onsemi MJ11012G

Overview

MJ11012G from onsemi is a high-current NPN Darlington power transistor in TO-3 metal package, rated for 60 V_CEO, 30 A_C, and 200 W dissipation at T_C = 25 °C, with minimum DC current gain h_FE = 1000 at I_C = 20 A - designed as output stage devices in complementary audio and industrial linear amplifiers.

For engineers reviewing the MJ11012G datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, thermal limits, safe operating area boundaries, TO-3 terminal mapping, and validated alternative transistors for high-power linear switching and amplifier output stages.

Technical Context

The MJ11012G implements a monolithic Darlington configuration with integrated base-emitter shunt resistor, enabling high DC current gain while maintaining robust thermal performance up to +200 °C junction temperature. Its structure supports low-saturation operation (V_CE(sat) ≤ 3 V at I_C = 20 A, I_B = 200 mA) and wide safe operating area (SOA) defined by bonding wire, thermal, and secondary breakdown limits.

Designed for complementary use with PNP MJ11015G, it shares identical TO-204AA (TO-3) mechanical outline and thermal resistance R_JC = 0.87 °C/W. Electrical characteristics are specified at T_C = 25 °C with pulse testing (300 µs, 2% duty cycle) for dynamic parameters including f_T = 4 MHz at I_C = 10 A.

Key Specifications

Pinout & Package

Package: TO-204AA (TO-3), metal can with isolated collector connected to case. Mounting flange serves as primary thermal path and electrically ties to collector terminal.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BDW83C and MJE13009, the MJ11012G delivers superior DC gain and thermal performance in TO-3 form factor, making it uniquely suited for high-fidelity linear output stages where low drive current, stable bias, and high SOA are mandatory - neither alternative matches its combination of 60 V rating, 1000 h_FE, and 0.87 °C/W thermal resistance.

Availability

MJ11012G is available at Aetrix Electronics and suitable for high-fidelity audio amplifiers, industrial linear power supplies, and DC motor drive outputs requiring stable component supply across extended production lifecycles.

Supply support for MJ11012G 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The MJ11012G belongs to onsemi's legacy high-power discrete transistor family, engineered specifically for linear amplifier output stages and industrial analog power control where reliability under sustained thermal stress is critical.

FAQ

What is the maximum continuous collector current rating for MJ11012G?

The MJ11012G is rated for 30 Adc continuous collector current at case temperature T_C = 25 °C. Derating is required above 25 °C at 1.15 W/°C, meaning usable current drops to approximately 20 A at T_C = 75 °C. This rating assumes proper heatsinking per the specified R_JC = 0.87 °C/W thermal resistance. The MJ11012G must not exceed this limit in sustained operation to avoid thermal runaway or bond wire failure.

Does MJ11012G have built-in protection features?

The MJ11012G incorporates a monolithic Darlington structure with an integrated base-emitter shunt resistor to improve turn-off reliability and reduce susceptibility to thermal runaway. It does not include avalanche ruggedness, built-in diodes, or overtemperature shutdown circuitry. Protection must be implemented externally via snubbers, current limiting, and thermal monitoring circuits. The MJ11012G relies on its +200 °C junction rating and SOA-defined operating boundaries for safe linear operation.

Can MJ11012G be used in parallel configurations?

Yes, the MJ11012G can be paralleled for higher current capacity, but requires careful attention to emitter ballasting resistors (typically 0.1–0.22 Ω) to ensure current sharing. Due to manufacturing variations in h_FE and V_BE(sat), unmatched devices will exhibit unequal current division leading to thermal imbalance. For reliable parallel operation, select matched units from same wafer lot and verify thermal coupling between devices using shared heatsink mass. The MJ11012G's monolithic construction improves consistency versus discrete Darlington pairs.

What is the safe operating area (SOA) limitation for MJ11012G at 50 V V_CE?

At V_CE = 50 V, the MJ11012G's SOA is limited to approximately 4 A continuous DC current due to secondary breakdown constraints, as shown in Figure 5 of the official datasheet. Pulse operation (≤300 µs, ≤2% duty cycle) extends this to ~6 A. Exceeding this boundary risks localized hot-spot formation and irreversible device failure. The MJ11012G's SOA must be respected in all linear-mode applications - especially in Class-AB amplifiers and adjustable power supplies - regardless of heatsink capability.

Is MJ11012G still in active production?

No - the MJ11012G is marked as discontinued per onsemi's October 2025 datasheet revision (Rev. 6). While no new wafers are being fabricated, Aetrix Electronics maintains legacy inventory and offers lifecycle management support including last-time buy coordination, cross-reference guidance, and obsolescence mitigation planning for customers dependent on the MJ11012G in existing designs.