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

Diodes Incorporated ZTX649

Name: ZTX649
Brand: Diodes Incorporated
SKU: ZTX649
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ZTX649

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: E-Line-3

Datasheet:: ZTX649.pdf

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

Quantity:: RFQ Add To RFQ list

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Inventory:1,351

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Product details

Overview

ZTX649 from Diodes Incorporated is an NPN silicon planar medium-power transistor rated for 25 V V_CEO, 2 A continuous collector current, and 1 W power dissipation at 25°C ambient. It features low saturation voltage (V_CE(sat) = 0.23 V @ I_C = 1 A, I_B = 100 mA), high DC current gain (h_FE = 100 @ I_C = 50 mA), and 150 MHz transition frequency - optimized for motor driver and DC-DC converter switching stages.

For engineers reviewing the ZTX649 datasheet, ZTX649 pinout, ZTX649 application, or ZTX649 equivalent, key selection criteria include verified V_CEO/I_C derating behavior, measured switching times (t_on = 55 ns, t_off = 300 ns), thermal resistance to ambient (175 °C/W on PCB), and TO-92 package compatibility with E-Line footprint.

Technical Context

The ZTX649 operates as a general-purpose medium-power NPN switch with specified breakdown limits: V_(BR)CBO = 35 V, V_(BR)CEO = 25 V, and V_(BR)EBO = 5 V. Its h_FE spans 70–300 across I_C = 50 mA to 6 A, supporting both linear and saturated switching modes.

Switching performance is characterized under pulsed conditions (300 µs pulse width, ≤2% duty cycle), with C_obo = 25–50 pF at V_CB = 10 V and f = 1 MHz. Thermal design must account for R_th(j–amb) = 175 °C/W (free air) or 116 °C/W (1 in² copper PCB).

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	25 V - Maximum safe collector-emitter voltage before avalanche in common-emitter configuration
I_C (continuous)	2 A - Continuous DC collector current rating at T_amb = 25°C with appropriate heatsinking
V_CE(sat)	0.23 V @ I_C = 1 A, I_B = 100 mA - Low conduction loss enabling efficient switching in 12 V motor drivers
f_T	150 MHz - Sufficient for PWM frequencies up to ~10 MHz with stable gain margin
R_th(j–amb)	175 °C/W - Junction-to-ambient thermal resistance in free air; requires PCB copper area derating per datasheet curve
t_on/t_off	55 ns / 300 ns - Verified turn-on/turn-off times under 500 mA load, 10 V supply, and matched base drive
h_FE	100 @ I_C = 50 mA, V_CE = 2 V - Confirmed DC current gain for reliable base drive sizing in linear amplification

Pinout & Package

Package: TO-92 (E-Line compatible, 3-216 outline), plastic encapsulated, through-hole mounting. Standard lead form with emitter (E), base (B), and collector (C) arranged in linear order.

Pin/Terminal	Circuit Role	Design Meaning
E (Emitter)	Current sink terminal in common-emitter configuration	Connected to ground or low-side return path; sets reference for V_BE bias and current sensing
B (Base)	Control input for minority-carrier injection	Requires current-limited drive (e.g., 100 mA max for 1 A I_C) to ensure saturation without overdrive
C (Collector)	High-side current output node	Carries switched load current; thermally coupled to package body - critical for SOA compliance

Key Features

Feature	Design Value
Low V_CE(sat)	0.23 V @ I_C = 1 A - Reduces conduction loss by >40% vs. standard 2N2222A in 12 V motor H-bridge legs
High f_T	150 MHz - Enables clean square-wave switching at PWM frequencies up to 5 MHz without gain roll-off
Robust SOA	Rated for 2 A DC and 6 A pulsed (ICM) - supports short-circuit tolerant operation in brushed DC motor stall conditions
Thermal stability	T_j range –55°C to +200°C - Validated for under-hood automotive auxiliary loads and industrial control enclosures
TO-92 compatibility	E-Line 3-216 footprint - Direct replacement for legacy ZTX650/ZTX651 in existing PCB layouts without rework

Applications

Brushed DC Motor Driver

12 V DC-DC Buck Converter

Use Scenario: Driving 12 V, 1.5 A brushed DC fan in HVAC control module with PWM at 20 kHz.

IC Role / Device Role / Timing Role: NPN switch in low-side configuration, handling commutation current and reverse EMF clamping via external diode.

Use Value: V_CE(sat) = 0.23 V minimizes I²R loss (0.08 W at 1.5 A), reducing thermal stress on TO-92 package during continuous duty.

Use Scenario: High-efficiency synchronous buck converter output stage with 12 V input, 5 V/2 A output.

