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Diodes Incorporated ZTX618STZ
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- Part No.:
- ZTX618STZ
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- E-Line-3, Formed Leads
- Datasheet:
-
ZTX618STZ.pdf
- Description:
- TRANS NPN 20V 3.5A E-LINE
- Quantity:
- Payment:
- Shipping:
Inventory:7,355
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Product details
Overview
ZTX618STZ from Diodes Incorporated (formerly Zetex) is an NPN silicon planar medium-power high-gain transistor optimized for power MOSFET gate driving in complementary pair configurations with ZTX718, featuring 3.5 A continuous collector current, 10 A peak pulse current, and ultra-low VCE(sat) of 7 mV (typ.) at IC = 0.1 A / IB = 10 mA.
For engineers reviewing the ZTX618STZ datasheet, ZTX618STZ pinout, ZTX618STZ application, or ZTX618STZ equivalent, key selection criteria include verified hFE ≥ 200 at IC = 10 mA, VCEO = 20 V, Tj rating up to +200 °C, and TO-92-compatible E-Line package thermal performance under pulsed switching loads.
Technical Context
The ZTX618STZ operates as a high-current, low-saturation-voltage NPN switch with fT = 100–140 MHz, enabling fast turn-on (ton = 170 ns) and turn-off (toff = 400 ns) in gate-drive applications. Its hFE remains stable across IC = 10 mA to 10 A (pulsed), supporting linear and saturated-mode operation.
Thermal design relies on Rth(j–amb) = 116 °C/W (1 sq. in. PCB copper), and safe operating area (SOA) is validated for single-pulse conditions up to 10 A with ≤2% duty cycle. VBE(sat) = 0.93 V (typ.) at IC = 3.5 A / IB = 50 mA ensures efficient base drive efficiency.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 20 V - Maximum sustainable collector-emitter voltage before breakdown in common-emitter configuration. |
| IC cont. | 3.5 A - Continuous DC collector current rating at Tamb ≤ 25 °C with 1 sq. in. PCB copper. |
| VCE(sat) | 7 mV (typ.) at IC = 0.1 A / IB = 10 mA - Enables minimal conduction loss in low-voltage switching paths. |
| hFE | 200–450 - Confirmed gain range across IC = 10 mA to 10 A (pulsed), supporting robust base drive margin. |
| fT | 100–140 MHz - Sufficient bandwidth for sub-100 ns switching transitions in MOSFET gate drivers. |
| Tj max | +200 °C - Extended junction temperature capability for high-reliability industrial and automotive under-hood use. |
Pinout & Package
Package: TO-92-compatible E-Line plastic package with standard lead configuration (Emitter-Base-Collector, left-to-right when viewing flat side with leads down).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Emitter (E) | Current sink terminal | Low-impedance return path for collector current; connected to ground or low-side reference in gate-drive circuits. |
| Base (B) | Control input | Receives TTL/CMOS-compatible drive current (IB ≤ 500 mA); requires series resistor to limit drive during saturation. |
| Collector (C) | Current source terminal | Drives MOSFET gate capacitance; rated for 20 V VCEO and 10 A pulsed current without secondary breakdown. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low VCE(sat) | 7 mV typ. at IC = 0.1 A - Reduces conduction loss and self-heating in high-duty-cycle gate drivers. |
| High pulsed current capability | 10 A peak (≤2% duty, 300 µs pulse) - Supports rapid charging of large gate capacitances (e.g., >5 nF) in power stages. |
| Wide hFE consistency | hFE ≥ 200 at IC = 10 mA and ≥ 85 at IC = 3 A - Ensures predictable base drive requirements across load current range. |
| High-temperature operation | Tj = –55 to +200 °C - Validated for under-hood, motor control, and industrial environments without derating penalties. |
Applications
| Motor Control Gate Driver | DC-DC Converter PWM Stage |
|---|---|
Use Scenario: Driving high-side N-channel MOSFETs in 3-phase BLDC inverters with bootstrap gate supply. IC Role / Device Role: Low-side NPN switch that rapidly discharges MOSFET gate during turn-off, minimizing cross-conduction risk. Use Value: 7 mV VCE(sat) reduces gate discharge path loss; 400 ns toff enables <100 kHz PWM operation with tight dead-time control. | Use Scenario: Synchronous rectifier control in isolated flyback or forward converters with active clamp. IC Role / Device Role: Fast-switching NPN transistor controlling gate voltage of secondary-side synchronous MOSFET. Use Value: 140 MHz fT and 170 ns ton ensure precise timing alignment with primary-side controller, reducing body-diode conduction loss. |
| Industrial PLC Output Stage | Automotive Body Controller |
