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Diodes Incorporated FZT857TA
- Part No.:
- FZT857TA
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- TO-261-4, TO-261AA
- Datasheet:
-
FZT857TA.pdf
- Description:
- TRANS NPN 300V 3.5A SOT-223-3
- Quantity:
- Payment:
- Shipping:
Inventory:6,914
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Product details
Overview
FZT857TA from Diodes Incorporated is a 300V NPN medium-power transistor in SOT223 package, designed for high-voltage switching applications requiring robust breakdown voltage and low saturation resistance. It delivers 3.5A continuous collector current, 155mV VCE(SAT) at 1A, and 87mΩ RCE(SAT), with AEC-Q101 qualification for automotive reliability.
For engineers reviewing the FZT857TA datasheet, FZT857TA pinout, FZT857TA application, or FZT857TA equivalent, key selection criteria include its 300V VCEO, high hFE up to 3A (min 15), low thermal resistance (RθJL = 8.8°C/W), and complementary PNP pairing with FZT957 in high-side switch and flyback converter designs.
Technical Context
This NPN bipolar junction transistor operates in linear and switching modes with specified DC current gain (hFE) from 100–300 across 10mA–3A, enabling stable amplification and saturated switching. Its 350V VCBO and 300V VCEO support high-voltage isolation in offline power supplies and industrial controls.
Thermal performance is defined for two PCB mounting conditions: 42°C/W RθJA on 52mm×52mm 2oz copper and 78°C/W on 25mm×25mm 1oz copper. Transient thermal impedance curves confirm safe operation under pulsed loads up to 5A ICM with 100µs–1s pulse widths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 300 V - Enables use in 230VAC mains-connected circuits without derating. |
| IC (continuous) | 3.5 A - Supports medium-power load switching in motor drivers and SMPS primary side. |
| VCE(SAT) @ 1A | <155 mV - Minimizes conduction loss and self-heating in high-duty-cycle operation. |
| RCE(SAT) | 87 mΩ - Equivalent on-resistance simplifies thermal modeling vs. MOSFET alternatives. |
| hFE @ 3A | 15 min - Ensures reliable base drive margin in high-current saturated switching. |
| fT | 80 MHz - Supports fast switching in PWM frequencies up to ~500 kHz with controlled rise/fall times. |
| RθJL | 8.8 °C/W - Enables direct thermal path to PCB copper, critical for compact heatsinkless designs. |
Pinout & Package
Package: SOT223 - Surface-mount plastic package with exposed collector tab for thermal conduction; 0.112g weight; UL 94V-0 rated molding compound; moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Emitter (E) | Current sink terminal | Connected to ground or low-side return path; requires low-inductance layout for switching stability. |
| Base (B) | Control input | Drives transistor into saturation; requires ≥600mA peak base current for full 3.5A IC conduction. |
| Collector (C) | High-voltage output terminal | Exposed metal tab - must be soldered to large copper pour for thermal management and electrical connection. |
Key Features
| Feature | Design Value |
|---|---|
| High-voltage blocking | VCEO = 300 V enables direct interface with 230VAC rectified rails in offline converters. |
| Low saturation loss | VCE(SAT) ≤ 155 mV at 1A reduces power dissipation to <155 mW, easing thermal design. |
| AEC-Q101 qualification | Validated for automotive underhood environments (-55°C to +150°C) with PPAP capability. |
| Complementary PNP pair | FZT957 shares identical SOT223 footprint and thermal specs for push-pull or H-bridge layouts. |
| Green construction | Halogen- and antimony-free (<900 ppm Br/Cl, <1000 ppm Sb) meets automotive and industrial RoHS+ requirements. |
Applications
| Industrial Motor Control | Automotive Lighting Driver |
|---|---|
Use Scenario: Driving 24V brushed DC motors in factory automation actuators with PWM speeds up to 20kHz. IC Role / Device Role / Timing Role: High-side NPN switch controlling motor current path; base driven by microcontroller GPIO with external resistor network. Use Value: 300V rating accommodates inductive kickback spikes; 3.5A IC supports >50W motor loads without forced air cooling. |
Use Scenario: Constant-current LED driver for headlamp high-beam modules in passenger vehicles. IC Role / Device Role / Timing Role: Linear current regulator in series with LED string; operated in active region with feedback from sense resistor. Use Value: Tight hFE specification up to 3A ensures stable current regulation across temperature; AEC-Q101 ensures field reliability. |
| Offline Flyback Converter | High-Voltage Sensing Interface |
Use Scenario: Primary-side switching transistor in 15W–30W isolated AC/DC adapters for industrial IoT gateways. IC Role / Device Role / Timing Role: Fast-switching NPN in self-oscillating or UC384x-controlled flyback topology; driven by transformer-coupled base signal. Use Value: 80MHz fT and 100ns tON support efficient 65–100kHz operation; 5A ICM handles startup surges. |
