Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

Diodes Incorporated FZTA42TA

Name: FZTA42TA
Brand: Diodes Incorporated
SKU: FZTA42TA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: FZTA42TA

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

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

Datasheet:: FZTA42TA.pdf

Description:: TRANS NPN 300V 0.5A SOT-223-3

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:8,133

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

FZTA42 from Diodes Incorporated is an NPN silicon planar high-voltage transistor in SOT-223 package, rated for V_CEO = 300 V, I_C = 500 mA, and P_tot = 2 W at T_amb = 25°C. It is designed for video output stages in TV sets and switch-mode power supply (SMPS) applications requiring robust high-voltage switching.

For engineers reviewing the FZTA42 datasheet, FZTA42 pinout, FZTA42 application, or FZTA42 equivalent, key selection criteria include verified V_CEO/V_CBO = 300 V, h_FE = 25–40 across 1–30 mA I_C, f_T = 50 MHz at 10 mA, V_CE(sat) = 0.5 V @ 20 mA/2 mA, and SOT-223 thermal performance in high-voltage linear/switching roles.

Technical Context

This NPN bipolar junction transistor operates with a minimum h_FE of 25 at I_C = 1 mA and maintains usable current gain up to I_C = 30 mA under V_CE = 10 V bias. Its 300 V breakdown ratings enable direct use in horizontal deflection and SMPS primary-side switching without external snubbers.

The device exhibits f_T = 50 MHz at I_C = 10 mA and V_CE = 20 V, supporting stable operation in video-frequency amplification and high-speed switching. C_obo = 6 pF at V_CB = 20 V ensures low capacitive loading in tuned collector circuits.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	300 V - supports direct connection to 270 V DC bus in offline SMPS without derating
I_C (continuous)	500 mA - enables medium-power switching in TV horizontal output and auxiliary SMPS rails
P_tot	2 W at T_amb = 25°C - requires SOT-223 copper pad ≥ 100 mm² for full thermal rating
h_FE	25–40 @ I_C = 1–30 mA - provides predictable base drive requirements for Class-B video drivers
f_T	50 MHz @ I_C = 10 mA - sufficient for 15.734 kHz horizontal deflection with margin
V_CE(sat)	0.5 V @ I_C = 20 mA, I_B = 2 mA - limits conduction loss to ≤10 mW in linear video output stage

Pinout & Package

Package: SOT-223 (4-pin, standard leadframe configuration with tab as Collector). Thermal pad must be soldered for rated power dissipation.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emitting terminal	Low-impedance return path; connects to ground or emitter degeneration resistor
2 (Base)	Control input	Receives current-limited drive; typical I_B = 2 mA for 20 mA I_C
3 (Collector)	High-voltage output node	Connected to 300 V rail; tab is electrically tied to this pin
4 (Collector Tab)	Thermal & electrical extension of Collector	Must be soldered to PCB copper for thermal management and electrical continuity

Key Features

Feature	Design Value
High V_CEO/V_CBO	300 V rating enables direct replacement of legacy TV horizontal output transistors without redesign
SOT-223 power package	2 W dissipation capability with PCB thermal relief - avoids need for TO-126 or TO-220 in space-constrained designs
Guaranteed h_FE range	25–40 across operating I_C ensures consistent base drive sizing across production lots
Low V_CE(sat)	0.5 V at 20 mA/2 mA reduces heat generation in linear video driver applications

Applications

TV Horizontal Deflection Output Stage

Offline SMPS Auxiliary Switch

Use Scenario: Drives flyback transformer primary in CRT television horizontal output circuit with 15.734 kHz switching.

IC Role / Device Role / Timing Role: NPN switching transistor operating in Class-B push-pull pair; handles peak collector voltage up to 300 V.

Use Value: Eliminates need for external clamping diodes due to guaranteed 300 V V_CEO and low stored charge.

Use Scenario: Controls auxiliary 12 V/5 V winding regulation in 20–60 W AC/DC adapters.

IC Role / Device Role / Timing Role: High-voltage NPN switch in optocoupler feedback loop or standby power control path.

Use Value: Supports reliable start-up and hold-on operation under 265 V AC input with minimal base drive overhead.

Video Amplifier Driver

High-Voltage Linear Regulator Pass Element

Use Scenario: Buffers composite video signal into 75 Ω coaxial cable with DC restoration.

IC Role / Device Role / Timing Role: Emitter-follower output stage biased at ~10 mA; delivers 1–2 Vpp into 75 Ω load.

Use Value: Stable h_FE and low V_CE(sat) preserve video signal fidelity and minimize thermal drift.

Use Scenario: Series pass element in 24–300 V input linear regulator for low-noise analog subsystems.

IC Role / Device Role / Timing Role: Voltage-controlled current source operating in active region with fixed base bias.

Use Value: 300 V V_CBO allows direct connection to unregulated HV rail; 2 W rating sustains 100 mA output at 20 V drop.

