Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

Diodes Incorporated ZTX1055A

Name: ZTX1055A
Brand: Diodes Incorporated
SKU: ZTX1055A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: ZTX1055A

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: E-Line-3

Datasheet:: ZTX1055A.pdf

Description:: TRANS NPN 120V 3A E-LINE

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:6,310

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

ZTX1055A from Diodes Incorporated (formerly Zetex) is an NPN silicon planar medium-power high-gain transistor in TO-92 package, rated for 120 V V_CEO, 3 A continuous collector current, and 6 A pulse current, with V_CE(sat) as low as 22 mV at I_C=0.1 A/I_B=5 mA - used in automotive switching circuits and audio driver stages.

For engineers reviewing the ZTX1055A datasheet, ZTX1055A pinout, ZTX1055A application, or ZTX1055A equivalent, key selection criteria include V_CEO ≥120 V, h_FE ≥275 at I_C=10 mA, f_T = 130 MHz, safe operating area up to +200°C junction temperature, and TO-92 mechanical compatibility with legacy E-line designs.

Technical Context

This NPN transistor employs a planar silicon structure optimized for medium-power linear and switching operation. Its high h_FE (up to 1200 at I_C=6 A) supports low-base-drive designs, while the 130 MHz f_T enables use in audio-frequency amplification and fast-switching applications up to ~50 kHz duty-cycled loads.

The device features low saturation voltage (22–310 mV across I_C = 0.1–3 A), enabling efficient power control in thermally constrained environments. Its −55°C to +200°C operating range and 1 W P_tot at T_amb=25°C support ruggedized automotive and industrial implementations without forced cooling.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	120 V - supports switching of 24–48 V automotive bus rails with margin against transients
I_C (continuous)	3 A - delivers sufficient drive for solenoids, relays, and Class-AB audio output stages
f_T	130 MHz - enables stable gain in audio preamp and wideband signal conditioning up to 20 kHz
h_FE (min)	275 @ I_C=10 mA - ensures reliable turn-on with microcontroller GPIO-level base drive
V_CE(sat)	22 mV @ I_C=0.1 A/I_B=5 mA - minimizes conduction loss in low-voltage logic-level switching
T_j max	+200°C - allows operation in engine bay or sealed industrial enclosures without derating
C_obo	17–30 pF @ V_CB=10 V - limits high-frequency Miller feedback in switching nodes

Pinout & Package

TO-92 package (E-Line compatible), 3-pin through-hole plastic case with standard C-B-E lead configuration (viewed from flat side, leads down: left-to-right = Collector–Base–Emitter).

Pin/Terminal	Circuit Role	Design Meaning
Collector (C)	Main current sink terminal	Connected to load return path; handles full switched current up to 6 A pulsed
Base (B)	Control input node	Receives current-limited drive (≤500 mA) to bias transistor into active/saturation region
Emitter (E)	Current source reference	Typically grounded or tied to low-impedance return; carries full I_C + I_B

Key Features

Feature	Design Value
High DC current gain	h_FE ≥275 at I_C=10 mA - reduces required base drive current by >3× vs. standard general-purpose transistors
Low saturation voltage	V_CE(sat) ≤120 mV @ I_C=1 A - cuts conduction loss by >50% compared to typical 2N2222-class devices
Extended temperature range	−55°C to +200°C operation - eliminates need for external thermal protection in under-hood automotive modules
Fast switching	t_on = 90 ns, t_off = 2400 ns - supports PWM frequencies up to 5–10 kHz with minimal dead-time overhead
Robust breakdown ratings	V_CBO = 175 V, V_CEO = 120 V - withstands ISO 7637-2 Load Dump transients in 12 V systems

Applications

Automotive Relay Driver

Audio Output Stage

Use Scenario: Driving 12 V/2 A automotive relay coil in body control module with MCU GPIO control.

IC Role / Device Role / Timing Role: Medium-power NPN switch providing galvanic isolation and current amplification between low-current MCU output and inductive load.

Use Value: V_CE(sat) ≤120 mV at I_C=1 A ensures <120 mW dissipation, eliminating heatsink requirement in compact PCB layout.

Use Scenario: Complementary emitter-follower output stage in portable audio amplifier feeding 8 Ω speaker.

IC Role / Device Role / Timing Role: Linear current buffer delivering peak 1.5 A transient current while maintaining low THD via high h_FE linearity.

Use Value: f_T = 130 MHz and low C_obo preserve bandwidth beyond 20 kHz, supporting full-range audio fidelity.

Industrial Solenoid Controller

DC Motor Speed Regulator

Use Scenario: Controlling 24 V/1.8 A solenoid valve in pneumatic control panel with PWM-based position modulation.

IC Role / Device Role / Timing Role: High-current saturated switch modulating average coil current via 1–5 kHz PWM.

Use Value: 6 A pulse rating and 200°C T_j max allow sustained 100% duty-cycle bursts during valve actuation without thermal shutdown.

Use Scenario: H-bridge half-bridge leg in 36 V brushed DC motor controller for warehouse automation cart.

IC Role / Device Role / Timing Role: Low-V_CE(sat) switching element minimizing I²R losses during bidirectional commutation.

Use Value: V_CE(sat) ≤220 mV at I_C=3 A limits conduction loss to <660 mW, enabling TO-92 mounting on standard FR-4 without copper pour.

