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

onsemi 2SC4256

Name: 2SC4256
Brand: onsemi
SKU: 2SC4256
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2SC4256

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: 2SC4256.pdf

Description:: TRANS NPN 1200V 0.01A TO-220AB

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Product details

Overview

2SC4256 from SANYO is an NPN triple diffused planar silicon transistor designed for high-voltage amplifier and switching applications, with V_CEO = 1200 V, I_C = 10 mA, P_C = 1.75 W, and f_T = 6 MHz - used in flyback converters, CRT horizontal deflection, and HV pulse generators.

For engineers reviewing the 2SC4256 datasheet, pinout, applications, or equivalent options, key selection criteria include breakdown voltage margin, Cob < 1.6 pF at V_CB = 100 V, ASO robustness under pulsed conditions, h_FE = 60–120 at I_C = 0.5 mA, and TO-220AB thermal performance up to T_j = 150 °C.

Technical Context

This device employs SANYO's High-Voltage Process (HVP) to achieve stable 1200 V collector-emitter breakdown while maintaining low output capacitance (C_ob = 1.6 pF @ V_CB = 100 V) and wide Safe Operating Area (ASO) - critical for repetitive high-voltage switching in inductive loads.

Its planar triple-diffused structure ensures consistent V_CE(sat) ≤ 5 V at I_C/I_B = 5 and V_BE(sat) ≤ 2 V under same conditions, supporting reliable gate-drive interfacing in HV switch-mode topologies without secondary saturation risk.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	1200 V - supports direct operation across >800 V DC bus rails without series stacking.
I_C	10 mA continuous - suitable for low-current HV amplification and signal-level switching.
P_C	1.75 W @ T_c = 25 °C - requires heatsinking for sustained operation above ~60 °C ambient.
f_T	6 MHz - enables linear amplification up to mid-RF frequencies in HV probe or pulse-shaping stages.
C_ob	1.6 pF @ V_CB = 100 V - minimizes Miller feedback in fast-switching HV configurations.
h_FE	60–120 @ V_CE = 5 V, I_C = 0.5 mA - provides predictable current gain for fixed-bias HV driver designs.
V_CE(sat)	≤5 V @ I_C/I_B = 5 - ensures low conduction loss when used as a saturated switch in low-duty-cycle HV pulses.

Pinout & Package

SANYO specifies TO-220AB package: isolated tab, vertical lead orientation, 3-pin through-hole mounting with mechanical screw-down capability for thermal management.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input terminal	Receives forward bias current to initiate conduction; requires current-limiting resistor due to low I_BO rating.
2 (Collector)	High-voltage output node	Connected to HV rail or inductive load; electrically isolated from tab per TO-220AB spec.
3 (Emitter)	Reference/return path	Common return for base drive and load current; tied to system ground or negative rail in NPN configuration.

Key Features

Feature	Design Value
High breakdown voltage	V_CEO = 1200 V enables single-device replacement of stacked transistors in HV power supplies.
Small Cob	C_ob = 1.6 pF reduces capacitive coupling and improves switching speed in HV pulse circuits.
Wide ASO	Forward-biased SOA extends to 10 ms pulses at rated V_CE, supporting CRT deflection and laser driver waveforms.
High reliability (HVP process)	HVP fabrication ensures stable parametric drift over temperature and lifetime in industrial HV modules.

