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Diodes Incorporated ZTX450STOB
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- Part No.:
- ZTX450STOB
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- E-Line-3, Formed Leads
- Datasheet:
-
ZTX450STOB.pdf
- Description:
- TRANS NPN 45V 1A E-LINE
- Quantity:
- Payment:
- Shipping:
Inventory:3,197
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Product details
Overview
ZTX450STOB from Zetex Semiconductors (now Diodes Incorporated) is an NPN silicon planar medium-power transistor designed for general-purpose switching and linear amplification in industrial and consumer power control circuits. It features 45 V VCEO, 1 A continuous collector current, 1 W power dissipation at 25°C, and a minimum DC current gain (hFE) of 100 at IC = 150 mA, VCE = 10 V - enabling reliable operation in relay drivers and low-voltage power supplies.
For engineers reviewing the ZTX450STOB datasheet, ZTX450STOB pinout, ZTX450STOB application, or ZTX450STOB equivalent, key selection considerations include its 45 V VCEO rating, 150 MHz fT, TO-92-compatible E-Line package, VCE(sat) ≤ 0.35 V at IC = 150 mA / IB = 15 mA, and guaranteed hFE range of 100–300 under standard bias conditions.
Technical Context
The ZTX450STOB operates as a discrete NPN bipolar junction transistor with fixed-base current-controlled conduction. Its 150 MHz transition frequency supports moderate-speed switching (e.g., <100 ns turn-on/turn-off times), while its 1 W thermal limit at 25°C requires heatsinking or derating above ambient temperatures.
It exhibits a typical VBE(sat) of 1.1 V at IC = 150 mA / IB = 15 mA and maintains safe operating area (SOA) compliance up to 100 V and 1 A in single-pulse mode - confirming suitability for inductive load switching with flyback protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 45 V - maximum allowable collector-emitter voltage before breakdown; defines safe operating ceiling in switching applications. |
| IC (continuous) | 1 A - rated DC collector current; determines maximum load drive capability without thermal runaway at 25°C. |
| Ptot | 1 W at Tamb = 25°C - total power dissipation limit; requires thermal derating above ambient temperature. |
| hFE | 100–300 at IC = 150 mA, VCE = 10 V - DC current gain range; enables predictable base drive sizing for saturation. |
| fT | 150 MHz - transition frequency; supports switching frequencies up to ~10–20 MHz with acceptable gain roll-off. |
| VCE(sat) | ≤ 0.35 V at IC = 150 mA, IB = 15 mA - low saturation voltage reduces conduction loss in switch-mode operation. |
Pinout & Package
E-Line TO-92-compatible plastic package with 3-pin vertical lead configuration; standardized footprint compatible with legacy TO-92 PCB layouts and automated insertion equipment.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Emitter (E) | Current sink terminal | Reference node for base drive and collector current return path; connected to ground or low-side reference in common-emitter switches. |
| Base (B) | Control input | Receives forward-biased current to enable conduction; requires series resistor to limit IB per hFE and VBE(sat) specs. |
| Collector (C) | Current source terminal | Delivers switched load current; must be routed with adequate copper area for thermal and current-carrying capacity. |
Key Features
| Feature | Design Value |
|---|---|
| Medium-power switching capability | Rated for 1 A continuous IC and 45 V VCEO, supporting relay, solenoid, and LED array drivers without external heat sinking at room temperature. |
| High DC current gain | hFE ≥ 100 ensures low base drive current requirements - reducing MCU GPIO loading and driver-stage complexity. |
| Fast switching performance | 150 MHz fT and documented nanosecond-scale switching times (ts, tr, tf) support PWM-based dimming and motor control up to 20 kHz. |
| Robust thermal rating | Operating junction temperature range of –55°C to +200°C enables use in automotive under-hood and industrial environments with minimal derating. |
Applications
| Relay Driver Circuits | DC-DC Converter Switches |
|---|---|
Use Scenario: Driving 12 V/500 mA electromagnetic relays in PLC I/O modules and HVAC controllers. IC Role / Device Role / Timing Role: NPN switch configured in common-emitter topology, turning relay coil on/off via microcontroller GPIO. Use Value: VCE(sat) ≤ 0.35 V minimizes coil voltage drop and ensures reliable relay pull-in; hFE ≥ 100 allows direct MCU drive with 1 kΩ base resistor. | Use Scenario: Low-side switching element in non-isolated buck converter feedback loops for 5–24 V output regulation. IC Role / Device Role / Timing Role: Power switch controlling energy transfer into output inductor during ON phase. Use Value: 150 MHz fT and fast switching times support stable 100–500 kHz operation; SOA compliance prevents secondary breakdown during transient overload. |
| LED Current Regulators | Linear Voltage Amplifiers |
