onsemi MJD117T4

Overview

MJD117T4 from ON Semiconductor is an NPN silicon Darlington transistor in D-PAK package, rated for 100 V V_CEO, 2 A DC collector current, and 20 W power dissipation at T_C = 25°C. It integrates a built-in damper diode between collector and emitter and delivers high DC current gain (h_FE ≥ 500 at I_C = 0.5 A), making it suitable for medium-power switching in motor drivers and relay interfaces.

For engineers reviewing the MJD117T4 datasheet, pinout, applications, or equivalent options, key selection considerations include its Darlington configuration for high current amplification, integrated clamp diode for inductive load protection, thermal performance in surface-mount D-PAK, and verified safe operating area up to 100 V / 2 A continuous operation.

Technical Context

The MJD117T4 operates as a monolithic NPN Darlington pair with internal base-emitter resistor network and integrated collector-to-emitter damper diode. Its architecture enables low base drive requirements while sustaining high voltage blocking (V_CEO = 100 V) and robust pulse current handling (I_CP = 4 A).

Designed for surface-mount use in thermally demanding applications, it features a D-PAK (TO-252) package with exposed drain pad for enhanced thermal conduction. Electrical behavior is characterized by V_CE(sat) ≤ 3 V at I_C = 4 A / I_B = 40 mA and f_T = 25 MHz, supporting moderate-speed switching up to ~100 kHz in linear-regulated or PWM-driven loads.

Key Specifications

Pinout & Package

Package: D-PAK (TO-252), surface-mount, with exposed thermal pad on collector side for PCB heat sinking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN Darlington transistor applications.

Compared with MJD112T4 and BD679A, the MJD117T4 uniquely combines 100 V blocking, integrated damper diode, and D-PAK thermal performance-making it the optimal choice for new SMT-based industrial switching designs where reliability, board space, and component count are critical.

Availability

MJD117T4 is available at Aetrix Electronics and suitable for DC motor control, relay driver circuits, solenoid actuator interfaces, and linear regulator pass element applications requiring stable component supply and long-term industrial availability.

Supply support for MJD117T4 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

ON Semiconductor is a global semiconductor manufacturer specializing in power management, analog, sensor, and discrete solutions for automotive, industrial, cloud, and IoT applications.

The MJD117T4 belongs to ON Semiconductor's high-voltage Darlington transistor family, designed specifically for robust, surface-mount switching in industrial control, motion systems, and power interface applications.

FAQ

What is the maximum continuous collector current rating for the MJD117T4?

The MJD117T4 has a maximum DC collector current rating of 2 A at T_C = 25°C. This value decreases with rising case temperature per the derating curve in the datasheet; at T_C = 100°C, the usable I_C drops to approximately 1.1 A. The MJD117T4 must be mounted on sufficient copper area or heatsink to maintain safe junction temperature under sustained load.

Does the MJD117T4 include an integrated clamp diode, and how is it connected?

Yes, the MJD117T4 includes a built-in damper diode connected between collector and emitter, with cathode at collector and anode at emitter. This configuration clamps inductive flyback voltage during turn-off, protecting the transistor from voltage overshoot. The MJD117T4 datasheet confirms this topology in its equivalent circuit diagram and specifies it as a key feature distinguishing it from non-clamped variants like MJD112T4.

What is the pin configuration of the MJD117T4 in the D-PAK package?

The MJD117T4 uses a standard D-PAK (TO-252) pinout: Pin 1 is Base, Pin 2 is Collector (connected to the exposed thermal pad), and Pin 3 is Emitter. This layout is confirmed in the mechanical drawings and pinout table of the official ON Semiconductor datasheet for MJD117T4, and matches industry-standard D-PAK orientation for NPN Darlington devices.

How does the DC current gain (h_FE) of the MJD117T4 vary with operating conditions?

The MJD117T4 exhibits h_FE = 500 (min) at I_C = 0.5 A, rising to 1000 (min) at I_C = 2 A, and reaching up to 12,000 at lower currents. This wide gain range means base drive must be sized for worst-case minimum h_FE at target load current. For example, driving 2 A load requires ≥2 mA base current using h_FE(min) = 1000, but ≥4 mA if relying on h_FE(min) = 500 at 0.5 A.

Can the MJD117T4 replace the MJD112T4 directly in existing designs?

No, the MJD117T4 is not a direct drop-in replacement for the MJD112T4 due to the presence of the integrated damper diode and differences in saturation voltage and gain profile. While both share identical pinout and package, the MJD117T4's internal diode alters circuit behavior in non-inductive applications and may affect timing or biasing. Review of schematic and layout is required before substitution; the MJD117T4 should only replace MJD112T4 when the damper diode functionality is explicitly needed and verified compatible.