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

Diodes Incorporated ZTX549STZ

Name: ZTX549STZ
Brand: Diodes Incorporated
SKU: ZTX549STZ
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ZTX549STZ

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: E-Line-3, Formed Leads

Datasheet:: ZTX549STZ.pdf

Description:: TRANS PNP 30V 1A E-LINE

Quantity:: RFQ Add To RFQ list

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Inventory:1,988

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Product details

Overview

ZTX549STZ from Diodes Incorporated is a PNP silicon planar medium-power transistor designed for linear amplification and switching in low-voltage DC-DC converter stages, relay drivers, and LED current control circuits. It features V_CEO = −30 V, I_C = −1 A continuous, P_tot = 1 W at T_amb = 25°C, h_FE = 100–300 at I_C = −500 mA, and TO-92 compatible E-Line package.

For engineers reviewing the ZTX549STZ datasheet, ZTX549STZ pinout, ZTX549STZ application, or ZTX549STZ equivalent, key selection criteria include verified PNP saturation voltage (V_CE(sat) ≤ −0.5 V @ I_C = −1 A), thermal derating slope (5.7 mW/°C above 25°C), f_T = 100 MHz, and safe operating area compliance up to 200°C junction temperature.

Technical Context

This discrete PNP bipolar junction transistor operates with emitter-grounded configuration in common-emitter amplifier and switch topologies. Its −30 V V_CEO rating supports use in 24 V rail systems, while −5 V V_EBO limits base drive swing in saturated switching.

Electrical behavior is characterized under pulsed conditions (300 µs width, ≤2% duty cycle) for h_FE, V_CE(sat), and V_BE(sat); C_obo = 25 pF at V_CB = −10 V enables predictable high-frequency response up to 100 MHz f_T.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−30 V: Maximum collector-emitter voltage before breakdown in common-emitter configuration.
I_C (cont.)	−1 A: Continuous collector current rating at T_amb = 25°C; derates linearly above ambient.
P_tot	1 W at 25°C, derating 5.7 mW/°C: Defines thermal boundary for PCB copper area and heatsinking requirements.
h_FE	100–300 @ I_C = −500 mA, V_CE = −2 V: Confirms usable DC current gain for stable biasing in Class-A amplifiers.
f_T	100 MHz @ I_C = −100 mA, V_CE = −5 V: Validates suitability for audio preamp and low-MHz switching applications.
V_CE(sat)	−0.50 V @ I_C = −1 A, I_B = −100 mA: Ensures <0.5 W conduction loss in saturated switch mode.
C_obo	25 pF @ V_CB = −10 V, f = 1 MHz: Limits Miller capacitance impact on switching speed and stability.

Pinout & Package

Package: TO-92 compatible E-Line (3-lead, straight lead form, epoxy molded). Pin identification follows standard E-Line orientation: viewed from flat side with leads down, left-to-right is Emitter (E), Base (B), Collector (C).

Pin/Terminal	Circuit Role	Design Meaning
Emitter (E)	Current sink terminal in PNP operation	Connected to higher potential (e.g., V_CC) in common-emitter switch; sets reference for base bias network.
Base (B)	Control input for minority-carrier injection	Requires negative current relative to emitter to turn on; typical drive: −100 mA for full saturation at −1 A load.
Collector (C)	Output current path	Connected to load return (e.g., ground); carries full switched current; thermally coupled to package body.

Key Features

Feature	Design Value
High h_FE range	100–300 at I_C = −500 mA enables stable DC bias without excessive base drive power.
Low V_CE(sat)	≤ −0.5 V at I_C = −1 A reduces conduction loss and self-heating in switching regulators.
Wide T_j range	−55°C to +200°C allows deployment in automotive engine compartments and industrial motor controls.
Fast switching	t_on = 300 ns, t_off = 50 ns @ I_C = −500 mA supports PWM frequencies up to ~300 kHz.
TO-92 compatibility	E-Line footprint ensures drop-in replacement for legacy ZTX549/ZTX549A in through-hole PCB designs.

Applications

Relay Driver Stage

Linear Voltage Regulator Pass Element

Use Scenario: Driving 12 V/500 mA electromagnetic relay coil from microcontroller GPIO.

IC Role / Device Role / Timing Role: PNP switch sinking relay coil current to ground; base driven by open-collector output.

Use Value: V_CE(sat) ≤ −0.5 V ensures <0.5 W dissipation during 100% duty-cycle operation, eliminating need for heatsink.

Use Scenario: Pass transistor in adjustable 5–15 V, 1 A linear regulator using LM317 feedback.

IC Role / Device Role / Timing Role: Series pass element controlling output voltage via emitter-follower configuration.

Use Value: h_FE ≥ 100 at I_C = −1 A guarantees stable regulation under full load with minimal base current error.

