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Diodes Incorporated FZT458QTA
- Part No.:
- FZT458QTA
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- TO-261-4, TO-261AA
- Datasheet:
-
FZT458QTA.pdf
- Description:
- TRANS NPN 400V 0.3A SOT-223-3
- Quantity:
- Payment:
- Shipping:
Inventory:956
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Product details
Overview
FZT458QTA from Diodes Incorporated is a 400V NPN medium-power transistor in SOT223 package, designed for high-voltage switching and linear amplification in industrial power supplies and motor control circuits. It delivers 300mA continuous collector current, exhibits VCE(sat) < 200mV at 20mA/2mA drive, and maintains hFE ≥ 100 up to 100mA - enabling efficient low-loss switching in flyback snubbers and relay drivers.
For engineers reviewing the FZT458QTA datasheet, FZT458QTA pinout, FZT458QTA application, or FZT458QTA equivalent, key selection criteria include its 400V VCEO rating, thermal resistance of 41.7°C/W on 50mm × 50mm copper, complementary pairing with FZT558, and AEC-Q101 readiness for automotive-grade reliability validation.
Technical Context
This NPN bipolar junction transistor operates in active and saturation regions for DC-coupled amplification and hard-switching applications. Its BVCEO = 400V and IC = 300mA support use in offline primary-side switching where isolation and voltage margin are critical.
The device features low VBE(sat) = 0.9V at IC = 50mA/IB = 5mA and fT = 50MHz, confirming suitability for moderate-speed switching (e.g., <500kHz PWM) while maintaining gain stability across –55°C to +150°C operating range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 400V - supports direct connection to 340VDC rectified mains without external clamping |
| IC (continuous) | 300mA - sufficient for driving small relays, gate resistors, or auxiliary power stage bias networks |
| VCE(sat) | <200mV @ IC=20mA/IB=2mA - minimizes conduction loss in low-duty-cycle switching nodes |
| hFE | 100–300 @ IC=1–100mA - enables stable current mirror or emitter-follower configurations with predictable gain |
| RθJA | 41.7°C/W (50mm×50mm 2oz Cu) - allows 3W dissipation at ≤100°C ambient with standard PCB heatsinking |
| fT | 50MHz - supports clean turn-on/turn-off in <500kHz SMPS feedback or protection circuits |
| ESD HBM | 4000V - reduces risk of handling damage during manual assembly or bench testing |
Pinout & Package
Package: SOT223 (Type DN), surface-mount, thermally enhanced plastic case with exposed collector tab; weight ≈ 0.112g; moisture sensitivity level 1 per J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Collector (Tab) | Main current output path and thermal interface | Exposed metal tab serves as both high-current terminal and primary heat sink contact point |
| Emitter | Current return path to ground/reference | Connected directly to PCB ground plane for low-inductance return and thermal conduction |
| Base | Control input for current amplification | Requires current-limited drive (max IB = 200mA) to avoid second breakdown during saturation |
Key Features
| Feature | Design Value |
|---|---|
| High breakdown voltage | VCEO = 400V ensures robust operation in 230VAC-derived 340VDC bus applications |
| Low saturation voltage | VCE(sat) < 200mV at 20mA reduces power loss by >60% vs. typical 300–500mV general-purpose transistors |
| Stable hFE over current range | hFE ≥ 100 up to IC = 100mA enables predictable base drive sizing without gain collapse |
| Thermally optimized package | RθJL = 19.41°C/W to solder point allows effective heat transfer to large copper areas |
| AEC-Q101 capable | Manufactured in IATF 16949-certified facilities with PPAP support for automotive subsystem qualification |
Applications
| Industrial Power Supply Snubber | Automotive HVAC Blower Control |
|---|---|
|
Use Scenario: Absorbs voltage spikes across flyback transformer primary during MOSFET turn-off in 24V–48V offline converters. IC Role / Device Role / Timing Role: NPN clamp transistor configured in active-clamp topology, triggered by auxiliary winding voltage. Use Value: With 400V VCEO and 200mV VCE(sat), it limits peak stress to <380V while dissipating <150mW per pulse. |
Use Scenario: Drives brushed DC blower motor in vehicle cabin climate systems using PWM-controlled base current. IC Role / Device Role / Timing Role: Medium-power switch interfacing microcontroller GPIO to motor coil via current-limiting resistor network. Use Value: Delivers 300mA continuous current with hFE ≥ 100 at 100mA, enabling single-stage drive without Darlington stacking. |
| LED Driver Current Sink | Isolated Feedback Transistor |
|
Use Scenario: Sinks constant current for high-brightness LED strings in streetlight auxiliary indicators. IC Role / Device Role / Timing Role: Linear-mode current regulator with emitter-degenerated bias, operating below 100°C junction temperature. Use Value: Maintains ±5% current accuracy over –40°C to +105°C due to stable hFE and low VBE(on) drift. |
