onsemi MJE2955T

Overview

MJE2955T from onsemi is a PNP silicon power transistor designed for general-purpose amplifier and switching applications, with 60 V_CEO, 10 A_C, 75 W dissipation at T_C = 25 °C, h_FE ≥ 20 at I_C = 4.0 A, and TO-220 package. It operates across −55 to +150 °C junction temperature range and supports robust thermal management via low R_θJC = 1.67 °C/W.

For engineers reviewing the MJE2955T datasheet, pinout, applications, or equivalent options, key selection considerations include safe operating area (SOA) limits at high V_CE/I_C, DC current gain stability over temperature, saturation voltage under high-current drive, and Pb-free TO-220 mechanical compatibility in power stage layouts.

Technical Context

The MJE2955T is a complementary PNP counterpart to the NPN MJE3055T, sharing identical TO-220 package, thermal resistance, and maximum ratings-enabling matched pair use in push-pull amplifiers and H-bridge drivers. Its SOA is defined by second-breakdown, bonding-wire, and thermal limits, with pulse operation validated up to 50 ms at T_J(pk) ≤ 150 °C.

Electrical behavior is characterized at T_C = 25 °C with pulse testing (≤300 µs, ≤20% duty cycle). Key dynamic performance includes f_T = 2.0 MHz at I_C = 500 mA, V_CE = 10 V, and f = 500 kHz, supporting audio-frequency switching and linear amplification where bandwidth and gain linearity are critical.

Key Specifications

Pinout & Package

Package: TO-220 (Case 221A-09, Style 1), 3-terminal plastic power package with collector connected to tab for direct heatsink mounting. Pin 1 = Base, Pin 2 = Collector, Pin 3 = Emitter, Pin 4 = Collector (dual-collector configuration).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TIP2955 and BD711, the MJE2955T offers superior f_T and lower thermal resistance in a dual-collector TO-220, making it preferred for high-fidelity audio output stages and thermally demanding 10 A switching applications where SOA and gain consistency are prioritized.

Availability

MJE2955T is available at Aetrix Electronics and suitable for audio power amplifiers, DC motor drivers, linear voltage regulators, and offline SMPS requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for MJE2955T 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 manufacturer specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MJE2955T belongs to onsemi's legacy silicon power transistor family, engineered for rugged, cost-effective linear and switching power applications where reliability, thermal performance, and complementary pairing are essential.

FAQ

What is the maximum safe operating voltage for MJE2955T in DC switching applications?

The MJE2955T has a rated V_CEO of 60 Vdc under open-base conditions, meaning it can safely block up to 60 V between collector and emitter when the base is open. For reliable long-term operation, design margins should limit steady-state V_CE to ≤48 V, especially under inductive load conditions where voltage spikes may exceed nominal rail levels. Always consult Figure 1 (Safe Operating Area) in the official MJE2955T datasheet for pulse and second-breakdown limits.

Does MJE2955T require a heatsink in continuous 5 A operation?

Yes - at 5 A collector current and V_CE = 2 V (typical linear operation), power dissipation exceeds 10 W. Given its R_θJC = 1.67 °C/W and maximum T_J = 150 °C, even with ambient at 25 °C, junction temperature would exceed safe limits without heatsinking. A minimum 2.5 °C/W heatsink (including interface resistance) is recommended for continuous 5 A use; thermal simulation using actual PCB layout and airflow is advised for final validation of the MJE2955T implementation.

Can MJE2955T be used as a direct replacement for MJE2955G?

No - MJE2955T and MJE2955G are distinct orderable variants. The "T" suffix denotes tape-and-reel packaging per the ordering table, while "G" indicates Pb-free compliance and specific assembly location/year coding. Electrically and thermally, both share identical specifications and TO-220 package. However, MJE2955T is not a drop-in replacement for legacy MJE2955G unless the bill-of-materials explicitly permits interchange based on current qualification status and sourcing documentation for the MJE2955T.

What is the base-emitter forward voltage of MJE2955T at rated current?

The MJE2955T exhibits V_BE(on) ≤ 1.8 Vdc at I_C = 4.0 A and V_CE = 4.0 Vdc, per the Electrical Characteristics table. This value reflects typical forward-biased junction behavior under high-current drive and is critical for calculating required base drive resistor values in fixed-bias configurations. At lower currents (e.g., 100 mA), V_BE drops to ~0.85 V, confirming standard silicon PNP junction characteristics across the operating range of the MJE2955T.

Is MJE2955T suitable for high-frequency switching above 100 kHz?

No - the MJE2955T has an f_T of 2.0 MHz, but its switching speed is limited by minority-carrier storage time and relatively high C_ob and C_ib. Measured turn-off delay and storage times exceed 1 µs under typical conditions, making it unsuitable for hard-switched operation above ~20 kHz. For >100 kHz applications, consider modern MOSFETs or RF BJTs. The MJE2955T remains appropriate for audio amplification, motor control PWM below 20 kHz, and linear regulation where bandwidth demands are modest.