IC Role / Device Role / Timing Role: NPN switch controlling gate of P-channel MOSFET in active-clamp topology; driven by UC3843 controller.

Use Value: 55 ns t_on ensures precise timing alignment with controller clock, minimizing shoot-through risk during dead-time transitions.

Industrial Relay Driver

LED Constant-Current Sink

Use Scenario: Driving 24 V, 800 mA industrial relay coil in PLC I/O module with optocoupler-isolated base drive.

IC Role / Device Role / Timing Role: Medium-power interface transistor translating logic-level signals to relay coil current.

Use Value: h_FE ≥ 100 at I_C = 800 mA guarantees full saturation with ≤8 mA base current, easing microcontroller GPIO loading.

Use Scenario: Precision 350 mA LED current sink in architectural lighting driver with analog dimming.

IC Role / Device Role / Timing Role: Linear-mode current regulator using emitter degeneration resistor and V_BE reference.

Use Value: Tight V_BE(on) = 0.8–1.0 V @ I_C = 1 A enables ±3% current accuracy across temperature with minimal feedback complexity.

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
ZTX650	V_CEO = 60 V, I_C = 2 A, V_CE(sat) = 0.35 V @ 1 A - higher voltage rating but higher saturation loss	Better suited for 48 V industrial bus interfaces where 25 V margin is insufficient	Select when system V_CC exceeds 30 V and SOA at elevated V_CE is critical
BCX56-10	V_CEO = 80 V, I_C = 1 A, h_FE = 63–160 - lower current rating, tighter h_FE spread	Preferred in space-constrained consumer electronics where 1 A load is sufficient and 80 V headroom is needed	Choose for cost-sensitive designs with <1 A peak current and no thermal derating constraints

Compared with ZTX650 and BCX56-10, the ZTX649 delivers optimal balance of low V_CE(sat), 2 A capability, and TO-92 thermal performance - making it preferred for 12–24 V motor and power conversion where efficiency and board-level heat management are prioritized.

Availability

ZTX649 is available at Aetrix Electronics and suitable for motor driver circuits, DC-DC converters, relay interface modules, and LED current regulation requiring stable component supply and long-term manufacturability.

Supply support for ZTX649 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.

The ZTX649 belongs to Diodes' legacy bipolar transistor product line, engineered for robustness and consistency in industrial control, automotive auxiliary systems, and power conversion where reliability under thermal and electrical stress is essential.

FAQ

What is the maximum safe operating temperature for the ZTX649 junction?

The ZTX649 has a specified junction temperature range of –55°C to +200°C. Operation above +150°C requires verification of SOA derating and thermal interface integrity. The device remains functional up to +200°C but exhibits reduced h_FE and increased leakage beyond +175°C.

Can the ZTX649 be used in linear amplifier configurations?

Yes - its h_FE of 70–300 across I_C = 50 mA to 2 A and low V_CE(sat) support Class-A and AB amplifier topologies. However, power dissipation must stay within 1 W at 25°C ambient, with strict thermal management due to R_th(j–amb) = 175 °C/W in free air.

Is the ZTX649 RoHS compliant and halogen-free?

Yes - Diodes Incorporated certifies the ZTX649 as RoHS compliant (2011/65/EU) and halogen-free per IEC 61249-2-21. The TO-92 package uses lead-free matte tin plating and meets JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1) requirements.

How does the ZTX649's Safe Operating Area compare to the 2N2222A?

The ZTX649 offers significantly wider SOA than the 2N2222A: 2 A DC vs. 0.8 A, 6 A pulsed vs. 1.6 A, and 1 W power dissipation vs. 0.5 W. Its higher V_CEO (25 V vs. 40 V) is offset by superior thermal resistance and lower V_CE(sat), making it more suitable for sustained medium-power switching.

ZTX649 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):: 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:: 240MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

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

ZTX649 FAQ

1.How can I place an order for ZTX649 through Aetrix?

Please submit a Request for Quotation (RFQ) for ZTX649 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 ZTX649 reliable?

The price and inventory of ZTX649 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX649 is usually 5 days.

3.What payment methods are accepted for ZTX649?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX649 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ZTX649?

ZTX649 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ZTX649 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 ZTX649?

For technical support, including ZTX649 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX649 requirements.

6.How does Aetrix verify that ZTX649 is sourced from the original manufacturer or authorized distributors?

All ZTX649 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 ZTX649 meets industry standards.

7.What is the process for return or replacement of ZTX649?

All ZTX649 units undergo pre-shipment inspection (PSI). If there is an issue with ZTX649, 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 ZTX649 part is unused and in its original packaging.

Return procedure for ZTX649:

1.Submit a request within 90 days.

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

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