Diodes Incorporated DDTC124EKA-7-F

Overview

DDTC124EKA-7-F from Diodes Incorporated is an NPN pre-biased small-signal transistor in SC-59 package with integrated bias resistors R1 = R2 = 22 kΩ, V_CEO = 50 V, I_C(max) = 30 mA, P_D = 200 mW, and DC current gain (h_FE) ≥ 56 at V_CE = 5 V, I_C = 5 mA - used for digital switching in microcontroller I/O interface circuits.

For engineers reviewing the DDTC124EKA-7-F datasheet, DDTC124EKA-7-F pinout, DDTC124EKA-7-F application, or DDTC124EKA-7-F equivalent, key selection criteria include input threshold voltage (V_IN(on) = 1.9 V typ), output saturation voltage (V_CE(sat) ≤ 0.3 V @ I_C/I_B = 5 mA/0.5 mA), resistor tolerance (±30%), and thermal resistance (R_θJA = 625 °C/W).

Technical Context

This device integrates two matched 22 kΩ bias resistors (R1 = R2) to configure a single-NPN digital switch with fixed base biasing, eliminating external resistor placement. It operates as a saturated switch with guaranteed turn-on at V_IN ≥ 1.9 V and maintains V_OUT ≤ 0.3 V under 5 mA load.

The SC-59 package supports surface-mount assembly on FR4 PCBs with J-STD-020C Level 1 moisture sensitivity, UL 94V-0 flammability rating, and lead-free matte tin plating over copper leadframe - optimized for high-volume consumer and industrial control boards.

Key Specifications

Pinout & Package

Package: SC-59 - three-terminal surface-mount plastic package (0.35–0.50 mm A dimension, 2.70–3.00 mm C dimension), UL 94V-0 rated, lead-free, 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 NSV12400MT1G and EMH12T2R, DDTC124EKA-7-F delivers higher guaranteed h_FE and matched R1/R2 topology - improving saturation reliability and noise rejection in space-constrained digital interface designs.

Availability

DDTC124EKA-7-F is available at Aetrix Electronics and suitable for microcontroller GPIO interfaces, LED driver circuits, relay driver stages, and logic-level signal inverters requiring stable component supply and long-term manufacturability.

Supply support for DDTC124EKA-7-F 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, cost-optimized components for industrial, computing, and consumer markets.

This part belongs to the DDTC R1 = R2 series of pre-biased transistors, designed specifically to simplify digital switching in space-constrained, high-volume applications by integrating matched bias resistors into standardized SMT packages.

FAQ

What is the function of the internal R2 resistor in DDTC124EKA-7-F?

R2 connects the base to emitter internally, forming a voltage divider with R1 to establish a stable DC bias point. This configuration improves noise immunity, reduces sensitivity to base current variations, and ensures predictable turn-on/turn-off behavior without external components - critical for reliable digital switching in noisy environments.

Can DDTC124EKA-7-F be used with 1.8 V logic inputs?

No - its typical V_IN(on) is 1.9 V at I_O = 5 mA, and minimum guaranteed V_IN(on) is not specified. At 1.8 V, the device may remain in cutoff or operate in linear region, causing excessive power dissipation and unreliable switching. It is validated for 3.3 V and 5 V logic families only.

Is thermal derating required for continuous operation at 30 mA?

Yes - at ambient temperatures above 25°C, power dissipation must be reduced per the derating curve. With R_θJA = 625 °C/W and P_D = 200 mW, junction temperature rises ~125°C at full load. For continuous 30 mA operation, ambient must stay below 25°C or PCB copper area must be increased to lower thermal resistance.

Does DDTC124EKA-7-F support reverse-biased operation (e.g., as a level shifter)?

No - it is a unidirectional NPN transistor with fixed internal resistor topology. The base-emitter junction is not rated for reverse breakdown, and R1/R2 values are optimized for forward-active switching only. Using it in reverse configurations risks parametric shift or permanent damage due to unintended conduction paths.