Use Scenario: Level-shifting interface between 3.3V microcontroller and 200V bus monitoring circuitry in battery management systems. IC Role / Device Role / Timing Role: Voltage translator isolating logic-level signals from high-voltage domain using emitter-follower configuration. Use Value: 350V VCBO provides margin against transients; low COBO (21pF) preserves signal integrity above 1MHz. |
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 |
|---|---|---|---|
| STN857 | Same VCEO (300V), but lower IC = 2A and higher VCE(SAT) = 250mV @ 1A; SOT223-3L package. | Limited to ≤15W loads; unsuitable for 3.5A sustained current paths. | Select only if thermal budget allows higher saturation loss and system current demand is ≤2A. |
| MJD857T4G | Higher IC = 5A, but lower VCEO = 200V; TO-252 package with larger footprint and RθJA = 62°C/W. | Requires PCB area increase and cannot replace FZT857TA in 230VAC-input designs. | Prefer when peak current exceeds 3.5A and voltage stress remains below 200V. |
Compared with STN857 and MJD857T4G, FZT857TA uniquely balances 300V blocking, 3.5A current, and SOT223 thermal efficiency-making it optimal for space-constrained, high-voltage industrial and automotive switching where both voltage margin and power density matter.
Availability
FZT857TA is available at Aetrix Electronics and suitable for industrial motor control, automotive lighting drivers, and offline flyback converters requiring stable component supply with AEC-Q101 compliance and green manufacturing standards.
Supply support for FZT857TA 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 and manufacturing operations across Asia and the Americas.
FZT857TA belongs to Diodes' high-voltage bipolar transistor product line, engineered specifically for ruggedized switching in automotive, industrial, and appliance power systems where reliability under thermal and voltage stress is non-negotiable.
FAQ
What is the maximum allowable case temperature for continuous operation?
The FZT857TA has an operating junction temperature range of –55°C to +150°C. With RθJL = 8.8°C/W and typical PCB copper area, sustained case temperatures up to +125°C are achievable at 3.5A IC with proper thermal pad design per Diodes' recommended SOT223 layout.
Can FZT857TA be used in avalanche mode?
No-FZT857TA is not rated or characterized for repetitive avalanche operation. Its safe operating area (SOA) curve defines limits only for forward-biased operation; exceeding VCEO risks permanent degradation. External clamping (e.g., TVS diode) is required for inductive load protection.
Is the base-emitter junction protected against reverse voltage?
Yes-the emitter-base breakdown voltage VEBO is rated at 7V minimum. Exceeding this (e.g., during negative base drive transients) may cause junction damage. A series base resistor and optional Schottky clamp are recommended in fast-switching applications.
How does the FZT857TA's hFE variation affect base drive design?
hFE ranges from 15 (min at 3A) to 300 (typ at 10mA). For 3.5A IC, design must assume hFE = 15, requiring ≥233mA DC base current. A 600mA peak-rated driver ensures margin during turn-on and accounts for hFE degradation at elevated temperature.
FZT857TA 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):
- 3.5 A
- Voltage - Collector Emitter Breakdown (Max):
- 300 V
- Vce Saturation (Max) @ Ib, Ic:
- 345mV @ 600mA, 3.5A
- Current - Collector Cutoff (Max):
- 50nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 100 @ 500mA, 10V
- Power - Max:
- 3 W
- Frequency - Transition:
- 80MHz
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-223-3
FZT857TA FAQ
1.How can I place an order for FZT857TA through Aetrix?
Please submit a Request for Quotation (RFQ) for FZT857TA 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 FZT857TA reliable?
The price and inventory of FZT857TA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FZT857TA is usually 5 days.
3.What payment methods are accepted for FZT857TA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FZT857TA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FZT857TA?
FZT857TA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FZT857TA 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 FZT857TA?
For technical support, including FZT857TA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FZT857TA requirements.
6.How does Aetrix verify that FZT857TA is sourced from the original manufacturer or authorized distributors?
All FZT857TA 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 FZT857TA meets industry standards.
7.What is the process for return or replacement of FZT857TA?
All FZT857TA units undergo pre-shipment inspection (PSI). If there is an issue with FZT857TA, 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 FZT857TA part is unused and in its original packaging.
Return procedure for FZT857TA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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