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Diodes Incorporated FCX458TA
- Part No.:
- FCX458TA
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- TO-243AA
- Datasheet:
-
FCX458TA.pdf
- Description:
- TRANS NPN 400V 0.225A SOT-89-3
- Quantity:
- Payment:
- Shipping:
Inventory:66,814
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Product details
Overview
FCX458TA from Diodes Incorporated is a 400V NPN high-voltage transistor in SOT89 package, designed for switching and amplification in high-voltage DC-DC converters, flyback controllers, and LED driver stages. It delivers 225mA continuous collector current, supports 400V VCEO, achieves VCE(sat) < 200mV at 20mA/2mA drive, and operates across –65°C to +150°C.
For engineers reviewing the FCX458TA datasheet, FCX458TA pinout, FCX458TA application, or FCX458TA equivalent, key selection criteria include high-voltage blocking capability (400V), low saturation voltage under moderate drive, thermal performance on 1oz copper PCBs, and automotive-qualified variant availability (FCX458Q).
Technical Context
This NPN bipolar junction transistor is optimized for high-voltage switching where robust breakdown margin and controlled saturation behavior are critical. Its BVCEO = 400V and BVCBO = 400V ensure reliable operation in circuits with transient overvoltage up to 320V applied across C–E or C–B terminals.
The device exhibits hFE = 100–300 across 1–100mA IC, enabling stable current gain in linear and saturated modes. With fT = 50MHz and Cobo = 5pF, it supports fast switching in sub-100kHz power stages while maintaining low capacitive loading on driving nodes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 400 V - Sustains 400V collector-emitter voltage before breakdown; enables use in 375V DC bus applications with safety margin. |
| IC (continuous) | 225 mA - Maximum steady-state collector current without thermal runaway on standard 1oz copper layout. |
| VCE(sat) | <200 mV @ 20mA/2mA - Low conduction loss reduces heat generation in switching regulators and LED current sinks. |
| hFE | 100–300 - Wide DC current gain range supports consistent base drive design across production lots and temperature. |
| fT | 50 MHz - Enables usable switching speeds up to ~5–10MHz with adequate gain margin for gate-driving or signal amplification. |
| RθJA | 178 °C/W (min pad) - Thermal resistance defines maximum power dissipation (0.7W) under still-air conditions on minimal PCB copper. |
| ESD HBM | 4,000 V - Robust electrostatic discharge immunity simplifies handling and board assembly without special ESD controls. |
Pinout & Package
Package: SOT89 - Surface-mount plastic package with exposed collector pad for enhanced thermal conduction; 3-terminal configuration with standardized footprint per JEDEC TO-243AA.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Collector (C) | Main current-carrying terminal, connected to exposed metal tab | Primary heat path to PCB; must be soldered to ≥15mm² 1oz copper for rated 0.7W dissipation. |
| Emitter (E) | Current return path, common reference node | Low-impedance connection point for load return; referenced in VBE and VCE measurements. |
| Base (B) | Control input for transistor turn-on/turn-off | Requires ~2mA drive for full saturation at 20mA IC; sensitive to ESD due to thin oxide layer. |
Key Features
| Feature | Design Value |
|---|---|
| High-voltage blocking | 400V VCEO rating enables direct use in offline switch-mode supplies without external snubbers. |
| Low-saturation switching | VCE(sat) < 200mV at 20mA ensures ≤4mW conduction loss, minimizing thermal stress in compact layouts. |
| Automotive-qualified variant | FCX458Q version meets AEC-Q101 requirements for temperature cycling, humidity, and mechanical shock. |
| Green packaging | Halogen- and antimony-free molding compound (<900ppm Br/Cl, <1000ppm Sb) satisfies RoHS 3 and ELV directives. |
Applications
| LED Driver Stages | Flyback Converter Switch |
|---|---|
Use Scenario: Constant-current switching stage in isolated LED drivers for street lighting and industrial signage. IC Role / Device Role / Timing Role: NPN switch controlling primary-side current pulses synchronized to transformer reset timing. Use Value: 400V rating accommodates reflected output voltage plus leakage spikes; low VCE(sat) maintains efficiency above 90% at 20–50mA loads. | Use Scenario: Primary-side power switch in 5–25W AC/DC flyback converters for industrial sensors and IoT gateways. IC Role / Device Role / Timing Role: High-voltage switching element driven by UC384x or similar PWM controller; handles 100–120kHz switching. Use Value: Stable hFE across temperature ensures predictable base drive requirements; 4kV HBM protects against layout-induced ESD during rework. |
| DC-DC Boost Regulators | High-Voltage Signal Amplifiers |
