onsemi MJD243T4

Overview

MJD243T4 from onsemi is an NPN silicon power transistor in DPAK-3 surface-mount package, rated for 100 V_CEO, 4.0 A continuous collector current, and 12.5 W dissipation at T_C = 25 °C. It delivers high DC current gain (h_FE = 40–180), low V_CE(sat) (0.3–0.6 V), and 40 MHz f_T, designed specifically for low-voltage, low-power audio amplifier stages.

For engineers reviewing the MJD243T4 datasheet, pinout, applications, or equivalent options, key selection criteria include its AEC-Q101 qualification, Pb-free RoHS-compliant DPAK-3 footprint, thermal resistance R_JC = 10 °C/W, and complementary pairing with MJD253T4 for push-pull output stages.

Technical Context

The MJD243T4 employs annular construction to minimize leakage and supports high-current linear operation with V_CEO = 100 V and I_C = 4.0 A. Its f_T = 40 MHz enables stable audio-frequency amplification up to ~20 kHz with adequate gain margin.

Thermally, it features R_JC = 10 °C/W and R_JA = 89.3 °C/W (FR-4, 75 mm², 2 oz Cu), enabling direct PCB heatsinking. The NJV prefix confirms automotive-grade traceability, AEC-Q101 qualification, and PPAP capability - critical for under-hood and infotainment systems.

Key Specifications

Pinout & Package

DPAK-3 (Case 369C) surface-mount package with exposed collector tab for thermal conduction and mechanical anchoring. Dimensions: 6.10 × 6.54 × 2.28 mm, pitch 2.29 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BD243C, MJD243T4 offers 33% higher continuous current and 50% lower saturation voltage in a surface-mount package - reducing board area by 60% and eliminating through-hole reflow steps. Against MJD243G, the T4 suffix guarantees tape-and-reel delivery optimized for automated pick-and-place, with identical device-level performance.

Availability

MJD243T4 is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial sensor transmitters, and compact audio amplifier modules requiring stable component supply, AEC-Q101 compliance, and SMT manufacturability.

Supply support for MJD243T4 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, and cloud infrastructure markets.

The MJD243T4 belongs to onsemi's complementary plastic power transistor family, engineered for high-reliability linear and switching applications where thermal robustness, gain consistency, and automotive qualification are mandatory.

FAQ

What is the maximum junction temperature rating for MJD243T4?

The MJD243T4 has an operating junction temperature range of −65 °C to +150 °C. This allows reliable operation in under-hood automotive environments and industrial enclosures with elevated ambient temperatures. Derating curves in Figure 1 confirm usable power dissipation down to T_C = 125 °C before reaching the 150 °C absolute maximum.

Is MJD243T4 pin-compatible with MJD253T4?

No - MJD243T4 (NPN) and MJD253T4 (PNP) share identical DPAK-3 pinout (Base, Collector, Emitter, Collector) and thermal/mechanical footprint, but they are complementary devices, not pin-compatible replacements. They are intended for paired use in push-pull or H-bridge topologies, not direct substitution.

Does MJD243T4 require a heatsink in typical audio amplifier applications?

In continuous 5 W output applications, the MJD243T4 can operate without an external heatsink if mounted on ≥75 mm² of 2 oz copper with thermal vias - per R_JA = 89.3 °C/W (Note 3). For sustained 10 W operation or ambient >60 °C, a small copper pour heatsink or clip-on fin is recommended to maintain T_J < 125 °C.

What does the "NJV" prefix in NJVMJD243T4G* indicate?

The "NJV" prefix identifies a version of MJD243T4 manufactured under onsemi's automotive-specific production flow, with enhanced traceability, lot-control rigor, and PPAP documentation support. It is fully AEC-Q101 qualified and functionally identical to standard MJD243T4G - the prefix signals compliance readiness, not electrical differentiation.

Can MJD243T4 be used in switching power supplies?

Yes - the MJD243T4 supports switching applications up to 20 kHz with t_f < 100 ns (Figure 9) and f_T = 40 MHz. However, its relatively high V_CE(sat) makes it less efficient than MOSFETs above 50 kHz; it is best suited for low-frequency SMPS auxiliary supplies, LED drivers, or relay drivers where bipolar drive simplicity outweighs conduction loss.