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Diodes Incorporated ZTX449STZ
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- Part No.:
- ZTX449STZ
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- E-Line-3, Formed Leads
- Datasheet:
-
ZTX449STZ.pdf
- Description:
- TRANS NPN 30V 1A E-LINE
- Quantity:
- Payment:
- Shipping:
Inventory:5,834
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Product details
Overview
ZTX449STZ from Diodes Incorporated is an NPN silicon planar medium-power transistor with VCEO = 30 V, IC = 1 A continuous, Ptot = 1 W at Tamb = 25°C, and fT = 150 MHz - used in linear amplification and switching stages of industrial power supplies and DC-DC converters.
For engineers reviewing the ZTX449STZ datasheet, ZTX449STZ pinout, ZTX449STZ application, or ZTX449STZ equivalent, key selection factors include verified VCE(sat) ≤ 1 V at IC = 1 A / IB = 100 mA, guaranteed hFE ≥ 100 at IC = 50 mA, and TO-92-compatible thermal performance up to +200°C junction temperature.
Technical Context
The ZTX449STZ operates as a general-purpose NPN bipolar junction transistor optimized for medium-current switching and analog amplification. Its design supports stable DC current gain (hFE) across IC = 50 mA–2 A and maintains low VCE(sat) under pulsed conditions (300 µs, ≤2% duty cycle).
It features a robust silicon planar structure with rated breakdown voltages of VCBO = 50 V and VEBO = 5 V, enabling reliable operation in 24 V rail systems with transient margin. The device's fT = 150 MHz and Cobo = 15 pF support moderate-frequency signal handling up to ~50 MHz in Class-A amplifier configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 30 V - maximum safe collector-emitter voltage before avalanche in common-emitter configuration |
| IC (continuous) | 1 A - sustainable DC collector current without derating at Tamb = 25°C |
| Ptot | 1 W - total package power dissipation limit at ambient 25°C; requires heatsinking above ~0.5 W in sealed enclosures |
| hFE (min) | 100 - minimum DC current gain at IC = 50 mA, VCE = 2 V, ensuring predictable base drive sizing |
| fT | 150 MHz - transition frequency at IC = 50 mA, VCE = 10 V, defining usable small-signal bandwidth |
| VCE(sat) | 0.5–1 V - collector-emitter saturation voltage range confirming low conduction loss in switch mode |
Pinout & Package
Package: TO-92 compatible molded plastic case with standard lead spacing and thermal profile; leads are tin-plated copper, compliant with JEDEC TO-92 outline dimensions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Emitter (E) | Current sink terminal in common-emitter configuration | Low-impedance reference node; must be connected to lowest potential in switching path |
| Base (B) | Control input for minority-carrier injection | Requires current-limited drive (e.g., 100 mA max) to avoid second breakdown during saturation |
| Collector (C) | Current source terminal in common-emitter configuration | Connected to load or supply rail; handles full switched current and associated inductive kick energy |
Key Features
| Feature | Design Value |
|---|---|
| High fT (150 MHz) | Enables use in audio preamplifiers and low-MHz switching regulators without gain roll-off |
| Guaranteed hFE ≥ 100 @ 50 mA | Reduces base drive circuit complexity and improves bias stability over temperature |
| VCEO = 30 V rating | Supports direct interface with 24 V industrial control rails and automotive battery-supplied modules |
| TO-92 mechanical compatibility | Allows drop-in replacement in legacy PCB footprints designed for PN2222A, BC547, or ZTX450 |
Applications
| Industrial Power Supply | DC-DC Converter Driver |
|---|---|
Use Scenario: Regulated 12 V output stage in 24 V input offline SMPS. IC Role / Device Role / Timing Role: Medium-power NPN switch driving primary-side gate or secondary-side synchronous rectifier control logic. Use Value: Low VCE(sat) minimizes conduction loss; TO-92 footprint enables compact layout in cost-sensitive designs. | Use Scenario: Base drive amplifier for MOSFET gate in isolated flyback converter. IC Role / Device Role / Timing Role: Current-buffering transistor delivering fast turn-on/turn-off pulses to high-capacitance gate loads. Use Value: fT = 150 MHz ensures adequate slew rate for <100 ns pulse edges at 500 kHz switching frequency. |
| Linear Voltage Regulator | Overcurrent Protection Circuit |
Use Scenario: Pass transistor in adjustable 3-terminal linear regulator (e.g., LM317-based). IC Role / Device Role / Timing Role: Series pass element dissipating variable power based on load current and dropout voltage. Use Value: 1 W Ptot and -55°C to +200°C Tj rating allow operation under sustained 500 mA loads with minimal heatsink. | Use Scenario: Current-sense switch triggering shutdown when load exceeds 800 mA. IC Role / Device Role / Timing Role: Fast-acting comparator output driver interfacing with latch or microcontroller interrupt pin. Use Value: Guaranteed hFE ≥ 100 ensures clean logic-level output swing even with weak sense resistor signals. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN medium-power transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ZTX450STZ | VCEO = 60 V, hFE min = 100 @ IC = 100 mA, Ptot = 1 W | Higher voltage headroom; same TO-92 package but higher VCEO reduces need for snubbers in inductive loads | Select when operating above 30 V rail or requiring enhanced avalanche margin |
| BC547C | IC = 100 mA, Ptot = 500 mW, hFE = 420 (typ), TO-92 | Lower current/power capability; higher hFE but unsuitable for >200 mA continuous loads | Use only in low-power signal amplification where ZTX449STZ's 1 A rating is unnecessary |
Compared with ZTX449STZ, ZTX450STZ offers higher voltage tolerance without sacrificing package or thermal compatibility, while BC547C trades current capacity for higher gain - making ZTX449STZ optimal for 0.5–1 A switching where both gain and ruggedness matter.