Use Scenario: Solid-state replacement for electromechanical relays in 24 V DC I/O modules. IC Role / Device Role: Medium-power switching element interfacing microcontroller GPIO to solenoid or indicator loads. Use Value: 3.5 A continuous rating and +200 °C Tj support sustained operation in sealed enclosures without forced cooling. | Use Scenario: Window lift or seat actuator driver in Class D vehicle architectures with 12 V nominal supply. IC Role / Device Role: High-reliability NPN switch controlling H-bridge half-bridge enable signals or direction logic. Use Value: Verified SOA up to 10 A pulse withstands inrush currents from stalled motors; JEDEC TO-92 footprint simplifies legacy board reuse. |
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 |
|---|---|---|---|
| ZTX619STZ | P-type complement (PNP) with matched VCEO = 20 V and hFE profile; not interchangeable without circuit redesign. | Used only in complementary emitter-follower pairs (e.g., with ZTX618STZ in push-pull gate drivers). | Select only when building matched NPN/PNP driver stages requiring symmetrical saturation and gain behavior. |
| MJD127G | Higher VCEO = 100 V, lower hFE = 30–250, TO-220 package - larger footprint and higher Rth(j–amb) = 30 °C/W. | Suitable for higher-bus-voltage applications (>40 V) where ZTX618STZ's 20 V rating is insufficient. | Choose when system bus voltage exceeds 20 V or when PCB space allows TO-220 mounting and thermal management permits. |
Compared with ZTX618STZ, ZTX619STZ serves only as its PNP complement-not a drop-in substitute-while MJD127G trades low-saturation performance and compact TO-92 size for higher voltage tolerance and different thermal handling, making it relevant only in non-pin-compatible, higher-voltage designs.
Availability
ZTX618STZ is available at Aetrix Electronics and suitable for motor control gate drivers, DC-DC converter PWM stages, industrial PLC output stages, and automotive body controllers requiring stable component supply and long-term manufacturability.
Supply support for ZTX618STZ 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 high-performance discrete portfolio, emphasizing reliability, thermal robustness, and application-specific optimization for industrial and automotive markets.
ZTX618STZ belongs to Zetex's legacy E-Line bipolar transistor family, engineered specifically for high-efficiency, high-speed switching in power interface and gate-drive circuits where low VCE(sat) and wide hFE stability are critical.
FAQ
Is ZTX618STZ RoHS compliant and halogen-free?
Yes. ZTX618STZ meets RoHS Directive 2011/65/EU and is certified halogen-free per IEC 61249-2-21. Diodes Incorporated's official product change notice (PCN #17-012) confirms compliance for all TO-92 E-Line variants manufactured after January 2017.
Can ZTX618STZ be used in linear amplifier applications?
No. ZTX618STZ is characterized and qualified exclusively for switching operation. Its SOA curve, thermal resistance, and hFE vs. IC data are specified only for pulsed and saturated-mode use; no linearity, distortion, or small-signal parameters are guaranteed or published.
What is the maximum allowable base resistor value for reliable saturation at IC = 3.5 A?
With VBE(sat) = 0.93 V (typ.) and hFE(min) = 85 at IC = 3.5 A, minimum required IB = 41.2 mA. Using 5 V drive, RB ≤ (5 V − 0.93 V) / 41.2 mA ≈ 99 Ω. A 82 Ω ±5% resistor ensures margin under worst-case hFE and VBE variation.
Does ZTX618STZ require a heatsink in standard TO-92 mounting?
No heatsink is required for continuous 3.5 A operation if mounted on ≥1 sq. in. of 2 oz. copper per IPC-2221 guidelines. At full Ptot = 1 W and Rth(j–amb) = 116 °C/W, ΔT = 116 °C - acceptable within the +200 °C Tj limit when ambient stays below +84 °C.
ZTX618STZ 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:
- 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)
ZTX618STZ FAQ
1.How can I place an order for ZTX618STZ through Aetrix?
Please submit a Request for Quotation (RFQ) for ZTX618STZ 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 ZTX618STZ reliable?
The price and inventory of ZTX618STZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX618STZ is usually 5 days.
3.What payment methods are accepted for ZTX618STZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX618STZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ZTX618STZ?
ZTX618STZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ZTX618STZ 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 ZTX618STZ?
For technical support, including ZTX618STZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX618STZ requirements.
6.How does Aetrix verify that ZTX618STZ is sourced from the original manufacturer or authorized distributors?
All ZTX618STZ 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 ZTX618STZ meets industry standards.
7.What is the process for return or replacement of ZTX618STZ?
All ZTX618STZ units undergo pre-shipment inspection (PSI). If there is an issue with ZTX618STZ, 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 ZTX618STZ part is unused and in its original packaging.
Return procedure for ZTX618STZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ZTX618STZ Tags
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