Diodes Incorporated DDTC115TUA-7

Overview

DDTC115TUA-7 from Diodes Incorporated is an NPN pre-biased small-signal transistor with a single built-in 100 kΩ bias resistor (R1 only), housed in a SOT323 surface-mount package. It delivers V_CEO = 50 V, I_C(max) = 100 mA, V_CE(sat) ≤ 0.3 V at I_C/I_B = 1 mA/0.1 mA, h_FE = 100–600, and operates across −55°C to +150°C - used for level-shifting and digital switching in space-constrained consumer and industrial control circuits.

For engineers reviewing the DDTC115TUA-7 datasheet, DDTC115TUA-7 pinout, DDTC115TUA-7 application, or DDTC115TUA-7 equivalent, key selection criteria include verified R1 = 100 kΩ tolerance (±30%), guaranteed V_CE(sat) performance under low-drive conditions, thermal derating compliance on FR4 PCBs, and AEC-Q101 readiness for automotive signal conditioning.

Technical Context

This device integrates a monolithic NPN transistor with a precision laser-trimmed 100 kΩ base bias resistor (R1), eliminating external bias components and reducing board area. Its epitaxial planar die construction ensures stable h_FE and low leakage (I_CBO, I_EBO ≤ 0.5 µA), while the SOT323 package supports automated placement and reflow soldering per J-STD-020 Level 1 moisture sensitivity.

Designed for DC-coupled digital interface and logic-level translation, it operates with base-emitter forward bias only - no second resistor (R2) - simplifying drive circuitry for microcontroller GPIO outputs. The 200 mW power rating and 625°C/W R_θJA are validated using minimum recommended pad layout on FR4.

Key Specifications

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.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DDTC114TUA-7-F and NSVDDTC115TUTBG, DDTC115TUA-7 offers optimal bias resistance for weak-drive GPIOs (e.g., 3.3 V LDO-powered MCUs), while the NSV variant adds formal automotive qualification without electrical trade-offs - making it ideal for Tier 1 supply chain traceability.

Availability

DDTC115TUA-7 is available at Aetrix Electronics and suitable for LED driver interfaces, microcontroller GPIO expansion, and industrial PLC input conditioning requiring stable component supply and long-term manufacturability.

Supply support for DDTC115TUA-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, specializing in high-reliability, energy-efficient components for automotive, industrial, and consumer markets.

DDTC115TUA-7 belongs to the R1-only series of pre-biased transistors, designed specifically to reduce component count and improve layout efficiency in digital interface and signal-switching applications.

FAQ

What is the function of the internal 100 kΩ resistor in DDTC115TUA-7?

The internal 100 kΩ resistor (R1) connects between the base and emitter terminals, providing fixed base bias to enable NPN transistor operation without external components. It ensures predictable turn-on behavior with low-drive logic sources such as 3.3 V microcontroller GPIOs, eliminating resistor matching errors and saving PCB space.

Can DDTC115TUA-7 replace a standard 2N3904 with external bias resistors?

Yes - DDTC115TUA-7 can replace a 2N3904 plus base resistor in low-to-medium current switching applications (≤100 mA). Its integrated R1 simplifies design, but note that its fixed 100 kΩ value sets specific base current; verify that resulting I_B provides sufficient overdrive for your load's required h_FE margin.

Is DDTC115TUA-7 suitable for automotive applications?

DDTC115TUA-7 is manufactured in IATF 16949-certified facilities and supports PPAP documentation; however, formal AEC-Q101 qualification applies to the NSVDDTC115TUTBG variant. For non-safety-critical automotive modules (e.g., interior lighting), DDTC115TUA-7 is widely deployed - consult Diodes' automotive product definitions for program-specific requirements.

What is the maximum allowable PCB trace length for DDTC115TUA-7 in high-frequency switching?

DDTC115TUA-7 is not optimized for RF or high-speed switching; its f_T = 250 MHz applies only under specified test conditions (V_CE = 10 V, I_E = −5 mA). For digital switching below 1 MHz, trace lengths up to 50 mm on standard FR4 are acceptable; for >10 MHz operation, layout must minimize parasitic inductance and capacitance using ground planes and short, direct connections.