onsemi MJF2955G

Overview

MJF2955G from onsemi is a complementary PNP silicon power transistor in an isolated TO-220 Fullpack package, rated for 90 V V_CEO(sus), 10 A continuous collector current, and 30 W power dissipation at T_C = 25°C. It serves as a high-reliability switching and linear amplifier device in industrial power supplies, motor control stages, and DC-DC converter output stages.

For engineers reviewing the MJF2955G datasheet, pinout, applications, or equivalent options, key selection criteria include its 4500 V_RMS isolation rating, Pb-free compliance, 4.0 °C/W junction-to-case thermal resistance, and verified compatibility with heatsink mounting per torque specification (6–8 in·lbs).

Technical Context

The MJF2955G is a bipolar junction transistor optimized for medium-power linear and switching operation, featuring a fully isolated overmolded package that eliminates need for insulating washers. Its electrical behavior is defined by h_FE = 5–100 (at I_C = 4–10 A), V_CE(sat) ≤ 2.5 V (at I_C = 10 A, I_B = 3.3 A), and f_T = 2.0 MHz - confirming suitability for audio amplification and PWM-driven load control up to ~100 kHz.

Thermal performance is governed by R_JC = 4.0 °C/W and R_JA = 62.5 °C/W, requiring active heatsinking for sustained >2 A operation. The device operates across –55°C to +150°C junction temperature range and meets UL 94 V-0 flammability standard at 0.125 in thickness.

Key Specifications

Pinout & Package

Package: TO-220 Fullpack (Case 221D, Style 2), Pb-free, fully isolated overmolded plastic housing with metal tab (collector) electrically isolated from leads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJE2955T and BD711, the MJF2955G provides certified isolation, higher voltage margin, and superior thermal resistance - making it the preferred choice for safety-compliant, high-reliability power conversion where layout space allows TO-220 Fullpack mounting.

Availability

MJF2955G is available at Aetrix Electronics and suitable for industrial power supplies, motor control modules, audio amplifier designs, and uninterruptible power supply (UPS) inverters requiring stable component supply and long-term lifecycle support.

Supply support for MJF2955G 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, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MJF2955G belongs to onsemi's complementary silicon power transistor family, engineered for robust general-purpose amplification and switching in safety-critical, high-reliability power systems.

FAQ

What is the maximum safe mounting torque for the MJF2955G?

The MJF2955G must be mounted using a 4-40 screw with torque limited to 6–8 in·lbs. Exceeding 10 in·lbs risks cracking the overmolded package and compromising its 4500 V_RMS isolation rating. onsemi validates this range using compression washers and thermocouple-monitored thermal testing per Application Note AN1040. Always verify torque with calibrated tools during MJF2955G assembly.

Does the MJF2955G require an insulating washer when mounted to a heatsink?

No - the MJF2955G features an isolated overmold package with 1500 V_RMS minimum isolation between leads and metal tab, eliminating the need for mica or silicone insulating washers. This reduces thermal resistance and system cost. However, the heatsink itself must remain at safe potential relative to circuit ground, as isolation applies only between internal leads and external tab/heatsink interface.

What is the difference between MJF2955G and MJF2955?

The MJF2955G is the Pb-free version of the MJF2955, identical in all electrical, thermal, and mechanical specifications except for RoHS-compliant lead finish and packaging marking. Both share TO-220 Fullpack (Style 2) package, 90 V/10 A ratings, and 4500 V_RMS isolation. The "G" suffix denotes Pb-free construction per JEDEC J-STD-020, with equivalent solderability and reliability profiles.

Can MJF2955G be used in parallel with other transistors for higher current handling?

Yes, but only with careful attention to current sharing: MJF2955G exhibits positive temperature coefficient for V_CE(sat), supporting inherent current balancing. Use matched h_FE devices, individual base resistors (not shared), and symmetric PCB layout with equal trace lengths. Derate total current by ≥20% and ensure uniform heatsinking - parallel operation beyond 15 A requires thermal simulation and validation per onsemi's AN-1040 guidelines for MJF2955G.

Is the MJF2955G suitable for Class D audio amplifier output stages?

The MJF2955G is not recommended for Class D audio output stages due to its 2.0 MHz f_T limit and relatively slow switching characteristics (typical t_on/t_off not specified in datasheet). While usable in low-frequency (<50 kHz) PWM applications, modern Class D amplifiers demand faster MOSFETs or dedicated gate drivers. For linear Class AB output stages up to 100 W, the MJF2955G remains well-suited when paired with MJF3055G.