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Diodes Incorporated ZTX957STOB
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- Part No.:
- ZTX957STOB
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- E-Line-3, Formed Leads
- Datasheet:
-
ZTX957STOB.pdf
- Description:
- TRANS PNP 300V 1A E-LINE
- Quantity:
- Payment:
- Shipping:
Inventory:9,780
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Product details
Overview
ZTX957STOB from Diodes Incorporated is a PNP silicon planar medium-power high-current transistor designed for switching and linear amplification in industrial power control circuits. It delivers -1 A continuous collector current, -300 V VCEO, -140 mV VCE(sat) at -1 A/-300 mA drive, and operates up to +200°C junction temperature - enabling use in high-voltage DC-DC converters and motor driver output stages.
For engineers reviewing the ZTX957STOB datasheet, ZTX957STOB pinout, ZTX957STOB application, or ZTX957STOB equivalent, key selection criteria include verified PNP polarity, TO-92-compatible E-Line package thermal resistance (Rth(j-amb) = 150°C/W), low saturation voltage under high current, gain stability up to 1 A, and safe operating area validated to 100 V/500 mA pulses.
Technical Context
The ZTX957STOB is a ruggedized PNP bipolar junction transistor optimized for high-voltage switching with controlled saturation behavior. Its -300 V VCEO rating and -330 V VCBO support operation in off-line power supplies and relay drivers where transient overvoltage immunity is critical.
It exhibits stable hFE of 100–200 across -10 mA to -1 A collector current and maintains -140 mV VCE(sat) at -1 A with -300 mA base drive, enabling efficient conduction in high-side switch configurations with minimal thermal penalty.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | -300 V - supports high-side switching in 24–200 V DC systems without breakdown risk |
| IC (continuous) | -1 A - enables direct drive of solenoids, relays, and small motors without external buffering |
| VCE(sat) | -140 mV @ -1 A/-300 mA - reduces conduction loss to ≤140 mW, easing thermal design on PCB |
| hFE | 100–200 @ -1 A - ensures reliable base drive margin in saturated switch applications |
| Tj max | +200°C - allows operation in sealed enclosures or high-ambient industrial environments |
| Rth(j-amb) | 150°C/W - defines minimum copper area (1 inch²) needed for 1.2 W dissipation at 25°C ambient |
| fT | 85 MHz - supports fast switching in PWM frequencies up to ~5 MHz with adequate gain |
Pinout & Package
Package: E-Line TO-92-compatible (3-327 outline), through-hole mounting, epoxy molded, lead-free compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Emitter (E) | Current sink terminal for PNP operation | Connected to higher potential rail; must handle full load current and provide reference for base bias |
| Base (B) | Control input for minority-carrier injection | Requires negative current relative to emitter; -300 mA drive needed for full saturation at -1 A |
| Collector (C) | Output current path to load | Connected to load return; withstands -300 V transients and dissipates majority of switching/conduction loss |
Key Features
| Feature | Design Value |
|---|---|
| Low VCE(sat) at high current | -140 mV @ -1 A ensures <140 mW conduction loss, reducing heatsink requirements |
| High VCEO rating | -300 V enables direct interface with 120/230 VAC-derived DC rails without snubbers |
| Wide operating temperature range | -55°C to +200°C junction allows deployment in automotive engine bays and industrial ovens |
| SPICE model availability | Validated behavioral model supports accurate transient simulation of switching waveforms and thermal stress |
| TO-92 footprint compatibility | E-Line 3-327 mechanical outline ensures drop-in replacement in legacy designs using standard TO-92 tooling |
Applications
| Industrial Relay Drivers | High-Voltage DC-DC Converters |
|---|---|
Use Scenario: Driving 24–48 V DC coils in programmable logic controller (PLC) output modules. IC Role / Device Role / Timing Role: High-side PNP switch controlling coil energization/de-energization with fast turn-off via base pull-up. Use Value: -140 mV VCE(sat) minimizes self-heating during sustained 1 A coil current, extending contact life and system uptime. | Use Scenario: Active clamp or synchronous rectifier in flyback/isolated forward converters operating from 300 V DC bus. IC Role / Device Role / Timing Role: PNP switch handling high-voltage reset paths with controlled dv/dt and low stored charge. Use Value: -300 V VCEO and 2500 ns toff enable robust clamping without avalanche stress or timing skew. |
| Motor Control Output Stages | Overvoltage Protection Circuits |
Use Scenario: Low-side current sink or high-side driver in brushed DC motor H-bridge half-bridges. IC Role / Device Role / Timing Role: Power switch delivering up to 1 A continuous current with gain-stable hFE across load range. Use Value: hFE ≥100 at -1 A ensures predictable base drive sizing and eliminates need for Darlington stacking. | Use Scenario: Crowbar element in regulated power supplies protecting downstream loads from >300 V transients. IC Role / Device Role / Timing Role: Fast-acting crowbar triggered by overvoltage comparator to short output to ground. Use Value: 108 ns ton and -330 V VCBO ensure sub-microsecond response before IC or load damage occurs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PNP high-voltage switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ZTX951 | VCEO = -200 V, VCE(sat) = -200 mV @ -1 A, Rth(j-amb) = 200°C/W | Limited to ≤200 V systems; higher conduction loss increases thermal load | Select when cost sensitivity outweighs voltage margin and thermal performance |
| MJD2955G | TO-220 package, IC = -12 A, VCEO = -60 V, lower voltage rating but higher current | Requires heatsink; unsuitable for >60 V applications despite higher current capability | Choose only for low-voltage, high-current linear regulation where TO-92 footprint is not required |
Compared with ZTX957STOB, ZTX951 trades 100 V blocking margin and 60 mV higher saturation voltage for lower cost, while MJD2955G offers 12× current capacity in a larger package but fails at voltages above 60 V - making ZTX957STOB uniquely balanced for medium-power, high-voltage discrete switching.
