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

onsemi 2SC3950E

Name: 2SC3950E
Brand: onsemi
SKU: 2SC3950E
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2SC3950E

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-225AA, TO-126-3

Datasheet:: 2SC3950E.pdf

Description:: TRANS NPN 20V 0.5A TO-126ML

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2SC3950E from SANYO Semiconductor is an NPN epitaxial planar silicon transistor designed for high-definition CRT display video output stages and wide-band amplification. It delivers f_T = 2.0 GHz, I_C = 500 mA continuous, V_CEO = 20 V, and operates in TO-126ML plastic package with micaless construction.

For engineers reviewing the 2SC3950E datasheet, pinout, applications, or equivalent options, key selection criteria include its 2.0 GHz gain-bandwidth product, 500 mA collector current capability, low V_CE(sat) (0.3–0.8 V at I_C = 300 mA), and suitability for CRT video driver and broadband amplifier designs requiring stable high-frequency linearity.

Technical Context

This transistor employs epitaxial planar process technology to achieve high-speed switching and linear amplification performance. Its f_T = 2.0 GHz at V_CE = 5 V, I_C = 100 mA confirms suitability for video bandwidths up to ~100 MHz with adequate gain margin.

The device exhibits h_FE = 40–200 (ranked C/D/E) at I_C = 50 mA and h_FE ≥ 20 at I_C = 500 mA, supporting both small-signal pre-driver and high-current output stage roles. Cob = 6.0 pF and Cre = 4.6 pF at V_CB = 10 V enable predictable high-frequency stability in tuned or broadband configurations.

Key Specifications

Parameter	Value and Actual Design Meaning
f_T	2.0 GHz - Enables video output amplification up to ~100 MHz with usable gain margin
I_C (continuous)	500 mA - Supports high-current CRT deflection or RGB driver loads without derating
V_CEO	20 V - Compatible with standard CRT video supply rails (e.g., +12 V to +18 V)
V_CE(sat)	0.3–0.8 V @ I_C = 300 mA, I_B = 30 mA - Minimizes power loss and thermal rise in output stage
Cob	6.0 pF @ V_CB = 10 V, 1 MHz - Low output capacitance preserves high-frequency response in common-emitter configuration
h_FE (min)	20 @ I_C = 500 mA - Ensures sufficient drive capability at full output current
P_C (T_c = 25°C)	5 W - Allows operation with minimal heatsinking in compact CRT monitor chassis

Pinout & Package

2SC3950E is housed in a TO-126ML plastic package - a micaless variant of TO-126 with integrated mounting tab, optimized for thermal conduction and mechanical robustness in video output applications.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to ground or low-impedance return path; carries full load current
2 (Collector)	Current source terminal	Drives CRT video load or tuned circuit; requires heat sinking due to power dissipation
3 (Base)	Control input	Accepts drive signal from preceding stage; bias network sets operating point for linear amplification

Key Features

Feature	Design Value
High f_T	2.0 GHz enables stable amplification across full HD CRT video bandwidth (up to ~100 MHz)
Large I_C capacity	500 mA continuous rating supports high-swing video output into capacitive CRT loads
Micaless TO-126ML	Eliminates insulating mica washer - improves thermal transfer to heatsink while reducing assembly steps
Low V_CE(sat)	0.3–0.8 V minimizes voltage drop and self-heating during peak current delivery
Low Cob/Cre	6.0 pF / 4.6 pF reduces Miller effect, preserving high-frequency gain and phase margin

Applications

High-Definition CRT Video Output	Wide-Band RF Amplifier
Use Scenario: Driving RGB cathode inputs in analog HD CRT monitors with 30–100 MHz pixel clock rates. IC Role / Device Role / Timing Role: Final-stage NPN video amplifier delivering high-current, low-distortion analog signals to CRT cathodes. Use Value: 2.0 GHz f_T and 500 mA I_C ensure flat frequency response and minimal slew-induced distortion at HD resolutions.	Use Scenario: Intermediate-frequency (IF) or VHF amplifier in legacy broadcast equipment or test instrumentation. IC Role / Device Role / Timing Role: Linear Class-A/AB broadband amplifier operating up to 100 MHz with fixed bias. Use Value: Low Cob (6.0 pF) and high h_FE maintain gain flatness and reduce tuning sensitivity across band.
Deflection Yoke Driver	Video Signal Distribution Amplifier
Use Scenario: Horizontal/vertical deflection output stage in CRT-based oscilloscopes or medical imaging displays. IC Role / Device Role / Timing Role: High-current switch/amplifier driving inductive yoke windings with fast edge fidelity. Use Value: 1 A pulse rating (I_CP) and low V_CE(sat) support sharp flyback transitions and minimize thermal stress.	Use Scenario: Splitting and buffering composite or component video signals for multi-display systems. IC Role / Device Role / Timing Role: Unity-gain buffer amplifier isolating source from multiple capacitive loads. Use Value: High f_T and low output impedance preserve signal integrity across 75 Ω coaxial paths up to 50 MHz.

High-Definition CRT Video Output

Wide-Band RF Amplifier

Use Scenario: Driving RGB cathode inputs in analog HD CRT monitors with 30–100 MHz pixel clock rates.

IC Role / Device Role / Timing Role: Final-stage NPN video amplifier delivering high-current, low-distortion analog signals to CRT cathodes.

Use Value: 2.0 GHz f_T and 500 mA I_C ensure flat frequency response and minimal slew-induced distortion at HD resolutions.

Use Scenario: Intermediate-frequency (IF) or VHF amplifier in legacy broadcast equipment or test instrumentation.

IC Role / Device Role / Timing Role: Linear Class-A/AB broadband amplifier operating up to 100 MHz with fixed bias.

