onsemi MJ11021G

Overview

MJ11021G from onsemi is a PNP complementary Darlington silicon power transistor in TO-204 (TO-3) metal package, rated for 250 V_CEO(sus), 15 A continuous collector current, and 175 W power dissipation at T_C = 25 °C. It delivers high DC current gain (h_FE ≥ 400 at I_C = 10 A), low saturation voltage (V_CE(sat) = 2.0 V typ. at I_C = 15 A), and is 100% SOA tested - used in high-current linear amplifiers and industrial motor control circuits.

For engineers reviewing the MJ11021G datasheet, pinout, applications, or equivalent options, key selection criteria include its PNP polarity, TO-3 thermal performance (R_JC = 0.86 °C/W), safe operating area under inductive switching, V_BE(sat) ≤ 3.8 V at I_C/I_B = 100, and Pb-free compliance per onsemi's RoHS strategy.

Technical Context

The MJ11021G implements a monolithic Darlington pair with integrated base-emitter shunt resistor to improve turn-off speed and reduce storage time (t_s = 2.7 μs). Its rugged construction supports reverse-bias safe operating area (RBSOA) up to 260 V and 15 A under clamped inductive turn-off with 10% duty cycle.

Thermal design relies on direct case-to-heatsink conduction via the metal TO-3 collector tab (pin 1 is base, pin 2 is emitter, case = collector). Transient thermal response is characterized by normalized r(t) curves enabling peak junction temperature calculation for pulsed loads up to 300 μs.

Key Specifications

Pinout & Package

Package: TO-204 (TO-3), metal can with isolated collector tab. Case serves as collector terminal; mounting screw hole centered on collector surface. Style 1 configuration confirmed per onsemi CASE 1-07 mechanical drawing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BDW93C and MJ11015G, the MJ11021G offers the highest V_CEO(sus) among actively available PNP Darlington TO-3 transistors, verified RBSOA for inductive loads, and ongoing Pb-free manufacturing - making it the preferred choice for 200–250 V industrial switching and linear applications.

Availability

MJ11021G is available at Aetrix Electronics and suitable for audio amplifier output stages, DC motor H-bridge high-side switches, and linear regulator pass elements requiring stable component supply, long-term obsolescence mitigation, and RoHS-compliant packaging.

Supply support for MJ11021G 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 specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, cloud, medical, and IoT applications.

The MJ11021G belongs to onsemi's legacy silicon power transistor family designed for high-reliability linear and switching power applications where ruggedness, SOA integrity, and thermal stability are critical - particularly in industrial motor drives and professional audio equipment.

FAQ

What is the maximum continuous collector current rating for MJ11021G?

The MJ11021G is rated for 15 A continuous collector current at case temperature T_C = 25 °C. Derating is required above this temperature at 1.16 W/°C, and actual usable current depends on heatsink performance and ambient conditions. The device also supports 30 A peak current under pulsed conditions (pulse width ≤ 5 ms, duty cycle ≤ 10%). This rating is validated across the full –65 °C to +175 °C junction temperature range.

Is MJ11021G pin-compatible with MJ11021 or MJ11022?

No - MJ11021G is the Pb-free version of MJ11021 (PNP), sharing identical pinout (Style 1: Pin 1 = Base, Pin 2 = Emitter, Case = Collector) and electrical specifications. However, MJ11022 is the complementary NPN device with opposite polarity and cannot be substituted. The MJ11021G and MJ11021 share the same TO-204 (TO-3) mechanical outline and terminal assignment; only the plating and material composition differ per RoHS compliance.

Does MJ11021G require a heatsink in typical applications?

Yes - the MJ11021G must be mounted to an appropriately sized heatsink in all applications exceeding ~5 W dissipation. With R_JC = 0.86 °C/W and maximum T_J = 175 °C, even at T_C = 50 °C, power dissipation must remain below ~145 W to avoid thermal runaway. For 15 A linear operation, a low-thermal-resistance heatsink (e.g., < 0.5 °C/W) with thermal interface material is mandatory to maintain safe junction temperatures.

What does the "G" suffix indicate in MJ11021G?

Per onsemi documentation, the "G" suffix in MJ11021G denotes a Pb-free (RoHS-compliant) package variant. It uses matte tin-plated leads and leadframe materials meeting JEDEC J-STD-609 Category 1 requirements. The "G" version maintains identical electrical, thermal, and mechanical specifications as the legacy MJ11021, including TO-204 (TO-3) outline, pin configuration, and SOA ratings - with no derating or layout changes required.

How is the Safe Operating Area (SOA) of MJ11021G verified?

The MJ11021G undergoes 100% Forward Bias SOA testing at V_CE = 44 V, I_C = 4.0 A, pulse width = 250 ms, and T_C = 25 °C. Reverse Bias SOA is characterized per Figure 5 of the datasheet under clamped inductive turn-off conditions (L = 200 μH, V_BE(off) = 0–5 V, R_BE = 47 Ω, duty cycle = 10%). These tests confirm second-breakdown immunity and bonding-wire current capacity for both DC and transient operation.