onsemi MJD112-001

Overview

MJD112-001 from ON Semiconductor is an NPN silicon Darlington transistor designed for medium-power switching applications, featuring 100 V collector-emitter sustaining voltage (V_CEO(sus)), 2 A DC collector current (I_C), and integrated base-emitter damper diode. It delivers high DC current gain (h_FE = 500–12,000 at I_C = 0.5–4 A) and is commonly used in relay drivers, lamp dimmers, and motor control circuits where high current amplification with low base drive is required.

For engineers reviewing the MJD112-001 datasheet, pinout, applications, or equivalent options, key selection considerations include its D-PAK package thermal performance, built-in emitter-collector damper diode, saturation voltage behavior under pulsed vs. DC conditions, and safe operating area limitations at elevated case temperatures.

Technical Context

The MJD112-001 implements a monolithic Darlington pair with internal base-emitter shunt resistors (R1 ≈ 10 kΩ, R2 ≈ 0.6 kΩ) and an integrated damper diode between collector and emitter. Its structure enables high current gain while reducing external component count in driver stages.

It operates with V_CE up to 100 V and supports pulse currents up to 4 A (I_CP) with 2% duty cycle. Thermal derating begins at T_C > 25°C, dropping linearly to zero dissipation at 150°C case temperature, per its 20 W P_C rating at T_C = 25°C.

Key Specifications

Pinout & Package

D-PAK (TO-252) surface-mount package with exposed drain pad for thermal enhancement; lead-formed for PCB mounting without bending.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BD679A and MJD122, the MJD112-001 provides optimal balance of 100 V blocking, integrated damper protection, and wide h_FE range - making it preferred for cost-constrained 24–48 V industrial switching where reliability under inductive stress is essential.

Availability

MJD112-001 is available at Aetrix Electronics and suitable for relay drivers, lamp dimmers, DC motor controllers, and linear regulator pass elements requiring stable component supply, long-term industrial lifecycle support, and consistent parametric performance across manufacturing lots.

Supply support for MJD112-001 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 (formerly Fairchild Semiconductor) is a global supplier of energy-efficient semiconductor components focused on power management, analog, sensors, and logic solutions for automotive, industrial, and cloud infrastructure markets.

The MJD112-001 belongs to ON Semiconductor's legacy power bipolar transistor portfolio, engineered specifically for robust, low-cost switching in industrial control, appliance, and power conversion systems where Darlington gain and integrated protection reduce bill-of-materials complexity.

FAQ

What is the maximum continuous collector current rating for MJD112-001?

The MJD112-001 has a maximum DC collector current (I_C) rating of 2 A at T_C = 25°C. This rating decreases with rising case temperature due to thermal derating - at T_C = 100°C, the usable I_C drops to approximately 1.2 A. The device also supports 4 A pulsed current (I_CP) with ≤2% duty cycle and ≤300 µs pulse width, as specified in its Absolute Maximum Ratings table.

Does MJD112-001 include a built-in damper diode, and how is it connected?

Yes, the MJD112-001 integrates a damper diode between collector and emitter terminals. As shown in its equivalent circuit diagram, the diode anode connects to the collector (Pin 2) and the cathode connects to the emitter (Pin 3). This configuration clamps inductive kickback voltage during turn-off, eliminating the need for an external flyback diode in relay or solenoid driver applications.

What is the typical V_CE(sat) of MJD112-001 under standard switching conditions?

The MJD112-001 exhibits V_CE(sat) = 2 V typical at I_C = 2 A and I_B = 8 mA, and 3 V typical at I_C = 4 A and I_B = 40 mA. These values reflect actual conduction losses under defined test conditions and must be validated in-circuit, as PCB layout, trace resistance, and thermal environment significantly impact measured saturation voltage in real-world MJD112-001 implementations.

Can MJD112-001 be used in linear regulator applications?

Yes, the MJD112-001 can serve as a pass transistor in adjustable linear regulators, particularly where 1.5–2 A output current and 5–15 V output range are required. Its high h_FE (≥500 at I_C = 0.5 A) reduces base drive current demand, improving regulation accuracy. However, designers must ensure adequate heatsinking - at 2 A and 5 V dropout, power dissipation exceeds 10 W, requiring careful thermal design for MJD112-001 reliability.

What package type does MJD112-001 use, and what are its thermal characteristics?

The MJD112-001 uses the D-PAK (TO-252) surface-mount package with an exposed collector pad for enhanced thermal conduction. Its maximum power dissipation is 20 W at T_C = 25°C, derating linearly to zero at T_C = 150°C. The package's low thermal resistance (R_θJC ≈ 1.25°C/W, inferred from P_C and ΔT) makes it suitable for compact, heatsink-integrated designs where TO-220 alternatives would require larger board area.