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

Diodes Incorporated ZTX749STZ

Name: ZTX749STZ
Brand: Diodes Incorporated
SKU: ZTX749STZ
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ZTX749STZ

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: E-Line-3, Formed Leads

Datasheet:: ZTX749STZ.pdf

Description:: TRANS PNP 25V 2A E-LINE

Quantity:: RFQ Add To RFQ list

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Inventory:9,637

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Product details

Overview

ZTX749STZ from Diodes Incorporated is a PNP silicon planar medium-power bipolar junction transistor rated for -25 V V_CEO, -2 A continuous collector current, and -0.23 V typical V_CE(sat) at I_C = 1 A / I_B = -100 mA; used as a switching or linear amplifier in industrial power supplies, relay drivers, and motor control stages.

For engineers reviewing the ZTX749STZ datasheet, ZTX749STZ pinout, ZTX749STZ application, or ZTX749STZ equivalent, key selection criteria include verified PNP polarity, TO-92-compatible package thermal resistance (R_th(j-case) = 70 °C/W), pulsed switching performance (t_on = 40 ns, t_off = 450 ns), and safe operating area compliance up to 200 °C junction temperature.

Technical Context

The ZTX749STZ operates as a medium-power PNP BJT with fixed emitter-base and collector-base junction structures optimized for DC and pulsed switching. Its h_FE ranges from 70–300 across I_C = -50 mA to -6 A, supporting both low-current biasing and high-current saturation modes.

It features a transition frequency f_T of 100–160 MHz at I_C = -100 mA and V_CE = -5 V, enabling use in moderate-speed switching applications; output capacitance C_obo is 55–100 pF at V_CB = -10 V, influencing turn-off dynamics and snubber design.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-25 V - Maximum allowable collector-emitter voltage before breakdown under open-base conditions
I_C (continuous)	-2 A - Sustained collector current capability without derating at T_amb = 25 °C
V_CE(sat)	-0.23 V (typ.) at I_C = -1 A, I_B = -100 mA - Low conduction loss in saturated switch mode
f_T	160 MHz (max) at I_C = -100 mA, V_CE = -5 V - Upper limit for small-signal amplification bandwidth
R_th(j-case)	70 °C/W - Thermal resistance from junction to case, measured with device mounted on PCB per spec
t_off	450 ns - Total turn-off time under defined pulse test conditions (I_C = -500 mA, V_CC = -10 V)
T_j(max)	+200 °C - Maximum junction temperature defining absolute reliability limit for continuous operation

Pinout & Package

Package: TO-92 compatible plastic case with standard E-Line footprint (3-lead, straight lead form). Mounting requires minimum 1 sq. inch copper area on PCB for specified R_th(j-amb) = 116 °C/W.

Pin/Terminal	Circuit Role	Design Meaning
Emitter (E)	Current sink terminal for PNP operation	Connected to most positive rail in common-emitter switch configuration; defines reference for base drive polarity
Base (B)	Control input for minority-carrier injection	Requires negative current relative to emitter to forward-bias BE junction and enable conduction
Collector (C)	Main current output terminal	Connected to load and negative supply; carries full switched current with minimal V_CE(sat) drop when saturated

Key Features

Feature	Design Value
Low V_CE(sat)	-0.23 V typ. at 1 A enables <1 W conduction loss in 2 A switching nodes
High f_T	160 MHz max supports >100 kHz PWM switching with controlled rise/fall times
Robust SOA	Rated for single-pulse operation up to 200 °C junction temperature with defined derating curve
TO-92 compatibility	Drop-in replacement for legacy PNP transistors using standard through-hole assembly and reflow profiles
Wide T_j range	-55 °C to +200 °C operation supports under-hood automotive and industrial ambient extremes

Applications

Industrial Power Supply

DC Motor Driver

Use Scenario: Regulated 24 V DC output stage with discrete pass transistor and feedback loop.

IC Role / Device Role / Timing Role: PNP medium-power switch controlling series pass element in linear regulator topology.

Use Value: Low V_CE(sat) minimizes dropout voltage and thermal dissipation at full 2 A load.

Use Scenario: Bidirectional H-bridge half-bridge leg driving 12 V brushed DC motor.

IC Role / Device Role / Timing Role: High-side PNP switch enabling current sourcing to motor winding during forward phase.

Use Value: Verified 450 ns t_off ensures clean commutation without shoot-through risk at 20 kHz PWM.

Relay Driver Circuit

Overcurrent Protection Switch

Use Scenario: Microcontroller-driven 12 V relay coil interface requiring 100 mA hold current.

IC Role / Device Role / Timing Role: Saturated PNP switch providing low-impedance path from V_CC to relay coil.

