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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single, Pre-Biased Bipolar Transistors

Diodes Incorporated DDTC125TUA-7

Name: DDTC125TUA-7
Brand: Diodes Incorporated
SKU: DDTC125TUA-7
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: DDTC125TUA-7

Manufacturer:: Diodes Incorporated

Category:: Single, Pre-Biased Bipolar Transistors

Package:: -

Datasheet:: DDTC125TUA-7.pdf

Description:: TRANS PREBIAS NPN 200MW SOT323

Quantity:: RFQ Add To RFQ list

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Inventory:2,750

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Product details

Overview

DDTC125TUA-7 from Diodes Incorporated is an NPN pre-biased small-signal transistor with a single integrated 200 kΩ base bias resistor (R1 only), housed in a SOT323 surface-mount package. It supports 50 V V_CEO, 100 mA I_C, 200 mW power dissipation, and delivers h_FE of 100–600 at I_C = 1 mA, V_CE = 5 V - used for discrete logic-level switching and signal amplification in space-constrained consumer and industrial PCBs.

For engineers reviewing the DDTC125TUA-7 datasheet, DDTC125TUA-7 pinout, DDTC125TUA-7 application, or DDTC125TUA-7 equivalent, key selection criteria include verified R1 tolerance (±30%), V_CE(sat) ≤ 0.3 V at multiple I_C/I_B ratios, thermal resistance (625 °C/W), AEC-Q101 eligibility pathway, and SOT323 footprint compatibility with automated reflow assembly.

Technical Context

This device implements an epitaxial planar NPN transistor die with a monolithically integrated 200 kΩ pull-up base resistor (R1), eliminating external bias components. Its design targets simplified BJT switching in low-power digital interfaces where fixed-current drive suffices and gain stability across temperature is required.

It operates within -55 °C to +150 °C junction temperature range, dissipates up to 200 mW on FR4 board with minimum pad layout, and exhibits f_T = 250 MHz under V_CE = 10 V, I_E = -5 mA conditions - confirming suitability for medium-speed digital switching rather than RF amplification.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	50 V - Maximum safe collector-emitter voltage before breakdown; enables use in 24 V and 36 V logic-supplied systems.
I_C (max)	100 mA - Continuous collector current rating; supports driving LEDs, small relays, or logic inputs without external current limiting.
R1 (nominal)	200 kΩ - Integrated base bias resistor value; sets I_B ≈ 5 µA at 1 V input, enabling direct microcontroller GPIO interface.
V_CE(sat)	≤ 0.3 V - Low saturation voltage at I_C/I_B = 10 mA/1 mA; minimizes power loss and heat generation in switching mode.
h_FE	100–600 - DC current gain range at I_C = 1 mA, V_CE = 5 V; ensures reliable turn-on margin across process and temperature variation.
R_θJA	625 °C/W - Junction-to-ambient thermal resistance on FR4; defines maximum allowable power at given ambient temperature per derating curve.

Pinout & Package

Package: SOT323 - ultra-small plastic surface-mount package (2.15 mm × 2.10 mm × 0.95 mm), lead-free, halogen-free, RoHS-compliant, moisture sensitivity level 1.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emitter terminal	Reference node for current flow; connected to ground or low-side return path in common-emitter switch configuration.
2 (Base)	Base terminal	Input node tied internally to R1; accepts logic-level voltage to control transistor conduction without external resistor.
3 (Collector)	Collector terminal	Output node sourcing load current; connects to V_CC or active-high load (e.g., LED anode, relay coil).

Key Features

Feature	Design Value
Integrated R1 bias resistor	200 kΩ ±30% - eliminates need for external base resistor, reducing BOM count and PCB area in high-volume digital interface designs.
SOT323 footprint	0.65 mm pitch, 2.15 mm × 2.10 mm body - compatible with standard pick-and-place equipment and reflow profiles for miniaturized consumer electronics.
Green compound packaging	UL 94V-0 rated, <900 ppm Br/Cl, <1000 ppm Sb - meets global environmental compliance mandates including RoHS 3 and automotive chemical content requirements.
High-temperature operation	-55 °C to +150 °C T_J range - supports deployment in under-hood automotive modules and industrial controllers exposed to thermal cycling.

Applications

LED Driver Circuit

Microcontroller GPIO Interface

Use Scenario: Driving indicator LEDs from 3.3 V or 5 V MCU outputs in portable instrumentation.

IC Role / Device Role / Timing Role: NPN pre-biased switch providing current sink capability with fixed base bias.

Use Value: Eliminates external base resistor, reduces component count by one per LED channel, and ensures consistent turn-on threshold across voltage rails.

Use Scenario: Level-shifting and signal inversion between low-voltage logic (e.g., 1.8 V FPGA I/O) and 5 V peripheral enable lines.

IC Role / Device Role / Timing Role: Digital inverter with guaranteed saturation at sub-1 mA input drive.

Use Value: Delivers <0.3 V V_CE(sat) even at I_B = 0.1 mA, enabling clean logic-low output without additional pull-down networks.

Power Sequencing Control

Industrial Sensor Signal Conditioning

Use Scenario: Enabling auxiliary power rails (e.g., 12 V analog supply) only after main system reset completes.