Applications

CRT Horizontal Deflection	Flyback Converter Switch
Use Scenario: Driving horizontal output transformer in analog CRT displays requiring precise 15.734 kHz sawtooth current pulses. IC Role / Device Role / Timing Role: NPN switching transistor operating in Class-B push-pull stage with snubber-assisted turn-off. Use Value: 1200 V V_CEO withstands flyback voltage spikes >900 V; low C_ob minimizes timing jitter in retrace interval.	Use Scenario: Primary-side switch in low-power offline flyback SMPS for AC/DC adapters and auxiliary supplies. IC Role / Device Role / Timing Role: High-voltage switching element controlling energy transfer during ON-time, turned off by transformer reset. Use Value: Wide ASO supports safe operation under transient overvoltage and short-circuit conditions without secondary breakdown.
Laser Diode Pulse Driver	HV Signal Amplifier
Use Scenario: Generating nanosecond-scale current pulses for pulsed laser diodes in time-of-flight sensors. IC Role / Device Role / Timing Role: Fast-switching NPN transistor gated by TTL-compatible logic to deliver controlled I_pulse into laser cathode. Use Value: Low V_CE(sat) and fast transition times enable sub-100 ns rise/fall edges with minimal overshoot.	Use Scenario: Amplifying low-level sensor signals referenced to high-voltage common-mode potentials (e.g., ion chamber detectors). IC Role / Device Role / Timing Role: Common-emitter HV amplifier stage providing isolation and gain before level-shifting circuitry. Use Value: Stable h_FE and low noise floor preserve signal integrity in high-impedance, high-common-mode applications.

CRT Horizontal Deflection

Flyback Converter Switch

Use Scenario: Driving horizontal output transformer in analog CRT displays requiring precise 15.734 kHz sawtooth current pulses.

IC Role / Device Role / Timing Role: NPN switching transistor operating in Class-B push-pull stage with snubber-assisted turn-off.

Use Value: 1200 V V_CEO withstands flyback voltage spikes >900 V; low C_ob minimizes timing jitter in retrace interval.

Use Scenario: Primary-side switch in low-power offline flyback SMPS for AC/DC adapters and auxiliary supplies.

IC Role / Device Role / Timing Role: High-voltage switching element controlling energy transfer during ON-time, turned off by transformer reset.

Use Value: Wide ASO supports safe operation under transient overvoltage and short-circuit conditions without secondary breakdown.

Laser Diode Pulse Driver

HV Signal Amplifier

Use Scenario: Generating nanosecond-scale current pulses for pulsed laser diodes in time-of-flight sensors.

IC Role / Device Role / Timing Role: Fast-switching NPN transistor gated by TTL-compatible logic to deliver controlled I_pulse into laser cathode.

Use Value: Low V_CE(sat) and fast transition times enable sub-100 ns rise/fall edges with minimal overshoot.

Use Scenario: Amplifying low-level sensor signals referenced to high-voltage common-mode potentials (e.g., ion chamber detectors).

IC Role / Device Role / Timing Role: Common-emitter HV amplifier stage providing isolation and gain before level-shifting circuitry.

Use Value: Stable h_FE and low noise floor preserve signal integrity in high-impedance, high-common-mode applications.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2SC3854	V_CEO = 1000 V, f_T = 4 MHz, C_ob = 2.0 pF - lower BV and bandwidth than 2SC4256.	Marginally suitable for 600–800 V flyback designs; not recommended for 1200 V CRT deflection.	Select only if system max V_CE < 900 V and bandwidth requirements ≤4 MHz.
BU2520A	V_CEO = 1500 V, I_C = 15 mA, P_C = 2.0 W - higher ratings but TO-220F package with non-isolated tab.	Requires insulating hardware for heatsink mounting; better for higher-current HV switching where thermal headroom is critical.	Prefer when needing >1200 V margin or >10 mA average current, and isolation can be managed mechanically.

Compared with 2SC4256, 2SC3854 offers reduced voltage headroom and bandwidth, limiting use in modern CRT or high-spike flyback systems; BU2520A delivers greater voltage/current capability but demands careful thermal interface design due to non-isolated tab - making 2SC4256 optimal for legacy HV signal switching where isolation and proven reliability are prioritized.

Availability

2SC4256 is available at Aetrix Electronics and suitable for CRT deflection circuits, flyback converter switches, laser pulse drivers, and HV signal amplifiers requiring stable component supply and long-lifecycle support.