Use Scenario: Transmits optocoupler output signal to primary-side controller in isolated AC/DC adapters. IC Role / Device Role / Timing Role: High-speed switching transistor converting phototransistor collector output into clean logic-level pulses. Use Value: 50MHz fT and 135ns ton support 200kHz feedback loop response with minimal propagation delay skew. |
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 |
|---|---|---|---|
| ZTX653 | VCEO = 300V, hFE = 100–250, RθJA = 60°C/W (SOT89) | Limited to 265VDC bus; higher thermal resistance requires larger copper area | Select when 300V rating suffices and SOT89 footprint is preferred for legacy layout compatibility |
| MJD44H11T4G | VCEO = 400V, IC = 8A, TO-220 package, VCE(sat) = 1.5V @ 4A | Higher current but 7.5× higher saturation loss; unsuitable for low-power signal switching | Choose only for high-current (>500mA) linear regulation where thermal mass outweighs efficiency loss |
Compared with ZTX653 and MJD44H11T4G, FZT458QTA uniquely balances 400V capability, sub-200mV saturation, and SOT223 thermal performance - making it optimal for space-constrained, medium-power switching where both voltage headroom and conduction efficiency matter.
Availability
FZT458QTA is available at Aetrix Electronics and suitable for industrial power supply snubbers, automotive HVAC blower controls, LED driver current sinks, and isolated feedback circuits requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for FZT458QTA 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 the Americas.
FZT458QTA belongs to Diodes' high-voltage bipolar transistor product line, engineered specifically for reliable switching and amplification in industrial, automotive, and consumer power systems where voltage margin and thermal efficiency are critical.
FAQ
What is the maximum safe operating voltage for FZT458QTA in continuous DC mode?
The absolute maximum VCEO is 400V at TA = +25°C. For continuous DC operation, derating is required above 25°C ambient: at 100°C ambient, maximum usable VCEO drops to approximately 320V based on thermal limits and SOA curves. Always maintain ≥20% voltage margin in final designs.
Can FZT458QTA replace a MOSFET in low-frequency switching applications?
Yes - for <100kHz switching with modest current (<300mA) and where gate drive simplicity matters, FZT458QTA offers lower cost and no gate charge concerns. However, its 2260ns toff and 0.2–0.5V VCE(sat) make it less efficient than MOSFETs above 50kHz or at higher currents.
Is FZT458QTA qualified for automotive use under AEC-Q101?
FZT458QTA is manufactured in IATF 16949-certified facilities and supports PPAP documentation. While not pre-qualified as a standard AEC-Q101 part, Diodes provides change-controlled versions (e.g., FZT458QTA-A) with full AEC-Q101 test reports upon request for automotive programs.
How should the SOT223 collector tab be connected for optimal thermal performance?
The exposed collector tab must be soldered to a minimum 25mm × 25mm 2oz copper pad (or larger) with ≥4 thermal vias (0.3mm diameter, spaced ≤2mm apart) connecting to internal ground planes. Avoid covering the tab with solder mask - bare copper contact is essential for achieving the rated 41.7°C/W RθJA.
FZT458QTA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- TO-261-4, TO-261AA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-223-3
FZT458QTA FAQ
1.How can I place an order for FZT458QTA through Aetrix?
Please submit a Request for Quotation (RFQ) for FZT458QTA 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 FZT458QTA reliable?
The price and inventory of FZT458QTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FZT458QTA is usually 5 days.
3.What payment methods are accepted for FZT458QTA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FZT458QTA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FZT458QTA?
FZT458QTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FZT458QTA 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 FZT458QTA?
For technical support, including FZT458QTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FZT458QTA requirements.
6.How does Aetrix verify that FZT458QTA is sourced from the original manufacturer or authorized distributors?
All FZT458QTA 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 FZT458QTA meets industry standards.
7.What is the process for return or replacement of FZT458QTA?
All FZT458QTA units undergo pre-shipment inspection (PSI). If there is an issue with FZT458QTA, 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 FZT458QTA part is unused and in its original packaging.
Return procedure for FZT458QTA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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