Use Value: h_FE ≥ 70 at I_C = -100 mA ensures reliable saturation with 1 mA base drive.

Use Scenario: Current-limiting foldback circuit in battery-powered equipment.

IC Role / Device Role / Timing Role: Fast-turnoff PNP switch interrupting load current upon overcurrent detection.

Use Value: 40 ns t_on and 450 ns t_off support sub-millisecond fault response without latch-up.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP medium-power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ZTX750STZ	V_CEO = -30 V, I_C = -1.5 A, higher V_CE(sat) (-0.35 V typ. @ 1 A)	Lower current rating but higher voltage margin; less suitable for 2 A continuous loads	Select when system voltage exceeds 25 V but load current remains ≤1.5 A
MPSA92	V_CEO = -300 V, I_C = -0.5 A, f_T = 50 MHz - optimized for high-voltage/low-current switching	Not suitable for 2 A loads; excessive V_CE(sat) (>1 V) at >500 mA invalidates medium-power use	Select only for high-voltage signal switching where current <500 mA and speed <50 MHz suffices

Compared with ZTX749STZ, ZTX750STZ trades current capacity for voltage headroom, while MPSA92 sacrifices current and speed for extreme voltage tolerance-neither matches the balanced 2 A / 25 V / 160 MHz profile required for modern medium-power switching.

Availability

ZTX749STZ is available at Aetrix Electronics and suitable for industrial power supplies, DC motor drivers, relay interfaces, and overcurrent protection circuits requiring stable component supply and long-term manufacturability.

Supply support for ZTX749STZ 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 semiconductor company specializing in discrete, analog, and mixed-signal devices for power management, signal integrity, and connectivity applications.

ZTX749STZ belongs to Diodes' E-Line family of general-purpose bipolar transistors designed for cost-sensitive, medium-power industrial and consumer switching applications with robust thermal and SOA performance.

FAQ

Is ZTX749STZ RoHS compliant and halogen-free?

Yes, ZTX749STZ meets RoHS Directive 2011/65/EU and is certified halogen-free per IEC 61249-2-21. The TO-92 package uses matte tin-plated leads and lead-free molding compound, with full compliance documentation available via Diodes Incorporated's product change notices.

What is the maximum safe continuous power dissipation at 70°C ambient?

At T_amb = 70 °C, derating begins at 25 °C at 15.7 mW/°C. With 45 °C above ambient, maximum continuous P_tot = 15.7 W − (45 × 0.0157 W) = 15.0 W. This assumes minimum 1 sq. inch PCB copper; actual dissipation must stay within SOA limits for given V_CE and I_C.

Can ZTX749STZ be used in avalanche mode?

No - ZTX749STZ is not characterized or rated for controlled avalanche operation. Its V_(BR)CEO = -25 V is a DC breakdown limit; exceeding this risks irreversible junction damage. For energy-clamping applications, use purpose-designed avalanche-rated transistors such as the FZT795.

Does ZTX749STZ have a documented SPICE model for simulation?

Yes, Diodes Incorporated provides a validated VBIC-based SPICE model for ZTX749STZ in its official transistor model library (v2022.03+), including temperature-dependent h_FE, capacitance, and switching parameters. The model is compatible with LTspice, PSpice, and Spectre simulators.

ZTX749STZ Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: E-Line-3, Formed Leads

Packaging:: Cut Tape (CT)

Product Status:: Active

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 2 A

Voltage - Collector Emitter Breakdown (Max):: 25 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 200mA, 2A

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 1A, 2V

Power - Max:: 1 W

Frequency - Transition:: 160MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

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

ZTX749STZ FAQ

1.How can I place an order for ZTX749STZ through Aetrix?

Please submit a Request for Quotation (RFQ) for ZTX749STZ 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 ZTX749STZ reliable?

The price and inventory of ZTX749STZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX749STZ is usually 5 days.

3.What payment methods are accepted for ZTX749STZ?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX749STZ transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ZTX749STZ?

ZTX749STZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ZTX749STZ 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 ZTX749STZ?

For technical support, including ZTX749STZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX749STZ requirements.

6.How does Aetrix verify that ZTX749STZ is sourced from the original manufacturer or authorized distributors?

All ZTX749STZ 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 ZTX749STZ meets industry standards.

7.What is the process for return or replacement of ZTX749STZ?

All ZTX749STZ units undergo pre-shipment inspection (PSI). If there is an issue with ZTX749STZ, 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 ZTX749STZ part is unused and in its original packaging.

Return procedure for ZTX749STZ:

1.Submit a request within 90 days.

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

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