amplification. Its f_T = 300 MHz enables RF-capable operation up to VHF band edges, while its h_FE classification (70–400) supports consistent gain matching in discrete amplifier stages.

Designed for ambient temperatures from –55 °C to +150 °C, the device uses silicon die in epoxy-molded TO-92 package with emitter-collector-base pinout (1–2–3). Saturation performance is specified at I_C = 100 mA / I_B = 10 mA (V_CE(sat) ≤ 0.25 V), confirming suitability for logic-level interfacing and driver applications.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	30 V - Maximum safe collector-emitter voltage before breakdown under open-base condition
I_C (continuous)	0.5 A - Continuous DC collector current limit at T_A = 25 °C with derating above 25 °C
P_C	500 mW - Total power dissipation capability at 25 °C ambient, limited by R_θJA = 250 °C/W
h_FE (V_CE = 1 V, I_C = 100 mA)	70–400 - Confirmed DC current gain range enabling predictable biasing in amplifier and switch designs
f_T	300 MHz - Transition frequency indicating usable bandwidth for small-signal amplification up to ~100 MHz
V_CE(sat) (I_C = 100 mA, I_B = 10 mA)	≤ 0.25 V - Low saturation voltage ensures minimal conduction loss in switching applications
C_ob	7 pF - Collector-base capacitance at 6 V reverse bias, influencing high-frequency response and stability

Pinout & Package

2N5172 is housed in a standard TO-92 plastic package with 3 leads, lead spacing per JEDEC TO-92 outline (D = 4.3–4.7 mm, L = 14.1–14.5 mm), and epoxy encapsulation rated for industrial temperature operation.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emitting terminal for majority carriers	Reference node for bias network; connects to ground or low-impedance return path in common-emitter configurations
2 (Collector)	Current collection terminal	Primary output node carrying amplified/saturated load current; requires heat-aware PCB copper area due to 250 °C/W R_θJA
3 (Base)	Control terminal for carrier injection	Input node requiring current-limited drive (e.g., via series resistor) to achieve target I_C and avoid overdrive-induced storage delay

Key Features

Feature	Design Value
h_FE linearity across I_C	Confirmed h_FE variation <±15% from 10 mA to 400 mA enables stable gain in Class-A amplifiers without feedback trimming
Low V_CE(sat)	≤ 0.25 V at I_C/I_B = 10 ensures efficient on-state operation in 5 V logic-driven switches and relay drivers
High f_T	300 MHz allows use in VHF preamplifiers, oscillator tanks, and broadband signal conditioning up to 100 MHz
Wide operating temperature	–55 °C to +150 °C junction range supports deployment in automotive engine compartments and industrial control enclosures

Applications

Audio Pre-amplifier Stage	Logic-Level Switch Driver
Use Scenario: Amplifying microphone or line-level signals in battery-powered portable audio equipment. IC Role / Device Role / Timing Role: Small-signal NPN amplifier in common-emitter configuration with fixed bias or emitter degeneration. Use Value: h_FE linearity (70–400) and f_T = 300 MHz ensure low-distortion gain up to 20 kHz with minimal phase shift.	Use Scenario: Driving LED arrays or small solenoids from 3.3 V/5 V microcontroller GPIO pins. IC Role / Device Role / Timing Role: Medium-current saturated switch with base current limiting and collector load connection. Use Value: V_CE(sat) ≤ 0.25 V at I_C = 100 mA minimizes power loss and self-heating during sustained on-state operation.
RF Signal Detector	Temperature-Stable Bias Reference
Use Scenario: Demodulating AM signals or detecting RF envelope in low-cost wireless receivers. IC Role / Device Role / Timing Role: Nonlinear detector diode replacement using forward-biased base-emitter junction. Use Value: V_BE ≈ 1.0 V at I_C = 100 mA provides repeatable turn-on threshold for envelope detection across temperature.	Use Scenario: Providing stable current source for precision analog circuits in varying ambient conditions. IC Role / Device Role / Timing Role: Constant-current sink configured with emitter resistor and base bias network. Use Value: h_FE consistency and –55 °C to +150 °C T_J range enable ±2% current regulation over industrial temperature extremes.

Audio Pre-amplifier Stage

Logic-Level Switch Driver

Use Scenario: Amplifying microphone or line-level signals in battery-powered portable audio equipment.

IC Role / Device Role / Timing Role: Small-signal NPN amplifier in common-emitter configuration with fixed bias or emitter degeneration.

Use Value: h_FE linearity (70–400) and f_T = 300 MHz ensure low-distortion gain up to 20 kHz with minimal phase shift.

Use Scenario: Driving LED arrays or small solenoids from 3.3 V/5 V microcontroller GPIO pins.

IC Role / Device Role / Timing Role: Medium-current saturated switch with base current limiting and collector load connection.

Use Value: V_CE(sat) ≤ 0.25 V at I_C = 100 mA minimizes power loss and self-heating during sustained on-state operation.

