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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

Diodes Incorporated ZTX855

Name: ZTX855
Brand: Diodes Incorporated
SKU: ZTX855
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ZTX855

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: E-Line-3

Datasheet:: ZTX855.pdf

Description:: TRANS NPN 150V 4A E-LINE

Quantity:: RFQ Add To RFQ list

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Inventory:2,771

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Product details

Overview

ZTX855 from Diodes Incorporated is a 150V NPN medium-power bipolar junction transistor in E-Line (TO-92 compatible) package, rated for 4A continuous collector current and 10A peak pulse current, with low V_CE(sat) of 210mV at 4A/400mA drive, operating up to +200°C junction temperature, and qualified to AEC-Q101 for automotive power control applications.

For engineers reviewing the ZTX855 datasheet, ZTX855 pinout, ZTX855 application, or ZTX855 equivalent, key selection considerations include its 150V V_CEO, 1.2W power dissipation on standard PCB layout, complementary pairing with ZTX955, and suitability for high-temperature switching in industrial motor drivers and automotive lighting ballasts.

Technical Context

This NPN transistor features a rugged silicon die optimized for high-voltage switching with BV_CEO = 150V and BV_CBO = 250V, enabling reliable operation in inductive load circuits where voltage spikes exceed 100V. Its f_T = 90MHz supports fast switching transitions with t_on/t_off of 66ns/2130ns under 1A/50V conditions.

Thermal design is supported by R_ΘJC = 50°C/W and R_ΘJA = 110°C/W (min pad layout), allowing stable 4A DC operation at ambient temperatures up to +85°C when mounted per JEDEC guidelines. The device uses matte tin-plated leads compliant with MIL-STD-202, Method 208.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	150 V - Maximum safe collector-emitter voltage before breakdown in common-emitter configuration
I_C (continuous)	4 A - Sustained collector current capability without thermal derating at T_A ≤ +85°C
V_CE(sat)	210 mV @ 4A/400mA - Low saturation voltage enables <0.84W conduction loss at full rated current
P_D	1.2 W - Power dissipation limit on minimum recommended PCB pad layout at +25°C ambient
f_T	90 MHz - Current gain-bandwidth product confirming suitability for audio-frequency and SMPS switching
T_J max	+200°C - Maximum junction temperature rating supporting operation in engine bay or industrial enclosures
h_FE	35–300 - DC current gain range across 10mA–10A, enabling flexible base drive design

Pinout & Package

E-Line (TO-92 compatible) package with molded green plastic case, UL 94V-0 flammability rating, 0.159g weight, and matte tin-plated leads solderable per MIL-STD-202, Method 208.

Pin/Terminal	Circuit Role	Design Meaning
Emitter (E)	Current sink terminal	Low-impedance return path; connected to ground or low-side reference in switch configurations
Base (B)	Control input	Receives forward-biased current to saturate transistor; requires ~400mA for full 4A conduction
Collector (C)	High-side current source	Connected to load and supply rail; handles full switched current and voltage transients

Key Features

Feature	Design Value
AEC-Q101 qualification	Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD (HBM ≥4kV)
High-temperature operation	Junction rated to +200°C, enabling use in under-hood or sealed industrial environments without derating
Low saturation voltage	V_CE(sat) ≤210mV at 4A ensures <1W conduction loss, reducing heatsink requirements
Complementary pairing	ZTX955 PNP counterpart allows matched push-pull or H-bridge designs with consistent thermal behavior
Halogen & antimony free	Meets "Green" definition: Br+Cl <1500ppm, Sb <1000ppm - supports RoHS-compliant manufacturing

Applications

Automotive LED Headlamp Driver

Industrial AC Motor Starter

Use Scenario: Switching 12–24V LED arrays drawing up to 3.5A in adaptive front-lighting systems.

IC Role / Device Role / Timing Role: High-side NPN switch controlling current path to LED string during PWM dimming cycles.

Use Value: 150V V_CEO withstands load-dump transients; 210mV V_CE(sat) limits thermal rise in compact headlamp housings.

Use Scenario: Driving contactor coils and small induction motors in HVAC and pump control panels.

IC Role / Device Role / Timing Role: Medium-power interface transistor amplifying microcontroller GPIO signals to energize 24V/2A solenoid loads.

Use Value: 4A I_C and +200°C T_J ensure robustness against coil back-EMF and enclosure temperature extremes.

DC-DC Converter Primary Switch

High-Voltage Relay Driver

Use Scenario: Low-frequency (≤100kHz) primary-side switch in isolated flyback converters for industrial power supplies.

