Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi MJD112-1G

Name: MJD112-1G
Brand: onsemi
SKU: MJD112-1G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: MJD112-1G

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-251-3 Short Leads, IPAK, TO-251AA

Datasheet:: MJD112-1G.pdf

Description:: TRANS NPN DARL 100V 2A IPAK

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:131

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

MJD112-1G from ON Semiconductor is an NPN silicon Darlington transistor designed for medium-power switching applications, featuring a 100 V collector-emitter sustaining voltage (V_CEO(sus)), 2 A DC collector current (I_C), and integrated damper diode between emitter and collector. 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, motor controls, and lamp ballasts.

For engineers reviewing the MJD112-1G datasheet, pinout, applications, or equivalent options, key selection considerations include its D-PAK surface-mount package, built-in E-C damper diode, saturation voltage behavior under pulsed vs. DC conditions, and thermal derating above 25°C case temperature.

Technical Context

The MJD112-1G implements a monolithic Darlington pair with internal base-emitter resistor network (R1 ≈ 10 kΩ, R2 ≈ 0.6 kΩ) and an integrated damper diode across emitter-collector terminals. Its high h_FE enables low-base-drive-current operation in power-switching circuits.

It operates with a maximum junction temperature of 150°C and exhibits a current gain bandwidth product (f_T) of 25 MHz at V_CE = 10 V and I_C = 0.75 A - sufficient for moderate-speed switching but not RF or high-frequency linear amplification.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO(sus)	100 V - Sustaining voltage under open-base condition; defines safe blocking capability in inductive load switching.
I_C (DC)	2 A - Continuous collector current rating at T_C = 25°C; requires heatsinking above ambient to maintain reliability.
h_FE	500–12,000 - Wide DC current gain range across 0.5–4 A collector current; reduces required base drive in driver stages.
V_CE(sat)	2–3 V - Saturation voltage at I_C = 2–4 A and corresponding I_B; determines conduction loss and thermal load in on-state.
f_T	25 MHz - Current gain–bandwidth product; sets upper limit for small-signal switching speed and AC response.
C_ob	100 pF - Output capacitance at V_CB = 10 V; impacts turn-off delay and snubber design in high-dV/dt environments.

Pinout & Package

Package: D-PAK (TO-252), surface-mount, single-ended heat sink tab (pin 2 = Collector, electrically connected to tab).

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input	Receives base current to enable Darlington conduction; internally biased via R1/R2 network.
2 (Collector)	Power output / Heat sink node	Main current path output; electrically tied to exposed metal tab for thermal dissipation.
3 (Emitter)	Power return / Reference node	Common emitter connection; damper diode anode is tied here, cathode to collector (pin 2).

Key Features

Feature	Design Value
Integrated damper diode	Eliminates need for external flyback diode in inductive load switching (e.g., relays, solenoids).
High DC current gain	Reduces required base drive current by up to 100× versus single bipolar transistors, easing microcontroller interface.
D-PAK surface-mount package	Enables automated assembly and provides superior thermal performance over TO-220 in space-constrained PCBs.
150°C max junction temperature	Supports operation in industrial environments with elevated ambient temperatures when properly heatsinked.

Applications

Relay Driver Circuits	Lamp Ballast Control
Use Scenario: Driving 12–24 V DC electromagnetic relays with coil currents up to 2 A in PLC I/O modules. IC Role / Device Role / Timing Role: Medium-power NPN Darlington switch providing galvanically isolated coil energization with fast turn-on/turn-off. Use Value: Built-in damper diode clamps inductive kickback, eliminating external components and reducing BOM count and board area.	Use Scenario: Controlling fluorescent lamp preheat and run current in electronic ballasts for commercial lighting fixtures. IC Role / Device Role / Timing Role: High-gain switching element regulating lamp current through series-pass configuration. Use Value: High h_FE ensures stable current regulation with minimal base drive error, improving lamp life and flicker suppression.
DC Motor Speed Control	Industrial Solenoid Actuation
Use Scenario: PWM-based speed control of 24 V brushed DC motors (e.g., conveyor drives, valve actuators) drawing ≤2 A continuous current. IC Role / Device Role / Timing Role: Low-side switching transistor handling motor current with integrated protection against back-EMF. Use Value: V_CEO(sus) = 100 V withstands motor back-EMF spikes during PWM commutation without external snubbers.	Use Scenario: Driving 24 V industrial solenoids in pneumatic/hydraulic control valves requiring ≥1.5 A hold current and robust surge tolerance. IC Role / Device Role / Timing Role: High-current switching device managing solenoid pull-in and hold phases with thermal margin. Use Value: 20 W collector dissipation at T_C = 25°C supports intermittent duty cycles without forced cooling in panel-mounted enclosures.

Relay Driver Circuits

Lamp Ballast Control

Use Scenario: Driving 12–24 V DC electromagnetic relays with coil currents up to 2 A in PLC I/O modules.

IC Role / Device Role / Timing Role: Medium-power NPN Darlington switch providing galvanically isolated coil energization with fast turn-on/turn-off.

Use Value: Built-in damper diode clamps inductive kickback, eliminating external components and reducing BOM count and board area.

Use Scenario: Controlling fluorescent lamp preheat and run current in electronic ballasts for commercial lighting fixtures.

IC Role / Device Role / Timing Role: High-gain switching element regulating lamp current through series-pass configuration.

Use Value: High h_FE ensures stable current regulation with minimal base drive error, improving lamp life and flicker suppression.

DC Motor Speed Control

Industrial Solenoid Actuation

Use Scenario: PWM-based speed control of 24 V brushed DC motors (e.g., conveyor drives, valve actuators) drawing ≤2 A continuous current.

