onsemi FJE5304D

Overview

FJE5304D from ON Semiconductor is an NPN triple diffused planar silicon transistor rated for 400 V V_CEO, 4 A DC collector current, and 30 W power dissipation at T_C = 25°C, with built-in free-wheeling diode and 0.6 μs storage time under inductive switching (V_CC = 200 V, I_C = 2 A). It is designed for high-voltage, high-speed power switching in electronic ballasts.

For engineers reviewing the FJE5304D datasheet, pinout, applications, or equivalent options, key selection criteria include its 400 V collector-emitter breakdown voltage, TO-126 package thermal resistance (R_θJC = 4.17 °C/W), fast inductive switching performance (t_stg = 0.6 μs), and integrated diode forward voltage (V_f = 2.5 V at I_F = 2 A).

Technical Context

The FJE5304D employs a triple-diffused planar structure to achieve wide safe operating area (SOA) and stable high-voltage switching up to 400 V. Its internal free-wheeling diode enables self-contained inductive load handling without external clamping components.

It delivers low saturation voltages-V_CE(sat) = 1.5 V at I_C = 2.5 A / I_B = 0.5 A-and tight storage time variance (0.6 μs typical under inductive load), supporting reliable timing-critical ballast control and lamp ignition circuits.

Key Specifications

Pinout & Package

Package: TO-126 3L (standard lead length), with terminals arranged as Emitter (Pin 1), Collector (Pin 2), Base (Pin 3) when viewed from front with tab down and leads facing downward.

Key Features

Applications

Equivalent & Alternatives

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

Compared with FJE5304D, FJP5304D offers superior thermal performance but adds BOM and layout complexity, while BU508AF trades speed and integration for extreme voltage capability-neither is pin-compatible, and both require PCB redesign.

Availability

FJE5304D is available at Aetrix Electronics and suitable for electronic ballast design, HID lamp control, and industrial flyback converter development requiring stable component supply and legacy Fairchild/ON Semiconductor product continuity.

Supply support for FJE5304D 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

ON Semiconductor (formerly Fairchild Semiconductor) is a global semiconductor supplier specializing in power management, analog, sensor, and logic devices for automotive, industrial, and consumer applications.

The FJE5304D belongs to ON Semiconductor's high-voltage bipolar power transistor family, engineered specifically for electronic lighting ballasts and inductive switching applications demanding reliability, SOA robustness, and integrated protection features.

FAQ

What is the maximum collector-emitter voltage rating for the FJE5304D?

The FJE5304D has a guaranteed minimum collector-emitter breakdown voltage (BV_CEO) of 400 V at I_C = 5 mA and I_B = 0. This rating is validated per the datasheet's Absolute Maximum Ratings table and applies under DC conditions at T_C = 25°C. For reliable long-term operation, design margins should be applied-especially in inductive switching applications where voltage spikes may exceed steady-state values. The FJE5304D is intended for use in 230 VAC systems with appropriate snubbing or clamping.

Does the FJE5304D include an integrated diode, and what is its forward voltage?

Yes, the FJE5304D incorporates a built-in free-wheeling diode. Its forward voltage drop (V_f) is specified as 2.5 V at I_F = 2 A, measured under standard test conditions. This diode is monolithically integrated into the same silicon die and shares the collector and emitter terminals-eliminating the need for an external flyback diode in half-bridge or single-ended inductive switching circuits. The FJE5304D datasheet confirms this feature in both the Features list and Electrical Characteristics table.

What is the thermal resistance from junction to case (R_θJC) for the FJE5304D?

The FJE5304D has a thermal resistance from junction to case (R_θJC) of 4.17 °C/W, as specified in the Thermal Characteristics section of its datasheet. This value is measured under standard mounting conditions with the TO-126 package's metal tab thermally coupled to a heatsink. It enables calculation of junction temperature rise above case temperature (ΔT_JC = P_C × R_θJC) and supports thermal design for continuous 30 W operation when properly heatsinked.

Is the FJE5304D still in active production, and what is its lifecycle status?

The FJE5304D is marked "DISCONTINUED" in its official ON Semiconductor datasheet (Rev. 2, November 2025), with a notice stating "THIS DEVICE IS NOT AVAILABLE" and advising customers to contact their ON Semiconductor representative for alternatives. While Aetrix Electronics maintains limited legacy inventory and supply support, new design-ins should consider qualified replacements such as FJP5304D or BU508AF, and verify availability through ON Semiconductor's official channels before committing to production.

What is the storage time (t_stg) of the FJE5304D under inductive load conditions?

The FJE5304D exhibits a typical storage time (t_stg) of 0.6 μs under inductive load switching conditions: V_CC = 200 V, I_C = 2 A, I_B1 = 0.4 A, V_BE(off) = −5 V, and L = 200 μH. This parameter is critical for timing-critical applications like electronic ballast lamp ignition, where consistent turn-off delay ensures reliable preheat and strike sequencing. The value is confirmed in the Electrical Characteristics table and illustrated in Figure 6 of the FJE5304D datasheet.