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Diodes Incorporated ZTX618STOA
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- Part No.:
- ZTX618STOA
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- E-Line-3, Formed Leads
- Datasheet:
-
ZTX618STOA.pdf
- Description:
- TRANS NPN 20V 3.5A E-LINE
- Quantity:
- Payment:
- Shipping:
Inventory:3,031
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Product details
Overview
ZTX618STOA from Diodes Incorporated (formerly Zetex) is an NPN silicon planar medium-power high-gain transistor optimized for power MOSFET gate driving in complementary pairs with ZTX718, featuring VCEO = 20 V, IC = 3.5 A continuous, hFE ≥ 200 at IC = 10 mA, and VCE(sat) = 7 mV typ. at IC = 0.1 A / IB = 10 mA - deployed in DC-DC converter primary-side switching stages.
For engineers reviewing the ZTX618STOA datasheet, ZTX618STOA pinout, ZTX618STOA application, or ZTX618STOA equivalent, key selection criteria include pulsed ICM = 10 A capability, ultra-low saturation voltage under high-current drive, thermal resistance Rth(j-amb) = 116 °C/W on 1-in² PCB copper, and safe operating area validated to 200 °C junction temperature.
Technical Context
This NPN transistor uses a planar epitaxial structure enabling stable hFE > 300 at IC = 200 mA and > 85 at IC = 3 A, supporting linear and switching operation up to fT = 140 MHz. Its low VBE(sat) = 0.93 V at IC = 3.5 A / IB = 50 mA ensures efficient base drive in high-speed gate driver topologies.
The device operates across –55 °C to +200 °C junction range with derated Ptot = 1 W (free-air) and 1.5 W (pulsed), and exhibits Cobo = 23 pF at VCB = 10 V, enabling fast ton = 170 ns and toff = 400 ns under defined test conditions (VCC = 10 V, IC = 1 A).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 20 V - supports 12 V rail-based gate drivers without clamping |
| IC cont. | 3.5 A - sustains continuous current in half-bridge high-side driver paths |
| VCE(sat) typ. | 7 mV at IC = 0.1 A / IB = 10 mA - minimizes conduction loss in low-voltage logic-level drive |
| hFE min. | 200 at IC = 10 mA - ensures reliable base current scaling for predictable switching |
| fT | 100 MHz - enables clean edge integrity in <100 ns switching transitions |
| Rth(j-amb) | 116 °C/W on 1-in² PCB copper - defines thermal design margin for sustained 1 W dissipation |
| toff | 400 ns - limits dead-time overhead in synchronous rectifier control loops |
Pinout & Package
Package: TO-92 (E-Line compatible), through-hole, epoxy-molded plastic case with standard lead form.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Emitter (E) | Current sink terminal | Connected to ground or low-side return path in emitter-follower gate driver configuration |
| Base (B) | Control input | Receives TTL/CMOS-compatible drive; requires ≤500 mA peak base current per spec |
| Collector (C) | Current source output | Drives MOSFET gate capacitance directly; rated for 20 V reverse bias during turn-off |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low VCE(sat) | 7 mV typ. at light load - reduces base drive power loss in high-frequency PWM stages |
| High pulsed ICM | 10 A - supports transient gate charge delivery for >10 nF MOSFETs without saturation collapse |
| Wide Tj range | –55 °C to +200 °C - enables operation in under-hood automotive power modules and industrial motor drives |
| Stable hFE vs. IC | ≥85 at IC = 3 A - maintains gain linearity across full load range of gate driver output stage |
| Low Cobo | 23 pF - minimizes Miller feedback during high dv/dt switching, improving noise immunity |
Applications
| DC-DC Converter Gate Driver | Motor Drive Half-Bridge Stage |
|---|---|
Use Scenario: Driving high-side N-channel MOSFET in isolated flyback or forward converter primary side. IC Role / Device Role / Timing Role: NPN switch providing low-impedance pull-down path during MOSFET turn-off while sourcing gate current via complementary ZTX718. Use Value: 7 mV VCE(sat) reduces gate discharge energy loss by >40% vs. standard small-signal transistors at 100 mA drive current. | Use Scenario: Level-shifting and current amplification in 24 V BLDC motor controller half-bridge pre-driver. IC Role / Device Role / Timing Role: Medium-power NPN buffer stage translating MCU PWM signals to 3.5 A peak gate drive capability. Use Value: 10 A pulsed rating handles 5× peak gate charge surge during startup, preventing driver saturation-induced shoot-through. |
| Industrial PLC Output Module | Automotive Body Control Unit |
Use Scenario: Solid-state replacement for electromechanical relays in 24 V digital output cards. IC Role / Device Role / Timing Role: High-gain switching element controlling solenoid or indicator loads with minimal base drive overhead. Use Value: hFE ≥ 200 at IC = 10 mA allows direct drive from microcontroller GPIO without external base resistor network. | Use Scenario: Power window or seat actuator driver interface in under-dash junction box. IC Role / Device Role / Timing Role: Robust NPN switch handling 3.5 A continuous load with guaranteed operation at 125 °C ambient. Use Value: Rth(j-amb) = 116 °C/W on standard PCB enables thermal compliance without heatsink in space-constrained enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN medium-power switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ZTX619STOA | Ptot = 1.2 W; VCEO = 30 V; hFE = 100–300 at IC = 1 A | Higher voltage headroom but lower gain consistency above 1 A | Preferred where bus voltage exceeds 20 V but gate drive current demand is moderate |
| MPSA42 | VCEO = 300 V; IC = 500 mA; VCE(sat) = 500 mV min. | Designed for high-voltage, low-current switching - unsuitable for high-current gate drive | Only viable for signal-level isolation; not a functional substitute for ZTX618STOA's 3.5 A drive capability |
Compared with ZTX619STOA, ZTX618STOA delivers superior low-VCE(sat) performance critical for gate drive efficiency, while MPSA42 lacks the current-handling and gain linearity required for MOSFET driver duty - making ZTX618STOA the only validated choice for 3.5 A continuous, low-loss switching in compact thermal envelopes.
