onsemi BU807TU

Overview

BU807TU from Fairchild Semiconductor is an NPN epitaxial silicon Darlington transistor designed for high-voltage, fast-switching horizontal output stages in 110° CRT video displays. It features VCEO = 150 V, IC = 8 A (DC), PC = 60 W at TC = 25°C, and includes a built-in speed-up diode between base and emitter.

For engineers reviewing the BU807TU datasheet, pinout, applications, or equivalent options, key selection considerations include collector-emitter sustaining voltage (VCEO(sus) = 150 V), saturation performance (VCE(sat) = 1.5 V @ IC = 5 A, IB = 50 mA), damper diode forward voltage (VF = 2 V @ IF = 4 A), and TO-220 package thermal derating behavior.

Technical Context

The BU807TU operates as a high-gain, high-voltage switching Darlington pair with integrated base-emitter speed-up diode to reduce turn-off time. Its structure supports pulsed collector current up to 15 A (300 µs, 1.5% duty cycle) and sustains 150 V under open-base conditions (VCEO(sus)) with IC = 100 mA.

Thermal design relies on case-mounted heatsinking: power dissipation de-rates linearly above TC = 25°C (0.48 W/°C), with maximum junction temperature limited to 150°C and storage range spanning −55°C to +150°C.

Key Specifications

Pinout & Package

BU807TU is housed in a through-hole TO-220 package with standard 3-pin configuration: Pin 1 = Base, Pin 2 = Collector (electrically connected to tab), Pin 3 = Emitter. The metal tab is electrically tied to the collector and serves as primary thermal path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BU806TU and BDW83C, the BU807TU uniquely balances 150 V sustained blocking, integrated damper functionality, and 8 A DC current in a single TO-220 device-making it optimal for cost-sensitive, space-constrained CRT horizontal output stages where component count and timing precision are critical.

Availability

BU807TU is available at Aetrix Electronics and suitable for CRT display manufacturing, industrial flyback power supplies, and high-current relay interface circuits requiring stable component supply and long-term production continuity.

Supply support for BU807TU 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 BU807TU belongs to Fairchild's high-voltage Darlington transistor family engineered specifically for horizontal deflection and flyback applications in analog video display systems.

FAQ

What is the maximum collector-emitter sustaining voltage for BU807TU?

The BU807TU has a collector-emitter sustaining voltage VCEO(sus) of 150 V when IC = 100 mA and IB = 0. This parameter defines the highest voltage the device can sustain in switching applications without breakdown under open-base conditions. It is measured under standardized pulsed test conditions and is critical for ensuring reliability in CRT horizontal output circuits where flyback spikes occur. The BU807TU datasheet confirms this value in the Electrical Characteristics table.

Does BU807TU include an integrated damper diode?

Yes, the BU807TU integrates a damper diode between collector and emitter, with a forward voltage VF of 2 V at IF = 4 A. This diode provides intrinsic flyback energy clamping during horizontal deflection, eliminating the need for an external diode in many CRT applications. The diode is explicitly documented in the "Features" section and verified in the Electrical Characteristics table under the VF parameter.

What is the pin configuration of BU807TU in the TO-220 package?

The BU807TU uses a standard TO-220 package with three leads: Pin 1 is Base, Pin 2 is Collector (connected to the metal tab), and Pin 3 is Emitter. This configuration is confirmed in the package outline diagram and "Features" section of the official Fairchild datasheet. Mounting requires electrical isolation of the tab unless the collector is at ground potential.

Can BU807TU replace BU806TU in existing designs?

The BU807TU is not a direct replacement for BU806TU due to lower voltage ratings: BU806TU specifies VCBO = 400 V and VCEO = 200 V versus BU807TU's 330 V and 150 V. Substitution is only safe if the circuit's peak operating voltage remains below 150 V. In CRT horizontal output stages where voltage margin is tight, using BU807TU instead of BU806TU may risk premature breakdown under transient conditions.

What is the safe operating area (SOA) limitation for BU807TU at 100°C case temperature?

At TC = 100°C, the BU807TU's maximum allowable collector current drops to approximately 3.5 A for DC operation, based on its linear power derating slope of 0.48 W/°C from 60 W at 25°C. The SOA curve in the datasheet shows further constraints for pulse durations - for example, at 100 µs pulse width, IC max is ~12 A. These limits must be respected to avoid second breakdown or thermal runaway.