onsemi FJP5021Y

Overview

FJP5021Y from Fairchild Semiconductor is an NPN silicon power transistor designed for high-voltage switching applications, with 800 V collector-base breakdown voltage (BVCBO), 500 V collector-emitter sustaining voltage (VCEX(sus)), and 5 A DC collector current rating. It features fast switching performance (tF = 0.1 µs typ.), wide forward-bias safe operating area (SOA), and TO-220 package for industrial motor drives and snubberless AC switch control.

For engineers reviewing the FJP5021Y datasheet, pinout, applications, or equivalent options, key selection criteria include its 500 V VCEO rating, 1 V VCE(sat) at IC = 3 A/IB = 0.6 A, hFE classification Y (30–50 at IC = 0.6 A), and suitability for clamped inductive load switching in solid-state relays and UPS systems.

Technical Context

The FJP5021Y operates as a high-voltage, medium-power NPN bipolar junction transistor optimized for ruggedized switching in inductive circuits. Its design incorporates wide SOA support, clamped VCEX(sus) = 500 V under L = 1 mH conditions, and low saturation voltages (VCE(sat) = 1 V, VBE(sat) = 1.5 V) at rated current.

It delivers 18 MHz fT at VCE = 10 V/IC = 0.6 A and exhibits fast transient response with tON = 0.5 µs, tSTG = 3 µs, and tF = 0.1–0.3 µs - enabling reliable operation in 20–100 kHz hard-switched converters and AC line commutated circuits.

Key Specifications

Pinout & Package

Package: TO-220 (3-lead, straight lead, insulated tab). Mounting hole ø3.60 mm; case temperature derating begins at TC > 25°C; max junction temperature 150°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD127 and BU508A, the FJP5021Y uniquely balances 500 V clamped sustaining voltage, 0.1 µs tF, and Y-class hFE consistency - making it optimal for cost-sensitive, thermally constrained 240 VAC industrial switching where snubber elimination and predictable drive gain matter.

Availability

FJP5021Y is available at Aetrix Electronics and suitable for industrial motor drives, AC solid-state relays, and uninterruptible power supplies requiring stable component supply and long-term manufacturing continuity.

Supply support for FJP5021Y 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

Fairchild Semiconductor was a U.S.-based analog and power semiconductor manufacturer, acquired by ON Semiconductor in 2016; known for high-reliability discrete power devices.

The FJP5021Y belongs to Fairchild's high-voltage NPN transistor product line, engineered specifically for snubberless AC switching, motor control, and industrial power conversion where ruggedness and consistent gain binning are critical.

FAQ

What is the maximum collector-emitter sustaining voltage (VCEX(sus)) for FJP5021Y?

The FJP5021Y has a guaranteed VCEX(sus) of 500 V under clamped inductive switching conditions (IC = 2.5 A, IB1 = –IB2 = 1 A, L = 1 mH). This parameter defines its ability to sustain voltage during turn-off in inductive loads without external snubbers - a key differentiator from standard VCEO ratings. The FJP5021Y datasheet confirms this value in the Electrical Characteristics table.

Is FJP5021Y pin-compatible with other TO-220 NPN transistors like MJE13009?

No, FJP5021Y is not pin-compatible with MJE13009. While both use TO-220 packages, their pinouts differ: FJP5021Y is Base–Collector–Emitter (1–2–3), whereas MJE13009 uses Emitter–Base–Collector (1–2–3). Using them interchangeably without PCB revision will cause circuit failure. Always verify pinout diagrams before substitution - the FJP5021Y pinout is explicitly defined as 1.Base, 2.Collector, 3.Emitter.

What does the 'Y' suffix indicate in FJP5021Y?

The 'Y' suffix in FJP5021Y denotes the hFE gain bin: guaranteed DC current gain of 30–50 at VCE = 5 V and IC = 0.6 A. This binning ensures tighter drive current predictability across production lots compared to unbinned variants. The FJP5021Y datasheet lists R (15–30), O (20–40), and Y (30–50) classifications - confirming Y is the highest-gain standard bin offered for this part.

Can FJP5021Y be used in linear amplifier applications?

FJP5021Y is not recommended for linear amplifier use. Its design emphasizes switching performance (tF = 0.1 µs, wide SOA) and high-voltage ruggedness, not linearity or low-noise characteristics. The datasheet provides no small-signal parameters (e.g., noise figure, distortion, or frequency response beyond fT), and its hFE variation across VCE and IC is not characterized for analog gain stability. For amplification, purpose-built RF or audio transistors should be selected instead of the FJP5021Y.

What thermal derating applies to FJP5021Y above 25°C case temperature?

FJP5021Y has a linear thermal derating slope of 0.4 W/°C above TC = 25°C, based on its 50 W maximum collector dissipation at TC = 25°C and 150°C maximum junction temperature. This means usable power drops to 40 W at TC = 50°C and 20 W at TC = 100°C. The derating curve is shown in Figure 8 of the FJP5021Y datasheet, and proper heatsinking is mandatory to maintain TJ ≤ 150°C under sustained 5 A load.