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

Diodes Incorporated FZT458TC

Name: FZT458TC
Brand: Diodes Incorporated
SKU: FZT458TC
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: FZT458TC

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: TO-261-4, TO-261AA

Datasheet:: FZT458TC.pdf

Description:: TRANS NPN 400V 0.3A SOT-223-3

Quantity:: RFQ Add To RFQ list

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Inventory:4,437

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Product details

Overview

FZT458TC from Diodes Incorporated is a 400V NPN medium-power transistor in SOT223 package, designed for high-voltage switching in industrial power supplies and lighting ballasts. It delivers 300mA continuous collector current, exhibits V_CE(sat) < 200mV at 20mA/2mA drive, and maintains h_FE ≥ 100 up to 100mA - enabling efficient linear and switching operation in flyback and boost converter primary-side control stages.

For engineers reviewing the FZT458TC datasheet, FZT458TC pinout, FZT458TC application, or FZT458TC equivalent, key selection criteria include its 400V V_CEO rating, low saturation voltage under moderate drive, thermal resistance of 41.7°C/W on 50mm × 50mm copper, and AEC-Q101 readiness for automotive auxiliary power modules.

Technical Context

This NPN bipolar junction transistor operates in active, saturation, and cutoff regions with defined safe operating area (SOA) up to 100V and 1A pulsed. Its f_T = 50MHz supports fast switching in <100kHz SMPS topologies, while C_obo = 5pF minimizes capacitive loading in gate-drive or snubber circuits.

Thermal design relies on junction-to-lead resistance (R_θJL = 19.41°C/W) and validated derating curves for 25mm × 25mm and 50mm × 50mm PCB copper areas. ESD robustness includes 4kV HBM and 400V MM ratings per JEDEC JESD22-A114/A115.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	400V - supports direct connection to 340V DC bus in offline AC/DC converters without external clamping.
I_C (continuous)	300mA - sufficient for driving small-signal MOSFET gates or controlling relay coils in PLC I/O modules.
V_CE(sat)	< 200mV @ 20mA/2mA - reduces conduction loss to < 4mW in low-duty-cycle switching applications.
h_FE	100–300 @ I_C = 1–100mA - enables stable current amplification across wide load ranges in analog feedback paths.
f_T	50MHz - ensures adequate gain margin for closed-loop compensation in 50–100kHz PWM controllers.
R_θJA	41.7°C/W (50mm × 50mm copper) - allows 3W dissipation at ≤ 85°C ambient with standard FR4 layout.

Pinout & Package

Package: SOT223 (Type DN), molded green plastic, UL 94V-0 rated, 0.112g weight, matte tin-plated leads solderable per MIL-STD-202 Method 208.

Pin/Terminal	Circuit Role	Design Meaning
Collector (C)	Main current output terminal	Connected to high-voltage rail or inductive load; thermally coupled to PCB copper via exposed pad for R_θJL = 19.41°C/W.
Emitter (E)	Current return path	Typically grounded or tied to low-side shunt; forms base-emitter junction with V_BE(sat) ≤ 0.9V at 50mA drive.
Base (B)	Control input	Receives TTL- or CMOS-compatible drive; requires 2–6mA for full saturation at 20–50mA collector current.

Key Features

Feature	Design Value
High breakdown voltage	V_CEO = 400V enables direct use in 230VAC rectified line-switching without series stacking.
Low saturation loss	V_CE(sat) < 0.2V at 20mA reduces heat generation in constant-current LED drivers.
Stable gain over temperature	h_FE retains ≥100 from –55°C to +100°C, supporting reliable operation in outdoor industrial enclosures.
AEC-Q101 readiness	Manufactured in IATF 16949 facilities; PPAP-capable for automotive HVAC blower control and body electronics.

Applications

Industrial Power Supply

LED Driver Circuit

Use Scenario: Flyback converter primary-side switch in 12W AC/DC adapter for factory sensors.

IC Role / Device Role / Timing Role: Medium-power NPN switch replacing MOSFET where gate drive simplicity and cost are prioritized.

Use Value: Eliminates need for level-shifting gate driver; 400V rating avoids external clamp diode in 340V DC bus designs.

Use Scenario: Constant-current regulator for 24V LED string in warehouse lighting fixtures.

IC Role / Device Role / Timing Role: Linear pass element controlled by op-amp feedback loop.

Use Value: V_CE(sat) < 200mV limits power loss to < 5mW at 25mA, reducing heatsink requirements.