Use Value: Low Cob (6.0 pF) and high h_FE maintain gain flatness and reduce tuning sensitivity across band.

Deflection Yoke Driver

Video Signal Distribution Amplifier

Use Scenario: Horizontal/vertical deflection output stage in CRT-based oscilloscopes or medical imaging displays.

IC Role / Device Role / Timing Role: High-current switch/amplifier driving inductive yoke windings with fast edge fidelity.

Use Value: 1 A pulse rating (I_CP) and low V_CE(sat) support sharp flyback transitions and minimize thermal stress.

Use Scenario: Splitting and buffering composite or component video signals for multi-display systems.

IC Role / Device Role / Timing Role: Unity-gain buffer amplifier isolating source from multiple capacitive loads.

Use Value: High f_T and low output impedance preserve signal integrity across 75 Ω coaxial paths up to 50 MHz.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN high-frequency power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
2SC3838	f_T = 1.2 GHz, I_C = 300 mA, V_CEO = 20 V, TO-126 package	Lower bandwidth and current handling; suitable only for SD CRT or lower-power IF stages	Select when cost sensitivity outweighs HD video bandwidth requirements
2SC4110	f_T = 2.5 GHz, I_C = 600 mA, V_CEO = 25 V, TO-220 package	Higher voltage/current ratings and thermal capacity; requires larger PCB footprint and heatsink	Select for next-generation CRT drivers or upgraded deflection circuits needing headroom

Compared with 2SC3950E, 2SC3838 offers reduced performance at lower cost for legacy SD applications, while 2SC4110 provides higher f_T, current, and voltage margins at the expense of larger TO-220 packaging - making 2SC3950E the optimal balance for space-constrained HD CRT video output stages.

Availability

2SC3950E is available at Aetrix Electronics and suitable for high-definition CRT display video output, wide-band amplifier, deflection yoke driver, and video distribution amplifier applications requiring stable component supply and long-term industrial availability.

Supply support for 2SC3950E 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

SANYO Semiconductor Co., Ltd. was a Japanese semiconductor manufacturer specializing in analog, power, and display interface devices before its acquisition by ON Semiconductor in 2011.

The 2SC3950E belongs to SANYO's high-frequency bipolar transistor product line, engineered specifically for analog video output stages in CRT-based display systems demanding high current, wide bandwidth, and thermal reliability.

FAQ

What is the maximum operating frequency supported by the 2SC3950E?

The 2SC3950E has a gain-bandwidth product (f_T) of 2.0 GHz at V_CE = 5 V and I_C = 100 mA. In practical video amplifier designs, it maintains usable gain up to approximately 100 MHz - sufficient for high-definition CRT pixel clocks and analog RGB bandwidth. Performance beyond this depends on biasing, layout, and load conditions.

Is the 2SC3950E pin-compatible with other TO-126 transistors like the 2SC2073?

No - the 2SC3950E uses the SANYO-specific TO-126ML pinout (Emitter–Collector–Base), whereas the 2SC2073 follows standard TO-126 (Emitter–Base–Collector). Swapping them without board revision will cause functional failure. Always verify pin assignment using the official 2SC3950E datasheet diagram before substitution.

What is the thermal resistance (R_θJC) of the 2SC3950E?

The 2SC3950E datasheet does not specify R_θJC directly, but its P_C = 5 W at T_c = 25°C and TO-126ML micaless construction imply typical R_θJC ≈ 5.0°C/W. For reliable operation, mount the 2SC3950E on a minimum 25 cm² copper area or dedicated heatsink to maintain junction temperature below 150°C under full load.

Does the 2SC3950E support pulse operation, and what are the limits?

Yes - the 2SC3950E supports pulsed collector current up to I_CP = 1000 mA with 10 ms duty cycle, as specified in its Absolute Maximum Ratings. This makes the 2SC3950E suitable for horizontal deflection yoke drive and other intermittent high-current applications where average power remains within 1.3 W (P_C at T_a = 25°C).

How is the h_FE binning implemented for the 2SC3950E?

The 2SC3950E is binned by h_FE at I_C = 50 mA into three ranks: C (40–80), D (60–120), and E (100–200). The suffix "E" in 2SC3950E indicates the highest gain bin. Designers selecting 2SC3950E can expect guaranteed h_FE ≥ 100, enabling simplified bias networks and improved consistency in video output gain matching.

2SC3950E Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-225AA, TO-126-3

Packaging:: Bulk

Product Status:: Active

Transistor Type:: NPN

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

Voltage - Collector Emitter Breakdown (Max):: 20 V

Vce Saturation (Max) @ Ib, Ic:: 800mV @ 30mA, 300mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 50mA, 5V

Power - Max:: 1.3 W

Frequency - Transition:: 2GHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126ML

2SC3950E FAQ

1.How can I place an order for 2SC3950E through Aetrix?

Please submit a Request for Quotation (RFQ) for 2SC3950E 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 2SC3950E reliable?

The price and inventory of 2SC3950E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2SC3950E is usually 5 days.

3.What payment methods are accepted for 2SC3950E?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2SC3950E transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2SC3950E?

2SC3950E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2SC3950E 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 2SC3950E?

For technical support, including 2SC3950E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2SC3950E requirements.

6.How does Aetrix verify that 2SC3950E is sourced from the original manufacturer or authorized distributors?

All 2SC3950E 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 2SC3950E meets industry standards.

7.What is the process for return or replacement of 2SC3950E?

All 2SC3950E units undergo pre-shipment inspection (PSI). If there is an issue with 2SC3950E, 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 2SC3950E part is unused and in its original packaging.

Return procedure for 2SC3950E:

1.Submit a request within 90 days.

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

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