IC Role / Device Role / Timing Role: Low-side switching transistor handling motor current with integrated protection against back-EMF.

Use Value: V_CEO(sus) = 100 V withstands motor back-EMF spikes during PWM commutation without external snubbers.

Use Scenario: Driving 24 V industrial solenoids in pneumatic/hydraulic control valves requiring ≥1.5 A hold current and robust surge tolerance.

IC Role / Device Role / Timing Role: High-current switching device managing solenoid pull-in and hold phases with thermal margin.

Use Value: 20 W collector dissipation at T_C = 25°C supports intermittent duty cycles without forced cooling in panel-mounted enclosures.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
FJD112F	Same die, identical electrical specs; differs only in tape-and-reel packaging and minor marking format per ON Semi's post-Fairchild nomenclature update.	No functional difference; suitable for same PCB layout and thermal design.	Select FJD112F for new designs requiring latest ON Semi part numbering compliance and full traceability.
MJD112T4G	Identical electrical characteristics and D-PAK package; differs in lead finish (matte tin vs. Pb-free NiPdAu) and moisture sensitivity level (MSL 1 vs. MSL 3).	Compatible in all circuit functions; requires requalification only if humidity exposure or solder process parameters differ significantly.	Choose MJD112T4G when RoHS-compliant matte tin plating and extended floor life are required for high-volume SMT production.

Compared with MJD112-1G, FJD112F offers identical performance with updated ON Semi branding and packaging logistics, while MJD112T4G provides equivalent functionality with enhanced surface finish and moisture resilience - both require no schematic or layout changes but differ in supply chain and process qualification scope.

Availability

MJD112-1G is available at Aetrix Electronics and suitable for relay driver circuits, lamp ballast control, and DC motor speed control requiring stable component supply and long-term industrial availability.

Supply support for MJD112-1G 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, and cloud power applications.

The MJD112-1G belongs to ON Semiconductor's legacy Fairchild discrete transistor portfolio, engineered for robust medium-power switching in cost-sensitive industrial controls where high current gain and integrated protection reduce system complexity.

FAQ

What is the maximum continuous collector current rating for MJD112-1G?

The MJD112-1G has a maximum DC collector current (I_C) rating of 2 A at case temperature T_C = 25°C. This rating decreases with rising case temperature per the power derating curve - at T_C = 100°C, usable I_C drops to approximately 1.1 A. For reliable operation, heatsinking must be applied to maintain T_C within limits specified in the MJD112-1G datasheet.

Does MJD112-1G include a built-in damper diode, and how is it connected?

Yes, the MJD112-1G integrates a damper diode between emitter and collector terminals, with cathode connected to the collector (pin 2) and anode to the emitter (pin 3). This configuration protects against inductive kickback in relay and solenoid applications, eliminating the need for an external flyback diode and simplifying PCB layout. The diode is monolithically fabricated alongside the Darlington pair.

What package type does MJD112-1G use, and is the collector electrically connected to the heatsink tab?

MJD112-1G uses the D-PAK (TO-252) surface-mount package. Yes, the collector (pin 2) is electrically and thermally connected to the exposed metal tab - this serves as both the primary heat dissipation path and a critical circuit node. PCB layout must isolate the tab from other potentials unless intentionally connected to system ground or collector rail.

How does the DC current gain (h_FE) of MJD112-1G vary with collector current?

The MJD112-1G exhibits a wide h_FE range: minimum 500 at I_C = 0.5 A, 1000 at I_C = 2 A, and 200 at I_C = 4 A (pulse), with typical values reaching up to 12,000 at lower currents. This non-linear gain profile means base drive must be sized for worst-case h_FE at the target operating current to ensure saturation across manufacturing and temperature variation - always verify using the MJD112-1G datasheet graphs.

Is MJD112-1G suitable for use in life support or medical implant applications?

No, the MJD112-1G is explicitly excluded from life support or medical implant applications. ON Semiconductor states that its products, including the MJD112-1G, are not authorized for use as critical components in life support systems or FDA Class 3 medical devices. Designers must select components with formal medical-grade certification and safety documentation for such applications - the MJD112-1G does not meet those requirements.

MJD112-1G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-251-3 Short Leads, IPAK, TO-251AA

Packaging:: Tube

Product Status:: Active

Transistor Type:: NPN - Darlington

Current - Collector (Ic) (Max):: 2 A

Voltage - Collector Emitter Breakdown (Max):: 100 V

Vce Saturation (Max) @ Ib, Ic:: 3V @ 40mA, 4A

Current - Collector Cutoff (Max):: 20µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 1000 @ 2A, 3V

Power - Max:: 1.75 W

Frequency - Transition:: 25MHz

Operating Temperature:: -65°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: IPAK

MJD112-1G FAQ

1.How can I place an order for MJD112-1G through Aetrix?

Please submit a Request for Quotation (RFQ) for MJD112-1G 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 MJD112-1G reliable?

The price and inventory of MJD112-1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MJD112-1G is usually 5 days.

3.What payment methods are accepted for MJD112-1G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MJD112-1G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MJD112-1G?

MJD112-1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MJD112-1G 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 MJD112-1G?

For technical support, including MJD112-1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MJD112-1G requirements.

6.How does Aetrix verify that MJD112-1G is sourced from the original manufacturer or authorized distributors?

All MJD112-1G 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 MJD112-1G meets industry standards.

7.What is the process for return or replacement of MJD112-1G?

All MJD112-1G units undergo pre-shipment inspection (PSI). If there is an issue with MJD112-1G, 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 MJD112-1G part is unused and in its original packaging.

Return procedure for MJD112-1G:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…