onsemi MJE270G

Overview

MJE270G from onsemi is an NPN complementary power Darlington transistor in TO-225 package, rated for 100 V_CEO(sus), 2.0 A continuous collector current, and 15 W total power dissipation at T_C = 25°C. It delivers high DC current gain (h_FE ≥ 1500 at I_C = 120 mA, V_CE = 10 V) and supports robust safe operating area (IS/B = 0.375 A at 40 V, 1.0 s), commonly used in linear power supplies and motor drive output stages.

For engineers reviewing the MJE270G datasheet, pinout, applications, or equivalent options, key selection criteria include sustained 100 V collector-emitter voltage capability, Darlington-level current gain, thermal resistance (R_JC = 8.33°C/W), TO-225 mechanical compatibility, and Pb-free RoHS compliance - all critical for industrial amplifier and relay driver designs requiring high-current switching with low base drive.

Technical Context

The MJE270G implements a monolithic Darlington pair architecture with integrated base-emitter resistor network to enable high h_FE (≥1500) while maintaining stable second-breakdown performance. Its V_CEO(sus) ≥ 100 V and I_S/B = 0.375 A at 40 V/1.0 s define its ruggedness in inductive load switching.

Thermal design is constrained by R_JC = 8.33°C/W and R_JA = 83.3°C/W, requiring heatsinking for operation above 1.5 W at ambient temperature. The device operates across −65°C to +150°C junction range and features V_BE(on) ≤ 2.0 V at I_C = 120 mA, supporting direct TTL/CMOS-compatible base drive.

Key Specifications

Pinout & Package

Package: TO-225 (Case 77-09, Style 3), plastic through-hole package with metal tab (collector-connected), 3-pin configuration (pins 1–3 labeled; pin 4 is internal collector tie).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TIP120 and BD679, the MJE270G provides superior voltage margin (100 V), higher current gain, and lower thermal resistance via TO-225 metal tab - making it optimal for industrial 72–80 V systems requiring rugged, heatsink-mountable Darlington switching.

Availability

MJE270G is available at Aetrix Electronics and suitable for linear power supplies, DC motor drivers, audio amplifier outputs, and industrial relay drivers requiring stable component supply and long-term manufacturability.

Supply support for MJE270G 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 manufacturer specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MJE270G belongs to onsemi's complementary silicon power transistor family, designed specifically for high-reliability linear and switching applications demanding high-voltage tolerance, rugged SOA, and Darlington-level gain in industrial control and power conversion.

FAQ

What is the maximum continuous collector current rating for the MJE270G?

The MJE270G is rated for 2.0 Adc continuous collector current at case temperature T_C = 25°C. Derating is required above 25°C at 0.12 W/°C. At ambient temperature (T_A = 25°C), the usable continuous current drops to 1.5 Adc due to higher thermal resistance (R_JA = 83.3°C/W). Proper heatsinking is essential to sustain full 2.0 A operation in real-world conditions.

Does the MJE270G have a built-in base-emitter resistor?

No, the MJE270G does not integrate a base-emitter resistor. It is a standard two-lead Darlington transistor (base, emitter, collector) requiring external base biasing. Unlike "digital transistors" (e.g., MMBT2222A with R1/R2), the MJE270G relies on discrete base drive circuitry - enabling precise control of saturation and switching speed in linear and switching applications.

What is the safe operating area (SOA) limit for the MJE270G at 40 V?

At V_CE = 40 V, the MJE270G supports a non-repetitive second-breakdown current of 0.375 A for 1.0 second, as specified in the datasheet under "Second Breakdown Collector Current with Base Forward Biased." This SOA boundary reflects the device's ability to handle transient inductive energy without destructive failure, provided adequate heatsinking and gate/base drive control are applied.

Is the MJE270G pin-compatible with the MJE271G?

No, the MJE270G (NPN) and MJE271G (PNP) are complementary devices with identical TO-225 package and pinout (Style 3: Pin 1 = Base, Pins 2&4 = Collector, Pin 3 = Emitter), but opposite polarity. They share mechanical compatibility and thermal characteristics, enabling symmetrical design in push-pull or quasi-complementary circuits - however, direct substitution is electrically invalid due to polarity reversal.

What does the "G" suffix indicate in MJE270G?

The "G" suffix in MJE270G denotes a Pb-free (lead-free) and RoHS-compliant version per EU Directive 2011/65/EU. It confirms that the device uses matte tin or other approved lead-free terminations and complies with onsemi's environmental specifications. The "G" variant replaces legacy leaded versions and is fully compatible in form, fit, and function - no requalification is needed for migration from non-G variants.