MJL4302

The MJL4302 is a PNP power transistor from ON Semiconductor that, together with the NPN MJL4281, forms a high-performance complementary pair specifically engineered for premium audio amplifier applications. Building on the success and reputation of the MJL21195/MJL21196 series, the MJL4281/MJL4302 pair represents an upgrade path for designers seeking higher voltage capability, better high-frequency performance, and improved overall sound quality. With a VCEO rating of 350V (compared to 250V for the MJL21195), the MJL4302 allows amplifier designs with significantly higher supply voltages, directly translating to higher output power capability. The transition frequency of 30 MHz typical is approximately 7.5x higher than the MJL21195’s 4 MHz, contributing to superior high-frequency response, faster slew rates, and reduced transient intermodulation distortion – all critical factors for high-fidelity audio reproduction. The 230W power dissipation rating and 0.55°C/W thermal resistance ensure reliable operation at high power levels when properly heatsunk. The MJL4302/MJL4281 pair is designed to be closely matched in electrical characteristics including gain, VBE, and thermal behavior, ensuring symmetrical push-pull operation with minimal distortion. Packaged in the robust TO-264 (TO-3P) through-hole format, these devices are suitable for high-power amplifier constructions. The ‘A’ suffix variant (MJL4302AG) offers improved specifications and tighter parameter distribution for the most demanding applications.

The MJL4302 is a PNP-type bipolar junction transistor where the primary charge carriers are holes. Current flows from the emitter to the collector when the base-emitter junction is forward biased (base negative with respect to emitter). As a PNP device, it operates with negative supply voltages (or in the negative half of a split supply), making it the natural complement to the NPN MJL4281 in push-pull amplifier configurations. The high transition frequency (fT) of 30 MHz means the transistor can maintain current gain at much higher frequencies than typical audio power transistors. This results in several performance benefits for audio applications: better high-frequency response extending well beyond the audible range, improved phase margin at audio frequencies, reduced transient intermodulation distortion, and the ability to reproduce fast musical transients with exceptional accuracy. The high 350V VCEO rating allows for higher rail voltages in amplifier designs. In a typical push-pull configuration with ±70V to ±100V supply rails, the MJL4302 handles the negative signal excursions while the MJL4281 handles the positive ones. The wide safe operating area ensures that the device can withstand the stress of driving real-world loudspeaker loads, which are highly reactive and present impedance that varies significantly with frequency and signal level. In Class AB operation, both transistors conduct a small idle current at the zero-crossing point, smoothly handing off conduction from one to the other as the signal swings through zero. Proper biasing and thermal compensation ensure stable operation and minimal crossover distortion across the full operating temperature range.

• High-end audiophile and high-fidelity power amplifiers
• Complementary push-pull output stages with MJL4281
• Professional audio equipment and concert amplifiers
• Studio reference monitors and mastering amplifiers
• High-voltage linear regulated power supplies
• Instrumentation and precision analog circuits