Availability
ZTX449STZ is available at Aetrix Electronics and suitable for industrial power supplies, DC-DC converter drivers, and linear voltage regulators requiring stable component supply and long-term BOM continuity.
Supply support for ZTX449STZ 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, specializing in high-reliability components for industrial, computing, and consumer markets.
The ZTX series targets medium-power bipolar transistors for cost-sensitive, thermally constrained applications where TO-92 compatibility and guaranteed hFE are critical design requirements.
FAQ
Is ZTX449STZ still in active production?
No - ZTX449STZ is marked obsolete by Diodes Incorporated per official documentation. However, Aetrix Electronics maintains legacy inventory with full traceability and offers engineering support for redesign alternatives including ZTX450STZ and pin-compatible replacements with validated parametric equivalence.
What is the maximum safe operating temperature for ZTX449STZ?
The ZTX449STZ has a specified junction temperature range of –55°C to +200°C. At ambient temperatures above 70°C, derating is required: power dissipation must be reduced linearly to zero at +200°C, following the 1 W rating at 25°C and thermal resistance θJA ≈ 125°C/W for standard TO-92 mounting.
Can ZTX449STZ replace PN2222A in existing designs?
Yes - ZTX449STZ shares the TO-92 package and exceeds PN2222A in VCEO (30 V vs. 40 V), IC (1 A vs. 800 mA), and fT (150 MHz vs. 250 MHz). Its higher hFE minimum (100 vs. 35–300) improves base drive predictability, though layout thermal relief should be verified due to its 1 W rating.
Does ZTX449STZ require a heatsink in 1 A switching applications?
At 1 A continuous with VCE(sat) ≈ 0.7 V, power dissipation is ~0.7 W. In free-air conditions, this exceeds safe TO-92 thermal limits; a minimal copper pour (≥1 cm²) or clip-on heatsink is recommended. Derating curves in the datasheet confirm >500 mA operation requires thermal management above 50°C ambient.
ZTX449STZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- E-Line-3, Formed Leads
- Packaging:
- Tape & Box (TB)
- Product Status:
- Obsolete
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 1 A
- Voltage - Collector Emitter Breakdown (Max):
- 30 V
- Vce Saturation (Max) @ Ib, Ic:
- 1V @ 200mA, 2A
- Current - Collector Cutoff (Max):
- 100nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 100 @ 500mA, 2V
- Power - Max:
- 1 W
- Frequency - Transition:
- 150MHz
- Operating Temperature:
- -55°C ~ 200°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- E-Line (TO-92 compatible)
ZTX449STZ FAQ
1.How can I place an order for ZTX449STZ through Aetrix?
Please submit a Request for Quotation (RFQ) for ZTX449STZ 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 ZTX449STZ reliable?
The price and inventory of ZTX449STZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX449STZ is usually 5 days.
3.What payment methods are accepted for ZTX449STZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX449STZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ZTX449STZ?
ZTX449STZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ZTX449STZ 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 ZTX449STZ?
For technical support, including ZTX449STZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX449STZ requirements.
6.How does Aetrix verify that ZTX449STZ is sourced from the original manufacturer or authorized distributors?
All ZTX449STZ 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 ZTX449STZ meets industry standards.
7.What is the process for return or replacement of ZTX449STZ?
All ZTX449STZ units undergo pre-shipment inspection (PSI). If there is an issue with ZTX449STZ, 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 ZTX449STZ part is unused and in its original packaging.
Return procedure for ZTX449STZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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