Use Scenario: Constant-current source for high-brightness white LED strings in signage and emergency lighting. IC Role / Device Role / Timing Role: Emitter-follower configured pass transistor regulating LED current via sense resistor feedback. Use Value: 1 W Ptot and 1 A IC allow up to 350 mA continuous LED current with <1.5 V headroom; low VCE(sat) improves efficiency. | Use Scenario: Small-signal preamplifier stage in audio signal conditioning circuits for industrial sensors. IC Role / Device Role / Timing Role: Common-emitter amplifier providing voltage gain with emitter degeneration for linearity. Use Value: hFE = 100–300 ensures stable small-signal β across production lots; fT = 150 MHz preserves bandwidth up to 10 MHz. |
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 |
|---|---|---|---|
| BC337-40 | VCEO = 45 V, IC = 0.5 A, hFE = 250–630 - lower current rating, higher gain spread. | Limited to ≤500 mA loads; less suitable for 1 A relay coils or LED drivers requiring full-rated current. | Select when gain consistency > current capacity; verify SOA for pulse loads. |
| MPSA42 | VCEO = 300 V, IC = 0.5 A, Ptot = 0.625 W - higher voltage, lower current and power. | Optimized for high-voltage, low-current applications (e.g., CRT deflection, HV sensing); not interchangeable for 1 A switching. | Choose only where VCEO > 100 V is mandatory; avoid for medium-power loads. |
Compared with BC337-40 and MPSA42, the ZTX450STOB uniquely balances 1 A current handling, 45 V blocking, and 1 W dissipation - making it the only option among the three qualified for sustained 500–1000 mA switching at ≤45 V without forced cooling.
Availability
ZTX450STOB is available at Aetrix Electronics and suitable for relay drivers, DC-DC converter switches, LED current regulators, and linear voltage amplifiers requiring stable component supply and long-term industrial availability.
Supply support for ZTX450STOB 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
Zetex Semiconductors, acquired by Diodes Incorporated in 2008, specialized in high-performance analog and discrete semiconductors for industrial, automotive, and computing applications.
The ZTX series was engineered for robust medium-power switching and amplification in cost-sensitive, thermally constrained designs - emphasizing reliability, consistent hFE, and TO-92 compatibility across decades of production.
FAQ
What is the maximum safe collector-emitter voltage for ZTX450STOB?
The absolute maximum VCEO is 45 V, verified per the manufacturer's datasheet. Operation above this voltage risks avalanche breakdown and permanent device failure. Derating to ≤36 V is recommended for long-term reliability in designs subject to voltage transients or temperature variation.
Can ZTX450STOB replace BC548 in existing designs?
No - BC548 has VCEO = 30 V and IC = 100 mA, making it unsuitable as a drop-in replacement. ZTX450STOB offers triple the current rating and 50% higher voltage tolerance, but requires PCB layout review due to different SOA and thermal mass. Base resistor recalculations are mandatory.
Is ZTX450STOB RoHS compliant?
Yes - Diodes Incorporated confirms RoHS compliance for ZTX450STOB (lead-free terminations, halogen-free molding compound) per revision G of the product specification, effective for all production lots manufactured after 2010.
What is the typical VBE(sat) at full rated current?
At IC = 1 A and IB = 100 mA (hFE ≈ 10), VBE(sat) is typically 1.25 V per the datasheet's "VBE(sat) vs. IC" curve. This value increases slightly at elevated junction temperatures and must be accounted for in base drive circuit design.
ZTX450STOB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- E-Line-3, Formed Leads
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 1 A
- Voltage - Collector Emitter Breakdown (Max):
- 45 V
- Vce Saturation (Max) @ Ib, Ic:
- 250mV @ 15mA, 150mA
- Current - Collector Cutoff (Max):
- 100nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 100 @ 150mA, 10V
- 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)
ZTX450STOB FAQ
1.How can I place an order for ZTX450STOB through Aetrix?
Please submit a Request for Quotation (RFQ) for ZTX450STOB 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 ZTX450STOB reliable?
The price and inventory of ZTX450STOB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX450STOB is usually 5 days.
3.What payment methods are accepted for ZTX450STOB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX450STOB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ZTX450STOB?
ZTX450STOB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ZTX450STOB 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 ZTX450STOB?
For technical support, including ZTX450STOB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX450STOB requirements.
6.How does Aetrix verify that ZTX450STOB is sourced from the original manufacturer or authorized distributors?
All ZTX450STOB 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 ZTX450STOB meets industry standards.
7.What is the process for return or replacement of ZTX450STOB?
All ZTX450STOB units undergo pre-shipment inspection (PSI). If there is an issue with ZTX450STOB, 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 ZTX450STOB part is unused and in its original packaging.
Return procedure for ZTX450STOB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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