Supply support for 2SC4256 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 specializing in power devices, optoelectronics, and analog ICs before its acquisition by Panasonic in 2011.

The 2SC4256 belongs to SANYO's high-voltage bipolar transistor product line, engineered specifically for reliability-critical analog switching and amplification in consumer display and industrial power conversion equipment.

FAQ

What is the maximum collector-emitter voltage rating for the 2SC4256?

The 2SC4256 has a maximum collector-emitter voltage rating (V_CEO) of 1200 V at T_a = 25 °C. This rating is validated under specified test conditions with I_B = 0 and applies to continuous DC operation. Derating is required above 25 °C ambient, and safe operation must remain within the Forward Bias ASO curve shown in the datasheet, especially under pulsed or inductive load conditions. The 2SC4256 is not rated for life-support or aircraft control systems.

Does the 2SC4256 have an isolated collector tab in its TO-220AB package?

Yes, the 2SC4256 uses the TO-220AB package variant, where the collector (pin 2) is electrically isolated from the metal tab. This allows direct mounting to a grounded or biased heatsink without shorting the collector node. Confirmation is found in SANYO's official package outline drawing PS No.2924–3/3 and the pin assignment diagram showing pin 2 as collector with isolation noted in mechanical specifications.

What is the typical DC current gain (h_FE) of the 2SC4256 at standard test conditions?

The typical DC current gain (h_FE) of the 2SC4256 is 60–120 when measured at V_CE = 5 V and I_C = 0.5 mA. This range reflects production lot variation and is guaranteed per SANYO's specification sheet No.2924–2/3. Gain decreases at higher currents and elevated temperatures, and the 2SC4256 is not characterized for h_FE below 0.1 mA or above 5 mA in the published data.

Can the 2SC4256 be used in avalanche mode?

No, the 2SC4256 is not rated or characterized for avalanche operation. Its absolute maximum ratings define V_CEO = 1200 V as a DC blocking voltage under specified test conditions, and SANYO explicitly warns against exceeding any rated values - including momentary overvoltage - which could cause irreversible failure. The device lacks avalanche energy rating (E_AS) or ruggedness characterization, and its HVP process targets stable linear and switching behavior, not controlled avalanche tolerance.

What is the output capacitance (C_ob) of the 2SC4256 and how does it affect switching performance?

The 2SC4256 has an output capacitance (C_ob) of 1.6 pF at V_CB = 100 V and f = 1 MHz. This low value directly reduces Miller effect and switching losses in high-voltage switching applications such as CRT deflection and flyback converters. Lower C_ob enables faster turn-off and improved waveform fidelity in pulse-driven circuits, as confirmed by SANYO's ITR06562 graph and specification table in document No.2924–2/3.

2SC4256 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):: 10 mA

Voltage - Collector Emitter Breakdown (Max):: 1200 V

Vce Saturation (Max) @ Ib, Ic:: 5V @ 200µA, 1mA

Current - Collector Cutoff (Max):: 1µA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 10 @ 500µA, 5V

Power - Max:: 1.75 W

Frequency - Transition:: 6MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220AB

2SC4256 FAQ

1.How can I place an order for 2SC4256 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2SC4256 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 2SC4256 reliable?

The price and inventory of 2SC4256 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2SC4256 is usually 5 days.

3.What payment methods are accepted for 2SC4256?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2SC4256 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2SC4256?

2SC4256 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2SC4256 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 2SC4256?

For technical support, including 2SC4256 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2SC4256 requirements.

6.How does Aetrix verify that 2SC4256 is sourced from the original manufacturer or authorized distributors?

All 2SC4256 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 2SC4256 meets industry standards.

7.What is the process for return or replacement of 2SC4256?

All 2SC4256 units undergo pre-shipment inspection (PSI). If there is an issue with 2SC4256, 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 2SC4256 part is unused and in its original packaging.

Return procedure for 2SC4256:

1.Submit a request within 90 days.

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

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