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

onsemi PN4250

Name: PN4250
Brand: onsemi
SKU: PN4250
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: PN4250

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: PN4250.pdf

Description:: TRANS PNP 40V 0.5A TO-92-3

Quantity:: RFQ Add To RFQ list

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Inventory:7,725

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Product details

Overview

PN4250 from Fairchild Semiconductor is a PNP general-purpose bipolar junction transistor (BJT) designed for amplification and switching in low-to-medium power circuits, with V_CEO = 40 V, I_C = 500 mA continuous, h_FE = 250–700 at I_C = 100 µA, and TO-92 package. It serves in signal conditioning, discrete logic interfacing, and load switching up to 300 mA collector current.

For engineers reviewing the PN4250 datasheet, pinout, applications, or equivalent options, key selection considerations include its PNP polarity, DC current gain range, saturation voltage under defined drive conditions, thermal resistance (R_θJA = 200 °C/W), and suitability for general-purpose analog and digital switching where moderate speed and low-cost discrete operation are required.

Technical Context

The PN4250 operates as a silicon PNP BJT fabricated using Fairchild's Process 68, optimized for stable DC gain and low V_CE(sat) in linear and saturated modes. Its breakdown ratings-V_(BR)CEO, V_(BR)CBO, and V_(BR)EBO-are all specified at 40 V, 40 V, and 5.0 V respectively, supporting robust operation in grounded-emitter configurations.

Small-signal parameters include Cob = 6.0 pF at V_CB = 5.0 V, h_ie = 6.0–20 kΩ, and noise figure NF = 2.0 dB at two bias points, confirming utility in audio-frequency amplification and low-noise preamplifier stages where junction capacitance and input impedance impact bandwidth and SNR.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum safe collector-emitter voltage before breakdown in common-emitter configuration
I_C (continuous)	500 mA - Continuous collector current handling capacity, enabling use in medium-current switches
h_FE	250–700 - DC current gain range at V_CE = 5.0 V, I_C = 100 µA, supporting predictable base drive design
V_CE(sat)	0.25 V max - Low saturation voltage at I_C = 10 mA / I_B = 0.5 mA, minimizing conduction loss in switching mode
R_θJA	200 °C/W - Junction-to-ambient thermal resistance in free-air, defining derating requirement above 25°C ambient
C_ob	6.0 pF - Output capacitance at V_CB = 5.0 V, f = 1 MHz, limiting high-frequency gain roll-off

Pinout & Package

PN4250 is housed in a standard through-hole TO-92 plastic package with straight leads and no lead clip. Pin identification follows JEDEC TO-92 orientation: flat side facing viewer, leads down, left-to-right = Emitter (E), Base (B), Collector (C).

Pin/Terminal	Circuit Role	Design Meaning
E (Emitter)	Current source terminal for PNP device	Connected to higher potential in typical common-emitter switch; sets reference for base bias network
B (Base)	Control terminal for minority-carrier injection	Receives forward-biased current to turn on transistor; requires series resistor for current limiting
C (Collector)	Current sink terminal	Connected to load and supply return path; carries full switched current in saturation

Key Features

Feature	Design Value
High DC current gain range	h_FE = 250–700 enables reliable switching with minimal base drive current across process variation
Low V_CE(sat)	≤0.25 V at I_C/I_B = 10 mA/0.5 mA reduces power dissipation in saturated switching applications
Robust breakdown ratings	V_(BR)CEO = V_(BR)CBO = 40 V supports operation in 24 V and 36 V industrial control rails without derating
Low noise performance	NF = 2.0 dB at audio frequencies allows use in low-level signal amplification without significant SNR degradation

Applications

Audio Pre-amplifier Stage	Discrete Logic Level Shifter
Use Scenario: Amplifying weak microphone or sensor signals in battery-powered portable audio equipment. IC Role / Device Role / Timing Role: PNP BJT configured in common-emitter topology to provide voltage gain with inverted output polarity. Use Value: h_FE ≥250 ensures sufficient gain margin at low quiescent current; Cob = 6.0 pF preserves bandwidth up to ~100 kHz.	Use Scenario: Translating TTL/CMOS logic outputs to higher-voltage control signals for relays or optocouplers. IC Role / Device Role / Timing Role: Saturated PNP switch turning on/off a 12 V load referenced to ground. Use Value: V_CE(sat) ≤0.25 V minimizes voltage drop and self-heating; I_C = 500 mA supports relay coils up to 24 Ω at 12 V.
Linear Voltage Regulator Pass Element	Industrial Sensor Interface Driver
Use Scenario: Acting as series pass transistor in adjustable linear regulators powering analog sensors. IC Role / Device Role / Timing Role: Linear-mode PNP emitter-follower providing current boost and low-output-impedance regulation. Use Value: R_θJA = 200 °C/W allows thermal management with minimal heatsinking at ≤100 mW dissipation.	Use Scenario: Driving resistive or capacitive loads in 4–20 mA transmitter front-ends or RTD excitation circuits. IC Role / Device Role / Timing Role: Precision current source/sink element controlled by op-amp feedback loop. Use Value: Tight V_(BR)EBO = 5.0 V and low IEBO = 20 nA ensure stable biasing and minimal leakage error in precision analog paths.

Audio Pre-amplifier Stage

Discrete Logic Level Shifter

Use Scenario: Amplifying weak microphone or sensor signals in battery-powered portable audio equipment.

IC Role / Device Role / Timing Role: PNP BJT configured in common-emitter topology to provide voltage gain with inverted output polarity.

Use Value: h_FE ≥250 ensures sufficient gain margin at low quiescent current; Cob = 6.0 pF preserves bandwidth up to ~100 kHz.