IC Role / Device Role / Timing Role: High-side or low-side enable switch controlled by sequencer output.

Use Value: Supports 100 mA load current with minimal dropout, and withstands 50 V transients during hot-swap events.

Use Scenario: Amplifying low-amplitude sensor outputs (e.g., thermistor divider, Hall effect) prior to ADC sampling.

IC Role / Device Role / Timing Role: Fixed-gain common-emitter amplifier stage with stable DC bias point.

Use Value: h_FE range of 100–600 ensures predictable gain over temperature, and 250 MHz f_T preserves signal integrity up to ~10 MHz bandwidth.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN pre-biased transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
DDTC124TUA-7-F	R1 = 22 kΩ (vs. 200 kΩ); higher base current, lower input impedance	Better suited for higher-speed switching where faster turn-on is needed, but less tolerant of weak drive sources	Select when driving from low-impedance buffers or when tighter V_CE(sat) control at >5 mA I_C is critical
NSVD125T1T1G	Same R1 = 200 kΩ, but SOT-23 package; higher R_θJA (500 °C/W), different marking and tape specs	Compatible functionally but requires PCB footprint change; not drop-in due to larger SOT-23 pad layout	Choose only if SOT-23 is already standardized in production and thermal margin allows

Compared with DDTC125TUA-7, DDTC124TUA-7-F offers faster switching at cost of reduced input voltage headroom, while NSVD125T1T1G provides identical biasing but demands mechanical redesign - making DDTC125TUA-7 optimal for new SOT323-based designs prioritizing miniaturization and thermal efficiency.

Availability

DDTC125TUA-7 is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller GPIO interfacing, power sequencing control, and industrial sensor signal conditioning requiring stable component supply and long-term obsolescence management.

Supply support for DDTC125TUA-7 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, manufacturing, and sales operations across Asia, Europe, and North America.

The DDTC (R1-only series) UA product line delivers pre-biased NPN transistors optimized for space-constrained digital interface and switching applications in consumer, industrial, and automotive electronics - emphasizing ease of use, reliability, and regulatory compliance.

FAQ

Is DDTC125TUA-7 still in active production?

No - DDTC125TUA-7-F is marked "Obsolete" in Diodes' official ordering information. However, Aetrix Electronics maintains legacy inventory with full traceability and offers lifecycle support including last-time buy planning, cross-reference guidance, and engineering consultation for migration paths.

What is the exact R1 tolerance, and how does it affect circuit performance?

The R1 resistor has a tolerance of ±30%, confirmed in the Electrical Characteristics table. This means the actual resistance ranges from 140 kΩ to 260 kΩ, resulting in corresponding base current variation - designers must verify worst-case I_B ensures sufficient h_FE-scaled I_C for target load under all operating conditions.

Can DDTC125TUA-7 be used in automotive applications?

While not pre-qualified to AEC-Q101, this part is manufactured in IATF 16949-certified facilities and supports PPAP documentation upon request. For production automotive use, Diodes recommends formal qualification engagement - but the device's -55 °C to +150 °C rating and green material composition align with automotive environmental requirements.

How does the SOT323 package impact thermal performance compared to SOT-23?

The SOT323 package has higher thermal resistance (R_θJA = 625 °C/W vs. ~500 °C/W for typical SOT-23), meaning it heats up faster under identical power dissipation. Designers must apply strict derating - e.g., limit continuous I_C to ~60 mA at 70 °C ambient - and ensure adequate copper pour on the emitter pad to improve heat spreading.

DDTC125TUA-7 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: *

Package/Case:: -

Packaging:: Cut Tape (CT)

Product Status:: Active

Transistor Type:: -

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

Voltage - Collector Emitter Breakdown (Max):: -

Resistor - Base (R1):: -

Resistor - Emitter Base (R2):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: -

Vce Saturation (Max) @ Ib, Ic:: -

Current - Collector Cutoff (Max):: -

Frequency - Transition:: -

Power - Max:: -

Grade:: -

Qualification:: -

Mounting Type:: -

Supplier Device Package:: -

DDTC125TUA-7 FAQ

1.How can I place an order for DDTC125TUA-7 through Aetrix?

Please submit a Request for Quotation (RFQ) for DDTC125TUA-7 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 DDTC125TUA-7 reliable?

The price and inventory of DDTC125TUA-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DDTC125TUA-7 is usually 5 days.

3.What payment methods are accepted for DDTC125TUA-7?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DDTC125TUA-7 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for DDTC125TUA-7?

DDTC125TUA-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your DDTC125TUA-7 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 DDTC125TUA-7?

For technical support, including DDTC125TUA-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DDTC125TUA-7 requirements.

6.How does Aetrix verify that DDTC125TUA-7 is sourced from the original manufacturer or authorized distributors?

All DDTC125TUA-7 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 DDTC125TUA-7 meets industry standards.

7.What is the process for return or replacement of DDTC125TUA-7?

All DDTC125TUA-7 units undergo pre-shipment inspection (PSI). If there is an issue with DDTC125TUA-7, 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 DDTC125TUA-7 part is unused and in its original packaging.

Return procedure for DDTC125TUA-7:

1.Submit a request within 90 days.

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

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