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
DZTA42	Direct replacement per Diodes Inc. obsolescence notice; identical V_CEO/I_C/h_FE, improved f_T = 60 MHz	Same TV/SMPS roles; enhanced high-frequency linearity for newer deflection ICs	Select DZTA42 for new designs; FZTA42 not recommended for production starts
MJD42	TO-252 package; V_CEO = 300 V, I_C = 500 mA, but h_FE min = 20 and P_tot = 1.5 W	Requires larger PCB area and reduced power margin; less suitable for compact TV chassis	Use only if SOT-223 footprint unavailable; verify thermal design with 0.5 W lower dissipation

Compared with FZTA42, DZTA42 offers higher f_T and active production status, while MJD42 trades SOT-223 compactness for TO-252 thermal robustness at lower power density - making DZTA42 the preferred upgrade path for continuity and performance.

Availability

FZTA42 is available at Aetrix Electronics and suitable for TV horizontal deflection circuits, offline SMPS auxiliary switches, video amplifier drivers, and high-voltage linear regulator pass elements requiring stable component supply despite its obsolete status.

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 and manufacturing operations across Asia and the Americas.

FZTA42 belongs to Diodes' high-voltage bipolar transistor product line, developed specifically for CRT television deflection and industrial power conversion where rugged 300 V operation and SOT-223 thermal efficiency are critical.

FAQ

Is FZTA42 still in production?

No. Diodes Incorporated officially discontinued FZTA42 in June 2021, as stated in DS33193 Rev. 5–4. It is marked "OBSOLETE – PART DISCONTINUED" in all official documentation. Aetrix Electronics supplies remaining authorized inventory with full traceability and no remarketing.

What is the correct pin 1 orientation for FZTA42 in SOT-223?

With the marking side up and leads pointing downward, pin 1 (Emitter) is the leftmost lead. Pin 2 (Base) is center-left, pin 3 (Collector) is center-right, and pin 4 is the large thermal tab on the right edge - electrically and thermally connected to pin 3.

Can FZTA42 replace FMMTA42?

No. FMMTA42 is an SOT-23 device rated for V_CEO = 300 V but with I_C = 200 mA and P_tot = 350 mW. FZTA42's 500 mA/2 W rating and SOT-223 footprint make it incompatible in both electrical capability and physical layout.

Why does the datasheet reference the FMMTA42 datasheet for typical characteristics?

Because FZTA42 shares the same die process and core transistor structure as FMMTA42. Diodes uses the FMMTA42 characterization curves (e.g., h_FE vs. I_C, f_T vs. I_C) as representative behavior, validated under identical test conditions - enabling accurate design modeling without redundant graph generation.

FZTA42TA 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

FZTA42TA FAQ

1.How can I place an order for FZTA42TA through Aetrix?

Please submit a Request for Quotation (RFQ) for FZTA42TA 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 FZTA42TA reliable?

The price and inventory of FZTA42TA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FZTA42TA is usually 5 days.

3.What payment methods are accepted for FZTA42TA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FZTA42TA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for FZTA42TA?

FZTA42TA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your FZTA42TA 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 FZTA42TA?

For technical support, including FZTA42TA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FZTA42TA requirements.

6.How does Aetrix verify that FZTA42TA is sourced from the original manufacturer or authorized distributors?

All FZTA42TA 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 FZTA42TA meets industry standards.

7.What is the process for return or replacement of FZTA42TA?

All FZTA42TA units undergo pre-shipment inspection (PSI). If there is an issue with FZTA42TA, 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 FZTA42TA part is unused and in its original packaging.

Return procedure for FZTA42TA:

1.Submit a request within 90 days.

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

Tech Hub

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…

2026-08-14 Jumper Cables: How to Use, Connect and Choose Them Safely

Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…

2026-08-11 LDO Regulator: Dropout Voltage, Noise, PSRR and Power Dissipation

LDO regulator guide covering low dropout voltage, power dissipation, thermal design, PSRR, output noise, capacitor stability, adjustable LDO circuits, LDO vs buck converter and datasheet selection chec…

2026-08-06 Conditional Access Module: CAM, CI/CI+ and DVB Security

Conditional Access Module guide covering CAM meaning, CI/CI+ interface, smart card authorization, DVB security workflow, TV and set-top box compatibility, internal electronics, ESD protection, connecto…

2026-08-03 Electronic Component Obsolescence: EOL Risks, Replacement Options and Last-Time Buy Strategy

Guide to electronic component obsolescence covering EOL risk, PCN/PDN notices, last-time buy planning, replacement options, form-fit-function validation, counterfeit risk and BOM lifecycle management.

2026-07-29 18650 Battery: Voltage, Capacity, Charging and Pack Design

18650 battery guide covering lithium-ion cell basics, 3.6V/3.7V voltage, 4.2V charging, mAh and Wh capacity, protected cells, chargers, BMS, series-parallel packs, holders, welding and sourcing checks.…

2026-07-27 Hall Effect Sensor: Working Principle, Types, Circuits and Applications

Hall effect sensor guide covering working principle, linear and digital sensors, Arduino circuits, current sensing, speed detection, automotive applications, A3144 examples, signal filtering and datash…

2026-07-20 Product Change Notification (PCN) in Electronic Components: Meaning and Supply Chain Response

Product Change Notification guide for electronic components, covering PCN meaning, PCN vs PDN/EOL, common change types, risk levels, form-fit-function review, engineering validation, BOM control, LTB/L…

2026-07-19 Blend Door Actuator: Symptoms, Location, Reset and Replacement Guide

A practical guide to blend door actuators, covering HVAC function, symptoms, location, AC and heater issues, reset and calibration, replacement cost, electrical diagnosis, compatibility checks, and rep…