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
ZTX1048A	V_CEO = 80 V, h_FE = 150–800, P_tot = 1 W	Lower voltage rating limits use to ≤24 V systems; reduced gain requires higher base drive	Select only when V_CEO margin <40 V suffices and cost is primary constraint
MJD122G	TO-220 package, V_CEO = 100 V, I_C = 5 A, P_tot = 20 W	Requires heatsink and PCB real estate; unsuitable for space-constrained TO-92 footprints	Choose for higher continuous current (>3 A) or elevated ambient temperature (>85°C)

Compared with ZTX1055A, ZTX1048A trades voltage headroom and gain for lower cost, while MJD122G provides higher power handling at the expense of board space and thermal design complexity - neither is pin-compatible, requiring layout revision.

Availability

ZTX1055A is available at Aetrix Electronics and suitable for automotive relay drivers, audio output stages, industrial solenoid controllers, and DC motor speed regulators requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ZTX1055A 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, integrating its high-performance analog and discrete portfolio into a global semiconductor supplier focused on reliability-critical applications.

The ZTX series was developed by Zetex specifically for demanding medium-power linear and switching roles in automotive and industrial environments where high gain, low saturation, and extended temperature capability are essential.

FAQ

Is ZTX1055A RoHS compliant?

Yes, ZTX1055A meets RoHS Directive 2011/65/EU requirements. Diodes Incorporated confirms lead-free termination (Pb-free) and halogen-free packaging per specification ZTX1055A-01, with full material declarations available upon request for qualified customers.

Can ZTX1055A replace BC337 in existing designs?

ZTX1055A offers significantly higher V_CEO (120 V vs. 45 V), I_C (3 A vs. 0.8 A), and h_FE (275 min vs. 100 min), but shares identical TO-92 footprint and C-B-E pinout. Direct replacement is electrically valid if voltage/current demands exceed BC337 limits and thermal margins are verified.

What is the maximum safe base current for continuous operation?

The absolute maximum base current is 500 mA, but continuous operation above 150 mA is not recommended without thermal analysis. At I_C=3 A, typical I_B=150 mA yields V_BE(sat)=950 mV and maintains safe junction temperature within 1 W P_tot limit at 25°C ambient.

Does ZTX1055A have SPICE model support?

Yes, an official PSpice-compatible model is provided in the original Zetex datasheet (Issue 3, Jan 1995), including parameters for IS, BF, VAF, CJC, CJE, TF, and TR. Diodes Incorporated hosts updated behavioral models on its product page for ZTX1055A under "Design Resources".

ZTX1055A Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: E-Line-3

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 3 A

Voltage - Collector Emitter Breakdown (Max):: 120 V

Vce Saturation (Max) @ Ib, Ic:: 310mV @ 150mA, 3A

Current - Collector Cutoff (Max):: 10nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 300 @ 1A, 10V

Power - Max:: 1 W

Frequency - Transition:: 130MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

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

ZTX1055A FAQ

1.How can I place an order for ZTX1055A through Aetrix?

Please submit a Request for Quotation (RFQ) for ZTX1055A 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 ZTX1055A reliable?

The price and inventory of ZTX1055A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX1055A is usually 5 days.

3.What payment methods are accepted for ZTX1055A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX1055A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ZTX1055A?

ZTX1055A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ZTX1055A 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 ZTX1055A?

For technical support, including ZTX1055A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX1055A requirements.

6.How does Aetrix verify that ZTX1055A is sourced from the original manufacturer or authorized distributors?

All ZTX1055A 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 ZTX1055A meets industry standards.

7.What is the process for return or replacement of ZTX1055A?

All ZTX1055A units undergo pre-shipment inspection (PSI). If there is an issue with ZTX1055A, 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 ZTX1055A part is unused and in its original packaging.

Return procedure for ZTX1055A:

1.Submit a request within 90 days.

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

Tech Hub

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…

2026-08-14 Jumper Cables: How to Use, Connect and Choose Them Safely

Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…

2026-08-11 LDO Regulator: Dropout Voltage, Noise, PSRR and Power Dissipation

LDO regulator guide covering low dropout voltage, power dissipation, thermal design, PSRR, output noise, capacitor stability, adjustable LDO circuits, LDO vs buck converter and datasheet selection chec…

2026-08-06 Conditional Access Module: CAM, CI/CI+ and DVB Security

Conditional Access Module guide covering CAM meaning, CI/CI+ interface, smart card authorization, DVB security workflow, TV and set-top box compatibility, internal electronics, ESD protection, connecto…

2026-08-03 Electronic Component Obsolescence: EOL Risks, Replacement Options and Last-Time Buy Strategy

Guide to electronic component obsolescence covering EOL risk, PCN/PDN notices, last-time buy planning, replacement options, form-fit-function validation, counterfeit risk and BOM lifecycle management.

2026-07-29 18650 Battery: Voltage, Capacity, Charging and Pack Design

18650 battery guide covering lithium-ion cell basics, 3.6V/3.7V voltage, 4.2V charging, mAh and Wh capacity, protected cells, chargers, BMS, series-parallel packs, holders, welding and sourcing checks.…

2026-07-27 Hall Effect Sensor: Working Principle, Types, Circuits and Applications

Hall effect sensor guide covering working principle, linear and digital sensors, Arduino circuits, current sensing, speed detection, automotive applications, A3144 examples, signal filtering and datash…

2026-07-20 Product Change Notification (PCN) in Electronic Components: Meaning and Supply Chain Response

Product Change Notification guide for electronic components, covering PCN meaning, PCN vs PDN/EOL, common change types, risk levels, form-fit-function review, engineering validation, BOM control, LTB/L…

2026-07-19 Blend Door Actuator: Symptoms, Location, Reset and Replacement Guide

A practical guide to blend door actuators, covering HVAC function, symptoms, location, AC and heater issues, reset and calibration, replacement cost, electrical diagnosis, compatibility checks, and rep…