onsemi FJL6820TU

Overview

FJL6820TU from Fairchild Semiconductor is a high-voltage NPN triple-diffused planar silicon transistor designed for horizontal deflection output in color display systems, featuring BVCBO = 1500 V, VCEO = 750 V, IC = 20 A (DC), PC = 200 W, and TO-264 package with base-collector-emitter pinout.

For engineers reviewing the FJL6820TU datasheet, pinout, applications, or equivalent options, key selection criteria include high-voltage blocking capability, low saturation voltage under high-current switching, thermal resistance of 0.625°C/W, and suitability for CRT horizontal deflection circuits requiring fast storage time (tSTG ≤ 3 µs) and fall time (tF ≤ 0.2 µs).

Technical Context

This transistor employs triple diffusion to achieve robust high-voltage operation up to 1500 V collector-base, enabling safe use in CRT flyback and horizontal deflection stages where rapid voltage reversal occurs. Its planar structure supports stable hFE across temperature (8–5.5 at IC = 1–11 A) and low VCE(sat) = 3 V max at IC = 11 A / IB = 2.75 A.

Thermal design is enabled by direct junction-to-case conduction via the TO-264 metal tab (RθjC = 0.625°C/W), and switching performance is optimized for resistive-load applications with tSTG ≤ 3 µs and tF ≤ 0.2 µs under specified IB1/IB2 conditions (2 A / –4 A) at VCC = 200 V.

Key Specifications

Pinout & Package

Package: TO-264 - Isolated metal tab with 3-terminal through-hole mounting; case serves as collector terminal; requires insulated mounting hardware for non-common-collector configurations.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 2SC5200 and BU508A, the FJL6820TU delivers uniquely high VCBO with matched TO-264 thermal and pinout compatibility for CRT horizontal deflection, whereas alternatives trade voltage margin, gain consistency, or mechanical fit-making FJL6820TU irreplaceable in its original design context without circuit or layout revision.

Availability

FJL6820TU is available at Aetrix Electronics and suitable for CRT display manufacturing, legacy video equipment repair, and industrial instrumentation maintenance requiring stable component supply and long-lifecycle support.

Supply support for FJL6820TU 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 semiconductor company specializing in power discrete devices, analog ICs, and interface solutions before its acquisition by ON Semiconductor in 2016.

The FJL6820TU belongs to Fairchild's high-voltage bipolar transistor product line, engineered specifically for CRT horizontal deflection and flyback power conversion in analog display systems.

FAQ

What is the maximum collector-emitter voltage rating for the FJL6820TU?

The FJL6820TU has a maximum collector-emitter voltage (VCEO) rating of 750 V at TC = 25°C with IB = 0. This rating defines the upper limit of voltage the device can block in common-emitter configuration during off-state, making it suitable for CRT horizontal deflection circuits where flyback voltages approach this threshold. Exceeding 750 V risks avalanche breakdown and permanent damage. The FJL6820TU must be operated within this limit under all conditions including transient spikes.

Does the FJL6820TU have a documented thermal resistance value, and how is it used in heatsink design?

Yes, the FJL6820TU specifies a junction-to-case thermal resistance (RθjC) of 0.625°C/W. This value is measured from the silicon die to the metal tab (collector terminal) and is essential for calculating required heatsink thermal resistance: RθsA = (TJmax − TA) / PD − RθjC − RθcS. For example, at PD = 200 W, TJmax = 150°C, and TA = 25°C, the heatsink must provide ≤ 0.625°C/W total resistance (including interface). The FJL6820TU's TO-264 package relies on this parameter for reliable thermal management.

Can the FJL6820TU be used in modern LCD or LED display backlight drivers?

No, the FJL6820TU is not suitable for modern LCD or LED backlight drivers. Its design targets high-voltage, high-current horizontal deflection in CRT systems-not low-voltage, high-frequency PWM switching used in LED drivers. The FJL6820TU lacks integrated gate drivers, fast MOSFET-level switching speed, and protection features required for contemporary backlight ICs. Using the FJL6820TU in such applications would result in excessive losses, poor efficiency, and potential failure due to mismatched voltage/current profiles.

What base drive current is required to fully saturate the FJL6820TU at its rated collector current?

To achieve full saturation at IC = 11 A, the FJL6820TU requires IB = 2.75 A, yielding a forced beta (IC/IB) of 4. This drive level ensures VCE(sat) remains ≤ 3 V as specified. At lower currents (e.g., IC = 1 A), hFE ≈ 8–10, so IB ≈ 100–125 mA suffices. However, the FJL6820TU's base drive circuit must deliver peak current up to 2.75 A with fast rise/fall times to meet tSTG and tF requirements. Insufficient drive degrades switching performance and increases power loss in the FJL6820TU.

Is the FJL6820TU still in production, and what is its status in Fairchild's portfolio?

The FJL6820TU is an obsolete part per Fairchild's product status definitions (Rev. H2 documentation). It was discontinued after Fairchild's acquisition by ON Semiconductor and is no longer in full production. Aetrix Electronics provides legacy supply support for the FJL6820TU with traceable, tested inventory sourced from authorized channels. Customers should consult ON Semiconductor's cross-reference tools for possible replacements, though no direct drop-in successor exists due to the FJL6820TU's unique high-voltage bipolar architecture.