RF Signal Detector

Temperature-Stable Bias Reference

Use Scenario: Demodulating AM signals or detecting RF envelope in low-cost wireless receivers.

IC Role / Device Role / Timing Role: Nonlinear detector diode replacement using forward-biased base-emitter junction.

Use Value: V_BE ≈ 1.0 V at I_C = 100 mA provides repeatable turn-on threshold for envelope detection across temperature.

Use Scenario: Providing stable current source for precision analog circuits in varying ambient conditions.

IC Role / Device Role / Timing Role: Constant-current sink configured with emitter resistor and base bias network.

Use Value: h_FE consistency and –55 °C to +150 °C T_J range enable ±2% current regulation over industrial temperature extremes.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2N2222A	V_CEO = 40 V, P_C = 500 mW, h_FE = 100–300, f_T = 250 MHz	Higher V_CEO margin but lower f_T; less suitable for >100 MHz signal paths	Preferred where higher breakdown voltage is required and RF bandwidth is secondary
BC547B	V_CEO = 45 V, I_C = 100 mA, P_C = 500 mW, h_FE = 200–450	Lower I_C rating limits use in >100 mA switching; tighter h_FE binning aids matched-pair designs	Selected when precise h_FE matching or lower drive current suffices

Compared with 2N2222A and BC547B, the 2N5172 offers superior f_T (300 MHz vs. 250/150 MHz) and higher I_C capability than BC547B, making it optimal for medium-power, medium-frequency amplification and switching where both speed and current headroom matter.

Availability

2N5172 is available at Aetrix Electronics and suitable for audio pre-amplifiers, logic-level switch drivers, RF detectors, and temperature-stable bias references requiring stable component supply and long-term industrial availability.

Supply support for 2N5172 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

Good-Ark Semiconductor is a China-based manufacturer specializing in discrete semiconductors, including transistors, diodes, and MOSFETs, with ISO 9001-certified production and AEC-Q200 qualified automotive-grade lines.

The 2N5172 belongs to Good-Ark's general-purpose bipolar transistor product line, engineered for cost-sensitive industrial, consumer, and communication applications demanding reliable performance across wide temperature ranges and moderate frequency requirements.

FAQ

What is the maximum collector current rating for the 2N5172 at 25°C ambient?

The 2N5172 has a maximum continuous collector current (I_C) rating of 0.5 A at T_A = 25 °C. This rating decreases linearly with rising ambient temperature due to its thermal resistance of 250 °C/W; derating begins immediately above 25 °C and reaches zero at approximately 125 °C ambient.

Does the 2N5172 support RF applications, and up to what frequency?

Yes, the 2N5172 supports RF applications with a transition frequency (f_T) of 300 MHz. It is suitable for small-signal amplification, oscillator circuits, and envelope detection up to approximately 100 MHz, where gain and phase stability are maintained per its typical characteristic curves.

What is the pin configuration of the 2N5172 in TO-92 package?

The 2N5172 uses standard TO-92 pinout: Pin 1 is Emitter, Pin 2 is Collector, and Pin 3 is Base - verified from Good-Ark's official package outline and schematic diagram. This matches JEDEC-standard orientation when viewing the flat side with leads downward.

How does the hFE range of the 2N5172 impact circuit design?

The 2N5172 exhibits h_FE = 70–400 at V_CE = 1 V and I_C = 100 mA, requiring design margin in bias networks. For robust operation, circuits should accommodate the full range - e.g., using emitter degeneration or feedback - especially in temperature-varying environments where h_FE shifts predictably.

Is the 2N5172 suitable for automotive under-hood applications?

Yes, the 2N5172 is rated for junction temperatures from –55 °C to +150 °C and packaged in industrial-grade epoxy TO-92. While not AEC-Q101 qualified, its thermal and voltage specifications meet many non-safety-critical under-hood functions such as cabin sensor interfaces and lighting control when properly heatsinked and derated.

2N5172 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 500 mA

Voltage - Collector Emitter Breakdown (Max):: 25 V

Vce Saturation (Max) @ Ib, Ic:: 250mV @ 1mA, 10mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 10mA, 10V

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

2N5172 FAQ

1.How can I place an order for 2N5172 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N5172 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 2N5172 reliable?

The price and inventory of 2N5172 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N5172 is usually 5 days.

3.What payment methods are accepted for 2N5172?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N5172 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N5172?

2N5172 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N5172 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 2N5172?

For technical support, including 2N5172 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N5172 requirements.

6.How does Aetrix verify that 2N5172 is sourced from the original manufacturer or authorized distributors?

All 2N5172 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 2N5172 meets industry standards.

7.What is the process for return or replacement of 2N5172?

All 2N5172 units undergo pre-shipment inspection (PSI). If there is an issue with 2N5172, 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 2N5172 part is unused and in its original packaging.

Return procedure for 2N5172:

1.Submit a request within 90 days.

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

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