Availability
ZTX957STOB is available at Aetrix Electronics and suitable for industrial relay drivers, high-voltage DC-DC converters, motor control output stages, and overvoltage protection circuits requiring stable component supply across extended temperature and voltage ranges.
Supply support for ZTX957STOB 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 power management and signal integrity solutions for industrial, computing, and automotive markets.
The ZTX957STOB belongs to Diodes' legacy high-voltage bipolar transistor product line, engineered specifically for robust switching in harsh-environment power interfaces where voltage endurance, thermal resilience, and proven reliability are mandatory.
FAQ
Is ZTX957STOB RoHS compliant and lead-free?
Yes, ZTX957STOB is RoHS compliant and manufactured with lead-free terminations per Diodes Incorporated's standard qualification. The E-Line TO-92 package meets JEDEC J-STD-020 moisture sensitivity level 1 and supports standard reflow and wave soldering profiles without special handling.
What is the maximum safe operating area (SOA) for pulsed operation?
The SOA curve in the datasheet confirms single-pulse operation up to 100 V and 500 mA for 1 ms, and 30 V/1 A for 100 µs. Derating is required above 25°C ambient; at 100°C case temperature, maximum DC current drops to approximately 400 mA to maintain junction temperature ≤200°C.
Can ZTX957STOB be used in linear amplifier configurations?
Yes - its hFE stability (100–200) from -10 mA to -1 A and low distortion characteristics support Class-A and AB audio or precision current source applications. However, thermal design must account for Ptot = 1.2 W at 25°C ambient, requiring careful heatsinking for sustained linear operation.
Does ZTX957STOB have an official SPICE model, and where can it be obtained?
Yes, Diodes Incorporated provides a verified PSpice-compatible SPICE model for ZTX957STOB, including thermal and charge storage effects. It is available for download directly from the product page on diodes.com under "Design Resources" → "Simulation Models", with no registration required.
ZTX957STOB 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:
- PNP
- Current - Collector (Ic) (Max):
- 1 A
- Voltage - Collector Emitter Breakdown (Max):
- 300 V
- Vce Saturation (Max) @ Ib, Ic:
- 200mV @ 300mA, 1A
- Current - Collector Cutoff (Max):
- 50nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 100 @ 500mA, 10V
- Power - Max:
- 1.2 W
- Frequency - Transition:
- 85MHz
- Operating Temperature:
- -55°C ~ 200°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- E-Line (TO-92 compatible)
ZTX957STOB FAQ
1.How can I place an order for ZTX957STOB through Aetrix?
Please submit a Request for Quotation (RFQ) for ZTX957STOB 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 ZTX957STOB reliable?
The price and inventory of ZTX957STOB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX957STOB is usually 5 days.
3.What payment methods are accepted for ZTX957STOB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX957STOB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ZTX957STOB?
ZTX957STOB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ZTX957STOB 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 ZTX957STOB?
For technical support, including ZTX957STOB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX957STOB requirements.
6.How does Aetrix verify that ZTX957STOB is sourced from the original manufacturer or authorized distributors?
All ZTX957STOB 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 ZTX957STOB meets industry standards.
7.What is the process for return or replacement of ZTX957STOB?
All ZTX957STOB units undergo pre-shipment inspection (PSI). If there is an issue with ZTX957STOB, 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 ZTX957STOB part is unused and in its original packaging.
Return procedure for ZTX957STOB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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