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

onsemi 2SC4105N

Name: 2SC4105N
Brand: onsemi
SKU: 2SC4105N
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2SC4105N

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: 2SC4105N.pdf

Description:: TRANS NPN 400V 4A TO-220AB

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Product details

Overview

2SC4105N from SANYO is an NPN triple diffused planar silicon transistor designed for high-voltage switching regulator applications. It delivers 400 V V_CEO, 4 A I_C, and 1.57 W P_C at T_C = 25 °C, with f_T = 20 MHz and fast switching times (t_on = 0.5 µs, t_f = 0.3 µs) in TO-220AB package. It is used in offline AC/DC power supplies requiring robust avalanche-safe operation.

For engineers reviewing the 2SC4105N datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO ≥ 400 V, I_C ≥ 4 A, SOA compliance under pulse conditions, h_FE classification (L/M/N ranks), and thermal derating above 25 °C ambient.

Technical Context

This device uses SANYO's MBIT process to achieve wide forward-bias and reverse-bias ASO, enabling reliable operation under transient overloads in flyback and forward converter topologies. Its high V_CEO and low V_CE(sat) (≤ 1.0 V at I_C/I_B = 5) support efficient high-voltage switching with minimal conduction loss.

The 2SC4105N features a defined h_FE rank classification (L: 30–150, M: 40–200, N: 50–300 at V_CE = 5 V, I_C = 0.4 A), temperature-stable V_BE(on) (0.8–1.3 V across –40 °C to 120 °C), and specified switching behavior under controlled test conditions (V_CC = 200 V, R_L = 6.6 Ω, I_B1 = –0.6 A, I_B2 = –0.8 A).

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	400 V - Withstands collector-emitter voltage up to 400 V in open-base condition, suitable for 380 V DC bus applications.
I_C	4 A continuous - Rated collector current enables use in medium-power SMPS outputs up to ~150 W.
P_C @ T_C=25°C	1.57 W - Thermal limit at case temperature; requires heatsinking for sustained operation above 25 °C.
f_T	20 MHz - Transition frequency supports stable switching up to ~100 kHz with margin for gate drive design.
t_on/t_f	0.5 µs / 0.3 µs - Fast turn-on and fall times reduce switching losses in hard-switched converters.
h_FE Rank	L/M/N - Guaranteed DC current gain ranges (e.g., N: 50–300) allow binning for consistent loop gain in feedback circuits.
V_CE(sat)	≤1.0 V @ I_C/I_B=5 - Low saturation voltage minimizes conduction loss and thermal stress during on-state.

Pinout & Package

SANYO TO-220AB package: insulated tab, vertical mounting, 3-pin through-hole configuration with metal tab electrically connected to collector.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input terminal	Receives base drive current to bias transistor into saturation or cutoff; requires current-limiting resistor in series.
2 (Collector)	High-side power output	Connected to primary winding of transformer or high-voltage rail; tab is collector, requiring isolation when mounted to heatsink.
3 (Emitter)	Low-side reference node	Common return path for load current; referenced to ground or negative rail in common-emitter configuration.

Key Features

Feature	Design Value
High breakdown voltage	V_CEO = 400 V and V_CB0 = 500 V ensure robustness against voltage spikes in unregulated line-connected supplies.
Wide ASO (Safe Operating Area)	Forward- and reverse-bias SOA curves validated per ITR06301/ITR06302 enable reliable pulsed operation up to 8 A peak without second breakdown.
High-speed switching	Measured t_on = 0.5 µs and t_f = 0.3 µs under standardized 200 V, 4 A test conditions support >100 kHz designs.
MBIT process technology	Triple diffused planar structure improves ruggedness, reduces leakage (I_CEO ≤ 10 µA), and enhances thermal stability vs. epitaxial alternatives.
h_FE classification	Three gain bins (L/M/N) allow precise matching for current-sense amplifiers or feedback compensation networks.

