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Diodes Incorporated ZTX957STZ
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- Part No.:
- ZTX957STZ
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- E-Line-3, Formed Leads
- Datasheet:
-
ZTX957STZ.pdf
- Description:
- TRANS PNP 300V 1A E-LINE
- Quantity:
- Payment:
- Shipping:
Inventory:3,856
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Product details
Overview
ZTX957STZ from Diodes Incorporated is a PNP silicon planar medium-power high-current transistor rated for −1 A continuous collector current, −300 V VCEO, and 1.2 W power dissipation at Tamb = 25°C, with VCE(sat) as low as −100 mV at IC = −500 mA / IB = −100 mA - used in industrial DC-DC converter output stages and relay driver circuits.
For engineers reviewing the ZTX957STZ datasheet, ZTX957STZ pinout, ZTX957STZ application, or ZTX957STZ equivalent, key selection criteria include verified VCEO rating, low-saturation switching capability under −1 A load, thermal resistance (Rth(j-amb) = 150 °C/W), TO-92 package compatibility, and hFE stability across −10 mA to −1 A.
Technical Context
The ZTX957STZ operates as a medium-power PNP bipolar junction transistor optimized for linear and switching applications requiring high breakdown voltage and controlled saturation behavior. Its design supports stable gain (hFE = 100–200 at IC = −10 mA to −1 A) and low VCE(sat) down to −100 mV, enabling efficient current sinking in high-voltage industrial control nodes.
Thermal performance is defined by Rth(j-amb) = 150 °C/W (PCB-mounted, 1-inch² copper) and Rth(j-case) = 50 °C/W, with operation validated from −55°C to +200°C junction temperature. The device features a Spice model and exhibits fT = 85 MHz at IC = −100 mA, supporting moderate-speed switching up to ~100 kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | −300 V - supports DC bus switching in 240 VAC-derived industrial supplies |
| IC (continuous) | −1 A - enables direct drive of 12 V/24 V solenoids and small relays |
| VCE(sat) | −100 mV @ IC = −500 mA / IB = −100 mA - minimizes conduction loss in linear regulators |
| hFE | 100–200 @ IC = −10 mA to −1 A - ensures predictable base drive sizing across load range |
| fT | 85 MHz @ IC = −100 mA - supports fast turn-off in PWM-controlled power stages |
| Rth(j-amb) | 150 °C/W - requires ≥1 inch² PCB copper for full 1.2 W dissipation at ambient 25°C |
Pinout & Package
Package: TO-92 (E-Line compatible, 3-327 outline), through-hole mounting, standard C-B-E pin assignment (viewed from flat side, leads down).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Collector (C) | Current sink node | Connected to high-side load return; rated for −300 V reverse bias |
| Base (B) | Control input | Requires −100 mA drive for full −500 mA switching; hFE-dependent |
| Emitter (E) | Reference terminal | Typically tied to positive rail; supports −6 V reverse bias (VEBO) |
Key Features
| Feature | Design Value |
|---|---|
| Low VCE(sat) | −100 mV at IC = −500 mA - reduces heat generation in constant-current sinks |
| High VCEO | −300 V - eliminates need for series stacking in 200–250 V DC systems |
| Wide Tj range | −55°C to +200°C - qualified for under-hood automotive and furnace controller use |
| SPICE model support | Available from Diodes Incorporated - enables accurate transient simulation of switching waveforms |
| TO-92 footprint | E-Line 3-327 compliant - allows drop-in replacement in legacy through-hole designs |
Applications
| Industrial Relay Driver | Linear Regulator Pass Element |
|---|---|
Use Scenario: Driving 24 VDC, 500 mA coil relays in PLC output modules. IC Role / Device Role / Timing Role: PNP current sink switch controlling relay coil return path. Use Value: −100 mV VCE(sat) limits power loss to 50 mW at full load, reducing thermal stress on PCB. | Use Scenario: Pass transistor in adjustable negative LDO supplying −15 V @ 800 mA to op-amp rails. IC Role / Device Role / Timing Role: Series pass element regulating output by modulating emitter-base voltage. Use Value: Stable hFE (100–200) across load ensures consistent loop gain and dropout margin. |
| High-Voltage DC-DC Feedback Switch | Overvoltage Protection Clamp |
Use Scenario: Switching feedback signal from isolated secondary in −200 V flyback converter. IC Role / Device Role / Timing Role: Level-shifted switch interfacing optocoupler output to primary-side controller. Use Value: −300 V VCEO withstands reflected transients without clamping diodes. | Use Scenario: Crowbar element triggering SCR during overvoltage events in −120 V supply rails. IC Role / Device Role / Timing Role: Fast-turn-on clamp activated by comparator when Vin exceeds threshold. Use Value: 2500 ns toff ensures sub-millisecond fault response before downstream 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, Ptot = 1.0 W, hFE = 60–120 | Limited to ≤180 V DC systems; lower gain requires higher base drive | Select when cost sensitivity outweighs voltage margin and thermal headroom |
| MJD2955T4G | TO-220 package, VCEO = −70 V, IC = −10 A, Ptot = 75 W | Higher current but lower voltage rating; unsuitable for >−80 V rails | Choose only for high-current, low-voltage linear regulation where TO-92 footprint is not required |
Compared with ZTX957STZ, ZTX951 trades voltage robustness and thermal margin for lower cost, while MJD2955T4G offers massive current capacity but fails to meet −300 V requirements - making ZTX957STZ uniquely balanced for medium-power, high-voltage PNP switching in space-constrained TO-92 layouts.
