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

Diodes Incorporated DDTC122TU-7

Name: DDTC122TU-7
Brand: Diodes Incorporated
SKU: DDTC122TU-7
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: DDTC122TU-7

Manufacturer:: Diodes Incorporated

Category:: Single, Pre-Biased Bipolar Transistors

Package:: SC-70, SOT-323

Datasheet:: DDTC122TU-7.pdf

Description:: TRANS PREBIAS NPN 50V SOT323

Quantity:: RFQ Add To RFQ list

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Inventory:3,000

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Product details

Overview

DDTC122TU-7 from Diodes Incorporated is an NPN pre-biased digital transistor in SOT-323 package, featuring integrated 220 Ω base-emitter resistor (R1) and open collector (R2), rated for 100 mA output current, 50 V V_CBO, and 40 V V_CEO, used in low-power logic-level switching and signal buffering in portable consumer electronics.

For engineers reviewing the DDTC122TU-7 datasheet, DDTC122TU-7 pinout, DDTC122TU-7 application, or DDTC122TU-7 equivalent, key selection criteria include its fixed R1 bias network, 5 V E-B breakdown rating, h_FE range of 100–600 at 1 mA, and SOT-323 thermal resistance of 625 °C/W on FR4 board.

Technical Context

This device integrates a monolithic NPN transistor with a single external-base resistor (R1 = 220 Ω) and no second bias resistor (R2 = open), enabling simplified single-resistor drive from microcontroller GPIOs. It operates as a saturated switch with guaranteed V_CE(sat) ≤ 0.3 V at I_C = 5 mA / I_B = 0.25 mA.

Designed for DC-coupled digital interface applications, it supports input voltage ranges up to +6 V and withstands −5 V reverse base-emitter stress. Its 200 MHz f_T supports moderate-speed switching but is not optimized for RF or high-frequency amplification.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum collector-emitter voltage before breakdown under open-base condition; defines safe DC switching headroom.
h_FE	100–600 - DC current gain at I_C = 1 mA, V_CE = 5 V; determines required base drive for saturation across process variation.
V_CE(sat)	≤ 0.3 V - Collector-emitter saturation voltage at I_C = 5 mA, I_B = 0.25 mA; ensures low conduction loss in power-efficient switching.
BV_EBO	5 V - Emitter-base breakdown voltage at I_E = 50 µA; limits allowable negative input swing during logic transitions.
P_D	200 mW - Maximum power dissipation on FR4 board; constrains continuous current handling at ambient temperature.
R_θJA	625 °C/W - Junction-to-ambient thermal resistance; dictates temperature rise per milliwatt under standard PCB layout.

Pinout & Package

Package: SOT-323 - ultra-small surface-mount plastic package (2.20 × 1.35 × 0.90 mm), moisture sensitivity level 1, lead-free matte tin plating, UL 94V-0 rated.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emitter terminal	Reference node for base bias; connects to ground or low-side return path in common-emitter switch configuration.
2 (Base)	Input control node	Accepts logic-level drive through internal 220 Ω resistor; no external bias required for TTL/CMOS-compatible operation.
3 (Collector)	Switched output node	Drives load between V_CC and collector; configured as open-collector output with active-low switching behavior.

Key Features

Feature	Design Value
Integrated R1 bias resistor	220 Ω nominal - eliminates external base resistor, reducing BOM count and PCB area in GPIO-driven switches.
R2 terminal configuration	Open - enables direct connection of external pull-up or feedback networks without internal interference.
AEC-Q101 qualification path	Available upon request - supports automotive-grade change control, PPAP, and IATF 16949 manufacturing for qualified variants.
Green compound packaging	Halogen- and antimony-free (<900 ppm Br/Cl, <1000 ppm Sb) - meets global environmental compliance mandates including RoHS 3.

Applications

LED Indicator Driver

Microcontroller GPIO Expander

Use Scenario: Driving discrete status LEDs from 3.3 V or 5 V MCU outputs with current limiting via V_CE(sat) and load resistor.

IC Role / Device Role / Timing Role: Low-side saturated switch controlling LED anode-to-V_CC current path.

Use Value: Eliminates need for discrete base resistor; ensures consistent turn-on with h_FE ≥ 100 even at low I_C = 2–5 mA.

Use Scenario: Adding extra digital output channels to resource-constrained MCUs by using one GPIO to drive multiple parallel transistors.

IC Role / Device Role / Timing Role: Digital buffer with gain, isolating MCU pins from capacitive or inductive loads.

Use Value: 200 MHz f_T supports clean edge transitions up to ~1–2 MHz; R1 stabilizes base voltage during fast toggling.

Level-Shifting Interface

Power Sequencing Control

Use Scenario: Translating 1.8 V logic signals to control 5 V peripherals where voltage translation must be unidirectional and low-cost.

IC Role / Device Role / Timing Role: Active-low level shifter with fixed R1 bias enabling reliable turn-on at sub-2 V input.

Use Value: Guaranteed V_I(on) ≤ 2.0 V at I_O = 20 mA ensures compatibility with modern low-voltage I/O standards.