Automotive Auxiliary Power

PLC Output Stage

Use Scenario: 12V-to-5V buck pre-regulator for infotainment system microcontroller supply.

IC Role / Device Role / Timing Role: High-voltage NPN switch in discrete buck topology with external inductor and diode.

Use Value: AEC-Q101-aligned manufacturing and 150°C max junction temperature support under-hood thermal environments.

Use Scenario: Solid-state relay replacement in digital output module driving 24V solenoid valves.

IC Role / Device Role / Timing Role: Low-side switch interfacing with FPGA or microcontroller GPIO.

Use Value: 300mA I_C and 4kV HBM ESD withstand enable direct MCU interface without buffer ICs.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ZTX458	V_CEO = 300V (lower), h_FE min = 100 @ I_C = 10mA, same SOT223 package	Not suitable for 340V DC bus; limited to ≤250V applications like telecom DC/DC	Select only if system voltage remains below 260V and thermal budget permits higher V_CE(sat).
FZT651	V_CEO = 400V, I_C = 1A, R_θJA = 50°C/W (worse), larger SOT89 package	Higher current capability but requires more board space and heatsinking	Choose when >300mA peak load current is required and SOT89 footprint is acceptable.

Compared with ZTX458 and FZT651, FZT458TC uniquely balances 400V rating, 300mA current, and SOT223 thermal performance - making it optimal for space-constrained, medium-power industrial and automotive auxiliary supplies where voltage margin and board area are critical.

Availability

FZT458TC is available at Aetrix Electronics and suitable for industrial power supplies, LED drivers, automotive auxiliary power modules, and PLC output stages requiring stable component supply across multi-year production cycles.

Supply support for FZT458TC 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.

FZT458TC belongs to Diodes' high-voltage bipolar transistor product line, engineered specifically for reliability-critical switching and linear regulation in industrial, automotive, and lighting applications where voltage headroom and thermal stability are essential.

FAQ

What is the maximum allowable junction temperature for FZT458TC?

The absolute maximum junction temperature is +150°C, with continuous operation supported from –55°C to +150°C. Derating begins at +25°C ambient using the published R_θJA = 41.7°C/W curve for 50mm × 50mm copper, limiting power dissipation to 3W at 25°C and 0W at 150°C ambient.

Is FZT458TC qualified for automotive applications?

FZT458TC is manufactured in IATF 16949-certified facilities and supports PPAP documentation. While not pre-qualified to AEC-Q101 out-of-box, Diodes offers AEC-Q101 qualification upon request for specific lots - confirmed via direct engagement with Diodes' automotive sales team.

Can FZT458TC replace a MOSFET in low-frequency switching?

Yes, in sub-100kHz applications where gate drive complexity or cost must be minimized. Its 50MHz f_T and 2.26µs t_off support clean turn-off in flyback and boost converters, though MOSFETs remain preferable above 200kHz due to lower gate charge and faster switching.

What is the recommended PCB layout for thermal performance?

Use a minimum 50mm × 50mm 2oz copper pour connected directly to the collector pad (Pin 1) for R_θJA = 41.7°C/W. Follow Diodes' SOT223 (Type DN) pad layout: 6.4mm × 3.3mm thermal pad with 1.2mm × 1.6mm solder mask openings and 8.0mm overall length clearance.

FZT458TC Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: TO-261-4, TO-261AA

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 300 mA

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

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 6mA, 50mA

Current - Collector Cutoff (Max):: 100nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 50mA, 10V

Power - Max:: 2 W

Frequency - Transition:: 50MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-223-3

FZT458TC FAQ

1.How can I place an order for FZT458TC through Aetrix?

Please submit a Request for Quotation (RFQ) for FZT458TC 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 FZT458TC reliable?

The price and inventory of FZT458TC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FZT458TC is usually 5 days.

3.What payment methods are accepted for FZT458TC?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FZT458TC transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for FZT458TC?

FZT458TC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your FZT458TC 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 FZT458TC?

For technical support, including FZT458TC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FZT458TC requirements.

6.How does Aetrix verify that FZT458TC is sourced from the original manufacturer or authorized distributors?

All FZT458TC 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 FZT458TC meets industry standards.

7.What is the process for return or replacement of FZT458TC?

All FZT458TC units undergo pre-shipment inspection (PSI). If there is an issue with FZT458TC, 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 FZT458TC part is unused and in its original packaging.

Return procedure for FZT458TC:

1.Submit a request within 90 days.

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

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