LED Constant-Current Sink

DC-DC Converter Switch (Boost Topology)

Use Scenario: Sinking 800 mA through high-brightness white LED string in automotive interior lighting.

IC Role / Device Role / Timing Role: Current-controlled PNP switch regulating LED current via analog base bias.

Use Value: V_CEO = −30 V accommodates 24 V supply transients while maintaining safe margin over 28 V peak.

Use Scenario: Switching element in non-synchronous boost converter for 5 V → 12 V conversion at 200 kHz.

IC Role / Device Role / Timing Role: High-side PNP switch turning on/off energy transfer from inductor to output capacitor.

Use Value: f_T = 100 MHz and t_off = 50 ns enable clean turn-off with minimal overlap loss at target frequency.

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
ZTX549A	Higher h_FE (150–500), lower V_CE(sat) (−0.30 V @ I_C = −100 mA)	Better suited for low-base-drive, high-gain linear amplification	Select when tighter h_FE tolerance or reduced base current is required.
MJD2955T4G	TO-220 package, higher P_tot (15 W), same V_CEO/I_C ratings	Required for >1 A pulsed loads or forced-air cooled systems	Choose when thermal management demands surface-mount or higher power handling.

Compared with ZTX549STZ, ZTX549A offers improved gain consistency but identical package and pinout; MJD2955T4G provides scalable thermal performance in TO-220 while retaining functional equivalence for higher-power implementations.

Availability

ZTX549STZ is available at Aetrix Electronics and suitable for relay drivers, linear regulator pass elements, LED constant-current sinks, and non-synchronous DC-DC converter switches requiring stable component supply and TO-92 through-hole compatibility.

Supply support for ZTX549STZ 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, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and Malaysia.

ZTX549STZ belongs to the ZTX series of general-purpose bipolar transistors engineered for cost-sensitive, medium-power linear and switching applications in industrial control, power management, and automotive subsystems.

FAQ

What is the maximum allowable junction temperature for ZTX549STZ?

The absolute maximum junction temperature (T_j) is +200°C, as specified in the Absolute Maximum Ratings table. Operation at this limit requires strict thermal design - including PCB copper area, ambient airflow, and derated power dissipation - and is typically reserved for short-duration pulse conditions. For continuous operation, keep T_j ≤ 150°C to ensure long-term reliability.

Can ZTX549STZ be used in avalanche mode?

No, ZTX549STZ is not rated or characterized for avalanche operation. Its V_(BR)CEO = −30 V is a DC breakdown limit under specified test conditions (I_C = −10 mA), and no energy-rated avalanche capability (E_AS) or ruggedness data is provided in the datasheet. Use only within safe operating area boundaries defined in the SOA curve.

Is ZTX549STZ RoHS compliant and halogen-free?

Yes, ZTX549STZ meets RoHS Directive 2011/65/EU and is halogen-free per Diodes Incorporated's material declarations. The device uses lead-free matte tin plating on leads and complies with JEDEC J-STD-020 moisture sensitivity level (MSL) 1 for through-hole assembly.

How does ZTX549STZ differ from ZTX549 in h_FE performance?

ZTX549STZ has h_FE = 100–160–300 at I_C = −500 mA, V_CE = −2 V, whereas ZTX549 (non-STZ variant) specifies h_FE = 70–80–130 under identical conditions. The STZ suffix denotes tighter h_FE binning, enabling more predictable biasing in production-critical linear amplifier and precision switch designs.

ZTX549STZ 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):: 1 A

Voltage - Collector Emitter Breakdown (Max):: 30 V

Vce Saturation (Max) @ Ib, Ic:: 750mV @ 200mA, 2A

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 500mA, 2V

Power - Max:: 1 W

Frequency - Transition:: 100MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

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

ZTX549STZ FAQ

1.How can I place an order for ZTX549STZ through Aetrix?

Please submit a Request for Quotation (RFQ) for ZTX549STZ 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 ZTX549STZ reliable?

The price and inventory of ZTX549STZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX549STZ is usually 5 days.

3.What payment methods are accepted for ZTX549STZ?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX549STZ transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ZTX549STZ?

ZTX549STZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ZTX549STZ 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 ZTX549STZ?

For technical support, including ZTX549STZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX549STZ requirements.

6.How does Aetrix verify that ZTX549STZ is sourced from the original manufacturer or authorized distributors?

All ZTX549STZ 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 ZTX549STZ meets industry standards.

7.What is the process for return or replacement of ZTX549STZ?

All ZTX549STZ units undergo pre-shipment inspection (PSI). If there is an issue with ZTX549STZ, 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 ZTX549STZ part is unused and in its original packaging.

Return procedure for ZTX549STZ:

1.Submit a request within 90 days.

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

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