onsemi MJE2955TTU

Overview

MJE2955TTU from onsemi is a PNP silicon power transistor in TO-220 package, rated for 60 V_CEO, 10 A_C, and 75 W dissipation at T_C = 25 °C, with h_FE ≥ 20 at I_C = 4 A and V_CE = 4 V - used in linear power supplies, motor control stages, and high-current switching circuits.

For engineers reviewing the MJE2955TTU datasheet, pinout, applications, or equivalent options, key selection criteria include safe operating area (SOA) limits at elevated case temperatures, V_CE(sat) ≤ 1.1 V at I_C/I_B = 10, thermal resistance R_θJC = 1.67 °C/W, and complementary pairing with MJE3055TTU for push-pull amplifier designs.

Technical Context

This PNP bipolar junction transistor operates in active, saturation, and cutoff regions with defined SOA boundaries up to T_J = 150 °C. Its DC current gain (h_FE) varies from 5.0 (min at I_C = 10 A) to 100 (max at I_C = 4 A), and f_T = 2.0 MHz ensures usable bandwidth in audio-frequency switching and analog amplification.

Thermal derating begins above 25 °C at 0.6 W/°C, and second-breakdown-limited pulse operation is validated for durations down to 100 µs. The device supports fixed-bias and emitter-follower configurations with V_EB(on) ≤ 1.8 V and V_CE(sat) ≤ 8.0 V under worst-case I_C = 10 A / I_B = 3.3 A conditions.

Key Specifications

Pinout & Package

Package: TO-220 (Case 221A-09, Style 1), 4-pin variant with pins 2 and 4 internally connected to collector; requires mechanical mounting to heatsink via tab (pin 2/4).

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 MJE2955TTU offers superior thermal performance (R_θJC = 1.67 °C/W) and verified SOA at 100 µs, making it preferred for high-reliability linear regulation and motor drive where thermal margin and transient robustness are critical.

Availability

MJE2955TTU is available at Aetrix Electronics and suitable for linear power supply regulation, DC motor drive stages, and audio amplifier output stages requiring stable component supply and long-term industrial lifecycle support.

Supply support for MJE2955TTU 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 MJE2955TTU belongs to onsemi's legacy plastic power transistor family designed for rugged, high-current linear and switching applications where reliability, thermal robustness, and complementary NPN/PNP pairing are essential.

FAQ

What is the maximum junction temperature for the MJE2955TTU?

The MJE2955TTU has an operating junction temperature range of −55 °C to +150 °C. This maximum value defines the upper thermal limit for reliable operation; exceeding it risks permanent degradation of h_FE, increased leakage, or bond-wire failure. Thermal design must ensure T_J stays within this bound using R_θJC = 1.67 °C/W and appropriate heatsinking.

Is the MJE2955TTU pin-compatible with the MJE2955T?

Yes, the MJE2955TTU is functionally and mechanically identical to the MJE2955T, sharing the same TO-220 package (Style 1), pinout (base-collector-emitter-collector), electrical specifications, and thermal characteristics. The "UU" suffix denotes tape-and-reel packaging per onsemi's ordering nomenclature, not a functional revision.

Does the MJE2955TTU require a heatsink in all applications?

Yes - the MJE2955TTU must be mounted to a heatsink in any application dissipating more than ~5 W continuously. With R_θJC = 1.67 °C/W and T_J(max) = 150 °C, even at T_C = 50 °C, power dissipation above ~60 W would exceed thermal limits. For safe operation at rated 75 W, a low-thermal-resistance heatsink and thermal interface are mandatory.

What is the safe operating area (SOA) limitation for pulsed operation of the MJE2955TTU?

The MJE2955TTU SOA curve (Figure 1) shows second-breakdown-limited operation down to 100 µs pulses at 10 A/60 V, provided peak junction temperature remains ≤150 °C. Pulse testing uses ≤300 µs width and ≤20% duty cycle. For longer pulses or higher duty cycles, thermal limitations dominate and require derating per the 0.6 W/°C curve.

Can the MJE2955TTU be used as a direct replacement for the TIP2955 in existing designs?

The MJE2955TTU can serve as a functional alternative to the TIP2955 in most linear and switching applications, given matching V_CEO, I_C, and package. However, its higher minimum h_FE at 10 A (5.0 vs. unspecified for TIP2955) and lower R_θJC (1.67 vs. 1.7 °C/W) may improve base drive efficiency and thermal margin - verify SOA alignment for high-energy transients.