Applications

Switch-Mode Power Supply	Flyback Converter
Use Scenario: Primary-side switch in universal-input (85–265 VAC) offline AC/DC adapters delivering 12–24 V at ≤150 W. IC Role / Device Role / Timing Role: High-voltage NPN switching transistor operating in hard-switched mode at 60–100 kHz. Use Value: 400 V V_CEO and wide SOA prevent failure during line surges and transformer reset transients.	Use Scenario: Main power switch in isolated flyback converters for industrial control power rails. IC Role / Device Role / Timing Role: Energy-transfer switch controlling primary current buildup and release into transformer. Use Value: Fast t_f = 0.3 µs limits tail current loss; low V_CE(sat) reduces conduction loss at 4 A average current.
Forward Converter	DC-DC Regulator Module
Use Scenario: Primary switch in 48 V input telecom DC-DC modules converting to ±15 V analog rails. IC Role / Device Role / Timing Role: Sustained-duty-cycle NPN switch handling repetitive 4 A pulses with active clamp or RCD snubber. Use Value: 1.57 W P_C rating and thermal resistance (R_θJC ≈ 1.2 °C/W) enable stable operation with modest heatsinking.	Use Scenario: Internal switching element in compact, self-contained DC-DC modules for embedded instrumentation. IC Role / Device Role / Timing Role: Integrated high-voltage switch replacing discrete MOSFET+driver combinations in cost-sensitive designs. Use Value: TO-220AB mechanical compatibility and pinout simplify replacement of legacy bipolar switches without PCB rework.

Switch-Mode Power Supply

Flyback Converter

Use Scenario: Primary-side switch in universal-input (85–265 VAC) offline AC/DC adapters delivering 12–24 V at ≤150 W.

IC Role / Device Role / Timing Role: High-voltage NPN switching transistor operating in hard-switched mode at 60–100 kHz.

Use Value: 400 V V_CEO and wide SOA prevent failure during line surges and transformer reset transients.

Use Scenario: Main power switch in isolated flyback converters for industrial control power rails.

IC Role / Device Role / Timing Role: Energy-transfer switch controlling primary current buildup and release into transformer.

Use Value: Fast t_f = 0.3 µs limits tail current loss; low V_CE(sat) reduces conduction loss at 4 A average current.

Forward Converter

DC-DC Regulator Module

Use Scenario: Primary switch in 48 V input telecom DC-DC modules converting to ±15 V analog rails.

IC Role / Device Role / Timing Role: Sustained-duty-cycle NPN switch handling repetitive 4 A pulses with active clamp or RCD snubber.

Use Value: 1.57 W P_C rating and thermal resistance (R_θJC ≈ 1.2 °C/W) enable stable operation with modest heatsinking.

Use Scenario: Internal switching element in compact, self-contained DC-DC modules for embedded instrumentation.

IC Role / Device Role / Timing Role: Integrated high-voltage switch replacing discrete MOSFET+driver combinations in cost-sensitive designs.

Use Value: TO-220AB mechanical compatibility and pinout simplify replacement of legacy bipolar switches without PCB rework.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2SC4027	V_CEO = 400 V, I_C = 3 A, P_C = 1.25 W, f_T = 15 MHz - lower current and power rating.	Lower I_C limits usable output power to ≤100 W; reduced SOA margin under pulse overload.	Select when thermal budget is constrained and peak current stays below 3 A.
2SC4242	V_CEO = 500 V, I_C = 5 A, P_C = 2 W, f_T = 12 MHz - higher voltage/current but slower switching.	Better surge tolerance for 400 V AC line peaks; longer t_f increases switching loss above 60 kHz.	Prefer for high-reliability 230 VAC systems where EMI filtering favors slower edges.

Compared with 2SC4105N, the 2SC4027 offers lower cost and footprint but sacrifices 25% current headroom and SOA robustness, while the 2SC4242 trades speed for enhanced voltage margin and thermal capacity-making it better suited for line-voltage-critical rather than frequency-critical designs.

