onsemi MJH6284

Overview

MJH6284 from onsemi is an NPN Darlington silicon power transistor designed for high-current, low-speed switching and linear amplifier applications in motor control systems. It delivers 20 A continuous collector current, 100 V collector-emitter sustaining voltage (V_CEO(sus)), and 160 W total device dissipation at T_C = 25°C - enabling robust operation in industrial DC motor drives and relay drivers.

For engineers reviewing the MJH6284 datasheet, pinout, applications, or equivalent options, key selection considerations include its monolithic construction with built-in collector-emitter diode, rugged reverse-bias safe operating area (RBSOA), Pb-free TO-247/TO-218 packaging, and verified h_FE ≥ 750 at I_C = 10 A.

Technical Context

The MJH6284 implements a monolithic Darlington pair architecture with integrated collector-emitter clamp diode, optimized for stable gain and thermal performance under high-current DC or pulsed loads. Its RBSOA is characterized up to 100 V and 20 A with defined second-breakdown limits at T_C = 25°C and duty cycles ≤ 10%.

It operates with base-emitter on voltage ≤ 2.8 V and saturation voltage ≤ 3.0 V at I_C = 20 A / I_B = 200 mA, supporting direct drive from logic-level controllers or dedicated gate/base drivers. Thermal resistance R_JC is rated at 0.78°C/W, enabling efficient heatsink-coupled thermal management.

Key Specifications

Pinout & Package

Available in Pb-free TO-247 (Case 340L, Style 3) and legacy TO-218 (SOT-93, Case 340D) packages. Both use identical 4-pin configuration with dual collector terminals for enhanced current handling and thermal path redundancy.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 2N6284 and BDW83C, the MJH6284 provides Pb-free compliance, TO-247 thermal performance, and guaranteed 100 V/20 A capability - making it the sole choice for new industrial motor control designs requiring reliability, regulatory alignment, and high-power density.

Availability

MJH6284 is available at Aetrix Electronics and suitable for industrial motor control, linear power regulation, and high-current switching applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MJH6284 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 management, analog, sensors, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The MJH6284 belongs to onsemi's high-reliability discrete power transistor family, engineered specifically for ruggedized industrial switching and amplification where thermal stability, second-breakdown immunity, and long-term parametric consistency are mandatory.

FAQ

What is the maximum continuous collector current rating for the MJH6284?

The MJH6284 is rated for 20 A continuous collector current (I_C) at case temperature T_C = 25°C. Derating is required above 25°C at 1.28 W/°C, and actual usable current depends on heatsink design and ambient conditions. At T_C = 100°C, the practical continuous I_C drops to approximately 10 A per the power derating curve in Figure 1 of the datasheet. The MJH6284 must be mounted on a thermally adequate heatsink to sustain rated current.

Does the MJH6284 have a built-in flyback diode, and how is it configured?

Yes, the MJH6284 features a monolithically integrated collector-emitter clamp diode, confirmed in the "Features" section and schematic diagram (Figure 3) of the datasheet. This diode is connected anode-to-emitter and cathode-to-collector, providing intrinsic protection against inductive voltage spikes during turn-off. It eliminates the need for an external freewheeling diode in relay, solenoid, or DC motor drive circuits - simplifying layout and improving reliability. The MJH6284 leverages this structure to meet RBSOA requirements without external components.

What package options are available for the MJH6284, and are they pin-compatible?

The MJH6284 is offered in two Pb-free packages: TO-247 (Case 340L, Style 3) and TO-218 (SOT-93, Case 340D). Both share identical 4-pin assignments (Pin 1 = Base, Pins 2 & 4 = Collector, Pin 3 = Emitter) and mechanical pinout, making them mechanically and electrically interchangeable. However, TO-247 offers superior thermal performance (same R_JC but better mounting rigidity) and is the only option available after June 2012 per FPCN# 16827. The MJH6284G part number denotes Pb-free compliance across both packages.

How does the MJH6284's DC current gain (h_FE) vary with operating conditions?

The MJH6284 exhibits h_FE = 750 (min) at I_C = 10 A and V_CE = 3.0 V, rising to 18,000 (max) under same conditions - reflecting Darlington gain variability. As shown in Figure 7, h_FE decreases with increasing junction temperature (e.g., ~50% reduction at T_J = 150°C vs. 25°C) and increases with decreasing I_C. Designers must verify bias stability across temperature and load; the MJH6284 is not recommended for precision current mirrors but excels in saturated-switch or class-AB amplifier roles where gain tolerance is acceptable.

Can the MJH6284 be used in high-frequency switching applications such as SMPS?

No, the MJH6284 is not suitable for high-frequency switching power supplies. Its current-gain bandwidth product (f_T) is specified at only 4.0 MHz, and switching times (e.g., t_s = 1.0 µs, t_f = 3.5 µs) indicate millisecond-scale transitions - optimized for low-speed motor control and relay driving (≤ 5 kHz). Attempting operation above 20 kHz will cause excessive switching losses and thermal runaway. For SMPS, MOSFETs or RF-optimized BJTs should be selected instead of the MJH6284.