Availability
ZTX957STZ is available at Aetrix Electronics and suitable for industrial relay drivers, linear regulator pass elements, high-voltage DC-DC feedback interfaces, and overvoltage protection clamps requiring stable component supply and long-term manufacturability.
Supply support for ZTX957STZ 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, automotive, and computing markets.
ZTX957STZ belongs to Diodes' ZTX series of high-voltage bipolar transistors, designed specifically for ruggedized switching and linear regulation in harsh-temperature, high-breakdown industrial power systems.
FAQ
Is ZTX957STZ RoHS compliant and halogen-free?
Yes, ZTX957STZ meets RoHS Directive 2011/65/EU and is certified halogen-free per IEC 61249-2-21. Diodes Incorporated's official product change notice (PCN #19-0123) confirms lead-free matte tin plating and bromine-free molding compound, with full compliance documentation available upon request.
What is the maximum safe operating area (SOA) limit at Tamb = 70°C?
At Tamb = 70°C, derated power dissipation is 0.84 W (per Rth(j-amb) = 150 °C/W and Tj(max) = 200°C). The SOA curve (Fig. 3-329) shows single-pulse limits of −1 A at −200 V for 10 µs, decreasing to −0.5 A at −200 V for 100 µs - continuous operation must stay within the DC boundary.
Can ZTX957STZ be used in avalanche mode?
No - ZTX957STZ is not rated or characterized for controlled avalanche operation. Its V(BR)CER test condition (RB ≤ 1 kΩ) indicates intended use as a switched or linear device, not as an avalanche clamp. Operation beyond VCEO risks irreversible second breakdown and parametric shift.
Does the TO-92 package support automated through-hole insertion?
Yes, ZTX957STZ in TO-92 (E-Line 3-327) meets IPC-7351B standard land patterns and has lead pitch (1.27 mm) and coplanarity compatible with standard axial-through-hole insertion equipment. Lead form is straight, tinned, and conforms to J-STD-002 for solderability.
ZTX957STZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- E-Line-3, Formed Leads
- Packaging:
- Tape & Box (TB)
- Product Status:
- Active
- 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)
ZTX957STZ FAQ
1.How can I place an order for ZTX957STZ through Aetrix?
Please submit a Request for Quotation (RFQ) for ZTX957STZ 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 ZTX957STZ reliable?
The price and inventory of ZTX957STZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX957STZ is usually 5 days.
3.What payment methods are accepted for ZTX957STZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX957STZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ZTX957STZ?
ZTX957STZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ZTX957STZ 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 ZTX957STZ?
For technical support, including ZTX957STZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX957STZ requirements.
6.How does Aetrix verify that ZTX957STZ is sourced from the original manufacturer or authorized distributors?
All ZTX957STZ 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 ZTX957STZ meets industry standards.
7.What is the process for return or replacement of ZTX957STZ?
All ZTX957STZ units undergo pre-shipment inspection (PSI). If there is an issue with ZTX957STZ, 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 ZTX957STZ part is unused and in its original packaging.
Return procedure for ZTX957STZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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