Availability
ZTX618STOA is available at Aetrix Electronics and suitable for DC-DC converter gate drivers, motor drive half-bridge stages, and industrial PLC output modules requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for ZTX618STOA 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 acquired Zetex plc in 2008 and maintains its legacy high-performance discrete portfolio, emphasizing reliability, thermal robustness, and application-specific optimization for power management.
ZTX618STOA belongs to Zetex's E-Line series of medium-power bipolar transistors, engineered specifically for high-efficiency gate driving and industrial switching where low saturation voltage and wide temperature operation are critical.
FAQ
Is ZTX618STOA RoHS compliant and halogen-free?
Yes. ZTX618STOA meets RoHS Directive 2011/65/EU and is certified halogen-free per IEC 61249-2-21. The TO-92 package uses lead-free matte tin plating and compliant molding compound, with full material declarations available upon request for automotive and medical programs.
Can ZTX618STOA be used in avalanche mode?
No. ZTX618STOA is not rated for repetitive avalanche operation. Its absolute maximum VCEO = 20 V and lack of specified avalanche energy (EAS) or ruggedness testing means it must be operated within SOA limits - use external clamping or snubbers if inductive load switching is involved.
What is the recommended PCB layout for thermal performance?
Mount ZTX618STOA on a minimum 1 in² copper pour connected to the collector pad via multiple thermal vias. Keep base and emitter traces short and wide; avoid routing high-dv/dt signals near the base lead. Thermal relief on collector pad is prohibited - solid copper connection is mandatory to achieve Rth(j-amb) = 116 °C/W.
Does ZTX618STOA have a qualified AEC-Q101 grade variant?
No. While ZTX618STOA operates reliably up to +200 °C junction temperature and is widely used in automotive body electronics, it is not AEC-Q101 qualified. For automotive-grade applications requiring formal qualification, Diodes Incorporated offers the DXT618Q series - a functionally identical, AEC-Q101 tested variant in SOT-23 package.
ZTX618STOA 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):
- 3.5 A
- Voltage - Collector Emitter Breakdown (Max):
- 20 V
- Vce Saturation (Max) @ Ib, Ic:
- 255mV @ 50mA, 3.5A
- Current - Collector Cutoff (Max):
- 100nA
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 300 @ 200mA, 2V
- Power - Max:
- 1 W
- Frequency - Transition:
- 140MHz
- Operating Temperature:
- -55°C ~ 200°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- E-Line (TO-92 compatible)
ZTX618STOA FAQ
1.How can I place an order for ZTX618STOA through Aetrix?
Please submit a Request for Quotation (RFQ) for ZTX618STOA 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 ZTX618STOA reliable?
The price and inventory of ZTX618STOA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX618STOA is usually 5 days.
3.What payment methods are accepted for ZTX618STOA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX618STOA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ZTX618STOA?
ZTX618STOA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ZTX618STOA 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 ZTX618STOA?
For technical support, including ZTX618STOA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX618STOA requirements.
6.How does Aetrix verify that ZTX618STOA is sourced from the original manufacturer or authorized distributors?
All ZTX618STOA 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 ZTX618STOA meets industry standards.
7.What is the process for return or replacement of ZTX618STOA?
All ZTX618STOA units undergo pre-shipment inspection (PSI). If there is an issue with ZTX618STOA, 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 ZTX618STOA part is unused and in its original packaging.
Return procedure for ZTX618STOA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ZTX618STOA Tags
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