IC Role / Device Role / Timing Role: Hard-switched NPN transistor handling 100V+ drain-source equivalents in self-oscillating topologies.

Use Value: BV_CBO = 250V and t_off = 2130ns accommodate slow snubber recovery while maintaining efficiency.

Use Scenario: Driving 48V/1A electromagnetic relays in telecom and railway signaling interfaces.

IC Role / Device Role / Timing Role: High-voltage buffer stage isolating logic-level control from relay coil inductance and arcing.

Use Value: 150V V_CEO and 10A I_CM safely absorb relay turn-off energy without clamping diode dependency.

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
ZTX851	Lower V_CEO (100V), same package and I_C (4A), higher V_CE(sat) (300mV @ 4A)	Not suitable for >100V bus applications; acceptable only in 24V/48V systems with tight voltage margins	Select only if cost sensitivity outweighs voltage headroom needs and thermal budget allows +0.4W extra loss
MJD127	Higher I_C (8A), TO-220 package, V_CEO = 100V, no AEC-Q101 qualification	Requires heatsink and larger board area; lacks automotive qualification and high-temperature rating	Prefer for non-automotive 48V industrial controls where footprint and qualification are secondary to current capacity

Compared with ZTX855, ZTX851 trades voltage margin for marginal cost reduction in low-voltage systems, while MJD127 offers higher current but sacrifices automotive compliance, thermal density, and board-space efficiency - making ZTX855 optimal for space-constrained, high-reliability 100–150V switching.

Availability

ZTX855 is available at Aetrix Electronics and suitable for automotive LED drivers, industrial motor starters, DC-DC converter switches, and high-voltage relay drivers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ZTX855 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, signal integrity, and protection solutions for automotive, industrial, and consumer markets.

The ZTX series targets medium-power bipolar switching applications demanding AEC-Q101 qualification, high-temperature operation, and TO-92-compatible packaging for legacy and space-constrained designs.

FAQ

What is the maximum continuous collector current for ZTX855 at +100°C ambient?

At +100°C ambient, ZTX855's continuous collector current is derated to approximately 2.4A based on its 1.2W power dissipation limit and R_ΘJA = 110°C/W. This assumes minimum recommended PCB pad layout and still-air conditions per Note 6 of the datasheet.

Is ZTX855 pin-compatible with standard TO-92 transistors?

Yes - ZTX855 uses the E-Line package, which is mechanically compatible with TO-92 but features joggled or straight leads depending on ordering code (ZTX855STZ vs. ZTX855). Pinout is E-B-C when viewed from flat face with marking, matching standard TO-92 orientation.

Does ZTX855 require an external flyback diode when switching inductive loads?

Yes - although ZTX855 has high V_CEO (150V), it lacks integrated clamp functionality. An external flyback diode (e.g., 1N4007) must be placed across the inductive load to suppress voltage spikes exceeding its breakdown rating during turn-off.

How does ZTX855's AEC-Q101 qualification differ from standard industrial grade?

ZTX855 undergoes accelerated stress testing per AEC-Q101, including HTGB, HTRB, and temperature cycling over -55°C to +150°C, plus ESD HBM ≥4kV - exceeding standard industrial qualification and validating suitability for automotive powertrain and body electronics.

ZTX855 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: E-Line-3

Packaging:: Bulk

Product Status:: Active

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 4 A

Voltage - Collector Emitter Breakdown (Max):: 150 V

Vce Saturation (Max) @ Ib, Ic:: 260mV @ 400mA, 4A

Current - Collector Cutoff (Max):: 50nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 1A, 5V

Power - Max:: 1.2 W

Frequency - Transition:: 90MHz

Operating Temperature:: -55°C ~ 200°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: E-Line (TO-92 compatible)

ZTX855 FAQ

1.How can I place an order for ZTX855 through Aetrix?

Please submit a Request for Quotation (RFQ) for ZTX855 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 ZTX855 reliable?

The price and inventory of ZTX855 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX855 is usually 5 days.

3.What payment methods are accepted for ZTX855?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX855 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ZTX855?

ZTX855 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ZTX855 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 ZTX855?

For technical support, including ZTX855 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX855 requirements.

6.How does Aetrix verify that ZTX855 is sourced from the original manufacturer or authorized distributors?

All ZTX855 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 ZTX855 meets industry standards.

7.What is the process for return or replacement of ZTX855?

All ZTX855 units undergo pre-shipment inspection (PSI). If there is an issue with ZTX855, 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 ZTX855 part is unused and in its original packaging.

Return procedure for ZTX855:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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