onsemi MJE702G

Overview

MJE702G from onsemi is a PNP silicon Darlington power transistor in TO-225 package, rated for 80 V_CEO, 4.0 A collector current, and 40 W power dissipation at T_C = 25°C, with typical DC current gain (h_FE) of 750 at I_C = 1.5 A and V_CE = 3.0 V - used in low-speed switching and linear amplifier stages for industrial control and power supply output stages.

For engineers reviewing the MJE702G datasheet, pinout, applications, or equivalent options, key selection criteria include its PNP polarity, built-in base-emitter resistors limiting leakage multiplication, 80 V breakdown rating, thermal resistance R_JC = 3.12 °C/W, and Pb-free TO-225 packaging compliant with RoHS.

Technical Context

The MJE702G is a monolithic PNP Darlington pair with integrated base-emitter shunt resistors to suppress leakage-induced secondary breakdown. It operates in linear and saturation regions with V_CE(sat) ≤ 2.5 V at I_C = 1.5 A and I_B = 30 mA, and supports safe operating area (SOA) up to second-breakdown limits under pulsed conditions.

Its thermal design centers on junction-to-case conduction (R_JC = 3.12 °C/W), enabling high-power operation when mounted to heatsinks; derating begins above 25°C at 0.32 W/°C. The device is characterized across –55°C to +150°C junction temperature range and validated for reliability under sustained DC and pulsed loads.

Key Specifications

Pinout & Package

Package: TO-225 (Case 77-09, Style 1), plastic through-hole package with metal tab connected to collector (pins 2 and 4). Pin 1 is emitter, pin 3 is base, pins 2 and 4 are collector terminals - dual-collector configuration improves current handling and thermal path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJE702G, MJE703G offers lower guaranteed gain and relaxed base drive requirements, while BDX54C delivers higher current capacity but lacks monolithic leakage control - making MJE702G optimal for precision, thermally constrained PNP switching where consistent h_FE and intrinsic stability are critical.

Availability

MJE702G is available at Aetrix Electronics and suitable for industrial relay drivers, linear power supply pass elements, and DC motor H-bridge legs requiring stable component supply, long-term manufacturability, and RoHS-compliant through-hole assembly.

Supply support for MJE702G 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, cloud, and consumer markets.

The MJE702G belongs to onsemi's legacy silicon power transistor family designed for robust, cost-effective linear amplification and low-speed switching in industrial control, power conversion, and audio systems.

FAQ

What is the maximum continuous collector current rating for the MJE702G?

The MJE702G is rated for 4.0 Adc continuous collector current at case temperature T_C = 25°C. Derating applies above 25°C at 0.32 W/°C, and actual usable current depends on heatsinking and ambient conditions. At T_C = 100°C, the effective I_C limit drops to approximately 1.6 A based on thermal constraints.

Does the MJE702G have built-in base-emitter resistors, and why are they important?

Yes, the MJE702G features monolithic base-emitter shunt resistors to limit leakage current multiplication at elevated temperatures. This prevents thermal runaway during standby or light-load conditions - a critical reliability feature absent in standard bipolar transistors and essential for stable operation in unattended industrial equipment.

What is the safe operating area (SOA) limitation for the MJE702G in pulse applications?

The MJE702G SOA is defined by second-breakdown limits up to 10% duty cycle pulses, with peak power governed by transient thermal impedance curves. For example, at 1 ms pulse width and 1% duty cycle, it supports up to ~120 W peak power; longer pulses require adherence to the SOA boundary in Figure 5 of the datasheet to avoid bond-wire or junction failure.

Can the MJE702G be used as a direct replacement for the MJE700G in existing designs?

No - the MJE702G is not a drop-in replacement for the MJE700G. While both are PNP Darlington transistors in TO-225, the MJE700G has V_CEO = 60 V and different h_FE test conditions. Substituting MJE702G into a MJE700G design may exceed voltage ratings in some circuits and alter bias point due to differing gain characteristics.

Is the MJE702G RoHS-compliant and what does the "G" suffix indicate?

Yes, the MJE702G is RoHS-compliant and Pb-free. The "G" suffix explicitly denotes the Pb-free version per onsemi's packaging standard, confirmed in the ordering information table and marking diagram - ensuring compatibility with lead-free soldering processes and meeting EU Directive 2011/65/EU requirements.