onsemi MJE271G

Overview

MJE271G from onsemi is a PNP 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 safe operating area up to 375 mA at 40 V for 1.0 s, making it suitable for linear audio output stages and industrial relay drivers.

For engineers reviewing the MJE271G datasheet, pinout, applications, or equivalent options, key selection criteria include its PNP Darlington topology, 100 V sustaining voltage, 15 W thermal capability at case temperature, high h_FE linearity across collector current range, and Pb-free TO-225 mechanical compatibility with legacy mounting footprints.

Technical Context

The MJE271G implements a monolithic Darlington pair structure with integrated base-emitter resistor network optimized for high-current switching and analog amplification. Its second-breakdown-limited safe operating area is defined at V_CE = 40 V, t = 1.0 s, with I_S/B = 375 mA under forward-biased base conditions.

Electrical behavior is characterized by low V_CE(sat) ≤ 3.0 V at I_C = 120 mA / I_B = 1.2 mA and V_BE(on) ≤ 2.0 V at same conditions, enabling efficient drive in emitter-follower configurations. f_T = 6.0 MHz confirms usable bandwidth for audio-frequency signal amplification and moderate-speed switching.

Key Specifications

Pinout & Package

Package: TO-225 (Case 77-09, Style 3), plastic through-hole package with metal tab connected to collector (pins 2 and 4). Dimensions: 10.6–11.1 mm D × 7.4–7.8 mm E × 14.5–16.63 mm L, with 2.04–2.54 mm lead pitch (e).

Key Features

Applications

Equivalent & Alternatives

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

Compared with BD139-16 and TIP2955, the MJE271G uniquely balances 100 V rating, high h_FE, and TO-225 mountability-making it optimal for space-constrained industrial controls where gain efficiency and transient immunity are prioritized over ultra-high power.

Availability

MJE271G is available at Aetrix Electronics and suitable for industrial relay drivers, audio amplifier output stages, linear voltage regulator pass elements, and DC motor speed controllers requiring stable component supply and long-term manufacturability.

Supply support for MJE271G 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, sensor, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The MJE271G belongs to onsemi's complementary silicon power Darlington transistor family, designed specifically for high-reliability linear and switching applications demanding high voltage, high gain, and rugged SOA performance in industrial control and audio systems.

FAQ

What is the maximum continuous collector current rating for the MJE271G?

The MJE271G has a maximum continuous collector current (I_C) rating of 2.0 Adc at case temperature T_C = 25°C. This rating decreases linearly above 25°C at 0.12 W/°C derating rate. At T_C = 100°C, the usable I_C drops to approximately 1.1 A. The MJE271G must be mounted on an adequate heatsink to sustain this current in real-world operation.

Is the MJE271G pin-compatible with the NPN MJE270G?

Yes, the MJE271G is complementary and mechanically pin-compatible with the MJE270G in the TO-225 package. Both share identical pinout: Pin 1 = Base, Pins 2 & 4 = Collector, Pin 3 = Emitter. This allows direct use in push-pull or complementary symmetry circuits without PCB redesign, provided polarity-aware biasing is implemented.

Does the MJE271G require a base resistor when used as a switch?

Yes, the MJE271G requires an external base current-limiting resistor when driven from logic-level or microcontroller outputs. Because it is a Darlington transistor, base current must be sized to achieve target collector current while accounting for h_FE variation. For example, driving 1.2 A load at h_FE = 1500 requires ~0.8 mA base current; a 4.7 kΩ resistor from 5 V MCU GPIO suffices, but layout and thermal stability must be verified.

What is the thermal resistance from junction to case (R_JC) for the MJE271G?

The MJE271G has a specified thermal resistance from junction to case (R_JC) of 8.33 °C/W. This value assumes proper mechanical mounting of the metal tab (collector) to a heatsink with thermal interface material. It is critical for calculating junction temperature rise: T_J = T_C + (P_D × R_JC). Exceeding 150°C junction temperature risks permanent degradation of the MJE271G.

Can the MJE271G be used in place of the discontinued MJE271?

Yes, the MJE271G is the Pb-free, RoHS-compliant replacement for the legacy MJE271. Electrical specifications-including V_CEO(sus), h_FE, SOA, and thermal parameters-are identical. The "G" suffix denotes green packaging; no circuit or layout changes are needed when upgrading from MJE271 to MJE271G in existing designs.