STMicroelectronics MJD3055T4

Overview

MJD3055T4 from STMicroelectronics is an NPN complementary power transistor in TO-252 (DPAK) surface-mount package, rated for 60 V V_CEO, 10 A I_C, and 20 W P_tot at T_c = 25 °C, used in high-current linear amplifiers and switching regulators.

For engineers reviewing the MJD3055T4 datasheet, MJD3055T4 pinout, MJD3055T4 application, or MJD3055T4 equivalent, key selection criteria include V_CE(sat) ≤ 1.1 V at I_C = 4 A / I_B = 0.4 A, h_FE ≥ 20 at I_C = 4 A, and R_thj-case = 6.25 °C/W for thermal design in motor drive H-bridge output stages.

Technical Context

The MJD3055T4 is a silicon NPN bipolar junction transistor fabricated with epitaxial base technology, optimized for cost-sensitive high-current switching and analog amplification. It operates with V_CEO = 60 V, I_C = 10 A DC, and exhibits f_T = 2 MHz at I_C = 0.5 A, V_CE = 10 V.

Its safe operating area (SOA) supports pulsed operation up to 300 µs with 1.5% duty cycle, and it pairs electrically with the PNP MJD2955T4 for complementary push-pull configurations in audio output stages and DC-DC converter topologies.

Key Specifications

Pinout & Package

Package: TO-252 (DPAK), surface-mount, 3-terminal configuration with exposed drain pad (pin 2) for thermal conduction and mechanical anchoring.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJE3055T and BD249C, the MJD3055T4 offers optimal balance of SMT manufacturability, 60 V robustness, and thermal performance in DPAK-making it preferred for space-constrained industrial power stages requiring surface-mount reliability and moderate power density.

Availability

MJD3055T4 is available at Aetrix Electronics and suitable for motor control, audio amplification, and linear regulator applications requiring stable component supply, long-term industrial availability, and RoHS-compliant packaging.

Supply support for MJD3055T4 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs and discrete devices for industrial, automotive, and consumer markets.

The MJD3055T4 belongs to ST's general-purpose power transistor product line, engineered for cost-effective, high-reliability linear and switching power applications in industrial automation and audio systems.

FAQ

Is MJD3055T4 pin-compatible with MJD2955T4?

No - MJD3055T4 (NPN) and MJD2955T4 (PNP) are complementary devices with identical TO-252 pinouts (Emitter-Collector-Base), but opposite polarity. Their pin assignments match mechanically, enabling direct placement in push-pull layouts without footprint redesign.

What is the maximum continuous collector current at T_c = 100 °C?

At T_c = 100 °C, the derated I_C is approximately 6.5 A, calculated using the 20 W P_tot rating and thermal resistance: P_tot = (T_j(max) − T_c) / R_thj-case = (150 − 100) / 6.25 = 8 W, then I_C ≈ √(P_tot × R_CE(sat)⁻¹) yields ~6.5 A for typical V_CE(sat).

Does MJD3055T4 require a base resistor in switching applications?

Yes - a series base resistor is mandatory to limit I_B within the 6 A absolute maximum rating. For I_C = 8 A and h_FE = 20, minimum I_B = 0.4 A; with 5 V drive, R_B = (5 V − 1.8 V) / 0.4 A = 8 Ω, selected from standard E24 values.

Can MJD3055T4 be used in avalanche mode?

No - the MJD3055T4 is not rated for repetitive avalanche operation. Its V_CEO = 60 V is a DC blocking rating; operation beyond this voltage risks irreversible breakdown. External clamping (e.g., TVS diode) is required for inductive load switching.