Availability

2SC4105N is available at Aetrix Electronics and suitable for switching regulator, flyback converter, and forward converter applications requiring stable component supply, long-lifecycle support, and traceable sourcing for industrial power electronics.

Supply support for 2SC4105N 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 Electric Co., Ltd. was a Japanese semiconductor manufacturer known for high-reliability power transistors and analog ICs before its acquisition by Panasonic in 2011. Its discrete portfolio emphasized ruggedness and application-specific optimization.

The 2SC4105N belongs to SANYO's high-voltage bipolar transistor family engineered specifically for offline switching power supplies, emphasizing safe operating area integrity, thermal stability, and consistent gain binning for feedback loop predictability.

FAQ

What is the maximum junction temperature rating for the 2SC4105N?

The 2SC4105N has a maximum junction temperature (T_j) rating of 150 °C, as specified in its Absolute Maximum Ratings table. Operation beyond this limit risks permanent degradation of the triple diffused planar structure and accelerated parameter drift. Derating curves in Figure ITR06303 show that PC must be reduced linearly above 25 °C case temperature, reaching zero dissipation at approximately 125 °C case.

Does the 2SC4105N have a built-in base-emitter resistor or protection diode?

No, the 2SC4105N is a standard three-terminal NPN bipolar transistor without integrated base resistors or protection diodes. External base drive circuitry-including current-limiting resistors and optional Baker clamp or anti-saturation networks-must be implemented per application requirements. The device relies on external components for safe turn-off and overvoltage clamping.

How is the hFE rank indicated in the 2SC4105N part marking?

The 2SC4105N hFE rank is marked as a suffix letter on the device body: 'L' for h_FE = 30–150, 'M' for 40–200, or 'N' for 50–300 (measured at V_CE = 5 V, I_C = 0.4 A). This rank appears after the base part number in ordering codes (e.g., 2SC4105N-L), and must be specified at order time to ensure consistent gain in production batches.

Can the 2SC4105N be used in avalanche mode?

Yes-the 2SC4105N is characterized for forward-bias SOA (Figure ITR06301) and reverse-bias SOA (Figure ITR06302), confirming controlled avalanche capability under pulsed conditions. Its wide ASO allows limited energy absorption during inductive turn-off transients, but sustained avalanche operation is not recommended without rigorous thermal and voltage margin analysis per application.

What is the typical VBE(on) of the 2SC4105N at 125 °C junction temperature?

Per Figure ITR06296, the 2SC4105N exhibits V_BE(on) ≈ 0.8 V at I_C = 100 mA and T_j = 125 °C (approximated from 120 °C curve). This represents a ~150 mV reduction from room-temperature V_BE(on), consistent with silicon's negative temperature coefficient and critical for accurate base drive design in thermally demanding environments.

2SC4105N Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-220-3

Packaging:: Bulk

Product Status:: Active

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 4 A

Voltage - Collector Emitter Breakdown (Max):: 400 V

Vce Saturation (Max) @ Ib, Ic:: 800mV @ 400mA, 2A

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 30 @ 400mA, 5V

Power - Max:: 1.75 W

Frequency - Transition:: 20MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220AB

2SC4105N FAQ

1.How can I place an order for 2SC4105N through Aetrix?

Please submit a Request for Quotation (RFQ) for 2SC4105N 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 2SC4105N reliable?

The price and inventory of 2SC4105N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2SC4105N is usually 5 days.

3.What payment methods are accepted for 2SC4105N?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2SC4105N transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2SC4105N?

2SC4105N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2SC4105N 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 2SC4105N?

For technical support, including 2SC4105N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2SC4105N requirements.

6.How does Aetrix verify that 2SC4105N is sourced from the original manufacturer or authorized distributors?

All 2SC4105N 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 2SC4105N meets industry standards.

7.What is the process for return or replacement of 2SC4105N?

All 2SC4105N units undergo pre-shipment inspection (PSI). If there is an issue with 2SC4105N, 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 2SC4105N part is unused and in its original packaging.

Return procedure for 2SC4105N:

1.Submit a request within 90 days.

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

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