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Diodes Incorporated FZTA42TC
- Part No.:
- FZTA42TC
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- TO-261-4, TO-261AA
- Datasheet:
-
FZTA42TC.pdf
- Description:
- TRANS NPN 300V 0.5A SOT-223-3
- Quantity:
- Payment:
- Shipping:
Inventory:7,410
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Product details
Overview
FZTA42 from Diodes Incorporated is an NPN silicon planar high-voltage transistor in SOT-223 package, rated for VCEO = 300 V, IC = 500 mA, and Ptot = 2 W at Tamb = 25°C. It serves as a video output stage switch or SMPS switching element in CRT TV horizontal deflection and offline flyback converters.
For engineers reviewing the FZTA42 datasheet, FZTA42 pinout, FZTA42 application, or FZTA42 equivalent, key selection criteria include verified 300 V breakdown rating, hFE range of 25–40 at IC = 1–30 mA, VCE(sat) ≤ 0.5 V at IC = 20 mA/IB = 2 mA, and fT = 50 MHz - all critical for high-voltage linear/switching gain stability and thermal margin in legacy analog video and power conversion designs.
Technical Context
This discrete NPN bipolar junction transistor operates in active or saturation mode with fixed base-driven control, requiring external bias networks to set operating point. Its 300 V VCEO and VCB0 ratings enable direct replacement of older high-voltage transistors in CRT sweep circuits without snubber redesign.
The device exhibits hFE variation from 25 to 40 across IC = 1–30 mA at VCE = 10 V, and delivers fT = 50 MHz at IC = 10 mA/VCE = 20 V - sufficient for horizontal deflection frequencies up to 15.734 kHz and SMPS switching below 500 kHz with predictable gain roll-off.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 300 V - supports direct connection to 240 VAC-derived DC rails in offline SMPS without intermediate voltage reduction |
| IC (continuous) | 500 mA - enables driving 100–200 W flyback transformer primary windings at <100 kHz switching |
| VCE(sat) | 0.5 V @ IC=20 mA/IB=2 mA - limits conduction loss to <10 mW in video output stage quiescent operation |
| hFE | 25–40 @ IC=1–30 mA - ensures stable base current design across production lots for fixed-bias video driver stages |
| fT | 50 MHz @ IC=10 mA/VCE=20 V - provides adequate small-signal gain margin for horizontal deflection linearity compensation |
| Ptot | 2 W @ Tamb=25°C - requires minimum 2.5 cm² copper pour on SOT-223 tab for safe 1.2 W continuous dissipation at 70°C ambient |
Pinout & Package
Package: SOT-223 (4-pin, single-gull-wing leadframe with exposed collector tab). Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector (tab), Pin 4 = Emitter (dual-emitter configuration).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Emitter | Primary emitter connection; used for low-impedance return path in grounded-emitter video output stage |
| Pin 2 | Base | Current-controlled input node; requires series resistor to limit IB ≤ 100 mA under worst-case drive |
| Pin 3 (Tab) | Collector | Thermally and electrically connected to PCB copper; must be isolated from other nets unless referenced to high-voltage rail |
| Pin 4 | Emitter | Secondary emitter terminal; internally tied to Pin 1 - used for mechanical stability and dual-solder-point reliability |
Key Features
| Feature | Design Value |
|---|---|
| High VCEO/VCB0 | 300 V rating allows direct interface with unregulated 350 V DC bus in CRT TV horizontal output stages |
| SOT-223 thermal performance | 2 W total dissipation with tab-to-PCB thermal resistance ≤ 30°C/W enables compact heatsink-free layout in space-constrained TV chassis |
| Dual-emitter construction | Pins 1 and 4 both connect to emitter - improves solder joint reliability and reduces bond wire stress in high-vibration consumer applications |
| Controlled hFE spread | 25–40 range at multiple IC points simplifies fixed-base bias network design without trimmer potentiometers |
Applications
| TV Horizontal Deflection Output Stage | Offline Flyback SMPS Switch |
|---|---|
|
Use Scenario: Driving horizontal deflection yoke in CRT television sets with 15.734 kHz sawtooth waveform generation. IC Role / Device Role / Timing Role: High-voltage NPN switch conducting during retrace interval; handles peak collector voltage >250 V and pulsed IC up to 400 mA. Use Value: 300 V VCEO eliminates need for external clamping diodes; VCE(sat) ≤ 0.5 V minimizes power loss during active scan period. |
Use Scenario: Primary-side switching transistor in 20–60 W AC/DC adapters using discontinuous conduction mode (DCM) flyback topology. IC Role / Device Role / Timing Role: Voltage-controlled current switch turning on/off at 65–100 kHz to regulate output via optocoupler feedback. Use Value: 500 mA IC rating supports 30 W output at 85–265 VAC input; fT = 50 MHz ensures stable gate drive response at 100 kHz switching. |
| Video Amplifier Load Driver | High-Voltage Relay Driver |
|
Use Scenario: Amplifying composite video signal to drive 75 Ω coaxial cable in broadcast monitoring equipment. IC Role / Device Role / Timing Role: Class-A emitter-follower buffer delivering ±1 Vpp into 75 Ω load with minimal distortion at 5 MHz bandwidth. Use Value: hFE ≥ 25 at IC = 10 mA ensures consistent current gain across temperature; Cobo = 6 pF avoids high-frequency peaking in video termination. |
