onsemi MJE270

Overview

MJE270 from onsemi is an NPN complementary silicon 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 linear amplifier and switching applications in industrial motor controls and power supplies.

For engineers reviewing the MJE270 datasheet, pinout, applications, or equivalent options, key selection criteria include safe operating area (IS/B = 0.375 A at 40 V, 1 s), second breakdown limits, thermal resistance (R_θJC = 8.33°C/W), V_CE(sat) ≤ 3.0 V at I_C = 120 mA, and Pb-free RoHS-compliant packaging.

Technical Context

The MJE270 is a monolithic NPN Darlington pair with integrated base-emitter resistor network enabling high current gain and simplified drive requirements. It operates in linear and switching modes with sustained V_CEO(sus) ≥ 100 V and second-breakdown-limited pulse capability up to 375 mA at 40 V for 1 s.

Its thermal design relies on low junction-to-case resistance (8.33°C/W) and requires heatsinking for continuous operation above ~1.5 W at ambient temperature; electrical behavior is characterized at T_C = 25°C with pulse testing (≤300 µs, ≤2% duty cycle) for dynamic parameters including f_T = 6.0 MHz.

Key Specifications

Pinout & Package

Package: TO-225 (Case 77-09, Style 3), plastic-encapsulated, through-hole, 4-pin with collector connected to pins 2 and 4 and backside tab (electrically tied to collector).

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 MJE270 provides higher voltage blocking, greater safe operating area margin, and better thermal management via its TO-225 collector-tab construction-making it preferred for industrial 48–72 V systems requiring reliability under transient overloads.

Availability

MJE270 is available at Aetrix Electronics and suitable for industrial motor control, linear power regulation, audio amplifier output stages, and relay/lamp driving applications requiring stable component supply and long-term manufacturability.

Supply support for MJE270 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 IoT markets.

The MJE270 belongs to onsemi's complementary silicon power Darlington transistor family, designed specifically for high-gain, medium-power linear and switching applications in industrial controls, power supplies, and audio systems.

FAQ

What is the maximum continuous collector current rating for the MJE270?

The MJE270 has a maximum continuous collector current (I_C) rating of 2.0 A at case temperature T_C = 25°C. This rating decreases with rising case temperature due to thermal derating of 0.12 W/°C, and actual usable current depends on heatsinking and ambient conditions. The MJE270 must be operated within its safe operating area curve to avoid second breakdown, especially under high-voltage, high-current pulses.

Does the MJE270 require a heatsink in typical applications?

Yes, the MJE270 requires a heatsink for any application dissipating more than ~1.5 W continuously, since its power dissipation at ambient temperature (T_A = 25°C) is only 1.5 W before thermal derating begins. Its R_θJA = 83.3°C/W makes ambient cooling insufficient beyond low-power operation; the collector-tab construction in TO-225 enables effective mounting to a heatsink, leveraging its R_θJC = 8.33°C/W for reliable thermal management.

Is the MJE270 pin-compatible with the MJE271?

No, the MJE270 (NPN) and MJE271 (PNP) are complementary devices with identical TO-225 package and pinout (Style 3: Pin 1 = Base, Pins 2&4 = Collector, Pin 3 = Emitter), but they are not interchangeable due to opposite polarity. Their shared mechanical layout allows symmetrical PCB placement in push-pull or H-bridge circuits, but each must be placed according to its NPN or PNP function; substituting one for the other will cause circuit failure.

What does the "G" suffix mean in MJE270G?

The "G" suffix in MJE270G denotes a Pb-free, RoHS-compliant package per EU Directive 2011/65/EU, with lead-free terminations and halogen-free molding compound. It replaces legacy leaded versions and is the currently manufactured and supported variant. The MJE270G is functionally identical to earlier non-G versions except for environmental compliance; no electrical or thermal parameter changes accompany the G-suffix designation.

Can the MJE270 be used in switching power supplies?

The MJE270 can be used in low-frequency (<20 kHz) switching applications such as PWM motor control or lamp dimming, but it is not optimized for high-frequency SMPS due to its 6.0 MHz f_T and relatively slow saturation/desaturation characteristics. For efficient high-frequency switching, MOSFETs or faster bipolar transistors with lower V_CE(sat) and shorter storage time are recommended; the MJE270 excels instead in linear regulation and moderate-speed switching where high gain and SOA are prioritized over speed.