Use Scenario: Enabling/disabling power rails in sequence using MCU-controlled enable lines with built-in current limiting.

IC Role / Device Role / Timing Role: Enable gate driver for PMOS high-side or NMOS low-side power switches.

Use Value: 100 mA I_C rating supports driving gate capacitance of small-signal MOSFETs; V_CEO = 40 V covers typical rail voltages.

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
DDTC122TK-7-F	SOT-23 package, same R1/R2 values, higher P_D = 300 mW, R_θJA = 417 °C/W	Better thermal performance and higher current capability; requires larger footprint	Select when board space allows and >100 mA peak load current or sustained power dissipation is needed.
NSVD122T1T1G	ON Semiconductor part, SOT-323, R1 = 220 Ω, R2 = open, V_CEO = 50 V, h_FE = 160–460	Higher V_CEO margin and tighter h_FE binning; identical pinout and footprint	Choose for designs requiring extended voltage headroom or tighter gain consistency across production lots.

Compared with DDTC122TU-7, DDTC122TK-7-F offers superior thermal handling in SOT-23, while NSVD122T1T1G provides higher V_CEO and narrower h_FE spread-both retain identical bias topology and SOT-323 compatibility where applicable.

Availability

DDTC122TU-7 is available at Aetrix Electronics and suitable for LED indicator drivers, microcontroller GPIO expansion, level-shifting interfaces, and power sequencing control requiring stable component supply and long-term obsolescence management support.

Supply support for DDTC122TU-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, serving industrial, computing, communications, and consumer markets with high-reliability components.

The DDTC series belongs to Diodes' pre-biased transistor product line, engineered specifically for cost-sensitive, space-constrained digital switching applications where simplified drive and robust DC characteristics are prioritized over RF performance.

FAQ

Is DDTC122TU-7 still in active production?

No-DDTC122TU-7 is officially obsolete per Diodes' DS30401 Rev. 7-4 (June 2021). Aetrix Electronics maintains legacy inventory and supports last-time-buy programs, cross-reference assistance, and engineering consultation for migration paths to functionally aligned alternatives like NSVD122T1T1G or DDTC122TK-7-F.

What is the meaning of "R2 = OPEN" in the marking table?

"R2 = OPEN" means the second internal bias resistor (typically connected between base and collector in dual-resistor configurations) is omitted. This leaves the collector terminal fully isolated from internal biasing, allowing external pull-up resistors, feedback networks, or direct connection to higher-voltage rails without interference from internal leakage paths.

Can DDTC122TU-7 replace a standard 2N3904 in switching circuits?

Yes-but only if the circuit uses base-resistor drive and does not require adjustable bias or linear amplification. DDTC122TU-7 integrates R1 = 220 Ω, so it replaces both the transistor and its base resistor. It is unsuitable for emitter-follower, analog amplifier, or variable-gain configurations due to fixed internal biasing and lack of base access.

Does DDTC122TU-7 support 1.8 V logic input levels?

Yes-its V_I(on) is specified ≤ 2.0 V at I_O = 20 mA, and test data shows functional turn-on down to ~1.5 V with reduced but usable current gain. For reliable 1.8 V operation, confirm system-level timing margins and ensure load current remains within 10–20 mA to maintain V_CE(sat) < 0.4 V.

DDTC122TU-7 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: SC-70, SOT-323

Packaging:: Tape & Reel (TR)

Product Status:: Discontinued at Digi-Key

Transistor Type:: NPN - Pre-Biased

Current - Collector (Ic) (Max):: 100 mA

Voltage - Collector Emitter Breakdown (Max):: 50 V

Resistor - Base (R1):: 220 Ohms

Resistor - Emitter Base (R2):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 1mA, 5V

Vce Saturation (Max) @ Ib, Ic:: 300mV @ 250µA, 5mA

Current - Collector Cutoff (Max):: 500nA (ICBO)

Frequency - Transition:: 200 MHz

Power - Max:: 200 mW

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323

DDTC122TU-7 FAQ

1.How can I place an order for DDTC122TU-7 through Aetrix?

Please submit a Request for Quotation (RFQ) for DDTC122TU-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 DDTC122TU-7 reliable?

The price and inventory of DDTC122TU-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DDTC122TU-7 is usually 5 days.

3.What payment methods are accepted for DDTC122TU-7?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DDTC122TU-7 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for DDTC122TU-7?

DDTC122TU-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your DDTC122TU-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 DDTC122TU-7?

For technical support, including DDTC122TU-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DDTC122TU-7 requirements.

6.How does Aetrix verify that DDTC122TU-7 is sourced from the original manufacturer or authorized distributors?

All DDTC122TU-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 DDTC122TU-7 meets industry standards.

7.What is the process for return or replacement of DDTC122TU-7?

All DDTC122TU-7 units undergo pre-shipment inspection (PSI). If there is an issue with DDTC122TU-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 DDTC122TU-7 part is unused and in its original packaging.

Return procedure for DDTC122TU-7:

1.Submit a request within 90 days.

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

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