Use Scenario: Driving electromagnetic relay coil rated for 24–48 VDC with inductive kickback suppression. IC Role / Device Role / Timing Role: Low-side switch controlling relay coil current up to 300 mA; absorbs inductive energy via internal B-E junction or external clamp. Use Value: VCEO = 300 V withstands >100 V flyback spikes without avalanche failure; 2 W Ptot accommodates 100 ms coil energization pulses. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage NPN switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DZTA42 | Direct replacement per Diodes Inc. obsolescence notice; identical pinout, same VCEO/IC/hFE, but improved consistency in fT and tighter VCE(sat) distribution | Same use in CRT deflection and SMPS; validated in existing DZTA42 reference designs with no layout change required | Select DZTA42 for new designs to ensure long-term supply and reduced parametric variation |
| MJD42 | TO-252 package; VCEO = 300 V, IC = 500 mA, but hFE min = 20 and fT = 30 MHz - lower gain-bandwidth product and larger footprint | Requires PCB pad redesign; suitable only where thermal mass >2.5 cm² copper is available and 50 MHz fT margin is non-critical | Choose MJD42 only if SOT-223 assembly capability is unavailable and TO-252 reflow profile is established |
Compared with FZTA42, DZTA42 offers identical form-fit-function with enhanced manufacturing consistency, while MJD42 trades SOT-223 compactness for TO-252 thermal robustness at the cost of reduced high-frequency gain - making DZTA42 the preferred drop-in upgrade and MJD42 a fallback for thermal-limited legacy board re-spins.
Availability
FZTA42 is available at Aetrix Electronics and suitable for CRT television repair, legacy SMPS refurbishment, and analog video signal conditioning requiring stable component supply and documented high-voltage switching behavior.
Supply support for FZTA42 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 US.
The FZTA42 belongs to Diodes' high-voltage bipolar transistor product line, engineered specifically for legacy consumer electronics applications demanding reliable 300 V switching in compact surface-mount packages.
FAQ
Is FZTA42 still in production?
No. Diodes Incorporated officially discontinued FZTA42 as of June 2021 and recommends DZTA42 as its direct replacement. Aetrix Electronics maintains limited legacy stock for repair and maintenance programs but does not accept new production orders for FZTA42 beyond existing commitments.
What is the thermal resistance RθJA for FZTA42 in SOT-223?
The typical junction-to-ambient thermal resistance is 62.5°C/W with standard JEDEC 2S2P copper pad (1 inch², 2 oz Cu, 2 internal planes). With 2.5 cm² (0.4 in²) of 2 oz Cu connected to the collector tab, RθJA improves to ~45°C/W - enabling 1.2 W continuous dissipation at 70°C ambient.
Can FZTA42 replace FMMTA42?
No. FMMTA42 is an SOT-23 device rated for VCEO = 300 V but only IC = 200 mA and Ptot = 350 mW. FZTA42's higher current and power ratings make it unsuitable as a direct substitute in SOT-23 footprints, and its SOT-223 package cannot be mounted on SOT-23 pads without mechanical modification.
Does FZTA42 have avalanche capability?
No. The datasheet specifies no avalanche energy rating (EAS) or ruggedness testing. It is rated for repetitive VCEO = 300 V under specified conditions but must be protected from inductive switching transients exceeding this voltage using external clamps or snubbers in relay or flyback applications.
FZTA42TC 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):
- 500 mA
- Voltage - Collector Emitter Breakdown (Max):
- 300 V
- Vce Saturation (Max) @ Ib, Ic:
- 500mV @ 2mA, 20mA
- Current - Collector Cutoff (Max):
- 100nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 40 @ 30mA, 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
FZTA42TC FAQ
1.How can I place an order for FZTA42TC through Aetrix?
Please submit a Request for Quotation (RFQ) for FZTA42TC 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 FZTA42TC reliable?
The price and inventory of FZTA42TC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FZTA42TC is usually 5 days.
3.What payment methods are accepted for FZTA42TC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FZTA42TC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FZTA42TC?
FZTA42TC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FZTA42TC 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 FZTA42TC?
For technical support, including FZTA42TC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FZTA42TC requirements.
6.How does Aetrix verify that FZTA42TC is sourced from the original manufacturer or authorized distributors?
All FZTA42TC 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 FZTA42TC meets industry standards.
7.What is the process for return or replacement of FZTA42TC?
All FZTA42TC units undergo pre-shipment inspection (PSI). If there is an issue with FZTA42TC, 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 FZTA42TC part is unused and in its original packaging.
Return procedure for FZTA42TC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
FZTA42TC Tags
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Diodes Incorporated
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Diodes Incorporated
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Micro Commercial Co
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Diodes Incorporated
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Nexperia USA Inc.
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Micro Commercial Co
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