Use Scenario: Step-up converter in battery-powered test equipment requiring 300V output from 24V input. IC Role / Device Role / Timing Role: Main switching transistor in discrete boost topology; operated in hard-switched mode with fixed frequency control. Use Value: BVCBO = 400V prevents avalanche failure during inductive kick; RθJL = 22°C/W allows direct thermal coupling to heatsink via collector pad. | Use Scenario: Linear amplifier stage in photomultiplier tube (PMT) anode chain or high-voltage sensor interface. IC Role / Device Role / Timing Role: Medium-gain, high-voltage common-emitter amplifier biased in active region for analog signal conditioning. Use Value: fT = 50MHz supports bandwidth up to 5MHz with 10dB gain; low Cobo minimizes Miller effect distortion at high collector voltages. |
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 |
|---|---|---|---|
| ZTX653 | VCEO = 300V, IC = 1A, SOT89 package, hFE = 100–800 | Limited to ≤300V systems; higher current rating but lower voltage margin than FCX458TA | Select when higher IC is required and system voltage remains below 270V DC. |
| MPSA42 | VCEO = 300V, TO-92 package, IC = 500mA, RθJA = 200°C/W | Lower thermal performance and no exposed pad; unsuitable for >0.5W continuous dissipation | Choose only for low-power, non-thermally constrained prototyping where SOT89 mounting is unavailable. |
Compared with ZTX653 and MPSA42, FCX458TA uniquely balances 400V blocking, SOT89 thermal efficiency, and low-saturation operation-making it optimal for space-constrained, medium-power high-voltage switching where voltage margin and thermal reliability are prioritized over raw current capacity.
Availability
FCX458TA is available at Aetrix Electronics and suitable for LED driver stages, flyback converter switches, and DC-DC boost regulators requiring stable component supply and long-term industrial lifecycle support.
Supply support for FCX458TA 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 centers across Asia and manufacturing in China, Taiwan, and the U.S.
The FCX458TA belongs to Diodes' high-voltage bipolar transistor product line, engineered specifically for industrial power conversion, lighting, and sensing applications demanding ruggedness, thermal efficiency, and regulatory compliance.
FAQ
What is the maximum safe operating voltage for FCX458TA in continuous DC applications?
The FCX458TA is rated for 400V VCEO and 400V VCBO at TA = 25°C. For continuous DC operation, derating is required above 25°C per the datasheet's thermal curves; at 100°C ambient, maximum recommended VCEO drops to approximately 320V to maintain reliability and avoid thermal runaway.
Can FCX458TA replace FCX458 in existing designs without layout changes?
Yes-FCX458TA uses the same SOT89 package, identical pinout (C/E/B), and identical electrical specifications as FCX458. The "TA" suffix denotes tape-and-reel packaging (1,000 units/reel); all parametric performance, thermal characteristics, and marking (N58) are identical to the base FCX458 part.
How does the exposed collector pad affect PCB layout and thermal design?
The exposed collector pad must be soldered to a minimum 15mm² area of 1oz copper to achieve the rated 0.7W power dissipation. Increasing copper area to 25mm² or 50mm² lowers RθJA to 83°C/W or 60°C/W respectively. Avoid thermal relief patterns; use solid copper pour connected directly to the pad with ≥4 thermal vias to inner ground planes if multilayer.
Is FCX458TA suitable for automotive applications?
The standard FCX458TA is not automotive-qualified, but its pin-compatible variant FCX458Q is AEC-Q101 qualified for temperature cycling, humidity, and mechanical shock. FCX458TA may be used in non-safety-critical automotive subsystems only after full qualification by the end customer per ISO/TS 16949 processes.
FCX458TA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- TO-243AA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 225 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:
- 1 W
- Frequency - Transition:
- 50MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-89-3
FCX458TA FAQ
1.How can I place an order for FCX458TA through Aetrix?
Please submit a Request for Quotation (RFQ) for FCX458TA 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 FCX458TA reliable?
The price and inventory of FCX458TA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FCX458TA is usually 5 days.
3.What payment methods are accepted for FCX458TA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FCX458TA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FCX458TA?
FCX458TA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FCX458TA 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 FCX458TA?
For technical support, including FCX458TA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FCX458TA requirements.
6.How does Aetrix verify that FCX458TA is sourced from the original manufacturer or authorized distributors?
All FCX458TA 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 FCX458TA meets industry standards.
7.What is the process for return or replacement of FCX458TA?
All FCX458TA units undergo pre-shipment inspection (PSI). If there is an issue with FCX458TA, 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 FCX458TA part is unused and in its original packaging.
Return procedure for FCX458TA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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