onsemi MJE5850

Overview

MJE5850 from onsemi is a PNP silicon power transistor designed for high-voltage, high-speed switching in inductive circuits where fast fall time is critical - specifically rated for 300 V_CEO(sus), 8 A continuous collector current, and 80 W total power dissipation at T_C = 25°C in TO-220 package. It is engineered for line-operated switch-mode applications including deflection circuits and motor controls.

For engineers reviewing the MJE5850 datasheet, pinout, applications, or equivalent options, this device requires attention to its reverse-biased SOA at 100°C, clamped inductive switching times (t_fi = 0.1 µs), V_CE(sat) ≤ 2.0 V at I_C = 4 A/I_B = 1 A, thermal resistance R_JC = 1.25°C/W, and Pb-free TO-220 package with pins configured as Base–Collector–Emitter–Collector.

Technical Context

The MJE5850 operates as a high-voltage PNP bipolar junction transistor optimized for inductive load switching, with guaranteed performance at 100°C junction temperature for saturation voltage, leakage, and switching times. Its safe operating area is defined under both forward-bias (second breakdown limited) and reverse-bias (RBSOA) conditions, with clamped inductive test conditions specifying t_sv ≤ 3.0 µs and t_c ≤ 1.5 µs at T_C = 100°C.

It features complementary pairing with the MJE13007 NPN series and supports base-emitter reverse biasing during turn-off to manage voltage overshoot in flyback and deflection topologies. The device uses a TO-220 case (221A-09, Style 1) with Collector internally connected to the tab for heatsinking, requiring electrically isolated mounting when used in grounded-collector configurations.

Key Specifications

Pinout & Package

Package: TO-220 (Case 221A-09, Style 1), with metal tab electrically connected to Collector (Pin 2 and Pin 4). Requires insulated mounting hardware when collector is not at ground potential.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP high-voltage switching transistor applications.

Compared with MJE5851 and BDW32G, the MJE5850 offers optimal balance of 300 V ruggedness, 8 A capability, and sub-microsecond inductive fall time - making it the preferred choice for cost-sensitive 200–300 V switch-mode systems where voltage margin and thermal headroom are tightly constrained.

Availability

MJE5850 is available at Aetrix Electronics and suitable for horizontal deflection circuits, offline switching regulators, and solenoid driver modules requiring stable component supply across extended production lifecycles.

Supply support for MJE5850 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 MJE5850 belongs to onsemi's Switch-mode Series of PNP silicon power transistors - developed specifically for high-reliability, high-speed inductive switching in CRT deflection, flyback converters, and electromagnetic actuator drivers.

FAQ

What is the maximum collector-emitter sustaining voltage for the MJE5850?

The MJE5850 has a rated collector-emitter sustaining voltage V_CEO(sus) of 300 Vdc under inductive switching conditions. This value is guaranteed per the datasheet's Maximum Ratings table and applies with I_C = 10 mA and I_B = 0. Exceeding this voltage risks second breakdown or avalanche failure, especially under unclamped inductive loads. The MJE5850 also supports V_CEV = 350 Vdc with base-emitter reverse bias applied.

Does the MJE5850 have a documented safe operating area for reverse-biased turn-off?

Yes, the MJE5850 includes a fully characterized Reverse Bias Safe Operating Area (RBSOA) shown in Figure 13 of its datasheet. This RBSOA is verified under clamped inductive test conditions at T_J = 100°C, with V_BE(off) between 2 V and 8 V. It defines the simultaneous V_CE/I_C limits during turn-off - critical for designing reliable flyback and deflection circuits where base reverse bias is used to reduce storage time.

What is the thermal resistance from junction to case for the MJE5850?

The MJE5850 has a maximum thermal resistance R_JC of 1.25°C/W, measured from junction to the metal tab (Collector). This value is specified in the Thermal Characteristics table and is essential for calculating heatsink requirements. For example, maintaining T_J ≤ 125°C at 80 W dissipation requires a heatsink with θ_CS + θ_SA ≤ 0.94°C/W when ambient is 25°C and mounting interface resistance is accounted for.

Is the MJE5850 pin-compatible with other transistors in the MJE585x family?

Yes, the MJE5850 shares identical TO-220 package outline (Case 221A-09, Style 1), pin configuration (Base–Collector–Emitter–Collector), and mechanical dimensions with MJE5851 and MJE5852. All three devices use the same pinout and thermal footprint, enabling direct PCB reuse across voltage variants - though electrical differences (e.g., V_CEO(sus) = 300 V vs. 350 V vs. 400 V) require validation in the target application.

What is the typical fall time of the MJE5850 under clamped inductive load?

The MJE5850 exhibits a typical current fall time t_fi of 0.1 µs under clamped inductive load conditions (I_CM = 4 A, V_CEM = 250 V, I_B1 = 1.0 A, V_BE(off) = 5 V, T_C = 25°C), as specified in the Switching Characteristics table. This parameter is critical for minimizing crossover loss in switch-mode topologies and is guaranteed ≤ 0.5 µs across the full operating temperature range.