Use Scenario: Translating TTL/CMOS logic outputs to higher-voltage control signals for relays or optocouplers.

IC Role / Device Role / Timing Role: Saturated PNP switch turning on/off a 12 V load referenced to ground.

Use Value: V_CE(sat) ≤0.25 V minimizes voltage drop and self-heating; I_C = 500 mA supports relay coils up to 24 Ω at 12 V.

Linear Voltage Regulator Pass Element

Industrial Sensor Interface Driver

Use Scenario: Acting as series pass transistor in adjustable linear regulators powering analog sensors.

IC Role / Device Role / Timing Role: Linear-mode PNP emitter-follower providing current boost and low-output-impedance regulation.

Use Value: R_θJA = 200 °C/W allows thermal management with minimal heatsinking at ≤100 mW dissipation.

Use Scenario: Driving resistive or capacitive loads in 4–20 mA transmitter front-ends or RTD excitation circuits.

IC Role / Device Role / Timing Role: Precision current source/sink element controlled by op-amp feedback loop.

Use Value: Tight V_(BR)EBO = 5.0 V and low IEBO = 20 nA ensure stable biasing and minimal leakage error in precision analog paths.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP general-purpose amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC557	V_CEO = 45 V, I_C = 100 mA, h_FE = 110–800, TO-92	Lower I_C rating limits use in >100 mA switching; higher h_FE min improves low-drive sensitivity	Select when lower base current or tighter gain consistency is prioritized over current capacity
MPSA92	V_CEO = 300 V, I_C = 500 mA, h_FE = 25–300, TO-92	Higher voltage rating but lower h_FE range; suited for HV switching, not low-noise amplification	Select when operating above 40 V supply or requiring avalanche-rated breakdown performance

Compared with BC557 and MPSA92, the PN4250 offers balanced trade-offs: higher current capability than BC557 and superior low-noise gain uniformity versus MPSA92, making it optimal for 24–40 V industrial interface and audio preamp designs where both gain stability and 300–500 mA drive are needed.

Availability

PN4250 is available at Aetrix Electronics and suitable for industrial control interfaces, audio signal conditioning, and discrete logic level translation requiring stable component supply and long-term obsolescence management.

Supply support for PN4250 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 power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The PN4250 belongs to Fairchild's legacy general-purpose bipolar transistor family, engineered for cost-sensitive, reliability-critical applications in industrial automation, consumer audio, and sensor signal chains.

FAQ

What is the maximum continuous collector current rating for the PN4250?

The PN4250 has a maximum continuous collector current (I_C) rating of 500 mA at T_A = 25°C. This rating assumes proper PCB copper area and ambient airflow; derating is required above 25°C per the 5.0 mW/°C thermal derating factor specified in the datasheet. The PN4250 is rated for 300 mA operation in general-purpose amplifier and switch roles per its official application description.

Is the PN4250 a PNP or NPN transistor?

PN4250 is a PNP bipolar junction transistor. Its absolute maximum ratings, electrical characteristics tables (including V_(BR)CEO, h_FE, and V_CE(sat) test conditions), and functional description as a "PNP General Purpose Amplifier" confirm its PNP polarity. The pinout-Emitter, Base, Collector left-to-right with flat side facing the viewer-is standardized for TO-92 PNP devices.

What is the typical DC current gain (h_FE) of the PN4250 at low collector current?

The PN4250 exhibits a DC current gain (h_FE) ranging from 250 to 700 when measured at V_CE = 5.0 V and I_C = 100 µA. This wide gain spread reflects process variation across the Fairchild Process 68 fabrication line and must be accounted for in base bias design. The PN4250 datasheet explicitly cites this condition for h_FE specification.

Can the PN4250 be used in audio amplifier circuits?

Yes, the PN4250 is suitable for audio amplifier circuits, particularly as a low-noise preamplifier stage. Its noise figure is specified at 2.0 dB under two audio-relevant bias conditions, and its small-signal parameters-including h_ie = 6.0–20 kΩ and Cob = 6.0 pF-support stable gain up to ~100 kHz. The PN4250's PNP polarity also enables complementary designs in Class-A or push-pull configurations.

What is the thermal resistance (R_θJA) of the PN4250 in free air?

The PN4250 has a junction-to-ambient thermal resistance (R_θJA) of 200 °C/W when mounted on a standard FR-4 PCB with no added heatsinking. This value is measured under natural convection conditions and defines the temperature rise per watt of power dissipated. For example, at 100 mW dissipation, the junction temperature rises ~20°C above ambient. The PN4250's R_θJC is 83.3 °C/W, indicating case-to-junction conduction efficiency.

PN4250 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:: PNP

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

Voltage - Collector Emitter Breakdown (Max):: 40 V

Vce Saturation (Max) @ Ib, Ic:: 250mV @ 500µA, 10mA

Current - Collector Cutoff (Max):: 10nA (ICBO)

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

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

PN4250 FAQ

1.How can I place an order for PN4250 through Aetrix?

Please submit a Request for Quotation (RFQ) for PN4250 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 PN4250 reliable?

The price and inventory of PN4250 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PN4250 is usually 5 days.

3.What payment methods are accepted for PN4250?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PN4250 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for PN4250?

PN4250 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your PN4250 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 PN4250?

For technical support, including PN4250 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PN4250 requirements.

6.How does Aetrix verify that PN4250 is sourced from the original manufacturer or authorized distributors?

All PN4250 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 PN4250 meets industry standards.

7.What is the process for return or replacement of PN4250?

All PN4250 units undergo pre-shipment inspection (PSI). If there is an issue with PN4250, 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 PN4250 part is unused and in its original packaging.

Return procedure for PN4250:

1.Submit a request within 90 days.

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

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